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The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The onset of lactation is characterized by marked increases in calcium (Ca) metabolism. Recently emphasis was placed on understanding the profile and dynamics of blood Ca and serotonin in the peripartal cow in response to this change using a randomized 2 × 2 factorial design. The aims of our study were to determine (1) how a prepartum DCAD diet and the magnitude of Ca decline at the onset of lactation alter circulating blood serotonin and ionized Ca concentration dynamics in the periparturient cow, and (2) the relationship of Ca versus serotonin during the peripartal period. Thirty-two multiparous Holstein cows were blocked by parity (2 vs. >2) to ensure equal parity number across the experiment, previous 305 d milk yield, and expected parturition date and randomly allocated to positive (+120 mEq/kg; +DCAD) or negative (−120 mEq/kg; −DCAD) DCAD diets from 251 d of gestation until parturition (n = 16/diet). Immediately after calving cows were continuously infused for 24 h with (1) an intravenous solution of 10% dextrose or (2) Ca gluconate (CaGlc) to maintain blood ionized Ca concentrations at 1.2 m M (normocalcemia), forming the following 4 treatment groups: negative DCAD and CaGlc (NCa), negative DCAD and dextrose (NDex), positive DCAD and CaGlc (PCa), and positive DCAD and dextrose (PDex; n = 8/treatment). Blood was sampled every 6 h from 102 h before parturition until 96 h postparturition. During the continuous infusion period (the 24 h immediately following parturition) cows were sampled every 30 min. Cows fed a −DCAD diet prepartum had greater circulating serotonin concentrations pre- and postpartum. Time series analyses demonstrated that the pooled mean effect size (ES) of the relationship between ionized Ca and serotonin 36 h before parturition was significantly positive (ES = 0.164) prepartum. We also observed that the overall pooled mean ES of the relationship between prepartum blood pH 24 h prior and serotonin was significantly positive (ES = 0.111); however, for individual treatment groups, relationships were identified between blood pH and serotonin 18 and 6 h before only for the NDex group. Our data suggest that serotonin is an important factor in the regulation of Ca homeostasis during the prepartal period and that the mechanism may be integrated with blood pH. [ABSTRACT FROM AUTHOR]

Simple Summary: Prepartum vaccinations of cows are performed to boost colostral antibodies available to calves in the first weeks of life. While beneficial effects of the vaccine for calves are well known, less has been investigated on its effects on the cow during the sensitive period around calving. There is evidence that vaccines have non-specific effects, including altered susceptibility to infectious diseases other than the targeted pathogens and involve the innate immune response of the vaccinated animal. Therefore, this study analyzed data from 73,378 cows on 20 farms in Germany to evaluate the effects of prepartum vaccination against neonatal calf diarrhea on mastitis, somatic cell count, and milk production. The results demonstrated that herd management had the highest influence, while prepartum vaccination had no significant impact on mammary health and milk yield. These findings suggest that prepartum vaccination does not compromise mammary health or milk productivity. Further research is recommended to explore non-specific vaccine effects on other organ systems, diseases, and production metrics in dairy cows. Prepartum vaccinations against neonatal calf diarrhea pathogens are administered in late pregnancy to provide passive immunity to calves through protective colostral antibodies. Potential non-specific effects of the vaccine on maternal innate immune responses and disease susceptibility during the sensitive transition period have not been addressed so far. In this retrospective study, data from 73,378 dairy cows on 20 farms in Germany were analyzed, using linear mixed-effects regression, quantile regression, and decision-tree-algorithms, to investigate the effects of prepartum vaccination on mammary health and milk yield by comparing non-vaccinated and vaccinated transition periods. Herd management-related factors were found to be most influential for mammary health and milk yield. Vaccinated cows were not significantly more likely to develop mastitis and did not have significantly different somatic cell counts and milk yields compared to non-vaccinated cows. Healthy primiparous cows with and without vaccination had similar energy-corrected milk yields. The study concludes that prepartum vaccination against calf diarrhea has no significant effects on mammary health and milk yield. Further research is recommended to investigate potential non-specific vaccine effects on other organ systems, infectious diseases, and production metrics of the dairy cow. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to investigate the effect of increasing MP supply in the prepartum, postpartum, or both diets on intake, performance, and metabolic indicators. Multiparous Holstein cows (n = 96) were assigned to 1 of 4 treatment groups at 28 d before expected calving following a randomized block design. Prepartum diets were formulated to contain either a control (CON; 85 g of MP/kg DM) or high (HI; 113 g of MP/kg DM) level of estimated MP. From calving to 21 DIM, diets were formulated to contain either a CON (104 g of MP/kg DM) or HI (131 g of MP/kg DM) level of estimated MP. To control the potential confounding effect of Met and Lys supply, diets were formulated to supply an equal amount at 1.24 and 3.84 g/Mcal of ME in both prepartum diets and 1.15 and 3.16 g/Mcal of ME in both postpartum diets, respectively. The combination of a pre- and postpartum diet resulted in 4 treatment groups: (1) CON-CON (CC; n = 23), (2) CON-HI (CH; n = 24), (3) HI-CON (HC; n = 22), and (4) HI-HI (HH; n = 23). A common lactation diet (113 g of MP/kg DM) was fed from 22 DIM to the end of the observation period at 42 DIM. Milk yield and DMI were collected daily, and plasma metabolic indicators (BHB, fatty acids [NEFA], PUN, and glucose) were determined twice weekly from −28 to 28 d relative to calving and once weekly from 29 to 42 DIM. Samples with BHB ≥1.2 mmol/L between 3 and 10 DIM were considered hyperketonemia events. Milk composition was determined weekly. Milk yield during 1 to 21 DIM was greater in HH (44.7 ± 1.0 kg/d) compared with CC (39.2 ± 1.0 kg/d) and HC (38.0 ± 1.0 kg/d) and milk yield in CH (42.4 ± 0.9 kg/d) was greater than HC, respectively. From 22 to 42 DIM, milk yield was greater in CH (53.3 ± 1.0 kg/d) and HH (54.1 ± 1.0 kg/d) compared with CC (49.6 ± 1.0 kg/d) and HC (49.3 ± 1.0 kg/d). Dry matter intake (% of BW) and concentrations of milk protein, fat, and total solids were not affected by treatment. Prepartum concentrations of PUN were greater in HI compared with CON. From 1 to 21 DIM, PUN concentrations were greater in CH and HH compared with CC and HC. From 1 to 21 DIM, concentrations of glucose were lower in HH compared with HC, and BHB were greater in CH and HH compared with HC. Concentrations of NEFA, as well as the number of hyperketonemia events did not differ by treatment during this time. From 22 to 42 DIM, concentrations of NEFA were greater in HH compared with HC and concentrations of BHB were greater in CH and HH compared with HC. Overall, feeding CH or HH increased lactation performance without altering intake or hyperketonemia events. Results from this study support formulating a fresh diet to reduce the negative MP balance during early lactation. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. This study aimed to evaluate the effects of dietary supplementation with different types of Saccharomyces cerevisiae fermentation products (SCFP) on lactational performance, metabolism, acute phase protein response, and antioxidant capacity in dairy cows from −21 to 56 DIM. A total of 180 multiparous Holstein dairy cows were blocked by parity, expected calving date, pre-trial BCS, and previous 305-d mature-equivalent milk yield, and then randomly assigned to 1 of 3 dietary treatments: the basal control diet (CON; n = 60), the basal diet supplemented with 40 g/d of XPC (XPC; n = 60; Diamond V, Cedar Rapids, IA), and the basal diet supplemented with 19 g/d of NutriTek (NTK; n = 60, Diamond V). Blood (n = 15, 13, and 12 in the CON, XPC, and NTK groups, respectively) was sampled at −7 (± 3), +3, +7, +21, and +28 d, and milk (n = 19, 18, and 15 in the CON, XPC, and NTK groups, respectively) was sampled from 1 to 8 wk from a subset of cows from −21 to 56 d relative to calving. Data were analyzed using the MIXED procedure in SAS (SAS Institute Inc.). All data were subjected to repeated measures ANOVA. Dietary treatment (Trt), time, and their interaction (Trt × time) were considered as fixed effects and cow as the random effect. Cows fed XPC and NTK had greater ECM yield. Supplementing NTK increased milk fat content and yield and 3.5% FCM yield compared with CON. Milk urea nitrogen was lower in XPC cows than CON. We found that SCFP supplementation decreased plasma BHB, ceruloplasmin, haptoglobin (HPT), and IL-1β concentrations, and it increased plasma P concentrations. In addition, cows fed NTK showed lower creatinine (CR) and cortisol concentrations but increased plasma Ca and myeloperoxidase concentrations than CON cows. In addition, cows fed NTK and XPC both had reduced plasma concentrations of serum amyloid-A (SAA) at 3 DIM compared with CON cows. Furthermore, SCFP cows had greater concentrations of plasma glucose and Ca than CON cows at 7 DIM, and greater concentrations of plasma P at 21 DIM. Between the groups fed different types of SCFP, plasma concentrations of nonesterified fatty acids, malondialdehyde, CR, SAA, and HPT were lower in cows fed NTK compared with cows fed XPC at 7 DIM. Overall, our results indicate the potential benefits of supplementing SCFP in transition dairy cows by modulating immunity and liver metabolic function and supporting ECM yield. The results also suggest that NutriTek at 19 g/d appears to support the performance and health of dairy cows better compared with XPC at 40 g/d, based on improved metabolic and inflammatory status during the transition period. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the effects of supplementing early-lactation cows with a dry pure glycerol product, delivered through the automated milking system (AMS) concentrate, in the first 21 DIM on metabolic markers, milking behavior, and milk production. In 5 commercial AMS dairy herds, 389 dairy cows were randomly assigned, controlling for parity, 21 d before expected calving to 1 of 2 treatments, within farm: (1) the control group (CON) which received the standard AMS pellet (n = 213) from 1 to 150 DIM; or (2) the glycerol group (GLY), which received the treatment AMS pellet (n = 176) formulated to additionally deliver 250 as fed g/d of glycerol product from 1 to 21 DIM, followed by the standard AMS pellet from 22 to 150 DIM. Across all farms, cows were fed partial mixed rations that were similar in ingredient and nutrient composition. One prepartum blood sample and 5 postpartum blood samples were collected from each cow to determine serum nonesterified fatty acids (NEFA), blood BHB, and blood glucose concentrations. Cow BCS was recorded every 21 d from −21 to 63 DIM. Data were collected and analyzed for the treatment period (1–21 DIM) and a follow-up period (22–150 DIM). We detected no treatment effect on serum NEFA concentrations in the first week of lactation. We detected a treatment by time interaction for blood BHB and blood glucose, where GLY cows tended to have increased BHB concentrations at 5 DIM and had decreased glucose concentrations at 9 and 12 DIM. We detected an interaction of BCS with treatment on the incidence of BHB ≥1.2 mmol/L, whereby over-conditioned CON cows (BCS ≥3.5) were 3.5 times more likely to have a high BHB test than CON cows with normal prepartum BCS. During the treatment period, GLY cows had 0.1 ± 0.05 more successful milkings per day, were delivered 0.27 ± 0.05 DM kg/d more AMS concentrate, and tended to yield 0.8 ± 0.47 kg/d more milk. During the follow-up period, GLY cows had 0.1 ± 0.04 more successful milkings per day, were delivered 0.18 ± 0.06 DM kg/d more AMS concentrate, and yielded 1.5 ± 0.53 kg/d more milk than CON cows. Glycerol supplementation allowed cows to maintain better BCS, as GLY cows lost less BCS from calving to 63 DIM than CON cows. Overall, the results of this study demonstrate that supplementing pure glycerol through the AMS concentrate for the first 21 DIM can reduce BCS loss in early lactation, improve milking behavior, and increase milk yield to mid-lactation. The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. [ABSTRACT FROM AUTHOR]

