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Metritis is a uterine disease that affects 10 to 30% of all lactating dairy cows and has detrimental effects on reproductive performance, milk production, and survival. Data regarding the identity and abundance of bacterial genes governing traits such as virulence, antibiotic resistance, and stress responses could enable identification of previously unknown agents that play a role in metritis pathogenesis. Moreover, such knowledge could lead to the development of improved treatments or preventive methods. Therefore, the objectives of this study were to characterize the uterine microbial population and to differentiate, for the first time, the microbial functional diversity in cows with metritis versus healthy cows. In addition, we aimed to identify relationships between microbial genes and postpartum uterine health. Uterine swabs were collected from 24 cows within 3 to 12 d in milk; 12 cows were diagnosed with metritis and the other 12 were healthy. Metritis was defined as a watery, reddish or brownish uterine discharge having a fetid smell, and rectal temperature greater than 39.5°C. Cows with a clear and viscous uterine discharge, not fetid or mucopurulent, were classified as healthy. Microbial metagenomic DNA from uterine swab samples was subjected to whole-genome shotgun sequencing on the Illumina MiSeq platform (Illumina Inc., San Diego, CA). The MG-RAST server (metagenomic rapid annotations using subsystems technology; http://metagenomics.anl.gov/) and STAMP software (http://kiwi.cs.dal.ca/Software/STAMP) were used to detect statistically significant differences in the abundance of taxonomic and functional features between the uterine microbial metagenomes of metritic and healthy cows. Our results showed an increased abundance of Fusobacteria and Bacteroidetes in metritic cows, confirming the potential role of those 2 taxa in the pathogenesis of metritis. The MG-RAST analysis revealed a significantly higher abundance of genes for protein transport across the cytoplasmic membrane and type VI bacterial secretion systems in the metritic microbiota. Additionally, genes coding for resistance to acid stress were exclusive to the metritis microbiota, suggesting that microbial resistance to acid stress is important for microbial survival in the infected uterus. On the other hand, genes coding for adhesion molecules, bacteriocins, and antibacterial peptides were significantly associated with the uterine microbiota of healthy cows, as was tolerance to colicin E2. [ABSTRACT FROM AUTHOR]

The main objective of this study was to evaluate the intrauterine administration use of 200 mL of 50% dextrose solution as a treatment against clinical endometritis (CE); CE cure rate and reproductive performance were evaluated. Additionally, the association of several relevant risk factors, such as retained placenta (RP), metritis, CE, anovulation, hyperketonemia, and body condition score with reproductive performance, early embryonic mortality, and CE were evaluated. A total of 1,313 Holstein cows housed on 4 commercial dairy farms were enrolled in the study. At 7 ± 3 DIM cows were examined for metritis and had blood collected to determine serum β-hydroxybutyrate concentration. To determine if cows had ovulated at least once before 44 ± 3 DIM, the presence of a corpus luteum was evaluated by ovarian ultrasonography at 30 ± 3 DIM and at 44 ± 3 DIM. At 30 ± 3 DIM, CE was diagnosed using the Metricheck device (SimcroTech, Hamilton, New Zealand); cows with purulent or mucopurulent vaginal discharge were diagnosed as having CE. Cows diagnosed with CE (n = 175) were randomly allocated into 2 treatment groups: treatment (intrauterine infusion of 200 mL of 50% dextrose) or control (no infusion). Clinical endometritis cows were re-evaluated as described above at 44 ± 3 DIM, and cows that were free of purulent or mucopurulent vaginal discharge were considered cured. Intrauterine infusion of dextrose tended to have a detrimental effect on CE cure rate, and treatment did not have an effect on first-service conception rate and early embryonic mortality. A multivariable Cox's proportional hazard model was performed to evaluate the effect of several variables on reproductive performance; the variables RP, CE, parity, anovulation, and the interaction term between parity and anovulation were associated with hazard of pregnancy. Cows that did not have RP or CE were more likely to conceive than cows that were diagnosed with RP or CE. Cows that had RP were at 3.36 times higher odds of losing their pregnancy than cows that did not have RP. In addition, cows diagnosed with CE were at 2.16 higher odds of losing their pregnancy than cows without CE. In conclusion, intrauterine infusion of 200 mL of 50% dextrose solution as a treatment for CE had a strong statistical tendency to decrease CE cure rate, did not improve first-service conception rate and early embryonic mortality, and did not decrease calving-to-conception interval. [ABSTRACT FROM AUTHOR]

Postpartum uterine diseases of dairy cows compromise animal welfare and may result in early removal from the herd or impaired reproductive performance. The relationship between poor immune status around calving and uterine diseases is well established; however, that between natural antibodies (NAb) and uterine health has not yet been studied. The objective of this study was to evaluate the association of circulating NAb levels around parturition with puerperal metritis, clinical endometritis, and the intrauterine presence of the Escherichia coli virulence factor FimH. One hundred six pregnant heifers were enrolled; NAb in serum samples collected at 30 ± 3 d prepartum and at 2 ± 1 and 35 ± 3 d in milk (DIM) were measured by ELISA. Puerperal metritis was defined as the presence of fetid, watery, red-brown uterine discharge and rectal temperature >39.5°C at 6 ± 1 DIM. Clinical endometritis was defined as presence of pus in the uterine lavage sample collected at 35 ± 3 DIM. The intrauterine presence of the fimH gene at 2 ± 1 DIM was evaluated by PCR. The overall optical density (wavelength of 650 nm) of ELISA-detected serum NAb was lower for cows diagnosed with puerperal metritis than for cows that did not have puerperal metritis. Additionally, cows diagnosed with clinical endometritis tended to have lower levels of NAb than did cows without clinical endometritis. Finally, FimH-positive cows had lower overall levels of serum NAb compared with FimH-negative cows. In conclusion, NAb detected in serum around parturition was associated with uterine health of dairy cows. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of intrauterine administration of 50 g of ultrapure mannose or a bacteriophage cocktail and the presence of Escherichia coli and Arcanobacterium pyogenes in the uterine lumen on uterine health and reproductive performance of lactating dairy cows. The study was conducted on a commercial dairy farm located near Ithaca, New York, from May 4 to January 20, 2011, and 597 cows were enrolled. The cows were divided randomly into 3 treatment groups, and treatments were administered at 2 ± 1 d in milk (DIM). Treatment 1 consisted of intrauterine administration of 50 g of ultrapure mannose powder divided in 4 pills; treatment 2 consisted of intrauterine administration of a bacteriophage cocktail that included 4 different phages in one pill, with a dose of approximately 107 plaqueforming units; and treatment 3 consisted of intrauterine administration of one empty pill (control). Intrauterine fluid swabs were collected on day of treatment and at 10 ± 3 DIM; uterine lavage samples were collected at 35 ± 3 DIM. Swabs and uterine lavage samples were cultured for E. coli and A. pyogenes. The intrauterine administration of mannose and bacteriophage did not affect uterine health, reproduction performance, or outcome of intrauterine secretion cultures for E. coli and A. pyogenes. Prevalence of intrauterine E. coli at 2 ± 1 DIM and A. pyogenes at 2 ± 1, 10 ± 3, and 35 ± 3 were affected by retained placenta. Additionally, prevalence of intrauterine E. coli at 10 ± 3 and A. pyogenes at 35 ± 3 DIM were associated with metritis, and cows that were diagnosed with clinical endometritis at 35 ± 3 DIM had greater prevalence of intrauterine E. coli at 2 ± 1 DIM and A. pyogenes at 35 ± 3 DIM. Furthermore, cows positive for E. coli at 2 ± 1 and 10 ± 3 DIM and for A. pyogenes at 10 ± 3 DIM had 1.63, 2.34, and 1.54 increased odds of having metritis. Cows positive for A. pyogenes at 35 ± 3 DIM and for E. coli at 2 ± 1 DIM had 19.8 and 2.66 higher odds of being diagnosed with clinical endometritis, respectively. Additionally, cows negative for E. coli at 2 ± 1 DIM were 1.39 times more likely to conceive than cows positive cows for E. coli. [ABSTRACT FROM AUTHOR]

