Hepatic mRNA expression for genes related to somatotropic axis,glucose and lipid metabolisms,and inflammatory response of periparturient dairy cows treated with recombinant bovine somatotropin

Objectives of this experiment were to evaluate the effects of recombinant bovine somatotropin (rbST) treatment of periparturient dairy cows on hepatic mRNA expression for genes related to the somatotropic axis, insulin, glucose, and lipid metabolism, inflammation, and oxidative stress. Holstein cows were enrolled in the experiment at 253 ± 3 d of gestation and assigned to 1 of 3 treatments: untreated control (n = 53), 87.5 mg of rbST (n = 56; rbST87.5), and 125 mg of rbST (n = 57; rbST125). Cows in the rbST87.5 and rbST125 treatments received weekly injections of rbST from ?21 to 28 d relative to calving. A subsample of cows (control = 20, rbST87.5 = 20, rbST125 = 20) was randomly selected for collection of liver samples according to expected calving date, BCS, and previous lactation 305-d mature equivalent milk yield. Only cows that had liver sampled at ?21 ± 3, ?7 ± 3, and 7 ± 3 d relative to calving were used in the current experiment. Blood, sampled weekly from ?28 to 21 d relative to calving, was used to determine the concentrations of growth hormone, insulin-like growth factor 1, insulin, cortisol, fatty acids, β-hydroxybutyrate, glucose, haptoglobin, and tumor necrosis factor-α. Liver samples were used to determine hepatic mRNA expression of 50 genes. Treatment with rbST increased growth hormone concentrations during the postpartum period (control = 9.0 ± 0.7, rbST87.5 = 15.3 ± 1.0, rbST125 = 18.5 ± 1.3 ng/mL) and increased insulin-like growth factor 1 concentrations during the prepartum period (control = 107.4 ± 7.2, rbST87.5 = 126.9 ± 6.6, rbST125 = 139.4 ± 6.9 ng/mL). Control cows had greater postpartum concentrations of β-hydroxybutyrate (control = 776.4 ± 64.0, rbST87.5 = 628.4 ± 59.7, rbST125 = 595.4 ± 60.9 µmol/L) than rbST cows. The rbST87.5 and rbST125 treatments upregulated the hepatic mRNA expression for somatotropic axis genes (GHR, GHR1A, IGF1, IGFBP3, and SOCS2) on d ?7 relative to calving and upregulated the mRNA expression for SOCS2 on d 7. On d ?7, rbST87.5 and rbST125 treatments increased mRNA expression for genes involved in hepatic lipid transport (ANGPTL4, APOA5, APOB100, and SCARB1) and downregulated mRNA expression for PPARD, which is involved in lipid storage. On d 7, rbST tended to upregulate the mRNA expression for genes involved in gluconeogenesis (PCK1) and fatty acid β-oxidation (ACOX1), and downregulated the mRNA expression for genes involved in inflammation (TNFRSF1A, ICAM1, CXCL1, MYD88, HIF1A, IL1RN, NFKBIA, and SOCS3) and oxidative stress (XBP1). Administration of rbST during the periparturient period may improve liver function and health by increasing hepatic capacity for gluconeogenesis and lipid transport and by reducing inflammation and oxidative stress.     

Effects of treatment of periparturient dairy cows with recombinant bovine somatotropin on health and productive and reproductive parameters

The objectives of the current experiment were to evaluate the effects of treating periparturient dairy cows with recombinant bovine somatotropin (rbST) on incidence of postpartum diseases and performance. Holstein (HO) and Jersey (JS) cows from 2 herds were enrolled in the experiment at 253 ± 3 d of gestation and assigned to the control (n = 432) and rbST125 (n = 437) treatments. Cows in the rbST125 treatment received 125 mg of rbST, weekly, from ?21 to 21 d relative to calving. Blood sampled weekly, from ?21 to 21 d relative to calving, from a subsample of cows was used to determine the concentrations of growth hormone (GH, HO = 106) and insulin-like growth factor 1 (IGF-1, HO = 147 and JS = 49). Cows were scored for body condition (BCS) at enrollment and at 1 ± 3, 30 ± 3, and 60 ± 3 d in milk (DIM). Cows were milked thrice daily and energy-corrected milk (ECM) yield was recorded for the first 30 DIM. Treatment of cows with rbST resulted in greater concentrations of GH during the prepartum (log₁₀ back-transformed concentrations of GH: HO-control = 7.83 and HO-rbST125 = 10.36 ng/mL) and postpartum (log₁₀ back-transformed concentrations of GH: HO-control = 10.45 and HO-rbST125 = 18.47 ng/mL) periods. Similarly, IGF-1 concentrations were higher during the prepartum (HO-control = 115.1 ± 4.9, HO-rbST125 = 137.7 ± 4.7, JS-control = 120.2 ± 8.3, JS-rbST125 = 167.1 ± 8.1 ng/mL) and postpartum (HO-control = 61.3 ± 4.0, HO-rbST125 = 75.2 ± 3.8, JS-control = 35.5 ± 6.9, JS-rbST125 = 54.6 ± 6.9 ng/mL) periods for rbST-treated cows. During the prepartum period, BCS was not affected by treatment, but during the postpartum period, BCS was reduced for rbST-treated cows (HO-control = 3.00 ± 0.03, HO-rbST125 = 2.90 ± 0.03, JS-control = 2.64 ± 0.02, JS-rbST125 = 2.61 ± 0.02). Cows from the rbST125 treatment tended to have lower incidence of retained fetal membranes (HO-control = 14.3, HO-rbST125 = 6.1, JS-control = 1.5, JS-rbST125 = 1.2%) and had reduced incidence of metritis (HO-control = 26.2, HO-rbST125 = 16.6, JS-control = 19.9, JS-rbST125 = 13.3%) compared with control cows. Ketosis incidence tended to be higher for rbST125 cows (HO-control = 9.4, HO-rbST125 = 11.3, JS-control = 8.5, JS-rbST125 = 13.4%) compared with control cows. The interaction between treatment and herd tended to affect yield of ECM during the first 30 DIM because HO cows treated with rbST during the periparturient period had greater yield than control HO cows (HO-control = 35.5 ± 1.0 vs. HO-rbST125 = 39.4 ± 1.0 kg/d), but treatment with rbST did not affect yield of ECM of JS cows (JS-control = 26.7 ± 0.6 vs. JS-rbST125 = 27.8 ± 0.6 kg/d). Treatment of periparturient dairy cows with 125 mg of rbST decreased the incidence of uterine disorders in HO and JS cows and increased yield of ECM during the first 30 DIM among HO cows, despite slightly increasing the incidence of ketosis.     

