Effects of a single transdermal administration of flunixin meglumine in early postpartum Holstein Friesian dairy cows: Part 1. Inflammatory and metabolic markers,uterine health,and indicators of pain

The objectives of this study were to assess the effects of a single transdermal administration of flunixin meglumine (FM) in early postpartum Holstein Friesian dairy cows on serum concentrations of inflammatory and metabolic markers, uterine health, and indicators of pain. The hypothesis was that the anti-inflammatory, antipyretic, and analgetic effects of the pharmaceutic agent would reduce systemic inflammation, resulting in improved metabolic and inflammatory profile, diminished incidence of metritis, and reduced expression of pain. A total of 500 cows (153 primiparous, 347 multiparous) from 3 different commercial dairy farms in the northeast of Germany were included in a randomized controlled clinical trial. Farms were preselected based on high haptoglobin concentrations in their fresh lactating cows. Cows were excluded if they had experienced dystocia, stillbirth, or twin birth, or if they showed any signs of milk fever, retained fetal membranes, or fever (>40°C). The cows were treated once with either FM (3.33 mg/kg) or a placebo as control (CON) through transdermal administration between 24 to 36 h postpartum (d 2). General health examinations were performed (daily from d 2–8 and additionally on d 15 postpartum), vaginal discharge was assessed using the Metricheck device (d 8 and 15 postpartum) and serum samples were analyzed for inflammatory and metabolic markers (d 2, 4, and 6 postpartum). Effects of treatment, parity, sampling day, and their interactions were evaluated using mixed effects models. Primiparous cows treated with FM showed lower serum haptoglobin concentrations (0.90 ± 0.08 vs. 1.17 ± 0.07 g/L; ± standard error of the mean) and higher serum albumin concentrations (35.5 ± 0.31 vs. 34.8 ± 0.31 g/L) on d 6 postpartum. They also had a lower risk for purulent vaginal discharge with or without a fever compared with CON cows on d 15 postpartum (odds ratio for CON vs. FM: 1.63, 95% CI: 1.26–2.00), and body temperature was lower throughout the first 15 d in milk (39.1 ± 0.11 vs. 39.2 ± 0.11°C). Multiparous cows treated with FM had lower serum β-hydroxybutyrate concentrations on d 4 postpartum (0.71 ± 0.05 vs. 0.78 ± 0.05 mmol/L) and d 6 postpartum (0.74 ± 0.05 vs. 0.80 ± 0.05 mmol/L). Regardless of parity, FM-treated cows were significantly less likely to abduct their tail from their body (14.3 vs. 23.6%) and show an arched back (27.9 vs. 39.7%) on the day after treatment compared with CON cows. It can be concluded that FM treatment slightly reduced inflammation and diminished the risk for metritis in primiparous cows, improved metabolic profile in multiparous cows, and reduced expressions of pain in all cows.     

Effects of flunixin meglumine on pyrexia and bioenergetic variables in postparturient dairy cows

Study objectives were to determine whether a nonsteroidal antiinflammatory drug would reduce parturition-induced inflammation and fever and consequently improve appetite, bioenergetic parameters, and production variables in transitioning dairy cows. Multiparous cows (n = 26) were randomly assigned to 1 of 2 treatments beginning at parturition: 1) flunixin meglumine (FM; 2.2 mg/kg of BW; Banamine, 50 mg/mL, Schering-Plough Animal Health, Kenilworth, NJ), or 2) saline (control) at 2.0 mL/45.5 kg of BW. All treatments were administrated i.v. daily for the first 3 d in milk (DIM). Individual milk yield and dry matter intake (DMI) were recorded daily for the first 35 DIM. Rectal temperature was measured daily at 0700 and 1600 h for the first 7 DIM. Milk composition was determined on 2, 7, 14, 21, 28, and 35 DIM and blood plasma was collected on 1, 2, 3, 4, 7, 14, 21, 28, and 35 DIM. Body weight and body condition score were determined on −7, 1, 7, 14, 21, 28, and 35 DIM. Flunixin meglumine treatment slightly increased rectal temperature (38.99 vs. 38.76°C) during the first 7 DIM and reduced overall DMI (22.04 vs. 19.48 kg/d), but there were no treatment differences in overall milk yield (35.2 kg/d), 3.5% fat-corrected milk (37.6 kg/d), energy-corrected milk (37.7 kg/d), DMI (2.97% of BW), or overall energy balance (−2.32 Mcal/d). There were no treatment differences in milk fat (3.91%), protein (3.32%), or lactose (4.57%). Treatment had no effect on plasma glucose (66.5 mg/dL) or nonesterified fatty acids (553 μEq/L), but plasma urea nitrogen tended to be less in FM-treated cows (16.4 vs. 14.5 mg/dL). Daily FM administration to cows for the first 3 d after parturition slightly increased rectal temperatures by 0.23°C, reduced feed intake, and did not improve production or energetic variables during the first 35 DIM in transition dairy cows.     

