Search

The present study evaluated the interaction of pregnancy type [PT; single (S) vs. twin (T)] and dry period feeding management [D; close-up (CU) diet ([NE.sub.1] = 1.54 Mcal/kg of DM)] throughout the entire dry period (8W) vs. far-off (FO) diet ([NE.sub.1] = 1.32 Meal/kg of DM) from 60 to 21 d before expected calving date (ECD) followed by CU diet until calving (3W). Treatments were arranged in a 2 x 2 factorial with a randomized block design with primiparous (n = 8) and multiparous (n = 39) Holstein cows. We hypothesized that increasing the duration of feeding a CU diet would improve metabolic status and lactation performance for cows with T, but not for cows with S. All cows were fed similarly in late lactation (90 to 60 d before ECD; diet [NE.sub.1] = 1.58 Mcal/kg of DM) and in early lactation (calving to 105 DIM; diet [NE.sub.1] = 1.71 Meal// kg of DM). Prepartum DMI as percentage of BW did not differ (P > 0.10) with D but tended to be greater (P = 0.10) for cows with S than with T. Cows with T tended to have greater (P = 0.08) BW than cows with S, but conceptus-free BW was less (P = 0.001) for cows with T than for cows with S. No differences (P > 0.10) were detected in prepartum BCS or BCS change with PT or D. Energy balance (EB) was greater for cows with S than with T (P < 0.001) and for cows fed 8W vs. 3W (P = 0.01). Cows with T had greater (P < 0.001) NEFA and a tendency for greater liver triglycerides (TG; P = 0.07) and plasma [beta]-hydroxybutyrate (BHBA; P = 0.06) than cows with S. Prepartum cows fed 3W had greater (P = 0.01) liver TG and greater (P = 0.02) plasma NEFA, but less (P = 0.02) plasma BHBA than cows fed 8W. Plasma glucose (P < 0.004) and liver glycogen (P = 0.02) were less for cows with T but were not affected (P > 0.10) by D. Postpartum, there was no effect (P > 0.1) of PT or D on mean DMI as percentage of BW, BW, and BCS, but there was an interaction (P = 0.02) of PT x D for mean BCS. Cows that calved T were in a more positive (P = 0.004) EB than cows that calved S. Milk production was 5.2 kg/d greater (P = 0.04) for cows fed 8W; however, they were in less (P = 0.01) EB than cows that received 3W. Postpartum cows that calved T had decreased concentrations of plasma NEFA (P = 0.02) and liver TG (P = 0.04) but greater concentrations of plasma glucose (P = 0.03) than cows that calved S. Plasma BHBA (P = 0.07) and NEFA tended (P = 0.06) to be greater for cows that received 8W than 3W. Neither PT nor D affected (P > 0.1) plasma glucose and liver glycogen. There was a tendency for an interaction of PT x D for plasma NEFA and liver TG. In contrast to our hypothesis, response to D was independent of PT. Based on milk production data from the present experiment, 8W is a more desirable feeding strategy than 3W. Key words: close-up diet, dairy cow, metabolic status, twinning doi:10.2527/jas.2009-2206

Forty-eight Holstein cows were used in a randomized block design to evaluate different dry period lengths and prepartum milking frequencies (MF) on subsequent milk production, milk composition, solids-corrected milk production, dry matter intake (DMI), and energy balance. Lactating cows, milked 2 times/d, began a 7-d covariate period 35 d prior to the expected calving date. Cows were milked 0 times/d (0x), 1 time/d (1x), and 4 times/d (4x) for the last 28 d of gestation. If milk production decreased to less than 0.5 kg/milking or 1 kg/d, milking via machine ceased; however, teat stimulation continued 1 or 4 times/ d according to the treatment assignment. All cows were milked 2 times/d postpartum (wk 1 to 10). Prepartum DMI tended to be greater for lx and 4x compared with 0x. Prepartum, cows milked lx produced 17% less milk than cows milked 4x (5.9 and 7.1 kg/d, respectively). There were no differences in prepartum and postpartum body condition scores, body weights, and DMI. Postpartum milk production by cows following their third or greater gestation was greater for 0x and 4x compared with 1x. Postpartum milk production by cows following their second gestation was significantly decreased with increased MF (0x vs. 1x and 4x). Regardless of parity, postpartum solids-corrected milk was greater for 0x compared with 1x and 4x. Postpartum fat yield was greater for 0x vs. 4x, with lx being intermediate. Postpartum protein yield was greater for 0x vs. 4x, whereas 0x tended to have greater protein yield than lx. Postpartum energy balance was greater for 1x and 4x relative to 0x. Continuous milking (1x and 4x) resulted in a loss of milk production in the subsequent lactation for cows following their second gestation; however, for cows following their third or greater gestation, increasing the MF from 1x to 4x in the last 28 d of gestation alleviated the loss in milk production. [ABSTRACT FROM AUTHOR]