Effects of supplementing a Saccharomyces cerevisiae fermentation product during the periparturient period on performance of dairy cows fed fresh diets differing in starch content

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the periparturient period (d ?28 ± 3 to 44 ± 3 relative to calving) on dry matter intake (DMI), milk production, apparent total-tract nutrient digestibility, and postpartum ovarian activity of dairy cows fed fresh diets varying in starch content. From d 28 ± 3 before the expected calving date until d 44 ± 3 after calving, 117 Holstein cows were fed diets with SCFP (SCFP; n = 59) or without (control, CON; n = 58). A common, basal, controlled-energy close-up diet (net energy for lactation: 1.43 Mcal/kg; 13.8% starch) was fed before calving. Cows within each treatment (CON or SCFP) were fed either a low- (LS; 22.1% starch) or high-starch (HS; 28.3% starch) diet from d 1 to 23 ± 3 after calving (fresh period), resulting in 4 treatment groups: LS-CON (n = 30), LS-SCFP (n = 29), HS-CON (n = 28), and HS-SCFP (n = 30). All cows were fed the HS diets from d 24 ± 3 to 44 ± 3 after calving (post-fresh period). Cows were assigned to treatment balanced for parity, body condition score, body weight, and expected calving date. Milk yield was higher for cows fed the LS diets compared with those fed the HS diets during the fresh period (34.1 vs. 32.1 kg/d), whereas DMI and 3.5% fat-corrected milk yield (FCM) were not affected by dietary starch content, and LS cows tended to lose more body condition than HS cows (?0.42 vs. ?0.35 per 21 d) during the fresh period. Overall DMI during the close-up and fresh periods did not differ between SCFP and CON cows. However, SCFP supplementation transiently increased DMI on d 1 (13.0 vs. 11.9 kg/d) and 5 (15.5 vs. 14.1 kg/d) after calving compared with CON. During the post-fresh period, SCFP cows tended to eat less than CON cows (19.8 vs. 20.6 kg/d) but had similar 3.5% FCM (44.9 vs. 43.6 kg/d), resulting in greater feed efficiency for SCFP cows (FCM/DMI; 2.27 vs. 2.13). Neither starch content of fresh diets nor SCFP supplementation affected the interval from calving to first ovulation or the incidence of double ovulation. These findings suggest that feeding low-starch diets during the fresh period can increase milk production of dairy cows during the fresh period, and that supplementation of SCFP may increase feed intake around calving and feed efficiency in the post-fresh period.     

Effects of pegbovigrastim administration on periparturient diseases,milk production,and reproductive performance of Holstein cows

The aim of this study was to evaluate the effects of treating Holstein cows with pegbovigrastim on periparturient diseases, milk production, and reproductive performance while exploring the mode of action of an immunomodulatory protein. Cows were randomly allocated to 1 of 2 treatments, untreated control (CTR, n = 423) and pegbovigrastim (PEG, n = 417). At 7 d from the anticipated calving date (d ?7), cows allocated to PEG received a subcutaneous injection of 15 mg of pegylated recombinant bovine granulocyte colony stimulating factor (pegbovigrastim injection, Imrestor, Elanco Animal Health, Greenfield, IN). A second injection was administered within 24 h after calving (d 0). Blood samples were obtained from a subset of cows (CTR, n = 103; PEG, n = 102) at ?7 and 0, 3, 7, and 14 d relative to parturition. Samples were used for hemogram and quantification of haptoglobin, nonesterified fatty acids, β-hydroxybutyrate, and trace and macro minerals. Vaginal cytobrush was performed on the same subset cows at d 0, 7, and 14 to assess the relative neutrophil count. Additionally, colostrum samples were collected to measure IgG, IgM, IgA, and lactoferrin concentrations. Postpartum disease occurrence was recorded from calving until 30 d in milk (DIM). Weekly milk yield was recorded for the first 12 wk after calving. Cows treated with PEG had a 3- to 4-fold increase in circulating polymorphonuclear leukocyte, lymphocyte, and monocyte numbers, with a peak at 3 d after treatment followed by a gradual decline, but the counts remained significantly greater compared with CTR at 14 DIM. The administration of PEG did not affect the incidence of clinical and subclinical mastitis, retained fetal membranes, metritis, puerperal metritis, and endometritis. Primiparous cows treated with PEG tended to have lower odds of developing hyperketonemia than CTR [odds ratio (OR) = 0.57, 95% confidence interval (CI) = 0.23 to 1.42]. Cows treated with PEG had higher odds of being diagnosed with lameness within 30 DIM compared with CTR (OR = 1.79, 95% CI = 1.16 to 2.76); however, we found no significant differences by 60 DIM. Treatment with PEG increased the odds of displaced abomasum (OR = 8.27, 95% CI = 1.02 to 66.6). Cows treated with PEG had higher odds of being diagnosed with 1 or more clinical diseases compared with CTR cows (OR = 1.39, 95% CI = 1.02 to 1.90). We observed no differences in linear scores or milk composition between treatments. Furthermore, primiparous cows treated with PEG produced more milk than CTR primiparous cows during the first 12 wk postpartum (PEG = 37.51 ± 0.66; CTR = 35.91 ± 0.65 kg), but no differences were observed on energy-corrected milk. Treatment did not alter reproductive performance; additionally, cows diagnosed with metritis or puerperal metritis and treated with PEG tended to have higher proportion of neutrophils in the vaginal mucosa when compared with CTR metritic cows. Although PEG treatment increased circulating polymorphonuclear leukocyte, monocyte, and lymphocyte numbers, as expected, it was detrimental to cow health because it increased morbidity.     