The objectives were (1) to evaluate the association of uterine lavage sample optical density (ULSOD) with uterine health, and (2) to estimate and evaluate a threshold value that will maximize the accuracy of ULSOD as a diagnostic tool for clinical endometritis. The study enrolled 1,742 cows from 3 dairy farms located near Ithaca, New York. The samples were collected at 35 ± 3 d in milk (DIM) by using low-volume uterine lavage. Cows with a purulent or mucopurulent secretion in the sample were diagnosed with clinical endometritis, whereas a subgroup of all studied cows was examined for cytological evidence of inflammation by endometrial cytology. Data for ULSOD measured at different wavelengths (200, 352, 620, 790, 860, and 960 nm) were available for 554 cows; all 1,742 cows had data for ULSOD measured at 620 nm (ULSOD620). Incidences of clinical endometritis, metritis, and retained placenta were 10, 15.2, and 5.6%, respectively. The ULSOD620 was associated with clinical endometritis. Receiver operating characteristic (ROC) analysis of the accuracy of optical density in the detection of clinical endometritis was conducted for ULSOD measured at different wavelengths; ULSOD620 was selected for further analysis because it presented the best ROC curve to detect clinical endometritis. The recommended threshold for ULSOD620 ROC was 0.058, where the sensitivity and specificity were 76.3 and 78.3%, respectively. The ROC analysis of the accuracy of optical density in the detection of endometritis defined as a percentage of neutrophils in the uterine lavage samples higher than 18% was conducted for ULSOD620. The recommended threshold was 0.059, where the sensitivity and specificity were 100 and 82.2%, respectively. Cows with ULSOD620 ≤0.058 were 1.21 times more likely to conceive than cows with ULSOD620 >0.058; moreover, the median calving-to-conception interval for cows that had ULSOD620 ≤0.058 was 122 d compared with 148 d for cows that had ULSOD620 >0.058. Cows that were positive for Arcanobacterium pyogenes, diagnosed with metritis, or had retained placenta had 4.0, 1.4, and 1.7 times higher odds of having ULSOD620 >0.058, respectively. Cows with ULSOD620 >0.058 had a higher percentage of neutrophils in the uterine lavage samples than cows with ULSOD620 ≤0.058. Uterine lavage sample optical density measured at 620 nm can be used as an objective indicator of uterine health in dairy cows, principally for clinical endometritis. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of claw horn disruption lesions (CHDL; sole ulcers and white line disease) and body condition score (BCS) at dry-off on survivability, milk production, and reproductive performance during the subsequent lactation. An observational prospective cohort study was conducted on a large commercial dairy in Cayuga County, New York, from September 2008 until January 2009. A total of 573 cows enrolled at dry-off were scored for body condition and hoof trimmed; digits were visually inspected for the presence of CHDL. The BCS data were recategorized into a 3-level variable BCS group (BCSG), with cows with BCS <3 placed in BCSG 1 (n = 113), cows with BCS = 3 placed in BCSG 2 (n = 254), and cows with BCS >3 placed in BCSG 3 (n = 206). Cows in BCSG 2 were 1.35 and 1.02 times more likely to conceive than cows in BCSG 1 and 3, respectively. The cull/death hazard for BCSG 1 cows was 1.55 and 1.47 times higher than for cows in BCSG 2 and BCSG 3, respectively. Milk yield for cows in BCSG 2 (44.6 kg/d, 95% CI 43.4-45.8) was significantly greater than that for cows in BCSG 1 (41.5 kg/d, 95% CI 39.8-43.3). Cows with previous lactation days open ≤91 had 1.6 times higher odds of being classified into BCSG 1 at dry-off; cows with previous lactation mature-equivalent 305-d milk >14,054 kg had a similar 1.6 times higher odds of being classified into BCSG 1. Claw horn disruption lesions were found in 24.4% of the cows (n = 140) at dry-off. Cows without CHDL were 1.4 times more likely to conceive than cows with CHDL. Additionally, lesion cows were 1.7 times more likely to die or be culled than nonlesion cows. Absence of CHDL did not have a significant effect on milk yield. These findings highlight the importance of claw health and BCS at the end of lactation on future survival and performance. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the relative efficacy of a novel, commercially available disinfectant agent (THexx Dragonhyde HBC, Hydromer, Branchburg, NJ) compared with formalin and copper sulfate. The hypothesis was 2 sided; therefore, the hypothesis was that the new agent would be better or worse compared with the industry gold standard footbath agents, formalin and copper sulfate. The study was conducted in a large commercial dairy farm located near Ithaca, New York, from June 18, 2009 to October 26, 2009. Two identical studies were conducted, the first comparing Dragonhyde (5% solution, twice weekly) and formalin (5% solution, twice weekly) and the second comparing Dragonhyde (5% solution, twice weekly) and copper sulfate (10% solution, twice weekly). The study design was identical for both studies with 4 pens (physically identical), 2 treatments (Dragonhyde vs. formalin and Dragonhyde vs. copper sulfate), 2 periods (crossing over the treatment within pen), and 3 repeated measures (3 observations per cow: enrollment, wk 2, and wk 4). For study 1, 406 cows were enrolled (n = 201 formalin and 205 Dragonhyde). For study 2, 356 cows were enrolled (n = 189 copper sulfate and 167 Dragonhyde). The adjusted odds of digital dermatitis lesion (DDL) throughout the study period were analyzed by mixed logistic regressionmodel. In study 1, the odds of DDL were 1.36 times higher for the formalin group compared with the Dragonhyde group. In study 2, the data were analyzed by a similar statistical model and the variable treatment did not significantly affect the overall prevalence of DDL. In conclusion, the performance of 3 hoof care products was evaluated and it was concluded that Dragonhyde performed better than formalin and that there was no difference between copper sulfate and Dragonhyde. [ABSTRACT FROM AUTHOR]

Lameness is the most significant challenge for the dairy industry to overcome, given its obvious disruption of animal welfare and severe economic losses. Sole ulcers and white line abscesses are ubiquitous chronic diseases with the highest associated economic losses among all foot lesions. Their underlying causes are still not fully understood. An observational cross-sectional study was carried out to investigate the association between claw horn lesions and the thickness of the digital cushion. The thickness of the digital cushion was evaluated by ultrasonographic examination of the sole at the typical ulcer site. A total of 501 lactating Holstein dairy cows were enrolled in the study. The prevalence of sole ulcers was 4.2 and 27.8% for parity 1 and parity >1, respectively. The prevalence of white line disease was 1.0 and 6.5% for parity 1 and >1, respectively. The prevalence of lameness (visual locomotion score ≥3) was 19.8 and 48.2% for parity 1 and >1, respectively. The prevalence of sole ulcers and white line diseases was significantly associated with thickness of the digital cushion; cows in the upper quartile of digital cushion thickness had an adjusted prevalence of lameness 15 percentage points lower than the lower quartile. Body condition scores were positively associated with digital cushion thickness. The mean gray value of the sonographic image of the digital cushion had a negative linear association with digital cushion thickness (R2 = 0.14), indicating that the composition of the digital cushion may have changed with its thickness. Furthermore, digital cushion thickness decreased steadily from the first month of lactation and reached a nadir 120 d after parturition. These results support the concept that sole ulcers and white line abscesses are related to contusions within the claw horn capsule and such contusions are a consequence of the lesser capacity of the digital cushion to dampen the pressure exerted by the third phalanx on the soft tissue beneath. [ABSTRACT FROM AUTHOR]

Raw milk and colostrum can harbor dangerous micro-organisms that can pose serious health risks for animals and humans. According to the USDA, more than 58% of calves in the United States are fed unpasteurized milk. The aim of this study was to evaluate the effect of UV light on reduction of bacteria in milk and colostrum, and on colostrum IgG. A pilot-scale UV light continuous (UVC) flow-through unit (45 J/cm²) was used to treat milk and colostrum. Colostrum and sterile whole milk were inoculated with Listeria innocua, Mycobacterium smegmatis, Salmonella serovar Typhimurium, Escherichia coli, Staphylococcus aureus, Streptococcus agalactiae, and Acinetobacter baumannii before being treated with UVC. During UVC treatment, samples were collected at 5 time points and bacteria were enumerated using selective media. The effect of UVC on IgG was evaluated using raw colostrum from a nearby dairy farm without the addition of bacteria. For each colostrum batch, samples were collected at several different time points and IgG was measured using ELISA. The UVC treatment of milk resulted in a significant final count (log cfu/mL) reduction of Listeria monocytogenes (3.2 ± 0.3 log cfu/mL reduction), Salmonella spp. (3.7 ± 0.2 log cfu/mL reduction), Escherichia coli (2.8 ± 0.2 log cfu/mL reduction), Staph. aureus (3.4 ± 0.3 log cfu/mL reduction), Streptococcus spp. (3.4 ± 0.4 log cfu/mL reduction), and A. baumannii (2.8 ± 0.2 log cfu/mL reduction). The UVC treatment of milk did not result in a significant final count (log cfu/mL) reduction for M. smegmatis (1.8 ± 0.5 log cfu/mL reduction). The UVC treatment of colostrum was significantly associated with a final reduction of bacterial count (log cfu/ mL) of Listeria spp. (1.4 ± 0.3 log cfu/mL reduction), Salmonella spp. (1.0 ± 0.2 log cfu/mL reduction), and Acinetobacter spp. (1.1 ± 0.3 log cfu/mL reduction), but not of E. coli (0.5 ± 0.3 log cfu/mL reduction), Strep. agalactiae (0.8 ± 0.2 log cfu/mL reduction), and Staph. aureus (0.4 ± 0.2 log cfu/mL reduction). The UVC treatment of colostrum significantly decreased the IgG concentration, with an observed final mean IgG reduction of approximately 50%. Development of new methods to reduce bacterial contaminants in colostrum must take into consideration the barriers imposed by its opacity and organic components, and account for the incidental damage to IgG caused by manipulating colostrum. [ABSTRACT FROM AUTHOR]

The objective was to compare the reproductive efficacy of Ultrasynch, a synchronization program based on functionality of the corpus luteum as determined by ultrasonography, with an Ovsynch protocol. A randomized field trial was conducted on a commercial dairy in Cayuga County, New York, during scheduled weekly pregnancy examinations. Cows (n = 745) determined nonpregnant 28 to 34 d after artificial insemination (AI) were randomly assigned to Ultrasynch or Ovsynch protocols. Cows assigned to the Ultrasynch management program (n = 366) were treated based on corpus luteum (CL) diameter: cows with a CL >23 mm received an injection of PGF2α and were bred via AI following detection of estrus (Ultra-PGF), whereas cows with a CL ≤23 mm received injections and were bred on an Ovsynch protocol. Cows assigned to the Ovsynch management program (n = 379) were placed on an Ovsynch protocol regardless of CL diameter. Pregnancy status was rechecked 28 to 34 d after AI; cows determined nonpregnant after initial enrollment were maintained in their assigned management group and received treatments based on CL diameter if in the Ultrasynch group and Ovsynch treatments if in the Ovsynch group. Hazard of pregnancy was similar between Ultrasynch and Ovsynch (hazard ratio = 1.10, 95% confidence interval = 0.88-1.36). Median days to conception were 98 and 87 for Ultrasynch and Ovsynch, respectively. The detection of estrus rate of cows in the Ultra-PGF group was 49%; better performance of an Ultrasynch management program may be achievable in a herd with a higher rate of estrus detection. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize, using metagenomic shotgun DNA sequencing, the intrauterine microbial population and its predicted functional diversity within healthy cows and cows presenting purulent vaginal discharge (PVD). Twenty Holstein dairy cows from a single farm were enrolled in the study at 25 to 35 d postpartum. Purulent vaginal discharge was diagnosed by retrieving and scoring vaginal discharge using the Metricheck device (Simcro, Hamilton, New Zealand). Intrauterine samples for metagenomic analysis were collected by the cytobrush technique from 8 cows diagnosed with PVD and 12 healthy cows. Pair-end sequencing was performed using the Illumina MiSeq platform (Illumina Inc., San Diego, CA). Metagenomic sequences were analyzed using the MG-RAST server (metagenomic rapid annotations using subsystems technology; http://metagenomics.anl. gov/), and the STAMP software (http://kiwi.cs.dal. ca/Software/STAMP) was used to study statistically significant differential abundance of taxonomic and functional features between the 2 metagenomes. Additionally, the total number of bacterial 16S rDNA copies was estimated by real-time PCR. Taxonomic analysis revealed that Bacteroidetes was the most abundant phylum in the uterine microbiota from cows with PVD, and Fusobacteria was almost completely absent in the healthy uterine microbiota. Moreover, species belonging to the genus Trueperella were present only in the uterine microbiota of PVD cows. The increased abundance of Fusobacteria and the unique presence of Trueperella in the PVD cows highlight the important role of these bacteria in the pathogenesis of PVD. Genes encoding cytolethal distending toxin were exclusive to the microbiota of PVD cows. Similarly, genes associated with lipid A modification were present only in samples from PVD cows; such modification is associated with greater resistance to cationic antimicrobial peptides. Conversely, genes encoding bacteriocins and ribosomally antibacterial peptide were exclusively found in the healthy uterine microbiota and dominated by tolerance to colicin E2. No difference was observed in total bacterial load between the 2 microbiotas. This study provides deep insight into the uterine microbial community in health and disease. The observations that the healthy microbiota is tolerant to colicin E2, whereas the uterine microbiota of PVD cows produces cytolethal distending toxins and modifies its lipopolysaccharides suggest that species-intrinsic factors may be more relevant than bacterial abundance to the development of disease or maintenance of health in the dairy cow postpartum uterus. [ABSTRACT FROM AUTHOR]