Inorganic sources of Mg are commonly used in dairy cow diets, but their availability varies significantly. This study assessed the relative availability of 4 commonly used inorganic Mg sources and a novel alkalinizing proprietary mineral blend [PMB; Multesium (GLC Minerals, LLC, Green Bay, WI, USA)]. The study was a duplicated 6 × 6 Latin square, with 12 nonlactating, non-pregnant Holstein dairy cows assigned to a square based on BW and parity. Cows were fed 90% of their voluntary DMI (diet contained 0.21% Mg). Each experimental period lasted 7 d. On d 2 of each period, urinary catheters were fitted. Total urine collection started on d 3 for 48 h with samples collected and measured every 12 h. On d 4, 30 g of Mg were administered as boluses with gelatin capsules: negative control (one empty capsule), magnesium oxide (MgO), magnesium sulfate (MgSO 4 ), calcium magnesium hydroxide [CaMg(OH) 4 ], calcium magnesium carbonate [CaMg(CO 3 ) 2 ], and PMB [a blend of Ca and Mg sources that includes CaMg(CO 3 ) 2 , CaMg(OH) 4 , and MgO]. Blood samples were collected at 0, 1, 2, 3, 12, and 24 h after treatment administration on d 4 of each treatment period. Urine and blood samples were analyzed for Mg and Ca concentration. Statistical analyses were conducted with PROC GLIMMIX including treatment, time, period, square, treatment × time, treatment × period, and time × period as fixed effects, and cow nested within square as a random effect in the model. Urinary Mg excretion for 4 of the Mg sources studied [PMB, MgO, CaMg(OH) 4 , and MgSO 4 ] increased significantly, representing an increase of at least 40.8% relative to control. The supplementation of CaMg(CO 3 ) 2 did not significantly increase relative to control. There were no significant changes in blood Mg concentration with treatment; but, a significant treatment × time effect was observed. Calcium-rich sources [PMB, CaMg(OH) 4 , CaMg(CO 3 ) 2 ] had lower blood Mg concentrations at 12 or 24 h after treatment than control and CaMg(CO 3 ) 2 . Based on urinary Mg excretion 24 h after treatment, 4 of the Mg sources evaluated (including PMB) showed a similar availability, however, the availability of the commercial CaMg(CO 3 ) 2 source included in our study was similar to the negative control (no-supplemented cows)., (© 2024, 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/).)

Escherichia coli has been attributed to playing a major role in a cascade of events that affect the prevalence and severity of uterine disease in cattle. The objectives of this project were to (i) define the association between the prevalence of specific antimicrobial resistance and virulence factor genes in E. coli with the clinical status related to uterine infection, (ii) identify the genetic relationship between E. coli isolates from cows with diarrhea, with mastitis, and with and without metritis, and (iii) determine the association between the phenotypic and genotypic antimicrobial resistance identified on the E. coli isolated from postpartum cattle. Bacterial isolates ( n = 148) were obtained from a larger cross-sectional study. Cows were categorized into one of three clinical groups before enrollment: metritis, cows with purulent discharge, and control cows. For genomic comparison, public genomes ( n = 130) from cows with diarrhea, mastitis, and metritis were included in a genome-wide association study, to evaluate differences between the drug classes or the virulence factor category among clinical groups. A distinct E. coli genotype associated with metritis could not be identified. Instead, a high genetic diversity among the isolates from uterine sources was present. A virulence factor previously associated with metritis ( fim H) using PCR was not associated with metritis. There was moderate accuracy for whole-genome sequencing to predict phenotypic resistance, which varied depending on the antimicrobial tested. Findings from this study contradict the traditional pathotype classification and the unique intrauterine E. coli genotype associated with metritis in dairy cows.IMPORTANCEMetritis is a common infectious disease in dairy cattle and the second most common reason for treating a cow with antimicrobials. The pathophysiology of the disease is complex and is not completely understood. Specific endometrial pathogenic Escherichia coli have been reported to be adapted to the endometrium and sometimes lead to uterine disease. Unfortunately, the specific genomic details of the endometrial-adapted isolates have not been investigated using enough genomes to represent the genomic diversity of this organism to identify specific virulence genes that are consistently associated with disease development and severity. Results from this study provide key microbial ecological advances by elucidating and challenging accepted concepts for the role of Intrauterine E. coli in metritis in dairy cattle, especially contradicting the existence of a unique intrauterine E. coli genotype associated with metritis in dairy cows, which was not found in our study., Competing Interests: The authors declare no conflict of interest.