Effects of rumen-protected glutamate supplementation during the periparturient period on digestibility,inflammation, metabolic responses,and performance in dairy cows

The objective of this study was to evaluate the effects of feeding rumen-protected glutamate during the periparturient period (d ?21 ± 3 to d 21 ± 3 relative to calving) on apparent total-tract digestibility (ATTD), inflammation, metabolic responses, and production performance of dairy cows. Fifty-two multiparous Holstein cows were blocked by parity, body condition score, and expected calving date, and randomly assigned to one of the experimental diets with rumen-protected monosodium glutamate (RP-Glu; intestinally available Glu = 8.8%) or without RP-Glu (control) at d ?21 ± 3 relative to expected calving date. The RP-Glu was fed at 4% and 3% of dietary dry matter, before and after calving, respectively. Prepartum diets contained 17.1% and 16.5% crude protein, and 13.1% and 13.3% starch, and postpartum diets contained 18.8% and 18.3% crude protein, and 22.5% and 22.7% starch on a dry matter basis, respectively for RP-Glu and control treatments. A subset of 19 cows was used to measure ATTD. Cows fed the RP-Glu had greater ATTD of dry matter (70.6 vs. 69.1%), crude protein (75.1 vs. 72.6%), and ether extract (66.0 vs 61.2%) on d 5 ± 1 after calving. Cows fed the RP-Glu also had greater dry matter intake (15.7 vs. 13.7 kg/d) on d 1 after calving. Cows fed the RP-Glu had greater plasma concentrations of Glu (4.60 vs. 3.89 µmol/dL) and insulin-like growth factor-1 (44.2 vs. 30.1 mg/mL), lower serum concentrations of free fatty acids (670 vs. 981 μEq/L) and total bilirubin (0.22 vs. 0.34 mg/dL), and lower plasma 3-methylhistidine concentration (1.28 vs. 1.50 μmol/dL) on d 4 after calving. However, these treatment effects observed between d 1 and d 5 ± 1 immediately after calving did not continue until d 21 after calving. Concentrations of serum amyloid A, serum haptoglobin, and plasma lipopolysaccharide binding protein were not affected by the treatment. In addition, no differences were observed for serum β-hydroxybutyrate concentration and milk yield during the postpartum period between the 2 groups, and cows fed the RP-Glu had a decreased lactose yield. These findings suggest that feeding RP-Glu during the periparturient period can increase digestive capacity and feed intake, and decrease mobilization of body fat and protein immediately after calving without increasing milk production.     

Effects of supplementing a Saccharomyces cerevisiae fermentation product during the periparturient period on the immune response of dairy cows fed fresh diets differing in starch content

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the periparturient period (d ?28 ± 3 to 44 ± 3 relative to calving) on mRNA abundance of genes in the rumen epithelium, inflammation indicators, oxidative status, and adaptive immunity of dairy cows fed diets with different starch content after calving. From d 28 ± 3 (± standard deviation) before the expected calving date to calving, Holstein cows (n = 38) received a common basal controlled-energy close-up diet (1.43 Mcal/kg, net energy for lactation; 13.8% starch) with (SCFP; n = 19) or without (CON; n = 19) SCFP, and cows within each treatment (CON or SCFP) were fed either a low- (LS; 22.1% starch) or high-starch (HS; 28.3% starch) diet from d 1 to 23 ± 3 after calving (fresh period). There were 4 treatment groups: LS + CON (n = 9), LS + SCFP (n = 10), HS + CON (n = 10), and HS + SCFP (n = 9). From d 24 ± 3 to 44 ± 3 after calving, all cows were fed the HS diets (post-fresh period). Animal assignment to treatments was balanced for parity, body condition score, and expected calving date. An interaction was observed between dietary starch content and SCFP on indices of oxidative stress; plasma concentrations of total antioxidant capacity tended to be reduced on d 21 after calving for SCFP compared with CON cows when a LS fresh diet was fed, but did not differ for cows fed HS fresh diets. Regardless of starch content, SCFP supplementation increased plasma concentrations of malondialdehyde at d 21 after calving compared with CON. Supplementing with SCFP reduced serum concentrations of haptoglobin on d 7 after calving, indicating reduced inflammation, and feeding LS fresh diets reduced mRNA abundance of IL receptor associated kinase-1 in rumen tissue at d 21 after calving, suggesting reduced immune activation in rumen tissue. Other than the anti-inflammatory effects indicated by lower serum haptoglobin concentration, no other effects of treatment on adaptive immunity were detectable. These results indicate that supplementing SCFP through the transition period and feeding low-starch diets during the fresh period may reduce inflammation.     