Association of postpartum hypocalcemia with early-lactation milk yield,reproductive performance,and culling in dairy cows

Periparturient hypocalcemia is frequently observed and considered as a gateway disease that is associated with various health issues. The objective of this study was to evaluate the association of hypocalcemia with early-lactation milk yield, reproductive performance, and culling across a large number of different managerial systems. A prospective cohort study was conducted based on a convenience sample of 125 dairy herds from 8 federal states of Germany between February 2015 and August 2016. A blood sample was drawn from 1,709 animals within 48 h after parturition and analyzed for serum calcium concentration. After discarding cows (n = 283) with missing data, a total of 1,426 cows were considered for final analyses. The median time from calving to sampling was 14.0 h (interquartile range = 5.0–24.9 h). For each herd, a record of the herd management software was requested 150 d after the last cow was sampled. Serum calcium concentration of each cow was associated with early-lactation milk yield (Dairy Herd Improvement Association equivalent test 1 to 3), reproductive performance [days in milk (DIM) at first artificial insemination (AI), pregnancy at first AI, time to pregnancy within 150 DIM], and culling (until 60 DIM) data. Generalized linear mixed models were used to analyze continuous or categorical data. Shared frailty models were used for time to event data. Five different thresholds were used to define hypocalcemia. Thresholds ranged from 1.8 to 2.2 mmol/L using 0.1-mmol/L increments. Clinical hypocalcemia was defined as serum calcium concentration <2.0 mmol/L in combination with clinical signs (e.g., recumbency). The effect of hypocalcemia on milk yield was conditional on parity. In primiparous cows a serum calcium concentration <2.0 mmol/L (6.4% of cows were below this threshold) had no effect on milk production, whereas there was a tendency for multiparous cows with a serum calcium concentration <2.1 mmol/L (63.2% of cows were below this threshold) to produce 0.80 kg/d more milk compared with multiparous cows at or above the threshold. Multiparous cows suffering from clinical hypocalcemia produced 2.19 kg/d less milk compared with normocalcemic cows in early lactation. Calcium status was not associated with days to first insemination. Cows with a serum calcium concentration <1.9 mmol/L (34.6% of cows below this threshold) had decreased odds (odds ratio = 0.56) of pregnancy at first AI. A serum calcium concentration <1.8 mmol/L (24.1% of cows below this threshold) had a significant effect on time to pregnancy. Compared with animals with a serum calcium concentration ≥1.8 mmol/L, the hazard of becoming pregnant within 150 DIM was reduced when cows had a serum calcium concentration <1.8 mmol/L (hazard ratio = 0.68). Cows with a serum calcium concentration <2.0 mmol/L (44.3% of cows were below this threshold) had a 1.69 times greater hazard of being culled within the first 60 DIM compared with normocalcemic animals. The present study shows that the association of hypocalcemia with milk yield was conditional on parity and serum calcium concentration measured once within 48 h after calving. Considering reproductive performance and culling in early lactation, a negative effect of postpartum hypocalcemia was demonstrated.     

Effects of feeding dry glycerin to early postpartum Holstein dairy cows on lactational performance and metabolic profiles

Effects of feeding a dry glycerin product (minimal 65% of food grade glycerol, dry powder) to 39 multiparous Holstein dairy cows (19 control and 20 glycerin-supplemented; lactation number = 2.2 ± 1.3 SD) on feed intake, milk yield and composition, and blood metabolic profiles were investigated. Dry glycerin was fed at 250 g/d as a top dressing (corresponding to 162.5 g of glycerol/d) to the common lactating total mixed ration from parturition to 21 d postpartum. Individual milk was sampled from 2 consecutive milkings weekly and analyzed for components. Blood was sampled from the coccygeal vein at 4, 7, 14, and 21 (±0.92, pooled SD) d in milk and analyzed for urea nitrogen, glucose, insulin, nonesterified fatty acids, and β-hydroxybutyrate. Urine was tested for the acetoacetate level weekly by using Ketostix. Average feed intake, milk yield and components, blood metabolites, and serum insulin concentrations were not affected by dry glycerin supplementation. Glycerin-supplemented cows experienced a more positive energy status (higher concentrations of plasma glucose, lower concentrations of plasma β-hydroxybutyrate, and lower concentrations of urine ketones), which was observed during the second week of lactation, suggesting that energy availability may have been improved. This glucogenic effect of dry glycerin did not result in an increase in feed intake or milk yield during the first 3 wk of lactation, likely because of the relatively less negative energy status of cows transitioning into lactation. The tendency toward higher milk yield for glycerin-supplemented cows during wk 6 of lactation (52 vs. 46 kg/d) after the supplementation period (dry glycerin was terminated at wk 3 of lactation) suggested a potential benefit of dry glycerin on subsequent milk production, perhaps through changes in metabolism, which requires further investigation.     

Associations of postpartum lying time with culling,milk yield,cyclicity, and reproductive performance of lactating dairy cows

The objectives were to evaluate the associations of lying time (LT) during the first 14 d in milk (DIM) with milk yield, cyclicity (CYC), culling within 60 DIM (CULL), and reproductive performance of lactating dairy cows. A total of 1,052 Holstein cattle (401 nulliparous heifers and 651 parous cows) from 3 commercial dairy farms had electronic data loggers (IceQube, IceRobotics, Edinburgh, UK) placed on a hind leg 14 ± 3 d before the expected parturition date and removed at 14 ± 3 DIM to assess their LT. Serum concentrations of β-hydroxybutyrate were determined at 7 ± 3 and 14 ± 3 DIM. Cases of retained placenta, metritis, mastitis, pneumonia, and digestive disorders within 30 DIM were recorded and lactating cows were categorized into 1 of 4 groups: (1) nondiseased (ND, n = 613; cows without ketosis or any other diagnosed health condition); (2) cows with only ketosis (KET, n = 152); (3) sick cows experiencing ≥1 health conditions but without ketosis (SICK, n = 198); or (4) cows with ketosis plus ≥1 health condition (KET+, n = 61). Ultrasound was performed at 28 ± 3 and 42 ± 3 DIM to assess ovarian cyclicity (presence or absence of corpus luteum). Milk yield at first Dairy Herd Improvement Association test was not associated with LT during the first 14 DIM, but it was negatively correlated with the coefficient of variation of LT during the first 14 DIM. Lactating dairy cows experiencing KET+ had the lowest milk yield compared with ND, regardless of parity. Parity, health status, and season were significantly associated with CYC and CULL. Lying time had a significantly linear association with the risk of being culled: for every 1-h increment of LT during 0 to 14 DIM, the risk of culling within 60 DIM increased by 1 percentage point. Lying time had a negative quadratic association with cyclicity at 42 DIM. Multiparous cows with a LT of 9 to 13 h/d had a significantly greater probability of pregnancy up to 300 DIM compared with cows with a LT >13 h/d. Regardless of parity, KET+ cows had significantly higher proportion of culling within 60 DIM and decreased probability of pregnancy up to 300 DIM compared with ND cows. These findings suggest that there is an optimum daily LT range for early postpartum cows housed in freestall barns, different from that reported for mid-lactation cows, with the potential for improved survival, health, and the overall performance (milk yield and reproduction).     