Objectives of this clinical trial were to evaluate the effects of injectable trace mineral supplementation (ITMS) on somatic cell count (SCC), linear score (LS), milk yield, milk fat and protein contents, subclinical mastitis cure, and incidence of clinical mastitis in cows with elevated SCC. Holstein cows from a commercial dairy farm in New York were evaluated for subclinical mastitis, defined as SCC ≥200 × 103 cells/mL on the test day preceding enrollment. Cows with a history of treatment for clinical mastitis in the current lactation and those pregnant for more than 150 d were not eligible for enrollment. Cows fitting inclusion criteria were randomly allocated to 1 of 2 treatment groups. Cows assigned to ITMS (n = 306) received 1 subcutaneous injection containing zinc (300 mg), manganese (50 mg), selenium (25 mg), and copper (75 mg) at enrollment (d 0). Control cows (CTRL; n = 314) received 1 subcutaneous injection of sterile saline solution. Following treatment, visual assessment of milk was performed daily, and cows with abnormal milk (i.e., presence of flakes, clots, or serous milk) were diagnosed with clinical mastitis (CM). Chronic clinical mastitis was defined as cows with 3 or more cases of CM. Milk yield, milk fat and protein contents, SCC, and LS were evaluated once monthly. Additionally, randomly selected animals were sampled to test serum concentrations of selected minerals on d 0 and 30 (n = 30 cows/treatment). Treatment did not affect serum concentrations of calcium, magnesium, phosphorus, potassium, copper, iron, manganese, selenium, and zinc on d 30. Injectable supplementation with trace minerals did not improve overall cure of subclinical mastitis (CTRL = 42.8 vs. ITMS = 46.5%), although a tendency was observed in cows with 3 or more lactations (CTRL = 27.1 vs. ITMS = 40.0%). Supplementation did not reduce treatment incidence of CM (CTRL = 48.2 vs. ITMS = 41.7%); however, it tended to reduce the proportion of cows diagnosed with chronic CM (CTRL = 16.9 vs. ITMS = 12.0%), particularly among first-lactation cows (CTRL = 18.4 vs. ITMS = 7.6%). Cure of subclinical mastitis was associated with higher serum concentrations of phosphorus and selenium on d 30. Supplementing trace minerals to cows with elevated SCC had no effect on milk yield, milk fat and protein contents, SCC, and LS. [ABSTRACT FROM AUTHOR]

Understanding the role of fimbrial subunits during bacterial adherence and the host’s immunological response against anchorage proteins is critical for the development of strategies to prevent pathogens from thriving. The objectives of the present study were to locate fimbria-related proteins in the genome of Trueperella pyogenes (CP007519), define their importance for bacterial adherence, and evaluate the association between serum antibodies against fimbrial subunits and uterine health in dairy cows. Using a BLASTp search through the GenBank database, 4 putative clusters for fimbrial assembly were identified in the genome of T. pyogenes, namely FimA, FimC, FimE, and the novel major fimbriae FimJ. The fimbrial proteins FimA, FimC, FimE, and surface-anchored protein (SAP) were cloned into the pET 26b (+) vector, expressed in Escherichia coli BL21, and purified using affinity chromatography. Serum antibodies against FimA, FimC, FimE, and SAP were determined by ELISA on d 260 ± 3 of gestation and at 2 ± 1 and 35 ± 3 d in milk (DIM) to assess the relationship between antigenicity against fimbrial proteins and parameters of uterine health. Antibodies against FimC and FimE were greater both pre- and postpartum in cows from which T. pyogenes was recovered by uterine flushing at 35 ± 3 DIM, whereas T. pyogenes infection was not associated with differences in serum concentrations of FimA and SAP antibodies. Likewise, concentrations of FimC antibodies were consistently greater in cows diagnosed with clinical endometritis at 35 ± 3 DIM compared with healthy counterparts. These results suggest that fimbrial proteins evaluated in the present study, particularly FimC and FimE, are important for maintenance of T. pyogenes in the uterus postpartum and development of uterine diseases in dairy cattle. Additional research is warranted to elucidate the mechanisms by which each fimbrial subunit contributes to the establishment of uterine diseases, evaluate its effect on fertility responses, and assess its relevance as a target for vaccine development. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the relationship between selected minerals' serum levels, energy metabolites, oxidative stress indicators, IL-8 and haptoglobin levels, and the potential for uterine diseases. Additionally, we investigated the effect of injectable trace mineral supplementation (ITMS) on metabolism, immune function, and animal health under field conditions involving a dairy herd with high milk production. The study was conducted in 1 dairy farm located near Ithaca, New York, with 270 multiparous cows were enrolled from October 3, 2012 until January 10, 2013. Cows were randomly allocated into 1 of 2 treatments groups: ITMS or control. Cows randomly assigned to the ITMS group received 2 injections of trace minerals at 230 and 260 d of gestation; each injection contained 300 mg of Zn, 50 mg of Mn, 25 mg of Se, and 75 mg of Cu. Retained placenta (RP) and metritis were diagnosed and treated by trained farm personnel. Clinical endometritis evaluation was performed by the investigators. Blood mineral levels, plasma nonesterified fatty acids and serum β-hydroxybutyrate concentrations, plasma IL-8 concentrations, serum haptoglobin concentration, and serum superoxidase dismutase and plasma glutathione peroxidase activities were measured at various time points before and after calving. Four groups of mixed general linear models were fitted to the data using MIXED procedure of SAS. Injectable trace mineral-supplemented cows had increased serum concentration of Cu, Se, and Zn. Conversely, ITMS did not affect energy metabolites or immune and oxidative stress parameters. Serum concentration of Ca, Cu, K, Mg, Mo, Ps, Pt, Se, and Zn varied according to days relative to parturition. Cows with RP had reduced serum concentrations of Ca, Mg, Mo, and Zn when compared with cows without RP. Cows affected with metritis had significantly lower serum concentrations of Ca, Mo, soluble P, total P, Se, and Zn than nonaffected cows. Serum concentration of Ca, Cu, Mo, and Zn were reduced in cows diagnosed with endometritis in comparison to nonaffected ones. [ABSTRACT FROM AUTHOR]

Diarrhea in calves has a significant effect on the dairy industry. A common management practice for preventing or decreasing the effects of such disease in preweaned calves is by the use of antimicrobials in milk or milk replacer. In this study, Escherichia coli antimicrobial resistance in fecal samples collected from calves 2 to 8 d of age that had or had not received antimicrobials in the milk and that had or had not signs of diarrhea by inspection of fecal consistency were investigated. Specifically, resistance of E. coli isolates to individual antimicrobials, multiresistance patterns, and presence of virulence factors were analyzed. Escherichia coli isolates were tested for susceptibility to 12 antimicrobials by use of a Kirby-Bauer disk diffusion assay. The study was conducted at 3 farms, 1 administering growth-promoting antimicrobials (GPA) in the milk and 2 not using GPA in the milk (NGPA). All isolates were susceptible to ciprofloxacin and cefepime. From the total isolates tested, 84% (n = 251) were resistant to at least 2 antimicrobials and 81% (n = 251) were resistant to 3 or more antimicrobials. When antimicrobial resistance was compared between GPA and NGPA, it was observed that the GPA group had higher odds of antimicrobial resistance for most of the individual antimicrobials tested. No significant correlation of virulence factors in GPA or NGPA and diarrheic or non-diarrheic (control) fecal samples was found. Of the 32 virulence factors evaluated, 21 were detected in the study population; the incidence of only 1 virulence factor was statistically significant in each of the diarrheic status (diarrheic or non-diarrheic) and treatment status (NGPA or GPA) groups. Phylogenetic analysis based on the nucleotide sequence of the DNA gyrase gene (gyrB) from 31 fecal E. coli isolates revealed 3 main clades. [ABSTRACT FROM AUTHOR]

The objective of this study was to isolate bacteriophages from environmental samples of 2 large commercial dairy farms using Escherichia coli isolated from the uteri of postpartum Holstein dairy cows as hosts. A total of 11 bacteriophage preparations were isolated from manure systems of commercial dairy farms and characterized for in vitro antimicrobial activity. In addition, a total of 57 E. coli uterine isolates from 5 dairy cows were phylogenetically grouped by triplex PCR. Each E. coli bacterial host from the uterus was inoculated with their respective bacteriophage preparation at several different multiplicities of infections (MOI) to determine minimum inhibitory MOI. The effect of a single dose (MOI = 10²) of bacteriophage on the growth curve of all 57 E. coli isolates was assessed using a microplate technique. Furthermore, genetic diversity within and between the different bacteriophage preparations was assessed by bacteriophage purification followed by DNA extraction, restriction, and agarose gel electrophoresis. Phylogenetic grouping based on triplex PCR showed that all isolates of E. coli belonged to phylogroup B1. Bacterial growth was completely inhibited at considerably low MOI, and the effect of a single dose (MOI = 10²) of bacteriophage preparations on the growth curve of all 57 E. coli isolates showed that all bacteriophage preparations significantly decreased the growth rate of the isolates. Bacteriophage preparation 1230-10 had the greatest antimicrobial activity and completely inhibited the growth of 71.7% (n = 57) of the isolates. The combined action of bacteriophage preparations 1230-10, 6375-10, 2540-4, and 6547-2, each at MOI = 102, had the broadest spectrum of action and completely inhibited the growth (final optical density at 600 nm ≤0.1) of 80% of the E. coli isolates and considerably inhibited the growth (final optical density at 600 nm ≤0.2) of 90% of the E. coli isolates. Restriction profile analysis demonstrated that all 4 phage preparations contained bacteriophages that were genetically distinct from each other according to the banding pattern of the fragments. The combination of several different bacteriophages can improve the spectrum of action, and the results of this study suggest that bacteriophages 1230-10, 6375-10, 2540-4, and 6547-2 should be used in combination as a cocktail. [ABSTRACT FROM AUTHOR]