Fetuin-A: A negative acute-phase protein linked to adipose tissue function in periparturient dairy cows

Fetuin-A (FetA) is a free fatty acid transporter and an acute-phase protein that enhances cellular lipid uptake and lipogenesis. In nonruminants, FetA is involved in lipid-induced inflammation. Despite FetA importance in lipid metabolism and inflammation, its expression and dynamics in adipose tissue (AT) of dairy cows are unknown. The objectives of this study were to (1) determine serum and AT FetA dynamics over the periparturient period and in mid-lactation cows in negative energy balance (NEB) after a feed restriction protocol and (2) characterize how an inflammatory challenge affects adipocyte FetA expression. Blood and subcutaneous AT were collected from 16 cows with high (≥3.75, n = 8) or moderate (≤3.5, n = 8) body condition score (BCS) at ?26 ± 7 d (far off) and ?8 ± 5 d (close up) before calving and at 10 ± 2 d after parturition (early lactation) and from 14 nonpregnant mid-lactation cows (>220 d in milk) after a feed restriction protocol. Serum FetA concentrations were 0.89 ± 0.13 mg/mL at far off, 0.96 ± 0.13 mg/mL at close up, and 0.77 ± 0.13 mg/mL at early lactation and were 1.09 ± 0.09 and 1.17 ± 0.09 mg/mL in feed-restricted and control cows, respectively. Serum and AT FetA contents decreased at the onset of lactation when lipolysis was higher. No changes in AT and serum FetA were observed after feed restriction induced NEB in mid-lactation cows. Prepartum BCS had no effect on serum FetA, but AT expression of AHSG, the gene encoding FetA, was reduced in periparturient cows with high BCS at dry-off throughout all time points. Circulating FetA was positively associated with serum albumin and calcium and with BCS variation over the periparturient period. The dynamics of AHSG expression were analogous to the patterns of lipogenic markers ABDH5, ELOVL6, FABP4, FASN, PPARγ, and SCD1. Expression of AHSG and FetA protein in AT was inversely correlated with AT proinflammatory markers CD68, CD44, SPP1, and CCL2. In vitro, bovine adipocytes challenged with lipopolysaccharide downregulated FetA protein expression. Adipocytes treated with FetA had lower CCL2 expression compared with those exposed to lipopolysaccharide. Overall, FetA is a systemic and local AT negative acute-phase protein linked to AT function in periparturient cows. Furthermore, FetA may support physiological adaptations to NEB in periparturient cows.     

Effects of intrauterine infusion of Escherichia coli lipopolysaccharide on uterine health,resolution of purulent vaginal discharge,and reproductive performance of lactating dairy cows

The objectives of the current experiment were to evaluate the effects of intrauterine infusion of Escherichia coli lipopolysaccharide (LPS) in cows diagnosed with purulent vaginal discharge (PVD) on intrauterine cell population, resolution of PVD, uterine health, and reproductive performance. Jersey cows (n = 3,084) were examined using the Metricheck device to diagnose PVD at 35 ± 6 d postpartum. Purulent vaginal discharge was defined as the presence of purulent (≥50% pus) discharge detectable in the vagina. Of the 310 cows positive for PVD, 267 cows were enrolled in the current experiment. To ensure proper timing of treatment and collection of samples, only 9 PVD-positive cows were treated per day. Selected cows were balanced at 35 ± 6 d postpartum for lactation number, body condition score, and milk yield and were randomly assigned to receive an intrauterine infusion of 20 mL of phosphate-buffered saline (PBS; control, n = 87), 20 mL of PBS with 150 µg LPS (LPS150, n = 91), or 20 mL of PBS with 300 µg of LPS (LPS300, n = 89). Uterine cytology was performed immediately before treatment and 1, 2, and 7 d after treatment to evaluate the effect of LPS treatment on intrauterine cell population. Cows were examined with the Metricheck device at 7 and 28 d after treatment to evaluate the effects of treatment on resolution of PVD. Reproductive status was recorded up to 200 d postpartum. Cows diagnosed with PVD had greater incidence of twinning, dystocia, retained placenta, and metritis after calving than cows without PVD. Count of polymorphonuclear leukocytes (PMNL) in uterine cytology 1, 2, and 7 d after intrauterine infusion was not statistically different among treatments. From d 0 to 1, however, PMNL count in uterine cytology of PBS cows increased by 5%, whereas the PMNL count in uterine cytology of LPS150 and LPS300 cows increased by 54 and 48%, respectively. Treatment did not affect the likelihood of cows being diagnosed with PVD 7 and 28 d after intrauterine infusion. Cows without PVD and LPS150 cows were more likely to be pregnant after the first postpartum AI than PBS cows. After the second postpartum AI, cows without PVD were more likely to be pregnant than PBS and LPS300 cows. Hazard of pregnancy up to 200 d postpartum was decreased for PBS and LPS300 cows compared with cows without PVD, and it tended to be decreased for LPS150 cows compared with cows without PVD. Intrauterine treatment with 150 µg of E. coli LPS of cows diagnosed with PVD improved likelihood of pregnancy after the first postpartum AI, but further research is needed to elucidate the mechanism by which LPS treatment improved fertility.     

Effects of supplementing a Saccharomyces cerevisiae fermentation product during the transition period on rumen fermentation of dairy cows fed fresh diets differing in starch content