Effects of postpartum uterine diseases on milk production and culling in dairy cows

The objective was to quantify the effect of postpartum uterine diseases on milk production and culling. Data from 2,178 Holstein cows in 6 herds enrolled in a randomized clinical trial were used. Milk production data from the first 4 Dairy Herd Improvement Association (DHIA) test-days and culling data from farm records were collected. Retained placenta (RP; ≥24 h after parturition) and metritis [≤20 d in milk (DIM)] were diagnosed by farm managers using standardized definitions. Farms were visited weekly and cows were examined at 35 and 56 (±3) DIM using endometrial cytology (cytobrush device), vaginal discharge scoring (Metricheck device), and measurement of cervical diameter by transrectal palpation. Diagnostic criteria for cytological endometritis (CYTO) and purulent vaginal discharge (PVD) were established based on a detrimental effect on subsequent reproduction. Statistical analyses were performed using linear mixed models, logistic regression models, and Cox proportional hazard models, accounting for the effects of experimental treatments and herd clustering. Milk production and culling were the outcomes. Primiparous and multiparous cows were modeled separately for milk production. Milk production of primiparous cows was unaffected by uterine diseases. The effect of metritis on milk production was variable over time in multiparous cows: it decreased production per cow by 3.7 kg at the first DHIA test, but was not different at later tests. Retained placenta decreased milk production by 2.6 kg/d in multiparous cows through the first 4 DHIA tests. The projected effects of metritis and RP in multiparous cows were reductions of 259 kg and 753 kg over 305 DIM, respectively; these effects were additive. Neither CYTO nor PVD affected milk production. Culling risks at 30 and 63 DIM were unaffected by RP and metritis. Culling hazard up to 300 DIM was unaffected by RP, metritis, CYTO, or PVD, whether or not pregnancy status, milk production, and displaced abomasum were accounted for. Uterine disease decreased pregnancy rate, which was a substantial risk factor for culling; however, if affected cows became pregnant they were not at greater risk of culling.     

Responses of Holstein cows to a low dose of somatotropin (bST) prepartum and postpartum

Objectives were to evaluate the effects of a low dose of bovine somatotropin (bST) injected prepartum and postpartum on body condition score (BCS), body weight (BW), and milk yield (MY) in cows as well as somatotropin insulin, insulin-like growth factor-I (IGF-I), glucose, and nonesterified fatty acids (NEFA) in plasma. Holstein cows nearing second or later parities were assigned randomly to control (CON = 98) or bST-treated (TRT = 95) groups. Biweekly injections of bST began 21 +/- 3 d before expected calving and continued through 42 d postpartum (CON vs. TRT; 0 vs. 10.2 mg of bST/ d). From 42 to 100 d postpartum, no cows received bST. During yr 1, somatotropin, IGF-I, insulin, NEFA, and glucose were measured in plasma samples from 82 cows. During yr 2, effects of bST on BCS and BW of 111 cows were evaluated, but no blood samples were collected. Milk yields through 100 d of all 193 cows were analyzed. Prepartum treatment with bST resulted in greater prepartum plasma concentrations of somatotropin, insulin, and numerically greater NEFA but did not affect glucose or IGF-I. Postpartum bST increased mean plasma concentrations of somatotropin and NEFA, but not INS, IGF-I, or glucose. Mean BCS of cows did not differ prepartum, around parturition, or postpartum. Although mean BW did not differ prepartum or around calving, cows receiving bST maintained greater BW postpartum. Cows receiving bST tended to have higher MY (6.6%) in the first 60 d of lactation, but differences did not persist through 100 d, including approximately 40 d when no cows received bST. Number of cows that were culled due to health (CON = 3 vs. TRT = 2) or died (CON = 3 vs. TRT = 1) were not affected by treatment. Low doses of bST in the transition period resulted in higher postpartum BW, quicker recovery of body condition during lactation, and significantly more milk during treatment.     