The use of pathogenic-specific antimicrobials, as proposed by bacteriophage therapy, is expected to reduce the incidence of resistance development. Eighty Escherichia coli isolated from uteri of Holstein dairy cows were phenotypically characterized for antimicrobial resistance to ampicillin, ceftiofur, chloramphenicol, florfenicol, spectinomycin, streptomycin, and tetracycline by broth microdilution method. The lytic activity of a bacteriophage cocktail against all isolates was performed by a similar method. Additionally, the effect of different concentrations of antimicrobials and multiplicities of infections (MOI) of the bacteriophage cocktail on E. coli growth curve was measured. Isolates exhibited resistance to ampicillin (33.7%), ceftiofur (1.2%), chloramphenicol (100%), and florfenicol (100%). All strains were resistant to at least 2 of the antimicrobial agents tested; multidrug resistance (≥3 of 7 antimicrobials tested) was observed in 35% of E. coli isolates. The major multidrug resistance profile was found for ampicillin-chloramphenicol-florfenicol, which was observed in more than 96.4% of the multidrug-resistant isolates. The bacteriophage cocktail preparation showed strong antimicrobial activity against multidrugresistant E. coli. Multiplicity of infection as low as 10-4 affected the growth of the E. coli isolates. The ratio of 10 bacteriophage particles per bacterial cell (MOI = 10¹) was efficient in inhibiting at least 50% of all isolates. Higher MOI should be tested in future in vitro studies to establish ratios that completely inhibit bacterial growth during longer periods. All isolates resistant to florfenicol were resistant to chloramphenicol and, because florfenicol was recently introduced into veterinary clinics, this finding suggests that the selection pressure of chloramphenicol, as well as other antimicrobials, may still play a relevant role in the emergence and dissemination of florfenicol resistance in E. coli. The bacteriophage cocktail had a notable capacity to inhibit the in vitro growth of E. coli isolates, and it may be an attractive alternative to conventional treatment of metritis by reducing E. coli in uteri of postpartum dairy cows. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of selective dry cow therapy (SDCT) strategies based on 2 different algorithms in comparison with blanket dry cow therapy for measures of udder health, milk yield, and culling in herds not using internal teat sealant. Cows from 2 commercial farms in west Texas were randomized into 3 different groups: SDCT algorithm 1 (ALG1; n = 455) cows treated with an intramammary antimicrobial at dry-off if SCC >200,000 cells/mL at any Dairy Herd Improvement Association test date or if the cow had 2 or more cases of clinical mastitis (CM) during the enrollment lactation; SDCT algorithm 2 (ALG2; n = 458) cows treated with an intramammary antimicrobial at dry-off if SCC >200,000 cell/mL at last test date or any case of CM during the enrollment lactation; and control cows (CON = 447) received blanket dry cow therapy. None of the cows enrolled in the study received an internal or external teat sealant. Data related to milk and SCC linear score (LSCC) were collected monthly. Milk yield and LSCC during the first 6 mo of lactation were analyzed using repeated measures ANOVA models, while Cox proportional hazards models were fitted to culling and CM data. The farm was fitted as a random effect in all models. The percentage of cows receiving antimicrobials at dry-off was 51.3%, 24.7%, and 100% for ALG1, ALG2, and CON, respectively. Treatment did not influence the IMI dynamics during the dry period. Additionally, no statistical differences related to treatment were observed for LSCC and milk yield. The LSCC for ALG1, ALG2, and CON cows was 2.44, 2.41, and 2.26, respectively. The average milk yield for ALG1, ALG2, and CON cows was 43.2, 43.2, and 44.0 kg/d, respectively. Treatment did not affect CM incidence or culling. The cumulative incidence of CM was 19.6%, 19.4%, and 21.4% for ALG1, ALG2, and CON cows, respectively. Additionally, the cumulative risk of death or culling was 18.5%, 17.1%, and 19.5% for ALG1, ALG2, and CON cows, respectively. In conclusion, SDCT strategies led to a decrease in antimicrobial drug use at dry-off, without significantly affecting the incidence of CM, the risk of culling, LSCC, or milk yield of dairy cows. However, numerical differences in LSCC and milk yield were observed between treatment groups., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The main objective of this study was to evaluate the effect of ceftiofur on metritis cure, milk yield, reproductive performance, and culling up to 300 DIM. The secondary objective was to evaluate the effect of metritis cure at 5 (early cure [ECURE]) and 14 (late cure [LCURE]) days after diagnosis on milk production, reproduction, and culling. A total of 422 Holstein cows diagnosed with metritis from 4 herds located in Texas, California, and Florida were enrolled in a randomized clinical trial. Cows diagnosed with metritis (fetid, watery, reddish or brownish uterine discharge) were blocked by herd and parity and were randomly allocated to receive systemic administration of ceftiofur (CEF) or to remain untreated (CON). In addition, 399 nonmetritic cows (NMET) were included for comparison purposes. Metritis cure was evaluated at 5 and 14 d after diagnosis and was defined as the absence of metritis clinical signs. Logistic regression models were fitted to the data to assess the effect of treatment on metritis cure. Milk yield was analyzed using a mixed linear model, while logistic regression, Cox proportional hazard, and Kaplan-Meier survival analysis models were fitted to culling and reproduction data. Cows treated with CEF had 1.86 (95% CI: 1.22-2.81) and 1.68 (95% CI: 1.02-2.75) greater odds of being cured than CON cows at 5 and 14 d after diagnosis, respectively. No effect of CEF was observed for milk yield; however, NMET cows had greater milk yield compared with metritic cows (CEF = 36.0, 95% CI = 33.8-38.1; CON = 36.1, 95% CI = 33.9-38.2; NMET = 36.9 kg/d, 95% CI = 34.8-39.4). Likewise, no effect of CEF was observed on reproductive performance and culling. Nonetheless, the likelihood of conceiving for NMET cows was 1.72 (95% CI = 1.41-2.12) and 1.64 (95% CI = 1.33-2.00) times greater than for CEF and CON cows, respectively. Ceftiofur-treated and CON cows had 2.93 (95% CI = 1.90-4.51) and 2.37 (95% CI = 1.51-3.71) greater hazard of culling compared with NMET, respectively. Regardless of treatment, no differences between ECURE and LCURE were observed on milk yield, reproduction, and culling throughout the entire lactation, but cows that cured at 5 or 14 d after diagnosis had greater milk production in the first 60 DIM compared with cows that did not cure (NCURE). Cows in ECURE and LCURE also had a 1.59 (95% CI = 1.16-2.16) and 1.49 (95% CI = 1.08-2.05) greater hazard of pregnancy and 0.43 (95% CI = 0.26-0.71) and 0.56 (95% CI = 0.34-0.92) hazard of culling compared with NCURE. Ceftiofur therapy increased metritis cure, but benefits to productivity and longevity were not observed. Also, cows that fail to cure have impaired lactation performance, but no differences regarding timing of cure were observed., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Our objective was to evaluate the accuracy of predictive models for metritis spontaneous cure (SC) and cure among ceftiofur-treated cows using farm-collected data only, and with the addition of hemogram variables and circulating concentration of metabolites, minerals, and biomarkers (BM) of inflammation measured at time of diagnosis. Data related to parity, calving-related issues, BCS, rectal temperature, and DIM at metritis diagnosis were collected from a randomized clinical trial that included 422 metritic cows from 4 herds in Texas, California, and Florida. Metritis was defined as the presence of red-brownish, watery, and fetid vaginal discharge, and cure was defined as the absence of metritis 14 d after initial diagnosis. Cows were randomly allocated to receive systemic ceftiofur therapy (2 subcutaneous doses of 6.6 mg/kg of ceftiofur crystalline-free acid on the day of diagnosis and 3 d later; CEF) or to remain untreated (control). At enrollment (day of metritis diagnosis), blood samples were collected and submitted to complete blood count (CBC) and processed for the measurement of 13 minerals and BM of metabolism and inflammation. Univariable analysis to evaluate the association of farm-collected data and blood-assessed variables with metritis cure were performed, and variables with P ≤ 0.20 were offered to multivariable logistic regression models and retained if P ≤ 0.15. The areas under the curve for models predicting SC using farm data only and farm + BM were 0.70 and 0.76, respectively. Complete blood count variables were not retained in the models for SC. For models predicting cure among CEF cows, the area under the curve was 0.75, 0.77, 0.80, and 0.80 for models using farm data only, farm + CBC, farm + BM, and farm + CBC + BM, respectively. Predictive models of metritis cure had fair accuracy, with SC models being less accurate than models predictive of cure among CEF cows. Additionally, adding BM variables marginally improved the accuracy of models using farm collected data, and CBC data did not improve the accuracy of predictive models., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Rumen-protected choline (RPC) promotes benefits in milk production, immunity, and health in dairy cows by optimizing lipid metabolism during transition period management and early lactation. However, the RPC success in dairy cows depends on choline bioavailability, which is affected by the type of protection used in rumen-protected choline. Therefore, our objectives were to determine the effects of a novel RPC on dry matter intake (DMI), identify markers of metabolism and immunity, and evaluate lactation performance. Dry Holstein (n = 48) cows at 245 ± 3 d of gestation were blocked by parity and assigned to control or RPC treatment within each block. Cows enrolled in the RPC treatment received 15 g/d of CholiGEM (Kemin Industries, Cavriago RE, Italy) from 21 d prepartum and 30 g/d of CholiGEM from calving to 21 d postpartum. During the transition period, DMI was measured daily, and blood was sampled weekly for energy-related metabolites such as β-hydroxybutyrate (BHB), glucose, and nonesterified fatty acids (NEFA), as well as immune function markers such as haptoglobin (Hp) and lipopolysaccharide-binding protein (LPB). Vaginal discharge samples were collected at the calving and 7 d postpartum and stored in microcentrifuge tubes at -80°C until 16S rRNA sequencing. The main responses of body condition score, body weight, DMI, milk yield, milk components, and immune function markers were analyzed using the GLIMMIX procedure of SAS with the effects of treatment, time, parity, and relevant covariates added to the models. The relative abundance of microbiome α-diversity was evaluated by 3 indexes (Chao1, Shannon, and Simpson) and β-diversity by principal coordinate analysis and permutational multivariate ANOVA. We found no differences in DMI in the pre- and postpartum periods. Cows fed RPC increased the yields of energy- and 3.5% fat-corrected milk and fat yield in primiparous and multiparous cows, with an interaction between treatment and parity for these lactation variables. However, we found no differences in milk protein and lactose up to 150 DIM between treatments. Glucose, NEFA, and BHB had no differences between the treatments. However, RPC decreased BHB numerically (control = 1.07 ± 0.13 vs. RPC = 0.63 ± 0.13) in multiparous on the third week postpartum and tended to reduce the incidence of subclinical ketosis (12.7% vs. 4.2%). No effects for Hp and LPB were found in cows fed RPC. Chao1, Shannon, and Simpson indexes were lower at calving in the RPC treatment than in the Control. However, no differences were found 7 d later for Chao1, Shannon, and Simpson indexes. The vaginal discharge microbiome was altered in cows fed RPC at 7 d postpartum. Fusobacterium, a common pathogen associated with metritis, was reduced in cows fed RPC. Rumen-protected choline enhanced lactation performance and health and altered the vaginal discharge microbiome which is a potential proxy for uterine healthy in dairy cows. The current study's findings corroborate that RPC is a tool to support adaptation to lactation and shed light on opportunities for further research in reproductive health., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Prior data from our group showed that first-lactation cows under organic management in United States have a high prevalence of Staphylococcus aureus, Streptococcus spp., and Staphylococcus chromogenes intramammary infections (IMI) in early lactation. Nonetheless, the relationship between IMI, udder health, and milk production in organically reared primiparous cows remains elusive. The objectives of this observational study were to investigate the relationship between presence and persistence of IMI in the first 35 d in milk (DIM) and somatic cell count (SCC) and milk production during the first 6 mo of lactation on first-lactation organic dairy cows. The analysis included a total of 1,348 composite milk samples collected during the first 35 DIM that were submitted for milk culture and 1,674 Dairy Herd Improvement Association (DHIA) tests during the first 180 DIM from 333 heifers in 4 organic dairy farms, enrolled between February 2019 and January 2020. The association between IMI in the first 35 DIM and new high SCC (SCC > 200,000 cells/mL) and milk production during the first 6 mo of lactation was investigated using Cox proportional hazards regression and mixed linear regression, respectively. The association between IMI persistence (harboring the same microorganism as reported by the laboratory for 2 or more samples) in the first 35 DIM and number of DHIA tests with high SCC during the first 6 mo of lactation was modeled using negative binomial regression. The presence of IMI by Staph. aureus (hazard ratio [HR] [95% confidence interval {CI}]: 3.35 [2.64, 4.25]) or Streptococcus spp. (HR [95% CI]: 2.25 [2.12, 2.39]) during the first 35 DIM was associated with an increased risk of new high SCC during the first 6 mo of lactation. Milk production was reduced when Streptococcus spp. were identified in milk samples. However, there was no evidence of a difference in milk production in Staph. aureus IMI. Isolation of non-aureus staphylococci and mammaliicocci was related to a mild increase in the hazards of high SCC (HR [95% CI]: 1.34 [0.97, 1.85]) and a decrease in milk production during one or more postpartum tests. Presence of gram-negative or Streptococcus-like organisms IMI was not associated with either high SCC or milk production. Presence of Bacillus IMI was associated with a lower hazard of new high SCC (HR [95% CI]: 0.45 [0.30, 0.68]), and higher milk production during the first 180 d of lactation (overall estimate [95% CI]: 1.7 kg/d [0.3, 3.0]). The persistence of IMI in the first 35 DIM was associated with the number of tests with high SCC during the lactation for all microorganisms except for Staphylococcus chromogenes. Therefore, our results suggest that the persistence of IMI in the first 35 DIM could be an important factor to understand the association between IMI detected in early lactation and lactational SCC and milk production in organic dairy heifers. Our study described associations between IMI, udder health, and milk production in first-lactation organic dairy cows that are consistent with findings from conventional dairy farms., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Previous studies have shown that organically raised dairy cows have an increased prevalence of Staphylococcus aureus compared with conventionally raised dairy cows. However, little information exists about the dynamics of intramammary infection (IMI) in primiparous cows during early lactation on organic dairy farms. The objective of this study was to describe the IMI dynamics of primiparous cows on certified organic farms during early lactation. This longitudinal study enrolled 503 primiparous cows from 5 organic dairy farms from February 2019 to January 2020. Quarter-level milk samples were collected aseptically on a weekly basis during the first 5 wk of lactation. Samples were pooled by cow and time point into composite samples inside a sterilized laminar hood and submitted for microbiological culture. For each of the different microorganisms identified, we estimated the prevalence in each postpartum sample, period prevalence (PP), cumulative incidence, and persistence of IMI. Logistic regression models were used to investigate whether the prevalence of IMI differed by farm or sampling time points and whether IMI persistence differed between detected microorganisms. Our findings revealed a high prevalence of Staphylococcus aureus (PP = 18.9%), non-aureus staphylococci and closely related mammaliicoccal species (PP = 52.1%), and Streptococcus spp. and Streptococcus-like organisms (PP = 32.1%) within the study population. The prevalence of these microorganisms varied significantly between farms. Staphylococcus aureus and Staphylococcus chromogenes exhibited significantly higher IMI persistence compared with other detected bacterial taxa, confirming the divergent epidemiological behavior in terms of IMI chronicity across different microorganisms. This study improves our understanding of the epidemiology of mastitis-causing pathogens in organically raised primiparous cows, which can be used to tailor mastitis control plans for this unique yet growing subpopulation of dairy cows., (© 2023, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Our objective was to investigate the association of early metritis [EMET, diagnosed at <5 d in milk (DIM)] and late metritis (LMET, diagnosed at ≥5 DIM) with circulating concentrations of energy metabolites, minerals, and haptoglobin (Hp) throughout the first 14 d postpartum. A total of 379 purebred Jersey cows were enrolled in a prospective cohort study from a single herd in west Texas. Cows were examined for metritis using the Metricheck device (Simcro Ltd.) at 4, 7, and 10 DIM. Cows identified by farm employees as possible metritis cases were also evaluated for metritis. Blood samples were collected for analysis of concentrations of Ca, Mg, and glucose at DIM 1 through 5, 7, 10, and 14. Albumin, urea, fructosamine, free fatty acids (FFA), creatinine, and β-hydroxybutyrate (BHB) were analyzed at DIM 3, 5, 7, 10, and 14, and Hp at DIM 1 through 5 and 7. Data were analyzed using the MIXED and PHREG procedures of SAS (SAS Institute Inc.). A series of mixed general linear models accounting for repeated measures were fitted to the data. The independent variables metritis [no metritis (NMET), EMET, and LMET], DIM of analyte assessment, and parity were forced in all models. Multivariable Cox proportional hazard models were built to assess the risk of pregnancy and culling within 150 DIM. The overall metritis incidence was 26.9% (EMET = 49; LMET = 53; NMET = 277). Average concentrations of glucose, Mg, and urea were not associated with metritis. The associations of Ca, creatinine, BHB, and fructosamine with metritis were dependent on the DIM of analyte assessment. Cows categorized as EMET and LMET had, on average, lower albumin and fructosamine compared with NMET cows. Both EMET and LMET cows had, on average, greater BHB than NMET cows. A greater FFA concentration was only observed in cows diagnosed with EMET compared with NMET cows (EMET = 0.58, LMET = 0.52, NMET = 0.48 mmol/L). Additionally, circulating Hp concentration was greater for LMET and EMET compared with NMET cows, and EMET cows had greater Hp compared with LMET cows (EMET = 1.15; LMET = 1.00; NMET = 0.84). In conclusion, several blood biomarkers were temporally associated with early versus late metritis diagnosis in postpartum Jersey cows. No meaningful differences were observed in production, reproduction, or culling between EMET and LMET cows. These results suggest that cows with EMET undergo a more severe degree of inflammation and negative energy balance compared with NMET cows., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The objective of this prospective cohort study was to characterize the metabolic profile, health, milk production, and reproductive outcomes of cows diagnosed with hyperketonemia (HK; β-hydroxybutyrate ≥1.2 mmol/L), hypoglycemia (HG; glucose ≤2.2 mmol/L), or concurrent HK and HG (HKHG). Glucose and β-hydroxybutyrate concentrations in whole blood were assessed using a handheld device (Precision Xtra, Abbott Laboratories) in lactating dairy cows (n = 2,418) between 3 and 9 d postpartum. Cows were categorized into 4 groups: no HK or HG (healthy; Norm = 1,821), HK only (HK = 232), HG only (HG = 161), and concurrent HK and HG (HKHG = 204). Subsequent milk production, along with health and reproductive outcomes, as recorded by farm personnel, were analyzed according to metabolic category. Serum collected on the day of cow-side diagnosis of hyperketonemia and hypoglycemia was evaluated for total calcium (tCa), magnesium (Mg), nonesterified fatty acids (NEFA), triglycerides (TG), and urea using an automated chemistry analyzer (Randox Daytona; Randox Laboratories Ltd.). Statistical analysis was carried out using SAS version 9.4 (SAS Institute Inc.). Hyperketonemia in multiparous cows was associated with greater incidence of metabolic abnormalities (hypomagnesemia, hypocalcemia, and elevated NEFA and urea). Hyperketonemia in primiparous and multiparous cows led to increased adverse health events (culling rate, retained fetal membranes, puerperal metritis, clinical ketosis, left displaced abomasum) relative to Norm cows. Multiparous cows with HKHG had fewer metabolic disturbances (hypomagnesemia, hypocalcemia, elevated NEFA) than HK cows. Cows with HKHG had an increased incidence of clinical ketosis and left displaced abomasum relative to Norm cows. Cows with HG had similar metabolic profiles to Norm cows and had lower incidence of retained fetal membranes and puerperal metritis than cows with HK. Multiparous cows with HG produced more milk than Norm cows from wk 10 to 20, whereas multiparous cows with HK produced less milk than Norm cows. For primiparous cows, HK did not have a negative effect on milk production compared with Norm cows., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Objectives of this retrospective cohort study were to determine the association of heat stress (HS) exposure during the periparturient period with production, health, reproduction, and survival during the first 90 d postpartum in dairy cows. A total of 5,722 Holstein cows (2,324 nulliparous and 3,397 parous) were categorized into environmental condition groups based on average temperature-humidity index (THI) exposure as thermoneutral (TN) or HS during the prepartum (PRE) and early postpartum (POST) periods into TN-TN (THI: PRE = 57.9 and POST = 63.7), TN-HS (THI: PRE = 68.2 and POST = 72.0), HS-TN (THI: PRE = 71.4 and POST = 65.6), and HS-HS (THI PRE = 72.2 and POST = 72.7). Nulliparous and parous cows were analyzed separately. In nulliparous cows, exposure to HS during the PRE, POST, or both PRE and POST periods was associated with a 1.7 kg/cow per day reduction in milk yield compared with TN-TN. Postpartum HS was associated with increases of 4.4 percentage points in incidence of retained placenta, 18.1 percentage points in incidence of metritis, and 2.0 percentage points in incidence of mastitis, but a reduction of 5.3 percentage points in pregnancy at first AI, and an increase of 4.5 percentage points in pregnancy loss compared with POST TN. Exposure to HS during PRE and POST periods was associated with increased removal from the herd. In parous cows, exposure to HS during PRE, POST, or both PRE and POST was associated with a 2.4-kg/cow per day reduction in milk yield when compared with TN-TN. There was an interaction between HS exposure PRE and POST and incidence of retained placenta, because POST HS was associated with an increase in incidence of 5.8 percentage points within PRE HS cows, whereas no difference was found within PRE TN cows. Postpartum HS was associated with an increase of 6.3 percentage points in incidence of metritis and tended to be associated with an increase of 1.9 percentage points in mastitis incidence compared with POST TN. There was an interaction between HS exposure PRE and POST and pregnancy per AI because POST HS was associated with reduced pregnancy incidence by 10.6 percentage points within PRE TN cows, whereas no difference was found within PRE HS cows. Removal from the herd increased in cows exposed to HS during the PRE or POST or PRE and POST. These data suggest that POST HS is associated with performance losses to a greater extent than prepartum HS and that nulliparous and parous cows are prompt to losses associated with exposure to HS during the transition period. The results corroborate findings from manipulative experiments that showed improved milk production and reproduction in cows under HS provided with heat abatement but adds insights to the associations between HS and health., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The objective of this study was to evaluate the effect of subcutaneous injections of 15 mg/mL Cu, 5 mg/mL Se, 60 mg/mL Zn, and 10 mg/mL Mn on health, performance, polymorphonuclear leukocyte (PMNL) function, circulating glutathione peroxidase (GPx) and superoxide dismutase (SOD) concentrations, and inflammation of dairy cows undergoing the transition period in high temperature-humidity index. A total of 923 multiparous cows from 2 commercial dairy farms were randomly allocated into 1 of 2 treatment groups as follows: control and injectable trace mineral supplementation (ITMS). Cows in the ITMS group received 7 mL of subcutaneous injections at dry-off (208 ± 3 d of gestation), 260 ± 3 d of gestation, and at 35 ± 3 d in milk (DIM). Data regarding health traits, reproductive performance, milk yield, and survivability were extracted from farm database software, and animals were followed-up until 300 DIM. For a subset of 142 cows from one herd, blood samples were collected at enrollment, and at 3 ± 1, 7 ± 1, 10 ± 1, and 35 ± 3 DIM to evaluate hematology, PMNL function, GPx and SOD concentrations, and circulating haptoglobin. Logistic regression was used to assess health and pregnancy per artificial insemination at first service. Cox proportional hazards models were used to evaluate hazard of pregnancy and culling. Mixed linear regression models accounting for repeated measures were used to assess all continuous variables collected over time. Parity, twinning, and previous gestation length were considered as potential confounders. Farm was included as a random effect. The ITMS cows tended to have lower incidence of metritis and stillbirth compared with control group. However, ITMS treatment did not influence the incidence of other diseases (e.g., mastitis, retained placenta), milk yield, reproductive performance, culling, and leukocyte count. Neutrophil-to-lymphocyte ratio, PMNL phagocytosis, and oxidative burst as well as intensity of the oxidative burst were greater for ITMS-treated cows in comparison to control cows. The ITMS cows had decreased expression of the adhesion molecule L-selectin on PMNL surface. The serum concentration of GPx and SOD were not affected by ITMS treatment. In conclusion, ITMS tended to reduce the incidence of metritis and stillbirth parturition, improved PMNL function, and improved the inflammatory status of dairy cows undergoing the transition period in high temperature-humidity index conditions. However, these findings did not translate into improved milk yield, reproductive performance, and survivability., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