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the transition period (d −28 ± 3 to 23 ± 3 relative to calving) on rumen fermentation and mRNA abundance of genes in the rumen epithelium of fresh cows (d 1 to 23 ± 3 after calving) fed diets differing in starch content. Eighteen ruminally cannulated multiparous Holstein cows were fed diets with SCFP (n = 9) or without (CON; n = 9) throughout the experiment. All cows were fed a common basal controlled-energy close-up diet (1.43 Mcal/kg, net energy for lactation; 13.8% starch) before calving. Cows within each treatment (CON or SCFP) were fed either a low-starch (LS; 22.1% starch) or high-starch (HS; 28.3% starch) diet during the fresh period. Cows were assigned to treatment after balancing for parity, body condition score, and expected calving date. Rumen pH was measured continuously for 72 h starting on d −10, −3, 1, 7, and 21 relative to calving date. Rumen papillae were collected on d −10 and 21 relative to calving. Supplementation of SCFP had no effect on rumen pH during d −10 to −8, but mean rumen pH tended to be higher (6.64 vs. 6.49) for SCFP cows than for CON cows during d −3 to −1. Feeding SCFP decreased the range of rumen pH variation compared with CON within the HS group during both d 7 to 9 (1.08 vs. 1.38) and d 21 to 23 (1.03 vs. 1.30) after calving. In addition, nadir rumen pH tended to be higher (5.64 vs. 5.44) and duration of pH below 5.8 tended to be shorter (116 vs. 323 min/d) for the SCFP group than for the CON group during d 21 to 23 after calving. Supplementation of SCFP increased the mRNA abundance of insulin-like growth factor-6 (1.10 vs. 0.69) before calving and decreased the mRNA abundance of putative anion transporter isoform 1 (1.12 vs. 2.27) after calving. Nadir rumen pH tended to be higher during d 1 to 3 (5.63 vs. 5.41) for LS cows than for HS cows, but rumen pH was not affected by dietary starch content during other time periods. Dietary starch content had no effect on mRNA abundance of genes in the rumen epithelium after calving. These results suggest that supplementation of SCFP may reduce the range of variation in rumen pH in fresh cows fed HS diets and the duration of subacute ruminal acidosis by the end of the fresh period regardless of dietary starch content and that decreasing dietary starch content during the fresh period may reduce the decrease in rumen pH immediately after parturition.     

Effect of injectable trace mineral supplementation on peripheral polymorphonuclear leukocyte function,antioxidant enzymes,health, and performance in dairy cows in semi-arid conditions

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

Timing of onset of somatotropin supplementation on reproductive performance in dairy cows

The objective of this field trial was to determine whether delaying the start of recombinant bovine somatotropin (rbST) supplementation from 9 to 10 wk postpartum to 17 to 18 wk postpartum would improve reproductive performance in lactating dairy cows. Cows from nine herds (n = 798 cows; 766 Holsteins, 32 Jerseys) were assigned at random to receive rbST supplementation at 14-d intervals beginning during wk 9 to 10 (n = 399) or wk 17 to 18 (n = 399) after calving. Effects of herd, season of calving, parity, and onset of rbST supplementation (9 to 10 wk vs. 17 to 18 wk) on days to first service and days open were determined. In primiparous but not multiparous cows, there tended to be fewer days to first service and fewer days open when onset of rbST supplementation was delayed. Percentages of cows pregnant at 150, 200, and 250 d postpartum were also examined. Time of onset of rbST did not affect percentages of multiparous cows pregnant at 150, 200, and 250 d postpartum. However, there appeared to be a slight tendency for percentages of pregnant primiparous cows to be greater at 200 and 250 d postpartum for those receiving rbST supplementation beginning at 17 to 18 wk compared to those receiving rbST starting at 9 to 10 wk. In conclusion, delaying the start of rbST supplementation to wk 17 to 18 postpartum had no beneficial effect on reproductive performance of multiparous cows but tended to improve some measures of reproductive performance in primiparous cows.     

Claw horn lesions in mid-lactation primiparous dairy cows under pasture-based systems: Association with behavioral and metabolic changes around calving

The objectives of this study were to describe the lying behavior of primiparous dairy cows under pasture-based systems during the pre- and postcalving period and characterize the association of lying behavior and analytes related to energy metabolism during this period with claw horn disruption lesion development later in lactation. Our convenience sample included 39 primiparous Holstein cows from 3 commercial farms that were assessed for body condition score (BCS; 5-point scale, 0.25-point increments) and had blood collected at wk ?3, ?2, ?1, 1, 2, and 3 relative to calving date. Blood samples were assayed for nonesterified fatty acids, β-hydroxybutyrate (BHB), and cholesterol concentrations. Electronic data loggers (HOBO Pendant G Acceleration, Onset Computer Corporation, Bourne, MA) recorded lying behavior at 1-min intervals from 3 wk before calving to 3 wk after calving. Starting at 4 wk after calving and until 16 wk after calving, cows were examined for claw lesions at approximately 4-wk intervals. Sole lesions and white line lesions were scored on a 0 to 10 scale. Of the 39 primiparous cows, 19 cows scored 0 at all exams during the entire study period and 20 cows had at least 1 severe lesion (score ≥4) between 8 and 16 wk after calving. Time spent lying before calving averaged 10.3 ± 0.3 h/d, but declined to 7.3 ± 0.3 h/d after calving (least squares means ± standard error). At calving, we noted an increase in the number of lying bouts (12.9 ± 0.45 bouts/d) compared with the pre- and postcalving averages of 11.6 (±0.53) and 9.1 (±0.47) bouts, respectively. Cows that developed claw lesions later in mid lactation spent less time lying down than cows without lesions during wk 3 after calving compared with healthy cows (7.29 ± 0.22 vs. 8.51 ± 0.16 h/d). Lesion cows had fewer lying bouts per day, and these bouts were of longer duration than no-lesion cows after calving. Increased odds of lesion were found to be associated with shorter lying times and fewer number of lying bouts during wk 3 (odds ratio = 1.23). Nonesterified fatty acids (747 ± 58 vs. 990 ± 86.85 µmol/L) and BHB (0.77 ± 0.06 vs. 0.60 ± 0.04 mmol/L) concentrations during wk 1 were greater in cows that developed claw lesions relative to cows that did not develop lesions. The BHB concentrations also remained higher in wk 2 for cows that developed claw lesions (0.63 ± 0.04 vs. 0.46 ± 0.03 mmol/L) compared with cows that did not develop any lesions. Cows that developed lesions experienced greater losses in BCS from wk ?3 to 3 than cows without lesions (0.74 ± 0.01 and 0.61 ± 0.01 BCS change, respectively). In summary, changes in lying behavior and energy metabolic status after calving were associated with claw horn disruption lesions in mid-lactation primiparous cows under pasture-based systems.     