Antimicrobial use in food-producing animals is under increasing scrutiny due to the potential effect on the selection of antimicrobial-resistant bacteria that may be transmitted to humans by direct contact, with the food chain, or the environment. Novel data monitoring commensal Escherichia coli from dairy farms is essential for understanding antimicrobial resistance (AMR) patterns and their association with herd health management practices. The objectives of this study were to: (1) compare the prevalence of antimicrobial resistance in the E. coli isolates from the hospital, fresh, and mid-lactation pens from 18 conventional dairy farms participating in an educational training program in antimicrobial stewardship practices in California and Ohio, and (2) to characterize the prevalence of antimicrobial resistance of commensal E. coli isolated from pooled fecal pat samples before and 3 mo after participating in the educational training program. Pooled fecal pat samples were collected from the hospital pen, the fresh pen (1 to 5 DIM), and the mid-lactation pens (90 to 150 DIM) on conventional dairies in CA (n = 9) and OH (n = 9). Fecal samples were collected as part of a larger study using a quasi-experimental design that assigned farms to the training intervention group (TG; 6 per state) or the control group (CG; 3 per state). For the TG, farm worker(s) identified as having the task of diagnosis and treatment of adult cows on the farm participated in a training program on antimicrobial stewardship practices. Pooled fecal samples (n = 7) were collected at enrollment and 3 mo after completing the intervention on each of the participating farms (n = 18), followed by culture for E. coli isolation and antimicrobial sensitivity testing using the broth microdilution methodology. Logistic regression models were used to evaluate the association between E. coli antimicrobial resistance patterns with the training intervention and farm-level factors. No effect was observed in the prevalence of resistant isolates between the control and intervention farms after the training was delivered. Isolates from the hospital pens were 2.48 (95% CI: 1.06-6.22, P = 0.03) and 5.61 (95% CI: 1.94-16.91, P < 0.001) times, more likely to be resistant to streptomycin and chloramphenicol, respectively, than isolates from the mid-lactation pens. Our findings indicate there was a higher prevalence of AMR in E. coli associated with the hospital pen within the farm, while the training program for 3 mo did not affect the prevalence of AMR in E. coli on the farms participating in the program. Further research efforts should be conducted to identify factors driving AMR at the pen level, as well as approaches that could be used to reduce the risk of disseminating AMR from sick pens to animals being housed and to other pens on the farm., (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/).)