Oral electrolyte solutions (OES) are a common, on-farm therapy to reestablish hydration and electrolyte balances in scouring and stressed calves. The objectives were to determine the effects of OES alkalinizing agent and the presence of a milk replacer feeding before OES administration on the abomasal environment in healthy Holstein calves. Abomasum cannulation was performed on 16 Holstein bull calves at 5 d of age. One calf was removed from the study before the calves were randomly assigned to treatments at 9 d of age. Treatments were arranged as a 2-by-2 factorial, with the following factors: oral electrolyte alkalinizing agent [acetate (A) or bicarbonate (B)] and liquid meal type milk replacer (MR) + OES (MR-A, MR-B), or OES only (OES-A, OES-B)]. The OES differed only by alkalinizing agent. On d 9, calves assigned to MR-A (n = 4) or MR-B (n = 4) received their morning MR aliquot 0.5 h before feeding 2 L of OES; the OES-A (n = 3) and OES-B (n = 4) treatment groups were fed 2 L of OES only. Peripheral blood samples and postprandial abomasal fluid samples were collected to assess abomasal pH, abomasal emptying rate (AER), and ex vivo abomasal Escherichia coli growth potential. Postprandial pH was greater in calves fed MR or B-based OES. Abomasal emptying rate was slower in calves receiving MR + OES, regardless of the alkalinizing agent. Ex vivo E. coli colony-forming unit counts were greater in calves fed either MR + OES or bicarbonate-based OES. Supplementing bicarbonate OES in addition to MR alters abomasal dynamics and may promote E. coli growth in postprandial abomasal fluid, partially due to sustained elevations in gastric pH and delayed gastric emptying rates. The OES containing sodium acetate limited ex vivo E. coli growth potential in abomasal fluid, thereby potentially reducing the risk of additional enteric bacterial complications associated with OES therapy., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The study's objectives were to identify cow-level and environmental factors associated with metritis cure to predict metritis cure using traditional statistics and machine learning algorithms. The data set used was from a previous study comparing the efficacy of different therapies and self-cure for metritis. Metritis was defined as fetid, watery, reddish-brownish discharge, with or without fever. Cure was defined as an absence of metritis signs 12 d after diagnosis. Cows were randomly allocated to receive a subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid (Excede, Zoetis) at the day of diagnosis and 3 d later (n = 275); and no treatment at the time of metritis diagnosis (n = 275). The variables days in milk (DIM) at metritis diagnosis, treatment, season of the metritis diagnosis, month of metritis diagnostic, number of lactation, parity, calving score, dystocia, retained fetal membranes, body condition score at d 5 postpartum, vulvovaginal laceration score, the rectal temperature at the metritis diagnosis, fever at diagnosis, milk production from the day before to metritis diagnosis, and milk production slope up to 5, 7, and 9 DIM were offered to univariate logistic regression. Variables included in the multivariable logistic regression model were selected from the univariate analysis according to P-value. Variables were offered to the model to assess the association between these factors and metritis cure. Additionally, the univariate logistic regression variables were offered to a recursive feature elimination to find the optimal subset of features for a machine learning algorithms analysis. Cows without vulvovaginal laceration had 1.91 higher odds of curing of metritis than cows with vulvovaginal laceration. Cows that developed metritis at >7 DIM had 2.09 higher odds of being cured than cows that developed metritis at ≤7 DIM. For rectal temperature, each degree Celsius above 39.4°C led to lower odds to be cured than cows with rectal temperature ≤39.4°C. Furthermore, milk production slope and milk production difference from the day before to the metritis diagnosis were essential variables to predict metritis cure. Cows that had reduced milk production from the day before to the metritis diagnosis had lower odds to be cured than cows with moderate milk production increase. The results from the multivariable logistic regression and receiver operating characteristic analysis indicated that cows developing metritis at >7 DIM, with increase in milk production, and with a rectal temperature ≤39.40°C had increased likelihood of cure of metritis with an accuracy of 75%. The machine learning analysis showed that in addition to these variables, calving-related disorders, season, and month of metritis event were needed to predict whether the cow will cure or not from metritis with an accuracy ≥70% and F1 score (harmonic mean between precision and recall) ≥0.78. Although machine learning algorithms are acknowledged as powerful tools for predictive classification, the current study was unable to replicate its potential benefits. More research is needed to optimize predictive models of metritis cure., (© 2021, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