Effect of source and amount of vitamin D on serum concentrations and retention of calcium,magnesium, and phosphorus in dairy cows

The objectives of the experiment were to determine the effects of supplementing 2 amounts of 25-hydroxyvitamin D₃ (calcidiol; CAL) compared with equal amounts of vitamin D₃ (cholecalciferol; CHOL) on serum concentrations, absorptions, and retentions of Ca, Mg, and P in periparturient dairy cows. One hundred seventy-seven (133 parous and 44 nulliparous) pregnant Holstein cows were enrolled in the experiment. Cows were blocked by parity and previous lactation milk yield (parous) or genetic merit for energy-corrected milk yield (nulliparous) and assigned randomly to receive 1 or 3 mg/d of CAL or CHOL in a 2 × 2 factorial arrangement of treatments. Treatments were provided to individual cows as a top-dress to the prepartum diet from 250 d gestation until parturition. The prepartum diet had a dietary cation-anion difference of ?128 mEq/kg of dry matter. All cows were fed a common postpartum diet containing 46 μg of vitamin D₃/kg of dry matter without further supplementation of treatments. Concentrations of vitamin D metabolites, Ca, Mg, and P in serum were measured pre- and postpartum, in addition to total-tract digestibility and urinary excretion of Ca, Mg, and P in the prepartum period. Feeding 3 mg compared with 1 mg of CAL increased serum 25-hydroxyvitamin D₃ (CAL1 = 94 vs. CAL3 = 173 ± 3 ng/mL). In comparison, the increment in serum 25-hydroxyvitamin D₃ from feeding 3 mg compared with 1 mg of CHOL was small (CHOL1 = 58 vs. CHOL3 = 64 ± 3 ng/mL). Feeding CAL increased prepartum concentration of P in serum compared with CHOL (CHOL = 1.87 vs. CAL = 2.01 ± 0.02 mM), regardless of the amount fed, but neither source nor amount affected prepartum Ca or Mg in serum. Feeding CAL increased serum Ca and P for the first 11 d postpartum compared with CHOL (CHOL = 2.12 vs. CAL = 2.16 ± 0.01 mM serum Ca; CHOL = 1.70 vs. CAL = 1.78 ± 0.02 mM serum P) but the amount of vitamin D did not affect postpartum concentrations of Ca, Mg, and P in serum. Feeding CAL increased prepartum apparent digestibility of Ca compared with CHOL (CHOL = 26.6 vs. CAL = 33.5 ± 2.8%) but treatments did not affect Ca retention prepartum. Neither source nor amount of vitamin D affected Mg and P apparent digestibility, but CAL decreased the concentration of P excreted in urine during the prepartum period (CHOL = 1.8 vs. CAL = 0.8 ± 0.3 g/d). Calcidiol tended to increase the amount of Ca secreted in colostrum (CHOL = 9.1 vs. CAL = 11.2 ± 0.9 g/d) and Ca excreted in urine postpartum (CHOL = 0.4 vs. CAL = 0.6 ± 0.1 g/d) compared with CHOL. Collectively, feeding CAL at 1 or 3 mg/d compared with CHOL in the last 24 d of gestation is an effective way to increase periparturient serum P concentration and postpartum serum Ca of dairy cows fed a prepartum diet with negative DCAD.     

Metabolic and blood acid-base responses to prepartum dietary cation-anion difference and calcium content in transition dairy cows

Dairy cows commonly undergo negative Ca balance accompanied by hypocalcemia after parturition. A negative dietary cation-anion difference (DCAD) strategy has been used prepartum to improve periparturient Ca homeostasis. Our objective was to determine the influence of a negative DCAD diet with different amounts of dietary Ca on the blood acid-base balance, blood gases, and metabolic adaptation to lactation. Multiparous Holstein cows (n = 81) were blocked into 1 of 3 dietary treatments from 252 d of gestation until parturition: (1) positive DCAD diet and low Ca (CON; containing +6.0 mEq/100 g DM, 0.4% DM Ca); (2) negative DCAD diet and low Ca (ND; ?24.0 mEq/100 g DM, 0.4% DM Ca); or (3) negative DCAD diet plus high Ca supplementation (NDCA; ?24.1 mEq/100 g DM, 2.0% DM Ca). There were 28, 27, and 26 cows for CON, ND, and NDCA, respectively. Whole blood was sampled at 0, 24, 48, and 96 h after calving for immediate determination of blood acid-base status and blood gases. Serum samples collected at ?21, ?14, ?7, ?4, ?2, ?1, at calving, 1, 2, 4, 7, 14, 21, and 28 d relative to parturition were analyzed for metabolic components. Results indicated that cows fed ND or NDCA had lower blood pH at calving but greater pH at 24 h after calving compared with CON. Blood bicarbonate, base excess, and total CO₂ (tCO₂) concentrations of cows in ND and NDCA groups were less than those of cows in CON at calving but became greater from 24 to 96 h postpartum. The NDCA cows had lower blood bicarbonate, base excess, and tCO₂ at 48 h and greater partial pressure of oxygen after calving compared with ND. Cows fed ND or NDCA diets had lower serum glucose concentrations than CON cows before calving but no differences were observed postpartum. Serum concentrations of total protein and albumin were greater prepartum for cows in ND and NDCA groups than for those in CON. Postpartum serum urea N and albumin concentrations tended to be higher for ND and NDCA cows. Cows fed ND or NDCA diets had elevated serum total cholesterol concentration prepartum. During the postpartum period, triglycerides and NEFA of cows fed ND or NDCA diets tended to be lower than those of CON. Cows fed the NDCA diet had greater postpartum total cholesterol in serum and lower NEFA concentration at calving than ND. In conclusion, feeding a prepartum negative DCAD diet altered blood acid-base balance and induced metabolic acidosis at calving, and improved protein and lipid metabolism. Supplementation of high Ca in the negative DCAD diet prepartum was more favorable to metabolic adaptation to lactation in dairy cows than the negative DCAD diet with low Ca.     