Associations of somatic cell count with milk yield and reproductive performance in grazing dairy cows

Poor udder health status can have a detrimental effect on milk yield and reproductive performance, leading to reductions in the dairy farm profit. The objective of this retrospective longitudinal study was to assess the associations of somatic cell count (SCC) with daily milk yield and reproductive performance. A database with 1,930,376 lactations from 867 Argentinean grazing dairy herds records collected for 14 years was used. The association of the evolution of SCC (healthy vs. new case vs. cured vs. chronic; with 150,000 SCC/mL as threshold) and of the severity of SCC [mild (150,000­–400,000 SCC/mL) vs. moderate (400,000–1,000,000 SCC/mL) vs. severe (>1,000,000 SCC/mL)] with the odds for conception were estimated. Finally, the associations of the linear score of SCC (LS-SCC) with daily milk yield were estimated depending on parity and milk production quartile. The odds ratios (CI 95%) for conception at first service were 0.921 (0.902–0.941), 0.866 (0.848–0.884), and 0.842 (0.826–0.859) for the new case, cured, and chronic cows compared with healthy cows, respectively. Also, the odds ratios (CI 95%) for conception were 0.902 (0.881–0.925), 0.837 (0.808–0.866) and 0.709 (0.683–0.736) for mild, moderate and severe cases compared with healthy cows, respectively. An increase of one point of LS-SCC was associated with decreases of 0.349, 0.539, and 0.676 kg in daily milk yield for first-, second-, and third-lactation cows, respectively. In conclusion, SCC is negatively associated with the risk for conception and with daily milk yield in grazing dairy cows. This negative relationship with conception is higher when SCC increase occurs after the service date and it is influenced by severity of mastitis, and in the case of milk yield, the negative association is influenced by parity, milk production quartile, and severity of mastitis.     

Late embryonic losses in supplemented grazing lactating dairy cows: Risk factors and reproductive performance

The main objective of this study was to evaluate the risk factors for late embryonic loss (LEL) in supplemented grazing dairy cows. Additional objectives were to assess the incidence of LEL and its association with the reproductive performance of cows. A data set containing productive, reproductive, and health records of 13,551 lactations was used. A retrospective case-control study involving 631 cows with LEL (cases) and 2,524 controls (4 controls per case within each study year) was run. A case of LEL was defined when the embryo had no heartbeat or there was evidence of detached membranes or floating structures including embryo remnants by ultrasonography (US) at 28 to 42 d post-artificial insemination (AI), whereas a non-case was defined as a cow diagnosed with positive pregnancy by US 28 to 42 d post-AI and reconfirmed as pregnant 90 ± 7 d post-AI. Four controls per case were randomly selected from the non-cases with a temporal matching criterion (±3 d around the date of the fecundating AI of the case). Multivariable logistic models were offered with the following predictors: year of LEL (2011 through 2015), season of LEL (summer vs. fall vs. winter vs. spring), parity (1 vs. 2 vs. ≥3), uterine disease (UD), non-uterine disease (NUD), body condition score at parturition, body condition score at 28 to 42 d post-AI (BCS-LEL), days in milk (DIM), and daily milk yield (MY). Statistical significance was set at P < 0.05 and a tendency was set at P ≤ 0.10. We found that 4.7, 22, and 23% of cows had LEL, UD, and NUD, respectively. Cases tended to have higher daily MY than controls (32.5 vs. 31.8 kg); also, cases had much longer calving to pregnancy interval (226 vs. 118 d), lower hazard of pregnancy [hazard ratio = 0.39, 95% confidence interval (CI) = 0.35–0.43], and higher odds for non-pregnancy [odds ratio (OR) = 2.89, 95% CI = 2.37–3.54] than controls. We found that the odds for LEL increased with parity number (OR = 2.48, 95% CI = 1.99–3.08 for parity ≥3) and with BCS-LEL <2.50 (OR = 1.81, 95% CI = 1.33–2.47). Conversely, the odds for LEL decreased with BCS-LEL >3.00 (OR = 0.70, 95% CI = 0.53–0.91). The odds for LEL increased with UD (OR = 1.23, 95% CI = 1.01–1.49), NUD (OR = 1.24, 95% CI = 1.01–1.54), DIM (OR = 1.03, 95% CI = 1.00–1.05), and daily MY (OR = 1.14, 95% CI = 1.04–1.25) in univariable models only. Finally, the odds for LEL were not associated with year, season, DIM, and body condition score at parturition. In conclusion, LEL is associated with extended calving to pregnancy interval, and among its risk factors are parity number and BCS-LEL.     

Effects of prepartum dietary protein level and feed intake on postpartum lactation performance and feeding behavior of multiparous Holstein dairy cows

An experiment was conducted to determine the effects of low and high metabolizable protein (MP) diets when fed for ad libitum and controlled intake during the prepartum period on postpartum lactation performance and feeding behavior of dairy cows. Thirty-six multiparous Holstein cows were blocked by parity, expected calving date, and previous lactation milk yield at −21 d relative to expected calving and were randomly assigned to 1 of 4 close-up period dietary treatments providing low MP (LMP) or high MP (HMP) diets with controlled intake (CNI) or ad libitum intake (ALI). The concentrations of MP were 65 and 90 g/kg dry matter for LMP and HMP diets, respectively, whereas intake was controlled to supply 100 and 160% of the NRC (2001) energy requirements for CNI and ALI groups, respectively. The concentration of net energy for lactation (NE_L) in the treatment diets was 1.50 Mcal/kg. All cows were fed a similar lactation diet after calving (1.50 Mcal/kg of NE_L and 83.3 g/kg of MP). The HMP diet increased dry matter intake during the first 3 wk and tended to increase dry matter intake over the 9 wk of lactation. Meal size and eating rate increased in the ALI cows during the prepartum period. Meal frequency increased with the HMP diet during the postpartum period. Milk yield increased by 15.2% with the HMP diet over the 9 wk of lactation. The HMP diet increased energy-corrected milk (ECM) yield in CNI versus ALI cows, whereas the LMP diet increased ECM yield in ALI versus CNI cows over the 9 wk of lactation. The increase in ECM yield of LMP-ALI versus LMP-CNI cows was supported by greater body condition loss and serum β-hydroxybutyrate over the 9 wk of lactation. Taken together, these data indicate that prepartum controlled intake of a high protein diet can provide the benefits of both strategies.     