Our objectives were to perform a proof-of-concept study to assess the association of a prolonged inflammatory state (based on a continually elevated haptoglobin concentration at the end of the first week after parturition) with mineral, protein, and energy balance markers in the first 2 wk after parturition, and milk production in the first 60 d of lactation in clinically healthy cows. We conducted a cohort study in 1 herd in west Texas that was milking Jersey and Jersey-Holstein crosses. Only multiparous Jersey cows were eligible for enrollment. Cows were classified as having or not having elevated haptoglobin concentrations based on plasma concentrations evaluated on d 4 and 7 postpartum. We used median concentrations of haptoglobin in the reference population (i.e., before the exclusion of cows diagnosed with clinical diseases) as the limits for categorizing cows into 2 groups: cows with plasma haptoglobin concentrations greater than the median values on both d 4 (0.49 g/L) and 7 (0.35 g/L) had continually elevated haptoglobin (with eHp); and cows with plasma haptoglobin concentrations lower than or equal to the median values of the reference population on d 4 or 7 did not have continually elevated haptoglobin (without eHp). Next, cows with clinical diseases in the first 2 wk of the postpartum period were excluded, so that 233 cows remained for the final analyses. Evaluated outcomes were average daily milk production across the first 60 d of lactation, plasma Ca, Mg, and glucose concentrations on d 1, 2, 3, 4, 5, 7, 10, and 14 postpartum, and β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), fructosamine, albumin, urea, and creatinine concentrations on d 3, 5, 7, 10, and 14 postpartum. Rectal temperatures measured on d 4, 7, and 10 postpartum were also analyzed. We performed statistical analyses using linear mixed models while accounting for the repeated effect of sampling time (plasma analytes and rectal temperature models) and weekly milk test (milk production model). Cows with eHp had lower plasma Ca concentrations in the first 2 wk after calving, but no differences in Mg, BHB, NEFA, glucose, or rectal temperatures compared to cows without eHp. Cows with eHp had lower plasma fructosamine, albumin, and urea concentrations in a time-dependent manner. They also had lower milk production (2.3 kg/d less than cows without eHp in the first 60 DIM). Our study demonstrated that 25% of cows without clinical disorders in the first 2 wk after parturition had continually elevated haptoglobin concentrations at d 7 after parturition relative to d 4, suggestive of a prolonged, low-grade systemic inflammatory state. More observational studies are needed to more fully characterize the duration of prolonged postpartum subclinical inflammation in cows without clinical diseases, as well as its long-term effects, and to evaluate the use of other potential markers of systemic inflammation to describe this disorder., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