Effect of maternal exercise on calf dry matter intake,weight gain,behavior, and cortisol concentrations at disbudding and weaning

The objective of this study was to determine the effect of maternal physical activity during late gestation on calf dry matter intake, weight gain, behavior, and cortisol concentration during disbudding and weaning. Fifty-five Holstein and 5 Jersey × Holstein crossbred calves were enrolled into the study during gestation. Calves were born from pregnant, nonlactating Holstein (n = 58) and Jersey × Holstein crossbred (n = 2) dairy cows. Cows were assigned to either confinement (n = 20 cows; 13 female calves, 7 male calves), exercise (n = 20 cows; 8 female calves, 12 male calves), or pasture (n = 20 cows; 11 female calves, 9 male calves) treatments at dry-off from January to November 2015. Enrollment in treatment was balanced by parity (1.8 ± 0.9), projected mature-equivalent fat-corrected milk (13,831 ± 2,028 kg/lactation), dam breed, and projected calving date. Cows assigned to confinement remained in the pen throughout the dry period. Cows assigned to exercise were walked 5 times/wk at a targeted 1.5 h at 3.25 km/h. Cows assigned to pasture were turned out 5 times/wk for a targeted 1.5 h/d. Treatments were terminated on the expected due date or at signs of calving. Calves were removed from cows immediately once observed by farm staff and subsequently weighed and moved into a straw deep-bedded hutch. Data loggers were attached to the rear fetlock of each calf ?3 d to +6 d relative to disbudding and weaning to monitor changes in lying behavior. Calves were weighed on d ?7, ?5, ?3, ?1, 0, 1, 3, 5, and 7, and grain was weighed the 7 d preceding and following disbudding and weaning. Blood was collected 24 h before and 0, 1, and 4 h after disbudding and d ?1, 0, 1, and 2 relative to weaning to determine cortisol concentrations. Data were analyzed using mixed linear model in SAS (SAS Institute Inc., Cary, NC). Calf weight gain decreased the day after disbudding and calves tended to have elevated cortisol concentrations 1 h after disbudding, regardless of maternal treatment. Calf weight gain decreased the day of and after weaning; calves had elevated cortisol concentrations the day after weaning, regardless of treatment. Behavior did not differ by treatment at disbudding, but calves from pasture cows lay down for less time compared with confinement and exercise maternal treatments and less frequently than exercise maternal treatments at weaning. More research investigating the significance of lying time and restlessness around stressful events is needed to further understand the implications of such behavioral responses.     

Heat stress abatement during the dry period influences metabolic gene expression and improves immune status in the transition period of dairy cows

Heat stress (HT) and photoperiod affect milk production and immune status of dairy cows. The objective was to evaluate the effects of HT abatement prepartum under controlled photoperiod on hepatic metabolic gene expression and cellular immune function of periparturient Holstein cows (n = 21). Cows were dried off 46 d before expected calving date and assigned to treatments by mature equivalent milk production. The treatments were 1) HT and 2) cooling (CL), both imposed during a photoperiod of 14L:10D. Rectal temperature was measured twice daily, whereas respiration rate was measured 3 times/wk at 1500 h during the entire dry period. After calving, cows were housed in a freestall barn with cooling, and milk yield was recorded daily up to 140 d in milk. Liver samples were taken at dry off, −20, 2, and 20 d relative to calving by biopsy. Under a similar schedule, neutrophil function was determined in blood of cows on HT (n = 12) and CL (n = 9). Blood samples were taken on −46, −32, −18, 0, 14, 28, and 42 d relative to calving for measurement of metabolites and were collected twice daily from −7 to 2 d relative to calving for prolactin (PRL) analysis. The HT cows had greater concentrations of PRL at 0 d relative to calving (150 vs. 93; SEM = 11 ng/mL) and had higher afternoon rectal temperatures (39.4 vs. 39.0; SEM = 0.04°C) and elevated respiration rates (78 vs. 56; SEM = 2 breaths/min) during the prepartum period compared with CL cows. Relative to HT cows, CL cows had greater hepatic expression of PRL-R, SOCS-3, and CAV-1 mRNA. Neutrophil oxidative burst was greater in CL cows relative to HT cows at 2 d (61 vs. 42; SEM = 6%) and at 20 d (62 vs. 49; SEM = 5%) relative to calving, and phagocytosis was greater in CL cows at 20 d (47 vs. 33; SEM = 4%) relative to calving compared with HT cows. Humoral response, as measured by IgG secretion against ovalbumin challenge, was greater for CL cows at −32 d (0.44 vs. 0.33; SEM = 0.05 OD) and −21 d (0.60 vs. 0.50 ± 0.04 OD) relative to calving compared with HT cows. These results suggest that HT abatement during the dry period improved innate and acquired immune status as measured by neutrophil function and immunoglobulin secretion against ovalbumin challenge, and altered hepatic gene expression related to PRL signaling in the periparturient period or subsequent lactation.     