Relationships between the concentration of insulin-like growth factor-1 in serum in dairy cows in early lactation and reproductive performance and milk yield

The objective of this study was to evaluate the relationships of different insulin-like growth factor-1 (IGF1) measures [5 distinct IGF1 concentrations on particular days, area under the curve (AUC), and linear regression coefficient] in the postpartum period in lactating dairy cows and reproductive performance. A total of 417 healthy multiparous Holstein-Friesian cows were enrolled in the study. Serum samples for the determination of the concentration of IGF1 were collected on d 0, 4, 10, 20, and 40 postpartum (pp). The concentration of total IGF1 in serum was determined by immunometric chemiluminescence immunoassay. All cows were examined for vaginal discharge as a sign of clinical endometritis at 20 d pp by external inspection and rectal palpation. The mean concentration of IGF1 ranged from 57 ± 18.9 ng/mL within the first 12 h pp to 74 ± 19.9 ng/mL at 40 d pp. On d 10 pp, first and all artificial insemination conception rates were greater in cows with IGF1 concentrations above the median compared with cows with IGF1 concentrations below the median. Cows with greater AUC (second to fourth quartile) conceived earlier (11.4, 16.0, and 18.8 d) than cows in the first IGF1 quartile (117.0 ± 43.6). Proportion of cows pregnant within 200 d pp increased significantly from the first to the third IGF1 quartile of AUC (58.7, 66.7, and 74.0%). The proportion of cows culled decreased from the first to the fourth IGF1 quartile. Correlations between IGF1 measures and days to pregnancy were significant (except for the linear regression coefficients) but low (R² = 0.0009 to 0.025). Differences between single or composite measurements of IGF1 were not significant. We could also demonstrate a statistically significant correlation between the concentration of IGF1 in serum and the average 10-d milk production (31.6 to 44.0 kg). In conclusion, our study indicates that single or multiple measurements of IGF1 concentration in the postpartum period have very limited value to predict individual fertility in dairy cows.     

The relationship between milk metabolome and methane emission of Holstein Friesian dairy cows: Metabolic interpretation and prediction potential

This study aimed to quantify the relationship between CH₄ emission and fatty acids, volatile metabolites, and nonvolatile metabolites in milk of dairy cows fed forage-based diets. Data from 6 studies were used, including 27 dietary treatments and 123 individual observations from lactating Holstein-Friesian cows. These dietary treatments covered a large range of forage-based diets, with different qualities and proportions of grass silage and corn silage. Methane emission was measured in climate respiration chambers and expressed as production (g per day), yield (g per kg of dry matter intake; DMI), and intensity (g per kg of fat- and protein-corrected milk; FPCM). Milk samples were analyzed for fatty acids by gas chromatography, for volatile metabolites by gas chromatography-mass spectrometry, and for nonvolatile metabolites by nuclear magnetic resonance. Dry matter intake was 15.9 ± 1.90 kg/d (mean ± SD), FPCM yield was 25.2 ± 4.57 kg/d, CH₄ production was 359 ± 51.1 g/d, CH₄ yield was 22.6 ± 2.31 g/kg of DMI, and CH₄ intensity was 14.5 ± 2.59 g/kg of FPCM. The results show that changes in individual milk metabolite concentrations can be related to the ruminal CH₄ production pathways. Several of these relationships were diet driven, whereas some were partly dependent on FPCM yield. Next, prediction models were developed and subsequently evaluated based on root mean square error of prediction (RMSEP), concordance correlation coefficient (CCC) analysis, and random 10-fold cross-validation. The best models with milk fatty acids (in g/100 g of fatty acids; MFA) alone predicted CH₄ production, yield, and intensity with a RMSEP of 34 g/d, 2.0 g/kg of DMI, and 1.7 g/kg of FPCM, and with a CCC of 0.67, 0.44, and 0.75, respectively. The CH₄ prediction potential of both volatile metabolites alone and nonvolatile metabolites alone was low, regardless of the unit of CH₄ emission, as evidenced by the low CCC values (<0.35). The best models combining the 3 types of metabolites as selection variables resulted in the inclusion of only MFA for CH₄ production and CH₄ yield. For CH₄ intensity, MFA, volatile metabolites, and nonvolatile metabolites were included in the prediction model. This resulted in a small improvement in prediction potential (CCC of 0.80; RMSEP of 1.5 g/kg of FPCM) relative to MFA alone. These results indicate that volatile and nonvolatile metabolites in milk contain some information to increase our understanding of enteric CH₄ production of dairy cows, but that it is not worthwhile to determine the volatile and nonvolatile metabolites in milk to estimate CH₄ emission of dairy cows. We conclude that MFA have moderate potential to predict CH₄ emission of dairy cattle fed forage-based diets, and that the models can aid in the effort to understand and mitigate CH₄ emissions of dairy cows.     