Although dietary phosphorus (P) deprivation extending from the dry period into early lactation impairs health and productivity of cows, restricting dietary P supply during the dry period not only appears to be innocuous but rather effectively mitigates hypocalcemia during the first wk of lactation. To investigate possible negative metabolic effects of P deprivation during the dry period, the present study tested the hypothesis that restricted dietary P supply during the dry period alters the liver transcriptome of dairy cows during the periparturient period. Thirty late-pregnant multiparous Holstein-Friesian dairy cows entering their second, third, or fourth lactation were assigned to either a dry cow ration with low (LP, 0.16% P in DM) or adequate P content (AP, 0.35% in DM) during the last 4 wk of the dry period (n = 15/group). Liver transcriptomics, which was carried out in a subset of 5 second-parity cows of each group (n = 5), and determination of selected hormones and metabolites in blood of all cows, was performed ∼1 wk before calving and on d 3 postpartum. Liver tissue specimens and blood samples were obtained by a micro-invasive biopsy technique from the right tenth intercostal space and puncture of a jugular vein, respectively. One hundred seventy-five hepatic transcripts were expressed differentially between LP versus AP cows in late pregnancy, and 165 transcripts differed between LP versus AP cows in early lactation (fold change >1.3 and <−1.3, P < 0.05). In late pregnancy, the enriched biological processes of the upregulated and the downregulated transcripts were mainly related to immune processes and signal transduction (P < 0.05), respectively. In early lactation, the enriched biological processes of the upregulated and the downregulated transcripts were involved in mineral transport and biotransformation (P < 0.05), respectively. The plasma concentrations of the hormones and acute-phase proteins (progesterone, insulin-like growth factor 1, serum amyloid α, haptoglobin, and 17β-estradiol) determined were not affected by P supply. These results suggest that P deprivation during the dry period moderately affects the liver transcriptome of cows in late pregnancy and early lactation, and causes no effects on important plasma hormones and acute-phase proteins indicating no obvious impairment of health or metabolism of the cows. [ABSTRACT FROM AUTHOR]

The onset of lactation is characterized by substantially altered calcium (Ca) metabolism; recently, emphasis has been placed on understanding the dynamics of blood Ca in the peripartal cow in response to this change. Thus, the aim of our study was to delineate how prepartum dietary cation-anion difference (DCAD) diets and the magnitude of Ca decline at the onset of lactation altered blood Ca dynamics in the periparturient cow. Thirty-two multiparous Holstein cows were blocked by parity, previous 305-d milk yield and expected parturition date, and randomly allocated to either a positive (+120 mEq/kg) or negative (−120 mEq/kg) DCAD diet from 251 d of gestation until parturition (n = 16/diet). Immediately after parturition cows were continuously infused for 24 h with (1) an intravenous solution of 10% dextrose or (2) Ca gluconate (CaGlc) to maintain blood ionized (iCa) concentrations at ∼1.2 m M (normocalcemia) to form 4 treatment groups (n = 8/treatment). Blood was sampled every 6 h from 102 h before parturition until 96 h after parturition and every 30 min during 24 h continuous infusion. Cows fed a negative DCAD diet prepartum exhibited a less pronounced decline in blood iCa approaching parturition with lesser magnitude of decline relative to positive DCAD-fed cows. Cows fed a negative DCAD diet prepartum required lower rates of CaGlc infusion to maintain normocalcemia in the 24 h postpartum relative to positive DCAD-fed cows. Infusion of CaGlc disrupted blood Ca and P dynamics in the immediate 24 h after parturition and in the days following infusion. Collectively, these data demonstrate that prepartum negative DCAD diets facilitate a more transient hypocalcemia and improve blood Ca profiles at the onset of lactation whereas CaGlc infusion disrupts mineral metabolism. [ABSTRACT FROM AUTHOR]

Recent studies have shown that cows with subclinical hypocalcemia (SCH) at 4 d in milk (DIM), regardless of their blood Ca concentration before that time point, suffer from an increased early-lactation disease risk and reduced milk yield, whereas cows experiencing a transient reduction in blood Ca that regain normocalcemia by 4 DIM are at a reduced risk of disease and have greater milk yields. With a goal of improving outcomes for dyscalcemic cows with SCH at 4 DIM, our primary objective was to assess the effect of a herd-level oral Ca bolus strategy that delayed supplementation to 24 and 48 h postpartum on productive performance of multiparous Holstein cows. Our secondary objectives were to assess the effects of delayed Ca bolus supplementation on blood Ca concentration, disease incidence within 30 DIM, and pregnancy risk to first service. At calving, multiparous cows on a single commercial dairy farm in Iran were randomly assigned to 1 of 3 treatment groups: (1) control, no Ca bolus administration (CON; n = 95); (2) traditional bolus, one Ca bolus administered immediately following calving and a second Ca bolus administered 24 h after calving (TRD, n = 102); or (3) experimental bolus, one Ca bolus administered 24 h after calving with a second Ca bolus administered 48 h after calving (EXP, n = 99). Blood samples were collected at 0, 24, 48, 72, and 96 h, and 7 d after parturition, with sampling occurring before bolus administration for the TRD (0 and 24 h) and EXP (24 and 48 h) groups. A general linear mixed model was created to analyze the change milk yield over the first 4 monthly tests and serum Ca concentrations over 7 DIM. Given the lack of disease events diagnosed within 30 DIM, no statistical analysis was conducted for this outcome. The effect of treatment group on risk of pregnancy to first service was assessed using Poisson regression. The incidence of dyscalcemia within CON cows was 72%. We found no difference in mean monthly milk yield among treatment groups across the first 4 tests, with an average monthly production of 51.8 ± 8.8 kg/d for CON cows, 52.5 ± 8.7 kg/d for TRD cows, and 51.8 ± 8.7 kg/d for EXP cows. Mean blood Ca concentration also did not differ across 7 DIM among treatment groups and was 2.04 mmol/L [95% confidence interval (CI) = 2.00 to 2.07 mmol/L] for CON cows, 2.06 mmol/L (95% CI = 2.03 to 2.09 mmol/L) for TRD cows, and 2.09 mmol/L (95% CI = 2.05 to 2.12 mmol/L) for EXP cows. The risk of pregnancy to first service was numerically greater for CON than TRD and EXP cows but not statistically different; however, our study was underpowered for this outcome. Under the conditions of our study, our findings suggest that delaying oral Ca bolus supplementation to 24 and 48 h postpartum has no effect on milk production across the first 4 monthly tests. [ABSTRACT FROM AUTHOR]