Research exploring specific associations of markers of negative energy balance and Ca in postpartum Jersey cows with lactation performance is lacking. Our objectives were to evaluate the associations of total Ca concentration (tCa) measured at 1 through 3 d in milk (DIM) and free fatty acids (FFA), β-hydroxybutyrate (BHB), and glucose measured at 3 DIM with (1) the risk of multiparous Jersey cows being diagnosed with early-lactation diseases and culling, (2) milk production in the first 9 wk of lactation, and (3) the risk of pregnancy in the first 150 DIM. A cohort study was performed in 1 dairy herd in Texas. Multivariable Poisson regression models were built to evaluate the association of the analytes of interest with the risks of early-lactation diseases and culling in the first 60 DIM (i.e., binary outcomes). Linear mixed models were used to evaluate the association of the analytes of interest with milk production within the first 9 wk of lactation, and a Cox proportional hazard model was built to assess the risk of pregnancy within 150 DIM. A total of 380 cows were used in the final analyses. Total Ca measured at 1 through 3 DIM was not associated with the risk of metritis. Cows with increased FFA and BHB had an increased risk of being diagnosed with metritis and clinical mastitis, respectively. Increased concentrations of glucose and FFA and decreased tCa at 3 DIM were associated with an increased risk of culling. Reduced tCa concentrations at 1 DIM (≤1.84 mmol/L) and 2 DIM (≤2.04 mmol/L) were associated with increased milk production across the first 9 wk of lactation compared with tCa concentrations above those thresholds. Total Ca was not associated with milk production when assessed at 3 DIM, whereas increased FFA (≥0.37 mmol/L) and decreased glucose (≤2.96 mmol/L) at 3 DIM were associated with increased milk production. None of the metabolites measured were associated with the risk of pregnancy in the first 150 DIM. Our results demonstrate that tCa concentration assessed in the first 3 DIM show temporary associations with milk production and culling in multiparous Jersey cows. Although increased concentration of FFA assessed at 3 DIM was associated with greater milk yield, it was a detrimental factor for the risk of metritis. This study attempted to better elucidate the relationship of tCa, FFA, BHB, and glucose assessed in early postpartum with health and performance of Jersey cows. Based on this study, assessments performed at 3 DIM using tCa concentration ≤1.99 mmol/L for increased risk of early-lactation culling and FFA ≥0.43 mmol/L for increased risk of metritis could be used as starting points. More studies evaluating the dynamics of energy balance markers and tCa in postpartum Jersey cows using a greater number of herds are needed to better inform dairy consultants on critical levels for exacerbated postpartum negative energy balance and subclinical hypocalcemia for the Jersey breed., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objective of this study was to assess the association between serum concentrations of haptoglobin (Hp), cortisol, and l-lactate following transport of dairy heifer calves within their first week of life with health, mortality, and growth during the preweaning period. Blood samples were collected at arrival and included a cohort of 168 Jersey and Jersey-cross calves from 8 different sources located in Minnesota. All calves were raised at a single facility in New Mexico. Incidence of respiratory disease (BRD) and mortality during the preweaning period (60 d of life) were extracted from the farm's software database. Individual body weight was measured at birth and at weaning to estimate average daily gain. No simple linear correlations were found between the biomarkers. The incidence of BRD during the preweaning period was 7.7%. While cortisol and l-lactate serum concentrations were not associated with BRD, Hp was negatively associated with BRD. Receiving operating characteristic curve analysis was performed to determine the optimal threshold value for Hp [threshold ≤0.63 μmol/L (63 μg/mL), area under the curve = 0.65]. A Cox's proportional hazards model revealed that calves with Hp concentration ≤0.63 μmol/L were more likely to be diagnosed with BRD (hazard ratio = 5.0, 95% confidence interval = 1.3-19.0). A mixed linear model showed that calves with Hp concentration ≤0.63 μmol/L tended to have lower average daily gain (454.4 vs. 479.9 g/d) during the preweaning period than calves with Hp >0.63 μmol/L at arrival. Overall mortality of the cohort was 3.5%, and Hp was not associated with mortality. Although circulating concentrations of l-lactate and cortisol measured at arrival were not associated with BRD incidence during the preweaning period of heifer calves transported within the first 4 d of life, calves with serum Hp concentration >0.63 μmol/L were less likely to be diagnosed with BRD and tended to grow more than calves with Hp ≤0.63 μmol/L. Further research is needed to replicate these results in a larger cohort and to better understand the possible influence of greater inflammatory status at arrival on health and growth of calves transported to a calf-raising facility., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

It is well established that subclinical mastitis (SCM), characterized by somatic cell count (SCC) >200,000 cells/mL, has a negative effect on the productivity, reproductive performance, and survivability of cows from conventional dairy herds. However, in organic herds, where the use of antimicrobial drugs is restricted for the treatment and control of intramammary infections (IMI) in dairy cows, little is known about the effect of SCM on performance and survivability. The objective of this study was to evaluate whether SCM diagnosed during the first month of lactation was associated with SCC linear score dynamics, milk production, fertility, and culling of dairy cows in USDA-certified organic herds. We collected data from 2 organic herds in New Mexico and Texas. A total of 1,511 cows that calved between June 2018 and May 2019 were included in the study and were followed until month 10 of the current lactation. Cows with SCC >200,000 cells/mL in the first month of lactation were considered to have SCM. We used mixed linear regression models accounting for repeated measures to assess the effect of SCM on monthly milk production and SCC linear scores. We used Cox proportional hazards models to evaluate the effect of SCM on the risk of pregnancy and culling. We considered parity, farm, previous gestation length, stillbirth, twinning, dystocia, and 2- and 3-way interactions as potential confounders. Cows diagnosed with SCM during the first month of lactation produced less milk than cows without SCM. Cows with SCM had elevated SCC linear scores during their previous lactation and throughout the subsequent months of lactation compared to cows without SCM. The effect of SCM on SCC linear scores was more pronounced in multiparous than primiparous cows. Subclinical mastitis during the first month of lactation did not affect the likelihood of pregnancy during the first 300 d in milk. Cows with SCM in the first month were more likely to die or be culled during the 300 d of lactation than cows without SCM. We observed that elevated SCC in the first month of lactation had detrimental effects on the milk yield and survivability of dairy cows in USDA organic herds, but it did not affect reproductive performance. We demonstrated that cows with SCM diagnosed in the first month of lactation continued to have elevated SCC linear scores throughout their entire lactation, and that elevated SCC was carried over from the previous lactation., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objectives of this study were (1) to characterize Ca levels and polymorphonuclear leukocyte (PMN) function in primiparous and multiparous animals following oral Ca bolus supplementation, and (2) to determine differential responses of boluses containing a lower dose of Ca than traditionally used in primiparous animals on Ca levels and PMN function. Jersey × Holstein crossbred animals (n = 104) were enrolled within 24 h of parturition. All animals were blocked by time relative to calving and randomly assigned to treatment. The Ca boluses were composed of a mixture of Ca chloride, Ca sulfate, and Ca propionate. For objective 1, animals were assigned to control (CON; no Ca supplementation), or a series of 2 Ca boluses given 24 h apart for a total of 50 g of Ca. Objective 2 treatments included control (CON; no Ca supplementation), a series of 2 Ca boluses given 24 h apart containing 50 g of Ca, or a series of 2 Ca boluses given 24 h apart containing 25 g of Ca. Blood samples were collected on d 1 (<24 h), 2, 3, 5, and 7 relative to parturition. Total serum Ca, serum haptoglobin, PMN intracellular Ca, PMN intracellular Ca after stimulation with an environmental Escherichia coli, PMN L-selectin surface expression, and PMN phagocytic and oxidative burst activities were analyzed. For objective 1 a tendency was detected for a treatment difference on basal intracellular PMN Ca and a treatment difference on E. coli-stimulated intracellular PMN Ca. We detected a parity × DIM effect for PMN oxidative burst intensity. However, no other interactions or parity effects on other functional PMN variables were detectable. In primiparous animals, we found a treatment difference for E. coli-stimulated intracellular PMN Ca among animals given 50 g of Ca but no treatment difference on basal intracellular PMN Ca. The 50 g of Ca treatment increased both PMN phagocytosis and oxidative burst intensities. Supplementing animals with 50 g of oral Ca increased intracellular PMN Ca and influenced PMN function., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Our objective was to assess the association of cow-related factors with metritis cure risk and economically important outcomes. In this prospective cohort study nested inside a randomized clinical trial, cows enrolled in a clinical trial that aimed to evaluate an alternative metritis therapy that had available plasma samples collected at metritis diagnosis were included. Metritis was defined as fetid, watery, reddish-brownish discharge with or without fever, and cure was defined as the absence of metritis signs 12 d after diagnosis. Cows were randomly allocated to remain untreated (CON; n = 147) or receive subcutaneous injections of 6.6 mg/kg of ceftiofur crystalline-free acid at enrollment and 72 h later (CEF, n = 168). Additionally, a random subset of 150 nonmetritic cows (NMET) was also included to compare milk production, reproductive performance, and culling responses. Cow-related factors evaluated include plasma concentrations of nonesterified fatty acids, β-hydroxybutyrate, and haptoglobin (Hp), parity, rectal temperature, and days in milk (DIM) at metritis diagnosis, vulvovaginal laceration (VL), BCS, dystocia, twins, and retained placenta. Among CON cows, DIM at metritis diagnosis was positively associated with metritis cure [threshold = 8, area under the curve (AUC) = 0.67], whereas plasma Hp concentration tended to be negatively associated with cure of metritis (threshold = 0.54 mg/mL, AUC = 0.64). Among CEF cows, DIM at metritis diagnosis (threshold = 5, AUC = 0.67) and dystocia were positively associated with metritis cure, whereas VL and Hp (threshold = 0.78 mg/mL, AUC = 0.76) were negatively associated with cure. For CON cows that were diagnosed with metritis after 8 DIM or had plasma Hp concentration ≤0.54 mg/mL, milk production, pregnancy, and culling risk were comparable to NMET cows. However, performance was impaired when cows that developed metritis at ≤8 DIM or had Hp >0.54 mg/mL were left untreated. Among CEF cows, Hp, DIM at metritis diagnosis, dystocia, and VL were associated with metritis cure. Milk yield, reproductive performance, and culling losses are more pronounced among CEF cows when metritis was diagnosed at ≤5 DIM, Hp >0.78 mg/mL, or if they had VL or dystocia. In conclusion, these data indicate that timing of the onset of metritis and inflammatory biomarkers could be used for the development of a selective therapy strategy for metritis, but more research is needed to identify more accurate predictors of metritis spontaneous cure and treatment failure., (The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