Ovarian activity and reproductive performance of dairy cows fed different amounts of phosphorus

Fifty-four multiparous Holsteins were utilized to determine the effect of dietary P on ovarian activity and reproductive performance. Cows were assigned at calving to diets containing 0.35 or 0.47% P. Ovarian activity was monitored 3 times weekly by ultrasonography, beginning 10 d after parturition until the end of a 60-d voluntary waiting period. After this period, cows were synchronized and bred using the Ovsynch protocol. During wk 2 of lactation, the number of small (3 to 5 mm in diameter) and large (>9 mm) follicles was similar between groups, but the number of medium (6 to 9 mm) follicles was lower for 0.35% P than for 0.47% P (1.2 vs. 1.9). Dietary P did not affect the number of days to first postpartum ovulation or the diameter of dominant and ovulating follicles. The multiple ovulation rate and the proportion of cows that were anovulatory or developed follicular cysts did not differ between groups. Dietary P amount did not influence corpus luteum development or blood progesterone concentration during the voluntary waiting period. The first service conception rate and pregnancy loss from 30 to 60 d after breeding were not affected. The overall pregnancy rate during the first 200 d of lactation (60.9 and 60.0%) and the number of services per pregnancy (2.1 and 1.9) did not differ between groups. Serum inorganic P was elevated from 6 to 7 mg/dL during the first 3 mo postpartum as dietary P was increased. Fecal P content measured during the first 16 wk of lactation averaged 0.63 and 0.89%, 29% lower for the 0.35% P group. Mean milk yield during the first 40 wk of lactation did not differ, averaging 40.5 and 39.0 kg/d for the 0.35 and 0.47% P groups, respectively. Overall, varying dietary P from 0.35 to 0.47% did not affect postpartum ovarian activity, reproductive performance, or milk production.     

Association of immediate postpartum plasma calcium concentration with early-lactation clinical diseases,culling, reproduction,and milk production in Holstein cows

The objective of this study was to evaluate the association of postpartum plasma Ca concentration with early-lactation disease outcomes, culling within 60 d in milk, pregnancy to first service, and milk production. A total of 1,453 cows from 5 commercial dairy farms in New York State were enrolled in a prospective cohort study from February to November 2015. Blood samples were collected within 12 h of parturition, and plasma was submitted to a diagnostic laboratory for total Ca measurement. Early-lactation disease, reproductive performance, and milk production from Dairy Herd Improvement Association (DHIA) test-day data were compiled from each farm's management software. Multivariable Poisson regression models were built to evaluate the association of plasma Ca with the risks of retained placenta (RP), metritis, displaced abomasum (DA), clinical mastitis, culling within 60 d in milk, and pregnancy to first service. Repeated-measures ANOVA were used to evaluate the association of Ca at parturition with milk production across the first 9 DHIA tests. Herd was considered a random effect in all models. Primiparous cows were modeled separately from multiparous cows if differential responses were observed. Calcium was not associated with the risk of RP, metritis, clinical mastitis, or pregnancy to first service in primiparous or multiparous cows. For multiparous cows only, higher Ca concentration tended to be associated with increased culling within the first 60 d in milk. Multiparous cows with Ca ≤1.85 mmol/L had an increased risk of being diagnosed with a DA compared with cows with Ca >1.85 mmol/L. For the milk production models, Ca was not associated with the amount of milk produced within the first 9 DHIA tests in primiparous cows; however, multiparous cows with Ca ≤1.95 mmol/L produced, on average, 1.1 kg more milk per day across the 9 DHIA tests than their multiparous counterparts with Ca >1.95 mmol/L. Our results indicate that plasma Ca concentration measured within 12 h of parturition is a poor predictor of early-lactation health outcomes. Reduced Ca concentration in the immediate postpartum period was associated with higher milk production in multiparous cows. From these results, we caution that studies attempting to categorize subclinical hypocalcemia based on a single sample in the immediate postpartum period could misclassify the disorder.     

Effects of silymarin, a natural hepatoprotector, in periparturient dairy cows

Silymarin, a natural acknowledged hepatoprotector used in humans to treat liver diseases, has been tested in dairy cows during peripartum, a period during which animals are subject to subclinical fatty liver. Ten grams of silymarin (76% pure extract consisting in flavonolignans, taxifolin, and other trace compounds) per day, was administered as a water suspension by an oral drench to 15 cows from d 10 before expected calving to 15 d after calving. Milk production was measured, and colostrum, milk, and blood samples were analyzed during the experimental period. Treated animals showed the peak of milk production at 55 +/- 1.85 d after calving, 1 wk before the control group (62 +/- 3.27 d); the average peak production was 41.6 +/- 1.05 kg for the treated group vs. 39.1 +/- 1.44 kg for the control; the treated animals maintained a greater milk production than control cows throughout lactation (9922.1 +/- 215.7 vs. 9597.8 +/- 225.4 kg). Milk composition was unaffected by treatment. No silymarin residues were detected in colostrum and all milk samples. After calving, body condition score (BCS) decrease was greater for control compared with treated cows. Glucose, urea, triglycerides (TG), total cholesterol, beta-hydroxibutyrate (BHBA), and gamma-glutamyl transferase (GGT) in plasma were unaffected by treatment. Plasma nonesterified fatty acids (NEFA) on d-7 were higher in treated cows compared with the control group (741 vs. 181 micromol/L). From this evidence, it is possible to conclude that silymarin beneficially affected lactation performances and body condition of treated animals. Blood and milk parameters do not indicate any adverse effects of feeding this natural compound.     