Feeding rumen-protected lysine altered immune and metabolic biomarkers in dairy cows during the transition period

This experiment was conducted to determine the effects of feeding rumen-protected lysine (RPL; AjiPro-L Generation 3, Ajinomoto Health and Nutrition North America Inc.) from −26 ± 4.6 d prepartum (0.54% RPL of dietary dry matter intake) to 28 d postpartum (0.39% RPL of dietary dry matter intake) on immunometabolic status and liver composition in dairy cows. Seventy-five multiparous Holstein cows, blocked by parity, previous 305-d mature-equivalent milk production, expected calving date, and body condition score during the far-off dry period were assigned to 1 of 4 dietary treatments in a randomized, complete block design with a 2 × 2 factorial arrangement of treatments. Treatments prepartum consisted of total mixed ration top dressed with RPL (PRE-L) or without RPL (PRE-C), and postpartum treatments consisted of total mixed ration top dressed PRE-L prepartum and postpartum, PRE-L prepartum and PRE-C postpartum, PRE-C prepartum and PRE-L postpartum, and PRE-C prepartum and postpartum in 300 g of molasses. Blood samples were taken on −7 ± 0.5, 0 ± 0.5, 7 ± 0.9, 14 ± 0.9, and 28 ± 0.5 d relative to calving. Whole blood samples were taken on −14 ± 0.5, −7 ± 0.5, 7 ± 0.9, and 14 ± 0.9 d relative to calving for oxidative burst and phagocytic capacity of monocytes and neutrophils. Liver samples were collected via a biopsy on −12 ± 4.95 and 13 ± 2.62 d relative to calving and analyzed for liver composition (triacylglyceride and carnitine concentrations), mRNA expression of hepatic genes, and protein abundance. Protein abundance was calculated by normalizing intensity bands for a specific protein with glyceraldehyde-3-phosphate dehydrogenase. Concentrations of haptoglobin and glutathione peroxidase activity in plasma were lower at d 0 for cows in PRE-L (102 µg/mL and 339 nmol/min per mL, respectively) compared with cows in PRE-C (165 µg/mL and 405 nmol/min per mL, respectively). Oxidative burst capacity in monocytes tended to be greater on d 7 postpartum for cows in PRE-L (65.6%) than cows in PRE-C (57.5%). Additionally, feeding RPL altered the mRNA expression in liver tissue prepartum [decreased INSR (insulin receptor), CPT1A (carnitine palmitoyltransferase 1A), and IL1B (interleukin 1 β)] and postpartum [increased IL8 (interleukin 8), EHMT2 (euchromatic histone lysine methyltransferase 2), TSPO (translocator protein), and SLC3A2 (solute carrier family 3 member 2); and decreased SLC7A1 (solute carrier family 7 member 1), SOD1 (superoxide dismutase 1), and SAA3 (serum amyloid A 3)] compared with cows not consuming RPL]. Additionally, cows in the PRE-C prepartum and PRE-L postpartum treatment tended to have greater protein abundance of mTOR postpartum compared with the PRE-C prepartum and postpartum treatment. Protein abundance of SLC7A7 (solute carrier family 7 member 7) pre- and postpartum tended to be greater and BBOX1 (gamma-butyrobetaine dioxygenase 1) tended to be less when RPL was consumed prepartum. In conclusion, cows that consumed RPL during the transition period had molecular changes related to liver composition, enhanced liver function indicated by greater total protein and albumin concentrations in plasma, and improved immune status indicated by decreased haptoglobin, glutathione peroxidase activity, and immune related mRNA expression.     

Mammalian target of rapamycin signaling and ubiquitin-proteasome–related gene expression in skeletal muscle of dairy cows with high or normal body condition score around calving

The objective of the current study was to investigate the effects of overconditioning around calving on gene expression of key components of the mammalian target of rapamycin (mTOR) pathway and ubiquitin-proteasome system (UPS) in skeletal muscle as well as the AA profiles in both serum and muscle of periparturient cows. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to either a high body condition group (HBCS; n = 19) or a normal body condition group (NBCS; n = 19) and were fed different diets until dry-off (d ?49 relative to calving) to amplify the difference. The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg). At dry-off, the NBCS cows (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 a 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. Blood samples and skeletal muscle biopsies (semitendinosus) were repeatedly (d ?49, +3, +21, and +84 relative to calving) collected for assessing the concentrations of free AA and the mRNA abundance of various components of mTOR and UPS. The differences in BCS and BFT were maintained throughout the study. The circulating concentrations of most AA with the exception of Gly, Gln, Met, and Phe increased in early lactation in both groups. The serum concentrations of Ala (d +21 and +84) and Orn (d +84) were lower in HBCS cows than in NBCS cows, but those of Gly, His, Leu, Val, Lys, Met, and Orn on d ?49 and Ile on d +21 were greater in HBCS cows than in NBCS cows. The serum concentrations of 3-methylhistidine, creatinine, and 3-methylhistidine:creatinine ratio increased after calving (d +3) but did not differ between the groups. The muscle concentrations of all AA (except for Cys) remained unchanged over time and did not differ between groups. The muscle concentrations of Cys were greater on d ?49 but tended to be lower on d +21 in HBCS cows than in NBCS cows. On d +21, mTOR and eukaryotic translation initiation factor 4E binding protein 1 mRNA abundance was greater in HBCS cows than in NBCS cows, whereas ribosomal protein S6 kinase 1 was not different between the groups. The mRNA abundance of ubiquitin-activating enzyme 1 (d +21), ubiquitin-conjugating enzyme 1 (d +21), atrogin-1 (d +21), and ring finger protein-1 (d +3) enzymes was greater in HBCS cows than in NBCS cows, whereas ubiquitin-conjugating enzyme 2 was not different between the groups. The increased mRNA abundance of key components of mTOR signaling and of muscle-specific ligases of HBCS cows may indicate a simultaneous activation of anabolic and catabolic processes and thus increased muscle protein turnover, likely as a part of the adaptive response to prevent excessive loss of skeletal muscle mass during early lactation.