Background: The goal of this study was to assess the microbial ecology and diversity present in the uterus of post-partum dairy cows with and without metritis from 24 commercial California dairy farms using shotgun metagenomics. A set subset of 95 intrauterine swab samples, taken from a larger selection of 307 individual cow samples previously collected, were examined for α and β diversity and differential abundance associated with metritis. Cows within 21 days post-partum were categorized into one of three clinical groups during sample collection: control (CT, n = 32), defined as cows with either no vaginal discharge or a clear, non-purulent mucus vaginal discharge; metritis (MET, n = 33), defined as a cow with watery, red or brown colored, and fetid vaginal discharge; and purulent discharge cows (PUS, n = 31), defined as a non-fetid purulent or mucopurulent vaginal discharge., Results: All three clinical groups (CT, MET, and PUS) were highly diverse, with the top 12 most abundant genera accounting for 10.3%, 8.8%, and 10.1% of mean relative abundance, respectively. The α diversity indices revealed a lower diversity from samples collected from MET and PUS when compared to CT cows. PERMANOVA statistical testing revealed a significant difference (P adjusted < 0.01) in the diversity of genera between CT and MET samples (R2 = 0.112, P = 0.003) and a non-significant difference between MET and PUS samples (R2 = 0.036, P = 0.046). ANCOM-BC analysis revealed that from the top 12 most abundant genera, seven genera were increased in the natural log fold change (LFC) of abundance in MET when compared to CT samples: Bacteroides, Clostridium, Fusobacterium, Phocaeicola, Porphyromonas, Prevotella, and Streptococcus. Two genera, Dietzia and Microbacterium, were decreased in natural LFC of abundance when comparing MET (regardless of treatment) and CT, while no changes in natural LFC of abundance were observed for Escherichia, Histophilus, and Trueperella., Conclusions: The results presented here, are the current deepest shotgun metagenomic analyses conducted on the bovine uterine microbiome to date (mean of 256,425 genus-level reads per sample). Our findings support that uterine samples from cows without metritis (CT) had increased α-diversity but decreased β-diversity when compared to metritis or PUS cows, characteristic of dysbiosis. In summary, our findings highlight that MET cows have an increased abundance of Bacteroides, Porphyromonas, and Fusobacterium when compared to CT and PUS, and support the need for further studies to better understand their potential causal role in metritis pathogenesis., (© 2023. The Author(s).)

The objective of this study was to identify alterations in the vaginal discharge (VD) metabolome and potential biomarkers to predict metritis development and a cure in dairy cows. This prospective cohort study was conducted on two dairies located in CA and TX. Vaginal discharge was evaluated and collected using the Metricheck ® device. Cows were examined for metritis at 4, 7, and 9 days in milk (DIM). Cows with a fetid, watery, and reddish-brown uterine discharge were classified as having metritis and randomized to receive ceftiofur ( n = 10) or remain untreated ( n = 7). A cure was defined as the absence of a fetid, watery, reddish-brown uterine discharge at 14 d after enrollment. Vaginal discharge samples were collected from 86 cows within 6 h after parturition, at 4 and 7 DIM, at metritis diagnosis, and at 4 and 7 days after metritis diagnosis. Cows with metritis (MET; n = 17) were paired with counterparts without metritis (HTH) of a similar DIM and parity ( n = 34). The uterine metabolome was evaluated using untargeted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). Metabolomic data were analyzed using the MetaboAnalyst 5.0. Data were log-transformed and auto-scaled for normalization. Univariate analyses, including the fold-change, were performed to identify the metabolites linked to metritis development and its cure and principal component analysis and partial least squares discriminant analysis were performed to explain metabolite variance between animals developing or not developing metritis and being cured or not being cured of metritis. Comparing HTH with MET cows at calving, 12 metabolites were upregulated, and one was downregulated. At four and seven DIM, 51 and 74 metabolites, respectively, were altered between MET and HTH cows. After metritis development, three and five metabolites were upregulated in cows that were cured and in cows that received treatment and were cured, respectively. In all scenarios, the metabolites lignoceric, malic, and maleic acids, ornithine, and hypotaurine, which are associated with arginine/aminoacyl-tRNA biosynthesis and taurine/purine metabolism, were upregulated in HTH cows. Metritis was associated with changes in the uterine metabolome. Cows not being cured of metritis had changes in the uterus metabolome independent of receiving ceftiofur or remaining untreated. Metabolome analysis may be an important tool to understand the vaginal discharge changes during postpartum and the dynamics of metritis development and cures and help to identify biomarkers to predict metritis being cured.