Characteristics of prolonged luteal phase identified by milk progesterone concentrations and its effects on reproductive performance in Holstein cows

A database of milk progesterone profiles consisting 497 lactations in 3 dairy herds from northern and western regions of Japan was used to identify the characteristics and associated risk factors for prolonged luteal phase (PLP) and its effects on subsequent reproductive performance in high-producing Holstein cows. Milk samples were collected twice weekly and progesterone concentrations in whole milk were determined by ELISA. Herds were visited monthly and examined by vaginoscopy and transrectal palpation. Resumption of ovarian cyclicity within 35 d postpartum followed by regular cycles was considered normal. Prolonged luteal phase was defined when progesterone concentrations were ≥5 ng/mL for ≥20 d of duration in any cycle postpartum. Delay of first ovulation to 35 to 60 d (delayed first ovulation type I), >60 d (delayed first ovulation type II), a luteal phase of <14 d except in the first cycle (short luteal phase), and the absence of luteal activity >14 d between 2 cycles (cessation of cyclicity) were the other categories of abnormal ovarian resumptions considered. The overall incidence of PLP in the 3 herds was 11.9% and a significantly higher proportion of PLP was observed in the first cycle postpartum compared with the second and third cycles. Approximately 83% of the PLP were 20 to 28 d in duration, and maximum progesterone concentration was significantly higher when PLP lasted >35 d compared with PLP of 20 to 35 d in duration. Higher parity, commencement of luteal activity ≤28 d postpartum, and postpartum complications significantly increased the occurrence of PLP within 90 d postpartum. Cows with PLP showed reduced conception rate to first artificial insemination (AI) and reduced pregnancy proportions within 100, 150, and 210 d postpartum. Based on survival analysis, PLP was associated with a 56% reduction in relative pregnancy rate and a 36% reduction in AI submission rate. Cows that experienced PLP had a longer interval from calving to first AI (74 d) and from calving to pregnancy (141 d) than cows without PLP (53 and 80 d), respectively. In conclusion, 11.9% of lactations had PLP, of which approximately two-thirds were seen in the first cycle postpartum. Most of the PLP were 20 to 28 d in duration. Higher parity, postpartum complications, and early commencement of luteal activity postpartum increased the risk for PLP. Occurrence of PLP adversely affected fertility by reducing pregnancy proportions and extending calving to conception interval.     

Effects of the dose and viability of Saccharomyces cerevisiae. 2. Ruminal fermentation,performance of lactating dairy cows,and correlations between ruminal bacteria abundance and performance measures

This study examined effects of the dose and viability of supplemented Saccharomyces cerevisiae yeast strain YE1496 on ruminal fermentation and performance of lactating dairy cows. A second objective was to examine correlations between ruminal bacteria abundance and performance measures. Four ruminally cannulated lactating cows (284 ± 18 days in milk) were assigned randomly to 1 of 4 treatment sequences in a 4 × 4 Latin square experimental design using four 21-d experimental periods. Cows were fed a nonacidotic total mixed ration comprising 22.5% starch (minimum ruminal pH >5.8), 41.7% corn silage, 7.60% wet brewers grain, and 50.7% concentrate on a dry matter (DM) basis. The diet was supplemented with no yeast (control), a low (5.7 × 10⁷ cfu/d; LLY) or high (6.0 × 10⁸ cfu/d; HLY) dose of live yeast, or a high dose of killed yeast (6.0 × 10⁸ cfu/d; killed by heating at 80°C for 1.5 h; HDY). Milk production and composition were measured twice daily from d 11 to 21 of each period, and rumen fluid samples were collected on d 21. In vivo digestibility was measured using chromic oxide as a marker. Pearson correlation analysis was used to assess whether animal performance parameters were correlated with relative abundance (RA) of ruminal bacteria. Supplemental LLY increased yields (kg/d) of milk (29.6 vs. 31.7) and milk protein (0.95 vs. 1.03), tended to increase milk fat yield (1.10 vs. 1.17) and ruminal acetate:propionate ratio (1.92 vs. 2.21), and increased in vivo apparent digestibility (%) of DM (64.5 vs. 69.1), neutral detergent fiber (NDF; 45.0 vs. 54.5), and ADF (53.1 vs. 60.9) compared with the control. Feeding HLY had no effects on milk yield compared with the control (30.0 vs. 29.6 kg/d). Feeding HDY tended to increase in vivo digestibility (%) of NDF (45.0 vs. 50.7), ADF (53.1 vs. 57.7), and the ruminal concentration of lactate (0.78 vs. 2.82 mM) but did not affect milk yield compared with the control. Dry matter and NDF digestibility correlated negatively with RA of unclassified Lachnospiraceae in both solid (r = ?0.50 and ?0.52, respectively) and liquid (r = ?0.56 and ?0.57, respectively) fractions, whereas milk yield correlated positively with RA of Lachnospiraceae [Ruminococcus] (an incompletely classified genus; r = 0.43) in the solid ruminal fraction. Supplemental LLY, HLY, or HDY increased or tended to increase DM, NDF, and ADF digestibility, but only LLY increased yields of milk, milk fat, and milk protein.     

Individual and combined effects of anovulation and cytological endometritis on the reproductive performance of dairy cows