The main objective of this study was to evaluate the efficacy of intrauterine administration of chitosan microparticles (CM) in curing metritis in dairy cows. A secondary objective was to evaluate the effects of metritis treatments on milk yield, survival, and reproductive performance. Cows with a fetid, watery, red-brownish vaginal discharge were diagnosed with metritis. Holstein cows (n = 826) with metritis from 3 dairies located in northern Florida were blocked by parity (primiparous or multiparous) and, within each block, randomly assigned to one of 3 treatments: CM (n = 276) = intrauterine infusion of 24 g of CM dissolved in 40 mL of sterile distilled water at the time of metritis diagnosis (d 0), 2 (d 2), and 4 (d 4) d later; ceftiofur (CEF; n = 275) = subcutaneous injection of 6.6 mg/kg ceftiofur crystalline-free acid in the base of the ear at d 0 and d 3; Control (CON; n = 275) = no treatment applied at metritis diagnosis. All groups could receive escape therapy if condition worsened. Cure was considered when vaginal discharge became mucoid and not fetid. A group of nonmetritic (NMET; n = 2,436) cows was used for comparison. Data were analyzed by generalized linear mixed and Cox's proportional hazard models. Cows in CM and CON had lesser risk of metritis cure on d 12 than cows in CEF (58.6 ± 5.0 vs. 61.9 ± 4.9% vs. 77.9 ± 3.9, respectively). The proportion of cows culled within 60 days in milk (DIM) was greater for cows in CM than for cows in CEF and CON (21.5 ± 2.7 vs. 9.7 ± 1.9 vs. 11.3 ± 2.0%, respectively). Treatment did not affect rectal temperature or plasma nonesterified fatty acids, β-hydroxybutyrate, and haptoglobin concentrations. Milk yield in the first 60 DIM differed for all treatments, and it was lowest for CM (35.8 ± 0.3 kg/d), followed by CON (36.8 ± 0.3 kg/d) and CEF (37.9 ± 0.3 kg/d). The hazard of pregnancy up to 300 DIM was lesser for CM than CEF (hazard ratio = 0.62; 95% CI: 0.50-0.76), for CM than CON (hazard ratio = 0.77; 95% CI: 0.62-0.95) and for CON than CEF (hazard ratio = 0.80; 95% CI: 0.65-0.99). Culling was greater, and milk yield and fertility were lesser for CEF than NMET. In summary, CM did not improve the cure of metritis, and was detrimental to milk yield, survival, and fertility compared with CON. In contrast, CEF increased the cure of metritis, milk yield, and fertility compared with CM and CON. Finally, the negative effects of metritis on milk yield culling and fertility could not be completely reversed by CEF., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

In the present study, we standardized processes of cloning and purification of recombinant bovine interleukin-8 (rbIL-8) from bacterial culture and assessed its biological activity in Holstein cattle. Plasmid containing a subclone of bovine IL-8 was expressed using Escherichia coli BL21 and cell lysate was purified by chromatography. The presence of rbIL-8 was assessed by Western blot analyses and function was confirmed in vitro using a chemotaxis chamber. Based on optical density values, chemoattractant properties of rbIL-8 were 10-fold greater compared with control wells. Two in vivo studies were conducted to assess the biological activity of rbIL8. For study 1, one-year-old Holstein heifers (n = 20) were randomly allocated to receive a single intravaginal administration containing 1,125 µg of rbIL-8 diluted in 20 mL of saline solution (rbIL-8, n = 10) or a single intravaginal administration of 20 mL of saline solution (control, n = 10). For study 2, nonpregnant lactating Holstein cows (n = 31) were randomly allocated to receive an intrauterine administration with 1,125 µg of rbIL-8 diluted in 20 mL of saline solution (rbIL-8, n = 11), a positive control consisting of resin-purified lysate of E. coli BL21 not transfected with the plasmid coding for rbIL-8 diluted in 20 mL of saline solution (E. coli, n = 10), and a negative control administered with 20 mL of saline solution (control, n = 10). An increase in vaginal neutrophils was observed in heifers treated with rbIL-8 within 3 h of treatment, but not in control heifers. Additionally, intrauterine administration of rbIL-8 increased the proportion of PMN cells in uterine cytological samples from 3.5% before treatment to 75.8% 24 h later-an increase that was not observed in the negative control group and cows treated with resin-purified lysate of E. coli. To further evaluate the effect of local and systemic rbIL-8 stimulation on the dynamics of circulating white blood cells, a third study was conducted. In study 3, nonpregnant 8-mo-old Holstein heifers (n = 30) were randomly allocated into 1 of 3 treatment groups: intravenous rbIL-8 (1,125 µg of rbIL-8 diluted in 5 mL of saline solution, n = 10); intravaginal rbIL-8 (1,125 µg of rbIL-8 diluted in 20 mL of saline solution; n = 10); or intravaginal saline (20 mL of saline solution, n = 10). Intravenous injection of rbIL-8 resulted in a transient increase in rectal temperature, which was greater at 2 h after treatment compared with cows treated intravaginally with rbIL-8 or heifers treated with saline solution. Heifers treated with rbIL-8 intravenously displayed a marked reduction in neutrophils, basophils, lymphocytes, and monocytes within the first 4 h posttreatment compared with heifers treated intravaginally. However, at 6 h after treatment, heifers treated with rbIL-8 intravenously displayed a rebound in white blood cell counts caused by an increase in neutrophil counts. These results show that the presented purification method is effective and results in biologically active rbIL-8 that can be used safely to modulate immune responses in cattle., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Intramammary infusion of antimicrobials (IA) and application of an internal teat sealant (ITS) at the end of the lactation is a common strategy to prevent and treat intramammary infections during the dry period. In heifers, precalving IA has been reported to improve udder health and milk quality; however, the effect of ITS in heifers housed in freestall barns is still unknown. The objective of this study was to investigate the effect of prepartum application of ITS or IA on udder health of dairy heifers. A total of 886 heifers were randomly allocated into 1 of 4 treatment groups when they were 245 ± 3 d pregnant. Control heifers (CON) did not receive any treatment. Heifers in the ITS group received the application of ITS containing 2.6 g of bismuth subnitrate. Animals in the IA group received intramammary administration of 62.5 mg of amoxicillin. Heifers in IA+ITS group received intramammary administration of amoxicillin followed by ITS application. The follow-up period was 270 d in milk (DIM). Clinical mastitis was diagnosed and treated by trained farm personnel throughout the study period. Composite milk somatic cell counts (SCC) were determined monthly for the first 9 mo of lactation by Dairy Herd Improvement Association. Subclinical mastitis was defined as a cow having a SCC >200,000 cells/mL for at least 1 test day and not diagnosed with clinical mastitis during the study period. At 7 ± 3 DIM, composite milk samples were collected for bacteriological analysis for a subset of the study animals. The presence of pathogens in milk at 7 ± 3 DIM was more frequently detected in the CON heifers compared with animals enrolled in the treatment groups. Heifers in IA+ITS group had a decreased incidence of clinical mastitis compared with CON heifers (12.9 vs. 21.4%). Additionally, the incidence of subclinical mastitis was decreased for IA+ITS heifers compared with CON counterparts (20.1 vs. 43.8%). During the first 9 mo of lactation, IA and IA+ITS heifers had lower SCC linear scores compared with ITS and CON counterparts. Although IA+ITS treatment successfully improved udder health, it did not result in better milk yield, fertility, and survivability. In conclusion, ITS alone was not effective in improving udder health; however, the combination of ITS and IA decreased the incidence of clinical and subclinical mastitis during the first 9 mo of lactation. Additionally, IA+ITS had a long-term effect on the SCC linear score throughout the study period., (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Escherichia coli are believed to be associated with postpartum metritis and endometritis but their role in the pathogenesis of both diseases is still undefined. In this study, uterine swabs for E. coli isolation were collected from 374 lactating Holstein cows housed on 4 commercial farms near Ithaca, New York. A total, 125 of 374 cows (33.4%) were positive for E. coli culture. Standard multiplex PCR protocols were used to screen the isolates for the presence of 32 virulence factor genes. Cows that had twin parturition were 4.4 times more likely to have intrauterine E. coli contamination than those that gave birth to single live female calves. Stillborn parturition and birth of single live male calves also increased the odds of intrauterine contamination by E. coli (3.7- and 1.6-fold, respectively) compared with birth of live female calves. Six virulence factors, common to extraintestinal and enteroaggregative E. coli, were found to be associated with metritis and endometritis: fimH, hlyA, cdt, kpsMII, ibeA, and astA. The virulence factor gene fimH was the most prevalent and the most significant: intrauterine E. coli carrying fimH and at least 1 of the other 5 identified virulence factors were pathogenic, and phylogenetic analysis based on the nucleotide sequence of DNA gyrase from 41 such IUEC revealed 2 clades., (Copyright © 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)