The objective was to determine whether replacing a portion of inorganic chloride trace minerals and cobalt carbonate in the diet with AA complexes of trace minerals and cobalt glucoheptonate will improve lactating cow performance, feed efficiency, and calf performance. In a clinical trial, 69 Holstein cows entering second lactation and greater were randomly assigned to 1 of 2 treatments, with the total dietary trace mineral concentration the same between treatments, starting 1 wk after dry off (50 to 57 d before expected parturition) until 154 d in milk (DIM): (1) an inorganic chloride trace mineral (ITM) blend consisting of Zn (75 mg/kg), Mn (65 mg/kg), and Cu (10 mg/kg) as hydroxychlorides and Co (1 mg/kg) as carbonate (n = 37) or (2) partial replacement of ITM with AA complexes of Zn (40 mg/kg), Mn (20 mg/kg), and Cu (3.5 mg/kg) and Co glucoheptonate (1 mg/kg; AATM; Availa-Dairy, Zinpro Corp.; n = 32). Dry matter intake (DMI) was recorded daily from enrollment through wk 8, and milk yields were recorded daily from calving through wk 22. Milk composition and body weights (BW) were collected weekly. Serum samples were analyzed for albumin (Alb), cholesterol (Chol), total bilirubin (Bili), aspartate aminotransferase (AST), haptoglobin, β-hydroxybutyrate (BHB), and Ca. A liver health index (LHI) was calculated based on Bili, Chol, and Alb concentrations. A liver functionality index (LFI) was calculated to standardize changes in Alb, Chol, and Bili from 4 to 29 DIM. Greater LHI and LFI indicate better health status. Colostrum was analyzed for IgG and Brix, and calf serum was analyzed for IgG. Calf growth was monitored through 9 wk of age (AATM: n = 12, ITM: n = 10). Data were analyzed using SAS software with mixed effects models and repeated-measures analysis, when applicable. Survival analysis for pregnancy by 154 DIM was analyzed by Cox proportional and Kaplan-Meier hazards models. Disorder incidence was tested with Fisher's exact test. Prepartum DMI as a percent of BW was lower in cows fed AATM and not significant postpartum. Cows fed AATM produced more milk from wk 1 to 8 and from wk 1 to 22. Energy-corrected milk yield and colostrum measures did not significantly differ between treatments. A treatment by time interaction was seen for AST and BHB; cows fed AATM tended to have lower AST concentrations at 28 DIM and lower concentrations in BHB through 29 DIM, though not statistically significant. Cows fed AATM had greater LHI at 4 DIM. Haptoglobin, Ca, LFI, hazard of pregnancy, risk to first service, survival curves, or services per pregnancy did not significantly differ. Calf serum IgG and birth weight did not significantly differ between treatments. Calves from dams fed AATM had greater average daily gain than calves from dams fed ITM. Overall, cows fed AATM during the dry period and early lactation had improved postpartum performance and potential health improvements. [ABSTRACT FROM AUTHOR]

Our previously published paper demonstrated that fermented ammoniated condensed whey (FACW) supplementation improved feed efficiency and metabolic profile in postpartum dairy cows. The objective of this study was to further explore the effects of FACW supplementation on liver triglyceride content, hepatic gene expression and protein abundance, and plasma biomarkers related to liver function, inflammation, and damage. Individually fed multiparous Holstein cows were blocked by calving date and randomly assigned to postpartum (1 to 45 d in milk, DIM) isonitrogenous treatments: control diet (n = 20) or diet supplemented with FACW (2.9% dry matter of diet as GlucoBoost; Fermented Nutrition, Luxemburg, WI, replacing soybean meal; n = 19). Liver biopsies were performed at 14 and 28 DIM for analysis of mRNA expression, protein abundance, and liver triglyceride content. There was marginal evidence for a reduction in liver triglyceride content at 14 DIM in FACW-supplemented cows compared with the control group. Cows supplemented with FACW had greater mRNA expression of glucose-6-phosphatase at 14 DIM relative to control. Supplementation with FACW increased mRNA expression of pyruvate carboxylase (PC), but did not alter cytosolic phosphoenolpyruvate carboxykinase (PCK1), resulting in a 2.4-fold greater PC:PCK1 ratio for FACW-supplemented cows compared with control. There was no evidence for a FACW effect on mRNA expression of propionyl-CoA carboxylase nor on mRNA expression or protein abundance of lactate dehydrogenase A or B. Cows supplemented with FACW had lower plasma urea nitrogen compared with control. Plasma l -lactate was greater for FACW-supplemented cows compared with control at 2 h before feeding time at 21 DIM. There was no evidence for altered expression of IL1B or IL10 , or blood biomarkers related to liver function and damage. Greater glucose-6-phosphatase and PC gene expression, together with greater blood glucose and similar milk lactose output, suggests that FACW increased the supply of glucose precursors, resulting in greater gluconeogenesis between 3 and 14 DIM. Greater hepatic PC:PCK1 ratio, together with previously reported decreased plasma β-hydroxybutyrate and the marginal evidence for lower liver triglyceride content at 14 DIM, suggests greater hepatic capacity for complete oxidation of fatty acids in FACW-supplemented cows compared with control. Overall, improvements in metabolite profile and feed efficiency observed with postpartum supplementation of FACW may be attributed to increased gluconeogenic and anaplerotic precursors, most likely propionate, due to modulated rumen fermentation. [ABSTRACT FROM AUTHOR]