Dairy farmworkers are commonly responsible for disease diagnosis and routine treatment decisions for cattle. This highlights the importance of farmworkers' knowledge and skills to successfully implement judicious use of antimicrobials in livestock production systems. The main objectives of this project were to develop and evaluate an on-farm educational program for farmworkers in antimicrobial stewardship in adult dairy cattle. A longitudinal quasi-experimental study design was used, by enrolling 12 conventional dairy farms in the United States (6 in California and 6 in Ohio). Farmworkers responsible for treatment decisions on the farm (n = 25) participated in a didactic and hands-on 12-wk antimicrobial stewardship training program led by the investigators. All antimicrobial stewardship training materials were available in Spanish and English. Interactive short videos with audio were developed to cover the learning objectives for each of the 6 teaching modules: antimicrobial resistance, treatment protocols, visual identification of sick animals, clinical mastitis, puerperal metritis, and lameness. Pre- and post-training assessments were administered using an online training assessment tool to evaluate changes in knowledge and attitudes about antimicrobial stewardship practices. Cluster analysis and multiple correspondence analyses were conducted to evaluate the association among categorical variables for participants' level of change in knowledge and its association with language, farm size, and state. A 32% average increase in knowledge was observed through an assessment conducted after completing the antimicrobial stewardship training, compared with the pre-training assessment. A significant improvement in 7 of 13 attitude questions related to antimicrobial stewardship practices on the farm was observed. Knowledge and attitude scores of participants on antimicrobial stewardship and identification of sick animals significantly improved after completing the antimicrobial stewardship training. The results observed in this study support the relevance of antimicrobial stewardship training programs targeting farmworkers to improve antimicrobial drug use knowledge and skills., (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 goals of this study were to evaluate factors affecting recovery and antimicrobial resistance (AMR) in intrauterine E. coli in post-partum dairy cows with and without metritis from commercial California dairy farms. Using a cross-sectional study design, a total of 307 cows were sampled from 25 farms throughout California, from which a total of 162 intrauterine E. coli isolates were recovered. During farm visits, cows within 21 days post-partum were categorized in one of three clinical presentation groups before enrollment: metritis (MET, n = 86), defined as a cow with watery, red or brown colored, and fetid vaginal discharge; cows with purulent discharge (PUS, n = 106), defined as a non-fetid purulent or mucopurulent vaginal discharge; and control cows, (CTL, n = 115) defined as cows with either no vaginal discharge or a clear, non-purulent mucus vaginal discharge. Cows diagnosed as MET had significantly higher odds for recovery of E. coli compared to cows diagnosed as CTL (OR = 2.16, 95% CI: 1.17-3.96), with no significant difference observed between PUS and CTL, and PUS and MET. An increase in days in milk (DIM) at the time of sampling was significantly associated with a decrease in the odds ratio for E. coli recovery from intrauterine swabs (OR = 0.94, 95% CI: 0.89-0.98). All intrauterine E. coli were resistant to ampicillin (AMP), with an AMR prevalence of 30.2% and 33.9% observed for chlortetracycline and oxytetracycline, respectively. Only 8.6% of isolates were resistant to ceftiofur (CEFT), one of the most common drugs used to treat cows on farms sampled. No significant difference in the prevalence of AMR was observed among clinical groups at the individual cow level. At the farm level, a significantly higher odds for isolating intrauterine E. coli resistant to chlortetracycline (OR: 2.6; 95% CI: 3.7-58.0) or oxytetracycline (OR: 1.9; 95% CI: 1.4-33.8) was observed at farms that used an intrauterine infusion of oxytetracycline as a treatment for metritis when compared to those farms that did not use this practice. Findings from this study indicate the need for further research supporting a broader understanding of farm practices driving AMR in cows with metritis, as well as data to increase the accuracy of breakpoints for AMR classification of intrauterine E. coli from cattle., (© 2022. The Author(s).)