The objective was to evaluate the individual and combined effect of anovulation and cytological endometritis (CTE) on the reproductive performance of dairy cows. A total of 1,569 cows from 3 data sets were used. In data set 1, 403 Holstein cows from 5 dairies in New York were used. In data set 2, 750 Holstein cows from 2 dairies, one in Florida and one in California were used. In data set 3, 416 dairy cows, 165 Holsteins, 36 Jerseys, and 215 Holstein-Jersey crossbreeds from a grazing dairy in Florida were used. Cyclicity and CTE was determined at 35 ± 3 (data set 2) or 49 ± 3 d in milk (data sets 1 and 3). A variable (VarCycCTE) containing all 4 possible permutations between cyclicity (cyclic = Cyc; anovular = Anov) and CTE (present = CTE; absent = Healthy) was created. In the combined data set (sets 1, 2, and 3), pregnancy per artificial insemination (P/AI) diagnosed at 30 to 38 d after first AI was affected by VarCycCTE, with AnovCTE cows having decreased P/AI compared with CycHealthy cows (21.3 vs. 46.7%), whereas AnovHealthy (37.9%) and CycCTE cows (36.0%) had intermediate P/AI. Pregnancy per artificial insemination for the individual data sets and for pregnancy diagnosed at 63 to 74 d after artificial insemination followed a similar pattern. Pregnancy loss was not affected by VarCycCTE. Hazard of pregnancy up to 300 d in milk was affected by VarCycCTE in the combined data sets 1 and 2, with AnovCTE [hazard ratio (HR) = 0.55], AnovHealthy cows (HR = 0.71), and CycCTE (HR = 0.8) having decreased hazard of pregnancy compared with CycHealthy cows. Median days open were 200, 159, 145, and 121 for AnovCTE, AnovHealthy, CycCTE, and CycHealthy, respectively. Hazard of pregnancy for the individual data sets followed a similar pattern. In summary, both anovulation and CTE were negatively associated with reproductive performance and, when combined, they had an additive negative effect.     

Direct-fed microbial supplementation and health and performance of pre- and postpartum dairy cattle: a field trial

A double-blind field trial was conducted on a commercial dairy to study the effects of feeding a direct-fed microbial (DFM) product consisting of 2 strains of Enterococcus faecium plus Saccharomyces cerevisiae yeast on prepartum and postpartum performance of Holstein cows. Treatments consisted of the normal pre- and post-fresh TMR supplemented with the DFM (2 g/cow per d) or a placebo. Treatments started approximately 10 d prepartum and continued until about 23 d in milk (DIM). A total of 366 Holstein cows were enrolled in 1 of 2 placebo groups or 2 DFM-supplemented groups. Groups were enrolled consecutively, starting with the placebo treatment. Sample size was limited to 4 groups because the cooperating dairy prematurely terminated the study due to increased health problems in one of the groups. Blood samples were taken during the prefresh period between 2 and 10 d prior to calving and at weekly intervals from 3 to 23 DIM. Blood concentrations of nonesterified fatty acids before calving and β-hydroxy-butyrate after calving were not affected by treatment. Supplementation with the DFM product increased milk fat percentage for the first lactation cows and increased milk protein percentage for the second and greater lactation cows during the first 85 DIM. Second-lactation cows fed the DFM product received fewer antibiotic treatments before 85 DIM than cows receiving the placebo. This validated the dairy producer's concern that cows consuming one of the diets (revealed to be the placebo diet after the study was completed) were experiencing more health problems. Most measures of milk yield were numerically increased by supplementation with the DFM product. However, differences in milk yield were not significant. Key covariates for main study outcomes included milk yield in the previous (first) lactation, body condition score prior to calving, days spent in the maternity pen, and stocking density of the pre-fresh pen.     

Associations between time in the close-up group and milk yield,milk components,reproductive performance,and culling of Holstein dairy cows fed acidogenic diets: A multisite study

The objective of this prospective cohort study was to evaluate the association between the prepartum days in the close-up group (DINCU) and milk yield, milk components, reproductive performance, and culling risk in the subsequent lactation for Holstein dairy cows. Dry cow feeding management of 20 farms was evaluated during 2 farm visits. All farms were feeding an acidogenic diet in the close-up group. Data from 14,843 cows were collected for 365 d following the second farm visit. Data sets of 13,314 cows were available for final statistical analysis after exclusion of cows with missing information about gestation length, cows with a gestation length shorter than 262 d or longer than 292, cows with 0 DINCU, and cows with >42 DINCU. At enrollment, 3,871 and 9,443 of those animals were nulliparous and parous cows, respectively. Continuous data such as energy corrected milk (ECM), the ratio of fat and protein, and somatic cell score (SCS) at first test day were analyzed using linear mixed models. Binary data such as stillbirth, culling within 60 DIM, and pregnancy within 150 DIM were analyzed using logistic regression models. Based on their different physiology, separate models were built for nulliparous and parous cows. All results displayed are the predicted least squares means from the multivariable analyses. A significant association between DINCU and milk yield at first test day was observed for nulliparous and parous cows. Nulliparous cows with 7, 21, or 35 DINCU had a first test day ECM of 31.8, 33.3, and 35.5 kg, respectively. Parous cows with 7, 21, or 35 DINCU had a first test day ECM of 42.8, 45.6, and 44.6 kg of ECM, respectively. In nulliparous cows, there was a tendency for an association between DINCU and the ratio of fat and protein at first test day. In parous cows, however, a significant association was observed. Parous cows with 7, 21, or 35 DINCU had a ratio of fat and protein of 1.31, 1.35, and 1.37, respectively. There was a significant association between DINCU and SCS at first test day in nulliparous and parous cows. In nulliparous cows with 7, 21, or 35 DINCU, SCS was 2.39, 2.49, and 2.85, respectively. In parous cows with 7, 21, or 35 DINCU, SCS was 2.46, 2.53, and 2.78, respectively. No associations were observed between DINCU and occurrence of stillbirth and DINCU and the risk of pregnancy within 150 DIM. The multivariable model predicted a tendency for an association between DINCU and the risk of being culled within 60 DIM in parous cows. Particularly, 0 to 6 DINCU were associated with a substantially increased risk of being culled. In conclusion, a short stay in the close-up group should be avoided to improve milk yield at first test day and to minimize culling risk for parous cows. A long stay in the close-up group (>30 d) was associated with reduced milk production and an increased ratio of fat and protein in milk of parous cows and increased SCS of nulliparous and parous cows.