Our objectives were to assess the effects of a diet with a negative dietary cation-anion difference (DCAD) before calving on phagocytosis (Pc) and oxidative burst (OB) function of circulating neutrophils, and to determine the associations of serum ionized (iCa) and total calcium (tCa) concentrations with Pc and OB in transition dairy cows. We hypothesized that multiparous cows fed a negative DCAD diet prepartum would have greater iCa and tCa, and thus improved Pc and OB. From 3 wk before expected parturition until calving, 38 healthy multiparous cows from 3 farms were assigned to negative DCAD treatment (TRT; −100 mEq/kg of diet dry matter; n = 21) or a control (CON; 95 mEq/kg of dry matter; n = 17) diet. Each farm was on one treatment or the other at a time, but all farms contributed cows to both groups. Urine pH was measured weekly and in TRT was 6.1 ± 0.8 with 80% of 50 samples <7 and 74% ≤ 6.5. Phagocytosis, OB, iCa, and tCa were measured at d −7, 1, and 4 relative to calving. Median fluorescence intensity for Pc (MFIP) and OB (MFIOB), and the shift of percentage of cells active for Pc (PPc) and OB (POB) were measured in isolated, stimulated neutrophils via flow cytometry. Outcomes were assessed with mixed linear regression models accounting for repeated measures. There were no differences between treatments in the 4 neutrophil function outcomes. Although MFIOB varied over time, there were no interactions of treatment with time for any outcome. Serum ionized and tCa did not differ between TRT and CON. The least squares means ± standard deviation for iCa were: d −7, 1.23 ± 0.12 vs. 1.21 ± 0.12; d 1, 1.07 ± 0.12 vs. 1.02 ± 0.12; d 4, 1.16 ± 0.12 vs. 1.17 ± 0.12 mmol/L for TRT and CON, respectively; and for tCa: d −7 2.39 ± 0.25 vs 2.44 ± 0.31; d 1, 2.01 ± 0.25 vs 1.97 ± 0.31; d 4, 2.33 ± 0.25 vs 2.32 ± 0.31 mmol/L, respectively. The proportion of blood samples with tCa <2.15mmol/L at d −7, 1 and 4 was 5, 76, and 13%, respectively, with no differences between TRT and CON. Correlations of iCa or tCa with each of the 4 polymorphonuclear leukocyte (PMN) function outcomes were weak (r < |0.3|). We did not observe the hypothesized differences in aspects of innate immunity in clinically healthy multiparous cows fed a negative DCAD. We underline that cows that experienced clinical disease were excluded from this study, which is important for interpretation of the results. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to examine production performance responses to feeding rumen-protected choline (RPC) or methionine (RPM), or both, during the periparturient period. Fifty-four Holstein cows (25 primiparous, 29 multiparous) were used in a randomized block design experiment with a 2 × 2 factorial treatment structure. Cows were blocked by expected calving date and parity and assigned to 1 of 4 treatments: CON (no RPC or RPM); RPC (13.0 g/d of choline ion); RPM (9 g/d of dl -methionine prepartum; 13.5 g/d of dl -methionine postpartum); or RPC + RPM. Treatments were applied once daily as a top-dress from 3 wk before through 5 wk after calving. Dry matter intake and milk production were recorded daily, and milk samples were obtained once weekly. Data were analyzed for primi- and multiparous cows separately, using a repeated-measures mixed model that included random effects of cow and block and fixed effects of RPC, RPM, week, and their interactions; week served as the repeated effect. Initial BW and previous lactation milk yield were included as covariates in the statistical model for multiparous cows. Feeding RPC without RPM increased milk yield for multiparous cows by 8.7 kg/d, but this increase was not observed when RPC was fed with RPM. In multiparous cows, feeding RPM increased milk fat concentration and tended to increase milk fat yield. Because of this, RPM increased fat-corrected milk (FCM) by 2.8 kg/d at wk 2 postpartum, and this increase was sustained through wk 5 postpartum. In contrast, RPM did not affect overall milk fat yield and concentration for primiparous cows. Feeding RPC increased milk yield for primiparous cows by 3.5 kg/d irrespective of RPM inclusion, which is contrary to observations in multiparous cows, where RPC increased milk yield only in the absence of RPM. These results indicate that responses to RPC during the periparturient period may be dependent upon supply of methionine. Our observations also demonstrate that primi- and multiparous cows respond differently to RPC and RPM supplemented individually or simultaneously during the periparturient period. This variation in response could have been mediated by putative differences in choline and methionine requirements of primiparous versus multiparous cows, or by differences in the levels of milk production between the 2 groups (36 vs. 25 kg of FCM/d). However, cows in this study did not experience severe negative energy balance (mean nadirs of −6.6 and −5.0 Mcal/d for multiparous and primiparous cows, respectively), which likely affected their responses to RPC and RPM. [ABSTRACT FROM AUTHOR]

Regrouping occurs when dairy cows are moved between pens, and this can negatively affect cow behavior and production. Pen changes occur frequently around calving, a time when cows are vulnerable to health problems. Regrouping cows along with a familiar conspecific after calving may make social integration easier, but little work has tested this hypothesis. The objective of this study was to compare lying behavior, feeding behavior, social behavior, and fecal cortisol metabolite concentrations (a physiological indicator of stress) between cows regrouped individually and cows regrouped with a familiar partner after calving. Holstein (n = 8) and Jersey (n = 26) cows were monitored from approximately 2 wk before until 7 d after calving. Cows were held in 1 of 2 identical maternity pens until they calved. After calving, cows were held in a transition pen for 3 d before being regrouped into the main lactation pen (regrouping of interest). On d 3 postpartum, cows were assigned to a treatment, balancing for parity and breed: regrouped into the lactation pen alone (individual; n = 17) or with a familiar partner (paired; n = 17). A familiar partner was defined as a cow that spent 3 d in the transition pen with the focal cow. Using live observation, we quantified the time cows spent feeding, standing or lying in the lying stalls, grooming, and standing in different locations in the pen during the 1 h immediately after regrouping. The frequency of competitive interactions at the feed bunk was also measured during this observation period. Lying behavior was monitored from 2 d before until 5 d after regrouping using a data logger. Fecal samples were collected for 5 d beginning on the day of regrouping to assess fecal cortisol metabolite concentrations (11,17-dioxoandrostane, 11,17-DOA). We found no effects of regrouping treatment on behaviors observed during the 1-h period immediately following regrouping. Cows that were regrouped with a partner had more lying bouts than cows moved individually (9.2 ± 0.4 bouts/d vs. 7.5 ± 0.4 bouts/d) and shorter lying bout durations (66.6 ± 3.9 vs. 78.1 ± 3.5 min/d); however, we also observed these differences during the day before regrouping, suggesting that the differences in lying behavior could not be explained by the regrouping treatment alone. Individually regrouped primiparous cows had higher 11,17-DOA concentrations than individually regrouped multiparous cows but we found no differences in 11,17-DOA between parities when cows were moved with a familiar partner. In addition, 11,17-DOA was higher in primiparous cows moved alone compared with primiparous cows moved with a partner. More research is needed to understand the mechanisms by which social familiarity affects behavior and the physiological stress response following regrouping; this may provide new insight into how to better transition cows into new environments. [ABSTRACT FROM AUTHOR]

Vitamin D supports several physiological functions, from mineral homeostasis to immune activity. The aim of this study was to provide 25-hydroxyvitamin D3 [25(OH)D3] to late gestation and early lactation dairy cows and evaluate the impact on lactational performance. Holstein cows (n = 100) that finished their first or greater lactation were enrolled in a randomized block design with a 2x2 factorial arrangement of treatments (n = 25 cows per treatment group). Prepartum treatments were 0 or 3 mg of 25(OH)D3 per cow daily from 28 d before expected calving until calving. Postpartum treatments were 0 or 1.5 mg of 25(OH)D3 per cow daily from calving until 63 d after calving. Treatments were top-dressed at feed delivery using a cornmeal carrier. The 25(OH)D3 source was Hy· D100. Prepartum [30 IU/kg body weight (BW)] and lactation (40 IU/kg BW) rations also provided a basal amount of cholecalciferol fed to NASEM 2021 recommendations. Dry cows were fed individually, and group housed in a bedded pack. Lactating cows were fed individually, group housed in a freestall, milked 3x/d, and milk sampled 6x/wk. Data were analyzed by ANOVA with repeated measures using the MIXED procedure of SAS (v. 9.4). The model contained fixed effects [prepartum treatment (PRE), postpartum treatment (POST; removed for prepartum data) week, and their interactions] and a random effect (block). Prepartum dry matter intake (DMI) averaged 16.3 kg/d and 2.04% of BW, was not affected by prepartum treatment (P = 0.89) and was decreased closer to calving (P = 0.01). As expected, week after calving affected (P = 0.05) lactational performance. Postpartum DMI was greater for cows fed 3-1.5 mg than those fed 0 to 1.5 mg (Table 1). Colostrum yield and quality were not affected by prepartum treatment (P = 0.91) and averaged 5.7 kg with an IgG content of 75.6 g/L. Actual milk yield was not affected by prepartum or postpartum treatments. Interestingly, there was a carryover effect of prepartum treatment on yield of 4% fat-corrected milk (FCM) and energy-corrected milk (ECM). Cows fed 3 mg during late gestation produced more than those fed 0 mg. Postpartum treatment did not affect componentcorrected milk yield. Providing additional vitamin D in the form of 25(OH)D3 to late gestation cows improved lactational performance by increasing intake and the yield of component-corrected milk. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the differences in the metabolic profiles in serum of dairy cows that were normal or overconditioned when dried off for elucidating the pathophysiological reasons for the increased health disturbances commonly associated with overconditioning. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to either a high body condition (HBCS; n = 19) group or a normal body condition (NBCS; n = 19) group and were fed different diets until dry-off to amplify the difference. The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg; mean ± standard deviation). At dry-off, the cows in the NBCS group (parity: 2.42 ± 1.84; body weight: 665 ± 64 kg) had a body condition score (BCS) <3.5 and backfat thickness (BFT) <1.2 cm, whereas the HBCS cows (parity: 3.37 ± 1.67; body weight: 720 ± 57 kg) had BCS >3.75 and BFT >1.4 cm. During the dry period and the subsequent lactation, both groups were fed identical diets but maintained the BCS and BFT differences. A targeted metabolomics (AbsoluteIDQ p180 kit, Biocrates Life Sciences AG, Innsbruck, Austria) approach was performed in serum samples collected on d −49, +3, +21, and +84 relative to calving for identifying and quantifying up to 188 metabolites from 6 different compound classes (acylcarnitines, AA, biogenic amines, glycerophospholipids, sphingolipids, and hexoses). The concentrations of 170 metabolites were above the limit of detection and could thus be used in this study. We used various machine learning (ML) algorithms (e.g., sequential minimal optimization, random forest, alternating decision tree, and naïve Bayes–updatable) to analyze the metabolome data sets. The performance of each algorithm was evaluated by a leave-one-out cross-validation method. The accuracy of classification by the ML algorithms was lowest on d 3 compared with the other time points. Various ML methods (partial least squares discriminant analysis, random forest, information gain ranking) were then performed to identify those metabolites that were contributing most significantly to discriminating the groups. On d 21 after parturition, 12 metabolites (acetylcarnitine, hexadecanoyl-carnitine, hydroxyhexadecenoyl-carnitine, octadecanoyl-carnitine, octadecenoyl-carnitine, hydroxybutyryl-carnitine, glycine, leucine, phosphatidylcholine-diacyl-C40:3, trans -4-hydroxyproline, carnosine, and creatinine) were identified in this way. Pathway enrichment analysis showed that branched-chain AA degradation (before calving) and mitochondrial β-oxidation of long-chain fatty acids along with fatty acid metabolism, purine metabolism, and alanine metabolism (after calving) were significantly enriched in HBCS compared with NBCS cows. Our results deepen the insights into the phenotype related to overconditioning from the preceding lactation and the pathophysiological sequelae such as increased lipolysis and ketogenesis and decreased feed intake. [ABSTRACT FROM AUTHOR]