Although puerperal metritis (PM) is a common infectious disease in dairy cattle, there are currently discrepancies between clinical case definitions within and between available peer-reviewed literature and on-farms practices. The inconsistent use of PM criteria across studies and on-farms practices can result in disparities related to recommendations for treating cows, affecting judicious use of antimicrobials. The objective of this study was to systematically review the peer-reviewed literature for clinical signs used for case definition of PM. The criteria used included local (e.g., vaginal discharge) and systemic clinical signs of infection (e.g., fever, drop in milk). The Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews protocols were used to screen commonly used databases. Following this protocol, one reviewer screened title and abstract for eligibility (n = 2,096), followed by full-text screening of selected articles (n = 396) by 2 reviewers to confirm eligible articles (n = 174). The most frequently cited reference article (37.5%) for the definition of PM was published in 2006, followed by articles published between 1998 and 2009 (13%). In 40.2% of articles, no reference was provided for definition of PM; vaginal discharge was described in terms of color, odor, and viscosity when related to the PM definition. Terms used for description of vaginal discharge color were red-brown (61.4%), red (5.1%), brown (8.6%), chocolate (4%), white (1.7%), yellow (0.5%), pink (5.7%), or gray (0.5%); vaginal discharge color was not reported in 24.1% articles. The vaginal discharge odor was described as fetid (75.8%), putrid (5.1%), foul (10.3%), or other (5.7%; e.g., abnormal, malodorous, odoriferous); odor was not mentioned in 7.4% of articles. The vaginal discharge viscosity was described as watery (74.1%), purulent (27%), mucopurulent (8.6%), thin (4%), serous (2.8%), or abnormal (2.3%) and was not mentioned in 11.5% of articles. Fever was included in 59.7% of articles as a criterion for PM diagnosis. The most used rectal temperature threshold was ≥39.5°C (56.8%), followed by ≥39.2°C (2.8%). Approaches used for vaginal discharge evaluation included rectal palpation (37.3%), intravaginal exploration with a gloved hand (18.4%), Metricheck (9.8%), or speculum (5.7%); and in 28.7% of articles, diagnostic tools used were not mentioned. Many of the color and odor vaginal discharge descriptions observed in the literature, used synonymous words to describe the same vaginal discharge sample, highlighting a lack of terminology consensus that could result in disagreements, especially due to the subjective character of these clinical evaluations of vaginal discharge color and odor. Although select consensus articles are available, it is common for studies to disregard a reference when defining PM cases. Furthermore, our findings highlight the need for a robust and clear consensus on criteria and terminology used to diagnose PM., (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/).)

Objective: We intend to study tuberculosis (TB) in one of the poorest communities in the US, hired agriculture workers, for most recent years (2000 to 2012) including the last recession period., Methods: Time-chart, simple mean differences, and logistic regressions were used to describe TB-prevalence and risk factors among US crop-workers. Data were drawn from the National Agricultural Workers Survey (NAWS)., Results: A high TB-prevalence was found among crop-workers with a dramatically increasing trend in recent years. Hispanic ethnicity, having farmworker family members, the presence of health insurance, and good spoken English were associated with an increased TB-prevalence., Conclusion: We found risk factors related to ethnicity and poor access to health care, a strong association between agriculture activity and TB, and an increase of TB-cases due to the 2008 downturn in this underserved population. We urge the health authorities to control this epidemic.

Fertility of dairy cows has decreased for the past several decades. Measures of energy balance (EB; e.g., change in EB, EB nadir, cumulative negative EB, or duration of negative EB) are related to reproductive performance. Our research group has concluded that modification of diets fed during the dry or transition period are unlikely to have significant effects on postpartum EB and fertility. Rather, more radical alterations in dairy management are needed if energy status of postpartum cows is to be improved. We have examined the potential to alter EB by shortening or eliminating the dry period. In an initial study, the effects of a 56, 28, and 0 d dry period on ovarian dynamics and reproductive performance of dairy cows were examined. Postpartum EB was improved by reducing the dry period; however, only significantly for the 0 d dry period. Cows on the 0 d dry period did not experience negative EB. Improvements in EB were a reflection of lower milk production and greater feed intake. Consistent with the improvements in EB, time to first ovulation and first service, first service conception rate, services per conception, and days open were all improved by reduction of dry period length. Because small animal numbers were used in the study, a second study was conducted on a commercial dairy with many more animals to determine if results from the initial trial could be duplicated. A comparison was made between a 55 and 34 d dry period. Shortening the dry period resulted in fewer days to first ovulation, fewer days open, and a greater percentage of cows pregnant at 150 days in milk, although the improvements in the latter two variables were only significant for cows in their third or greater lactation. A current study is being performed in a large commercial dairy to examine the effects of eliminating the dry period on reproduction utilizing a large commercial dairy.