The transition period in dairy cattle is characterized by many stressors, including an abrupt diet change, but yeast product supplementation can alter the rumen environment to increase dairy cattle productivity. Saccharomyces cerevisiae fermentation product (SCFP) was fed from −29 ± 5 to 42 d relative to calving (RTC) to evaluate the effects on feed intake, milk production, and metabolism. Treatments were control (n = 30) or SCFP (n = 34) incorporated into a total mixed ration. Cows were individually fed 3×/d prepartum and 2×/d postpartum. Blood samples were collected once during each of the following time points RTC: d −28 to −24 (wk −4), d −14 to −10 (wk −2), d 3 to 7 (wk 1), d 12 to 16 (wk 2), and d 31 to 35 (wk 5). Liver biopsies were taken once between d −19 and d −12 (wk −3) and at 14 d in milk. Cows were milked 2×/d, and samples were taken 2 d/wk for composition analysis. Dry matter intake did not differ by treatment, but SCFP increased meals per day and decreased time between meals. Body weight (measured at enrollment, d 0, and d 42 RTC) and body condition score (scored weekly) were not affected by treatment. Milk, energy-corrected milk, and fat-corrected milk yields did not differ by treatment. Milk fat concentration was greater for SCFP, with significant differences in wk 4 and 5. Milk lactose concentration tended to be greater for the control and milk urea nitrogen tended to be lesser for the control, but there were no treatment effects on milk protein concentration or somatic cell count. Assuming equal digestibility, energy balance deficit was greater for SCFP than for the control (−6.15 vs. −4.34 ± 0.74 Mcal/d), with significant differences in wk 4 and 5. Plasma concentrations of free fatty acids, β-hydroxybutyrate, glucose, and insulin did not differ with treatment, but cholesterol was greater for SCFP. Liver triglyceride increased and liver cholesterol decreased with time. Liver triglyceride did not differ by treatment, but liver cholesterol tended to be lesser in SCFP. Relative mRNA abundance of cholesterol-related genes (SREBF2 , HMGCS1 , HMGCR , MTTP , SPOB100 , APOA1), FGF21 , and CPT1A did not differ by treatment, but PCK1 tended to be greater for SCFP. The ketogenic transcript HMGCS2 was greater for SCFP, which aligns with SCFP increasing incidence of subclinical ketosis; however, BDH did not differ between treatments. In conclusion, SCFP supplementation increased meals per day with less time between meals, increased milk fat concentration, altered cholesterol metabolism, and increased incidence of subclinical ketosis, but early-lactation milk yield and metabolism were generally unaffected. [ABSTRACT FROM AUTHOR]

• Predicting calving time based on a novel monitoring system for ingestive behavior. • Evaluating performance with independent training and validation datasets of calving. • Variables of rumination behavior had most value to predict the start of calving. • Low positive predictive values despite satisfying sensitivity and specificity. • Positive predictive values increased for 24-h versus 168-h timeframe ante partum. Calving is an event with major impact on working routines in dairy farming and highly affects the physiological state of dairy cows. Hence, it is in the interest of livestock farmers to have information on approaching calving events to ensure a sound birth, health and welfare of the dairy cow and calf for profitable and sustainable milk production. Changes in the ingestive behavior of dairy cows due to the onset of calving have been revealed in several studies. Therefore, sensor data of these behaviors may be useful for automated prediction of calving time. The current study used sensor data of a novel monitoring device for ingestive behavior (RumiWatch noseband sensor, Agroscope, Ettenhausen, Switzerland and Itin+Hoch GmbH, Liestal, Switzerland) of 35 dairy cows for development and validation of a predictive model for calving time. Sensor data obtained from calving events on three farms were used as one training dataset and two independent validation datasets to evaluate the predictive performance of a Naïve Bayes classifier model for calving prediction at 1 h before the start of calving. The model performance was evaluated on an hourly basis for 168 h prior to the start of calving. Combined sensor variables with highest predictive performance were ruminating chews, ruminating boluses, and eating chews (sensitivity = 0.82, specificity = 0.87, positive predictive value = 0.04) in Validation Dataset 1, and ruminating chews per bolus, ruminating chews per minute, eating chews, other activity time, other chews (sensitivity = 0.69, specificity = 0.86, positive predictive value = 0.03) in Validation Dataset 2. These results indicate, that the sensitivity and specificity of the predictive model were satisfying, but the positive predictive value was low and the amount of false positive alerts was considerably high. Although the developed model is therefore not suitable for application in practice, we found that particularly variables of rumination behavior have predictive value and should be taken into consideration for future research on calving detection models. The findings of this study demonstrate that an assessment limited to the terms of sensitivity and specificity may be misleading, as these variables may achieve high values and suggest adequate performance, while the model is not appropriate in the light of its expected use. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of feeding synthetic zeolite A for 3 wk before expected calving on peripartal serum mineral concentrations, hypocalcemia, oxidant status, and performance. Holstein cows (n = 55) entering their second or greater lactations were assigned randomly to 1 of 2 dietary treatments starting 21 d before expected calving: control (CON: 40% corn silage, 33% wheat straw, and 27% concentrate; n = 29) or experimental [EXP: CON plus zeolite A (X-Zelit, Protekta Inc., Lucknow, ON, Canada/Vilofoss, Graasten, Denmark; n = 26) at an inclusion rate of 3.3% of dry matter, targeting 500 g/d as-fed]. Cows were fed the same postpartum diet and housed in individual tiestalls through 28 d in milk. Cows fed EXP had higher serum Ca concentrations as parturition approached and during the immediate postpartum period. Serum P concentrations were lower for the EXP-fed cows during the prepartum period and the first 2 d of lactation, whereas serum Mg concentrations were lower than those of the CON-fed cows only during the immediate periparturient period. Cows fed EXP had decreased prevalence of subclinical hypocalcemia (SCH) from d −1 through 3 relative to day of parturition, with the largest difference occurring within the first day postpartum. Prepartum dry matter intake tended to be decreased and rumination was decreased in cows fed EXP; however; postpartum dry matter intake, rumination, milk yield, milk component yield, and colostrum measurements did not differ between treatments. Cows fed EXP tended to have increased hazard of pregnancy by 150 d in milk when controlling for parity compared with CON-fed cows; potential reproductive benefits merit further study. This study demonstrated that zeolite A supplementation during the prepartum period results in markedly improved serum Ca concentrations around parturition and similar postpartum performance compared with controls and is effective at decreasing hypocalcemia in multiparous Holstein cows. [ABSTRACT FROM AUTHOR]

Low-grade inflammation has been implicated as a contributor to metabolic disease during the transition to lactation. In previous work, administration of sodium salicylate (SS) for 7 d led to hypoglycemia in mature dairy cows in early lactation. The purpose of this study was to identify the mode of action underlying this response to SS. Twenty mature (parity 3) cows were assigned alternately at time of calving to either control or SS treatments; the control received a molasses placebo in drinking water, whereas SS received 2.3 g/L of SS with the molasses carrier in drinking water for 7 d after parturition. Blood samples were collected daily. A glucose turnover assay was performed on d 7, followed by liver, muscle, and adipose tissue biopsies. There were no treatment effects on intake of dry matter or water. Tumor necrosis factor α mRNA abundance tended to be decreased by SS in adipose tissue but not in muscle or liver, and plasma haptoglobin and adiponectin concentrations were not altered by treatment. Treatment did not significantly alter plasma glucose or insulin concentrations, but plasma glucagon concentration tended to be increased by SS and the insulin: glucagon molar ratio was significantly decreased. Cows on SS had a tendency for a 25% decrease in glucose turnover rate compared with control cows. However, there were no differences in transcript abundance of pyruvate carboxylase (PC) or glucose-6-phosphatase (G6PC) in liver or of glucose transporter 4 (GLUT4) in any of the tissues. Finally, SS did not alter insulin receptor substrate-1 phosphorylation in muscle or adipose, but tended to increase phosphorylation of AMPactivated protein kinase and decrease protein kinase B phosphorylation in adipose tissue. These findings may be explained by enhanced hepatic insulin sensitivity leading to posttranscriptional suppression of gluconeogenesis and adaptive responses to decreased glucose supply in the pancreas and adipose tissue. [ABSTRACT FROM AUTHOR]

During the peripartum period, dairy cows often have signs of inflammation. Various stresses, including infectious and metabolic diseases, have been discussed as causative for this inflammation. In this study, expression profiles for 17 immune markers were measured in whole blood preparations from 78 dairy cows over a time frame starting 1 wk before calving to 4 wk after calving. Additionally, the effects of far-off and close-up feeding on immune function of dairy cows during the peripartum period were investigated. Cows were assigned to 1 of 2 feeding levels in late lactation to achieve a low and high BCS at the time of dry-off (approximately 4.25 and 5.0 on a 10-point scale). Following dry-off, both herds were managed to achieve a BCS of 5.0 one month before calving; this involved controlled feeding (i.e. maintenance) and over-feeding of ME during the far-off dry period. Within each far-off feeding-level treatment, cows were offered 65, 90, or 120% of their precalving ME requirements for 3 wk precalving in a 2 × 3 factorial arrangement. Analysis of gene expression profiles from blood cells revealed effects of time indicating that the transition cow's immune system counteracts the peripartum inflammation, whereas later postcalving it becomes activated to provide protection against postpartum infections. Far-off feeding affected (P < 0.05) the expression of 2 of the investigated genes at calving. Interleukin-6 (IL-6) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in unstimulated, peripheral leukocytes were lower (P < 0.05) in animals from the Far-Off_Over-fed group compared with the Far-Off_Control-fed group. Close-up feeding had several effects on gene expression, indicating that immune function in Feed120 animals was distinct from the Feed90 and Feed65. In conclusion, feeding management precalving becomes an important intervention to ensure immunocompetence at and after calving. [ABSTRACT FROM AUTHOR]

High-producing dairy cows with high pre-calving body condition score (BCS) are more susceptible to metabolic disorders and oxidative stress. The aim of present study was to evaluate the effects of close-up BCS and 3 times Se-vitamin E (SeE) injection on BCS change, blood metabolites, oxidative status, and milk yield in high-producing Holstein cows. A total of 136 multiparous cows were divided into 2 groups based on their BCS including high (HB = 4.00 ± 0.20) and moderate (MB = 3.25 ± 0.25) at 3 wk before expected calving time. Then, each group was divided into 2 subgroups: 3 rounds of SeE injection at 21 d before, and 0 and 21 d after calving (+SeE), and no SeE injection (-SeE). Four final experimental groups were HB+SeE, MB+SeE, HB-SeE, and MB-SeE (34 cows each). Results indicated that interaction effect of BCS and SeE affected serum glucose, and the MB+SeE group had the highest level. The HB cows lost more BCS compared with MB cows during the postcalving period. Moreover, serum insulin concentration increased after SeE injection. The HB cows had higher serum nonesterified fatty acids at 14 d after calving. The MB cows tended to have higher activity of blood glutathione peroxidase over the study period. Furthermore, the SeE-injected cows tended to have higher activity of blood glutathione peroxidase at 28 d after calving. Serum albumin level was increased by SeE injection. The HB cows had greater milk production than MB cows, and SeE-injected cows tended to have higher milk fat percentage and higher fat: protein ratio compared with nonsupplemented cows. It was concluded that SeE injection had beneficial effects on some blood metabolites, albumin as a blood antioxidative parameter, and lactation performance in high-producing dairy cows, especially cows with moderate close-up BCS. [ABSTRACT FROM AUTHOR]

A degree of negative energy balance is commonly experienced by cows during early lactation. This physiological state, if pronounced or prolonged, leads to partial oxidation of nonesterified fatty acids as an energy source and, consequently, increasing blood β-hydroxybutyrate (BHB) concentrations and potentially development of ketosis in postpartal dairy cows. Twenty-four multiparous Holstein cows received a common prepartal and postpartal diet. Cows were fitted with an accelerometer mounted laterally on the distal left hind leg using vet wrap from −30 to 15 d relative to parturition. A retrospective analysis was performed using the postpartal BHB data at 8 time points from 0 to 15 d in milk measured with the Precision Xtra (Abbott Diabetes Care, Alameda, CA). Cows with an average blood BHB <1.4 mmol/L were designated nonketotic (NONKET; n = 12), and those with ≥1.4 mmol/L were designated ketotic (KET; n = 12). A total of 8 samples per cow were used for this analysis. Subsequent analyses of behavioral patterns and blood biomarkers were performed using this group effect. On average, blood BHB reached subclinical levels (1.4 ± 0.3 mmol/L; mean ± standard error of the mean) at 3 d postpartum for all cows in this study. Behavioral patterns were obtained from accelerometer data, and correlation analysis was performed between these behaviors such as standing and lying time from −30 to 3 d relative to parturition and blood BHB concentration at 3 d postpartum. The strongest correlation was obtained between standing time at 3 d before calving and blood BHB at 3 d postpartum. Dry matter intake was greater (ca. 3 kg/d) in NONKET cows than in KET cows. An interaction of group × time for milk yield resulted in an overall increase of 5.7 kg/d in NONKET cows in comparison with KET. The blood concentrations of biomarkers for liver function (γ-glutamyltransferase and glutamic-oxaloacetic transaminase), inflammation (IL-6), and metabolism (nonesterified fatty acids) were increased at various time points in KET cows in comparison with NONKET during the transition period. Overall, lower bilirubin in NONKET cows than in KET further confirmed an impaired liver function in the latter group of cows. Our findings revealed the potential for establishing correlations between prepartal behavioral patterns derived from accelerometer data and postpartal subclinical ketosis, and further confirming the latter by physiological alterations in biomarkers related to inflammation and liver function. Our data also indicate that cows with a predisposition to postpartal subclinical or clinical ketosis will remain standing for fewer hours during the days leading to parturition, which decreased DMI, and this condition was further reflected in lower milk yield. [ABSTRACT FROM AUTHOR]

Intense lipolysis triggers an inflammatory response within adipose tissue characterized by adipose tissue macrophage (ATM) infiltration; however, the mechanisms triggering this process are poorly characterized in transition dairy cows. The aim of this study was to determine the association between ATM infiltration and body fat mobilization in the transition period, markers of excessive lipolysis, and adipose tissue expression of genes related to chemotactic and inflammatory responses. Subcutaneous adipose tissue samples were taken from the tailhead of 9 multiparous Holstein cows, 27 ± 2.2 d (far-off) and 10 ± 1.5 d (close-up) before and 9 ± 0.3 d after calving (fresh). Blood samples were collected by coccygeal venipuncture 2 h before adipose sample collections. Body condition score (BCS) was assessed independently by 3 experienced technicians at every time point. Based on BCS loss intensity between the close-up and fresh period, cows were divided into 2 groups: low BCS loss (LBCSL, change in BCS <0.25 units, n = 5) and high BCS loss (HBCSL, change in BCS >0.25 units, n = 4). Although none of the LBCSL cows had a health event, all cows in the HBCSL group suffered from one or more clinical disorder (retained placenta, milk fever, or ketosis) in the transition period. The number of ATM was determined by immunohistochemistry, and expression of selected chemotactic and inflammatory genes was determined by reverse-transcription quantitative real-time PCR in subcutaneous adipose tissue samples. The proportion of ATM in subcutaneous adipose tissue increased in HBCSL during the postpartum period. The proportion of ATM was not associated with serum β-hydroxybutyrate or free fatty acid concentrations on the day of adipose tissue collection. The ATM infiltration in the fresh period was associated with local expression of the chemotactic genes, C-C motif chemokine ligand 22 (CCL22), osteopontin (SPP1), and the receptor for SPP1, cluster of differentiation 44 (CD44). This supports a potential chemotactic role of CCL22 and SPP1 for ATM in bovine adipose tissue. None of the genes encoding pro- or anti-inflammatory mediators, tumor necrosis factor (TNF), IL6, and IL10 were associated with the proportion of ATM. Our results indicate that ATM infiltration of subcutaneous adipose tissue is associated with body fat mobilization in early-lactation dairy cows and supports a role for ATM in the adaptation of adipose tissues to the metabolic challenges of the transition period. [ABSTRACT FROM AUTHOR]

The determinants of metabolic and reproductive health disorders in the peripartum period and the degree to which feeding and lying space and management can influence health are only partially understood. The objective of this randomized controlled study was to determine whether providing noncompetitive feeding and lying access in the close-up dry period improves health and immune function. Forty-eight Holstein cows of all parities were randomly assigned to a treatment group of 6 to 10 cows in 1 pen with either 80% cows to stalls and 90 cm of feeding space per cow (understocked) or 120% stocking density and 45 cm of feeding space per cow (overstocked) for 3 wk before expected calving. All cows wore electronic data loggers to monitor daily standing and lying time. Video recordings representing d 7 to 9 after group formation were reviewed, and a competition index (C_Ind) was calculated for each cow by dividing the number of times a cow displaced another as an actor by its total number of actor and reactor displacements. Cows were categorized as high success (C_Ind ≥0.6), moderate success (0.4 ≤ C_Ind <0.6), or low success (C_Ind <0.4). Weekly blood samples measured nonesterified fatty acids, β-hydroxybutyrate, calcium, glucose, albumin, aspartate aminotransferase, bilirubin, haptoglobin, insulin, and insulin-like growth factor-1 from 3 wk before to 5 wk after calving. Measures of innate immune function (neutrophil phagocytosis and oxidative burst) were assessed at −2, −1, 1, 2, 3, and 5 wk relative to calving. Liver biopsies were collected at wk 1 and 3. Cows in the understocked group spent significantly more time per day lying; the back-transformed least squares means and 95% confidence interval were 14.8 h (13.9–15.6) versus 12.8 h (12.0–13.7). Controlling for parity, there was no difference between treatments in β-hydroxybutyrate, nonesterified fatty acids, glucose, insulin, insulin-like growth factor 1, aspartate aminotransferase, bilirubin, or haptoglobin concentrations. Throughout the study, cows in the understocked treatment had higher mean calcium and tended to have higher albumin and at 3 wk after calving tended to have lower mean liver triacylglycerol content. Overall, there was no treatment effect on phagocytosis, but cows with a higher C_Ind in the understocked treatment group had greater oxidative burst function. There was no effect of treatment on endometritis. Despite increased competition and lower lying time, the expected harmful effects of crowding and competition on metabolic indicators and innate immune function were mostly not observed. Although this does not refute the importance of access to feeding and lying space, these results indicate that metabolic and reproductive health is more complex than can be explained solely by exposure to what are understood to be best practices for space allowances. [ABSTRACT FROM AUTHOR]

During early lactation, dairy cows experience a severe metabolic load often resulting in the development of various diseases. The inevitable deficiency in nutrients and energy at the onset of lactation requires an optimal adaptation of the hepatic metabolism to overcome metabolic stress. We conducted a whole-liver transcriptome analysis for the transition cow to identify novel factors crucial for metabolic adaptation. Liver samples were obtained from 6 Red Holstein dairy cows (parity 2 to 7, mean ± standard deviation: 3.7 ± 2.3) at 3 time points: T1 = 22 ± 4 d antepartum, T2 = 10 ± 2 d postpartum, and T3 = 17 ± 2 d postpartum. Using RNA sequencing (RNA-seq), we studied the transcriptomic profile of the transition cow before and after parturition. We performed a differential gene expression analysis (DGEA) and gene-set enrichment analysis (GSEA) for biological processes (gene ontology, GO) and pathways (Kyoto Encyclopedia of Genes and Genomes, KEGG). Among the 10,186 expressed genes, we discovered 1,063 differentially expressed genes (false discovery rate = 5%). The GSEA revealed 16 biological processes and 7 pathways significantly (false discovery rate = 5%) associated with the hepatic changes of the transition cow. Our results confirm that major hepatic changes are related to energy mobilization after parturition; in particular, they are related to fatty acid oxidation/metabolism, cholesterol metabolism, and gluconeogenesis. Using the STRING database (https://string-db.org/), we investigated interactions between significant genes and identified 9 key genes (CYP7A1, APOA1, CREM, LOC522146, CYP2C87, HMGCR, FDFT1, SGLE, and CYP26A1) through which the different processes involved in the metabolic adaptation interact. Comparing our main results with the literature, we could identify further genes that have not yet been associated with the transition period (e.g., CPT1B, ADIPOR2, LEPR, CREB3L3, and CCND1) and that are mainly involved in processes controlled by AMP-activated protein kinase, an important regulator of energy homeostasis. [ABSTRACT FROM AUTHOR]

The objective of our study was to extend the limited research available on the association between concentrations of milk fatty acids and elevated nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) concentrations in early lactation dairy cattle. Measurement of milk fatty acids for detection of cows in excessive negative energy balance has the potential to be incorporated in routine in-line monitoring systems. Blood samples were taken from 84 cows in second or greater lactation 3 times per week between 3 to 14 d in milk. Cows were characterized as hyperketonemic (HYK) if blood BHB concentration was ⩾1.2 mmol/L at least once and characterized as having elevated concentrations of NEFA (NEFAH) if serum NEFA concentration was ⩾1 mmol/L at least once. Composition of colostrum and milk fatty acids at wk 2 postpartum was used to investigate the potential diagnostic value of individual fatty acids and fatty acid ratios for the correct classification of cows with NEFA and BHB concentrations above these thresholds, respectively. Receiver operating characteristic (ROC) curves were used to identify thresholds of fatty acid concentration and fatty acid ratios when ROC area under the curve was ⩾0.70. Correct classification rate (CCR, %) was calculated as {[(number of true positives + number of true negatives)/total number tested] × 100}. None of the colostrum fatty acids yielded a sufficiently high area under the curve in ROC analysis for the association with HYK and NEFAH. The following fatty acids and fatty acid ratios were identified for an association with NEFAH (threshold, CCR): C15:0 (⩽0.65 g/100 g, 68.3%); cis-9 C16:1 (⩾1.85 g/100 g, 70.7%); cis-9 C18:1 (⩾26 g/100 g, 69.5%), cis-9 C18:1 to C15:0 ratio (⩾45, 69.5%); cis-9 C16:1 to C15:0 (⩾2.50, 73.2%). Several fatty acids were associated with HYK (threshold threshold, CCR): C6:0 (⩽1.68 g/100 g, 80.5%), C8:0 (⩽0.80 g/100 g, 80.5%), C10:0 (⩽1.6 g/100 g, 79.3%); C12:0 (⩽1.42 g/100 g, 82.9%); C14:0 (⩽6.10 g/100 g, 84.1%); C15:0 (⩽0.50 g/100 g, 82.9%), cis-9 C18:1 (⩾30 g/100 g, 81.7%). The use of fatty acid ratios did not improve CCR over using individual fatty acids for the classification of HYK. Colostrum fatty acid composition was not useful in predicting NEFAH or HYK between 3 to 14 d in milk. Accuracy of milk fatty acids and fatty acid ratios to correctly classify cows with elevated concentrations of NEFA and BHB between 3 to 14 d in milk was moderate and overall higher for HYK. Determining changes in the fatty acid composition of milk fat from milk samples at wk 2 postpartum for the detection of cows with elevated concentrations of BHB and NEFA can currently not be recommended to replace direct measurement. Future applications should target repeated milk sampling between 3 to 14 d in milk to identify the best sampling for determination of milk fatty acid composition within the first 2 wk postpartum. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate the effects of prepartum protein supplementation on subsequent milk yield, milk composition, feed intake and tissue mobilisation by using regression analysis. The data were compiled from 15 peer-reviewed articles that included 47 treatments. Crude protein content of prepartum diets ranged from 97 to 206g/kg DM. For the evaluation of potential interaction between prepartum protein supplementation and basal diet, diets were categorised as grass silage-based, maize silage–soya bean meal (SBM) and other diets (alfalfa/grass hay/straw). A significant interaction (P<0.05) between dietary protein content and type of diet was found in milk protein yield and postpartum dry matter intake. This suggests that the impact of prepartum protein feeding on subsequent lactation performance may depend on the composition of basal diet. Milk protein yield and postpartum dry matter intake responses to prepartum SBM supplementation in maize silage-based diets were negative. Higher impact was observed when the proportion of hay or straw was high in the prepartum diet. In grass silage-based diets, the production responses were intermediate and more variable than in the other groups. No relationship was found between prepartum protein supplementation and postpartum tissue mobilisation. In conclusion, excessive prepartal SBM supplementation in maize silage-based diets may decrease milk protein yield and dry matter intake during early lactation. Positive responses to increased prepartal protein supply can be achieved in hay or straw based diets. [Copyright &y& Elsevier]

The objective was to study the effect of increasing dietary NEL (Mcal/d) and CP (%) levels on BW (kg), DMI (kg), and ADG (kg/d) in the dry-off period, and its influence on BW, DMI, NEL intake, milk yield (MY, kg), MY efficiency and reproductive traits during 105 DIM. Thirty Holstein cows (BW = 703.4 \plusmn; 16.4 kg; eight weeks before expected calving) were stratified by BW and randomly assigned to one of three treatments. During the dry-off period, cows were individually fed with one of three diets containing 1.46 and 16.9, 1.58 and 18.7, or 1.83 and 19.3 Mcal/kg and % CP, respectively, for the low, medium and high diets. After calving, cows were fed 1.46 and 16.9, 1.77 and 1.92, or 2.10 and 19.5 Mcal/kg and % CP, respectively, for the low, medium and high diets. Results were analyzed using mixed procedures for repeated measures. The model included treatment, week and the interaction of treatment x week. Reproductive traits were analyzed using mixed procedures in a CRD with treatment as a main effect. No differences on BW were observed during the dry period, except cows fed high and low diets showed higher ADG than those fed medium diets. Cows had similar (P > 0.05) DMI from week -7 through week -4 before calving; conversely, DMI from week -3 through calving was higher for cows on the high diet. Pospartum cows fed high and medium diets were heavier than those fed low diets, whereas no treatment effect (P > 0.05) was observed for ADG. Cows on the high level diet had higher DMI than the medium and low diet cows. A interaction treatment x week (P < 0.05) indicates differences in MY among treatments; on average, MY of cows fed the high diet was 7.0 and 15.3 kg higher than those fed on the medium or low diets, respectively. In contrast, calves BW at birth, days to first estrous, days open and service per conception were similar among treatments groups. In conclusion, increasing dietary levels of ENL and CP during the dry period increased DMI, BW, and ADG. Likewise, in pospartum period, increasing the levels of ENL and CP were associated with increased DMI, BW changes, and MY. [ABSTRACT FROM AUTHOR]

Thiazolidinediones (TZD) are potent, synthetic ligands for PPAR-γ that have been shown to reduce plasma nonesterified fatty acids (NEFA) and potentiate the action of insulin in peripheral tissues of several species. Holstein cows (n = 9) entering second or greater lactation were used to determine whether late prepartum administration of 2,4-TZD would affect periparturient metabolism and production. Cows were fed a TMR during the prepartum period to provide no more than 150% of predicted energy requirements. During the postpartum period cows were fed a common TMR for ad libitum intake. Cows were administered either 2,4-TZD (4.0 mg/kg BW) or saline (control) by intrajugular infusion once daily from 25 d before expected parturition until parturition. Plasma samples were collected daily from 26 d prior to expected parturition through 7 d postpartum. Plasma NEFA concentrations were similar for cows assigned to the two treatments during much of the prepartum period, but were decreased at parturition and during the first 7 d postpartum for cows administered 2,4-TZD (treatment by time, P = 0.009). Plasma glucose concentrations were not affected (P > 0.10) by treatment. Average DMI was greater for cows administered 2,4-TZD compared to controls (14.8 vs. 13.8 kg/d; P < 0.05). Cows administered 2,4-TZD had lower milk yield than controls during the immediate postpartum period but then produced more milk than controls during the remainder of the postpartum study period (treatment by time, P < 0.01). Differences in milk fat and milk protein content measured on d 8 postpartum were not significant (P > 0.10). Administration of TZD during the late prepartum period has the potential to substantially improve metabolic health and production of transition dairy cows and warrants further investigation. [ABSTRACT FROM AUTHOR]

Plane of nutrition before parturition might affect hepatic gluconeogenic capacity, which might impact subsequent cow health and productivity. Our objectives were to determine the effects of nutrient intake during far-off (FO) and close-up (CU) dry periods, and their interaction, on adaptations in metabolism of propionate and alanine in liver slices. Multiparous Holstein cows (n = 71) were assigned to treatments in a 3 (FO diet) × 2 (CU diet) factorial arrangement. During the FO period (d -60 to -25) cows received a high-straw control diet fed for ad libitum intake (FOCA) to meet NRC recommendations for NEL , a higher-density diet fed ad libitum to exceed NRC recommendation for NEL by 60% (FOHA), or the higher-density diet at restricted intake to meet 80% of NEL requirements (FOHR). During the CU period (d -24 until parturition), cows were fed one diet for either ad libitum intake (CUA) or in restricted (CUR) amounts to provide 80% of NEL requirements. All cows received a lactation diet postpartum. Liver slices from biopsies at d -30, -14, +1, +14, and +28 relative to parturition were utilized to determine in vitro conversion of [1-14 C] alanine and [1-14 C] propionate to glucose and CO2 . Interactions of FO and CU diets were not significant. Gluconeogenesis from propionate was numerically greater on d -14, +1, and +14 and was significantly greater on d -14 and d +28 for FOHR cows than for FOCA and FOHA. Oxidation of propionate to CO2 on d -14 tended (P = 0.08) to be lower for FOCA than for FOHA and FOHR. Gluconeogenesis from alanine tended (P = 0.06) to be greater for CUR on d +14 and was also numerically greater on d +1 and +28. Oxidation of alanine to CO2 did not differ among treatments. The CU treatment had minimal impact on gluconeogenesis and substrate oxidation. Cows restricted in energy intake during the FO dry period had greater hepatic gluconeogenic capacity prepartum and postpartum than cows allowed to consume energy in excess of requirements. [ABSTRACT FROM AUTHOR]

The objective of the study was to determine the effect of partial replacement of forage NDF with byproduct NDF in close-up diets of dairy cattle on periparturient metabolism and performance. Holstein cows (n = 45) and heifers (n = 19) were fed diets containing either 1) 30% oat hay (1.6 Mcal NEL/kg, 12.8% CP, 42.4% NDF) or 2) 15% oat hay and 15% beet pulp (1.6 Mcal NEL/kg, 13.2% CP, 40.5% NDF) from -21 d relative to expected parturition until parturition. After parturition, animals received a lactation diet (1.7 Mcal NEL/kg, 17.1% CP, 35.0% NDF). Animals were group-fed from -21 to -10 d relative to expected parturition and individually fed from -10 d relative to expected parturition until 14 DIM. Animals were required to have at least 5 d of prepartum intake data to remain on the study. Body weight and BCS were determined weekly. Blood was collected and serum from the start of study and -5, -3, -1, 1, 3, 5, 7, 9, 11, and 13 d relative to actual parturition was analyzed for content of NEFA and BHBA. Milk yield was measured. Data were analyzed as a randomized design and subjected to analysis of variance using the MIXED procedure of SAS. Close-up diet did not affect (P > 0.10) DMI (1.48% BW), energy balance (116%), or serum content of NEFA (381 μEq/L) and BHBA (6.0 mg/dL) during the last 5 d prepartum. Prepartum BW (776 kg) and BCS (3.56) were similar (P > 0.10) between treatments. There was no carryover effect (P > 0.10) of close-up diet on DMI (2.20% BW), energy balance (69%), milk yield (34.7 kg), BW (691 kg), BCS (3.32), or serum content of NEFA (723 μEq/L) and BHBA (12.6 mg/dL) during the first 14 DIM. Partial replacement of forage NDF (oat hay) with byproduct NDF (beet pulp) did not affect periparturient metabolism or performance. Further investigation of replacement level is needed. [ABSTRACT FROM AUTHOR]