N. Chapinal

The association of serum metabolites with clinical disease during the transition period

The objective of this observational field study was to validate the relationship of serum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and calcium with disease in early lactation across different management systems. Fifty-five Holstein freestall dairy herds located across the United States and Canada were selected and visited weekly for blood sample collection from 2,365 cows. Only diseases that were consistently recorded across herds and blood samples collected before the disease occurred were considered. Metabolite concentrations in serum in wk -1 relative to calving were considered as predictors of retained placenta (RP) and metritis, and metabolite concentrations in serum in wk -1 and wk +1 relative to calving were considered as predictors of displaced abomasum (DA). For each disease, each metabolite, and week of sampling in the case of DA, a critical threshold was calculated based on the highest combined sensitivity and specificity and used to categorize the serum concentrations into high and low risk categories. Multivariable logistic regression models were built for each disease of interest and week of sampling, considering cow as the experimental unit and herd as a random effect. Cows with precalving serum NEFA concentrations ≥ 0.3 mEq/L were more likely to develop RP [odds ratio (OR) = 1.8; 95% confidence interval (CI) = 1.3 to 2.6] and metritis (OR = 1.8; 95% CI = 1.5 to 2.9) after calving than cows with lower NEFA concentrations. Precalving NEFA ≥ 0.5 mEq/L (OR = 2.4; 95% CI = 1.5 to 3.7), postcalving NEFA ≥ 1.0 mEq/L (OR = 2.7; 95% CI = 1.7 to 4.4), and postcalving calcium ≤ 2.2 mmol/L (OR = 3.1; 95% CI = 1.9 to 5.0) were associated with subsequent risk of DA. In conclusion, elevated serum NEFA concentrations within 1 wk before calving were associated with increased risk of RP, metritis, and DA after calving. Serum NEFA and calcium concentrations in the 2 wk around calving in combination were associated with the risk of DA.

Using gait score, walking speed, and lying behavior to detect hoof lesions in dairy cows

The objective was to determine whether changes in the different components of gait, walking speed, and lying behavior were associated with hoof pathologies in lactating Holstein cows. In experiment 1, 53 cows had their gait scored, their walking speed estimated, and their lying behavior monitored before clinical assessment of the hooves. Multiparous cows with ulcers scored higher than cows without ulcers for overall gait score [numerical rating score (NRS); 3.3 +/- 0.2 vs. 2.8 +/- 0.2], back arch, joint flexion, asymmetric steps, and reluctance to bear weight. Although cows with ulcers did not walk more slowly than cows without ulcers (1.4 m/s), they spent more time lying down (827.8 +/- 29.1 vs. 738.2 +/- 15.5 min/d) because of longer lying bouts (93.3 +/- 5.9 vs. 79.7 +/- 3.4 min). In experiment 2, 47 cows were monitored for hoof health and changes in gait score from 4 wk before to 24 wk after calving. Differences were found after calving between cows that developed an ulcer and cows that did not for NRS (3.1 +/- 0.1 vs. 2.35 +/- 0.1), back arch, joint flexion, asymmetric steps, and reluctance to bear weight. Numerical rating score, back arch, and asymmetric steps were able to discriminate cows with ulcers at least 4 wk before the diagnosis. Cows that developed a sole ulcer had a faster decline in lying time during the periparturient period and a faster increase beginning in wk 2 after calving. The NRS was a more consistent predictor of sole ulcers than lying behavior or speed. The NRS was able to discriminate cows with ulcers across studies at a high intraobserver accuracy and reasonable specificity and was able to predict the presence of ulcers at least 4 wk before diagnosis. Abduction/adduction of the rear legs, head bob, and tracking-up did not consistently discriminate cows with ulcers, and we suggest that these measures are less useful for on farm gait assessment. Compared with the other gait attributes, back arch, joint flexion, asymmetric steps, and reluctance to bear weight best predicted the presence of sole ulcers.

The association of serum metabolites in the transition period with milk production and early-lactation reproductive performance

The objective was to examine the associations of peripartum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and calcium with milk production in early lactation and pregnancy at the first artificial insemination (AI) across different management systems. Fifty-five Holstein freestall dairy herds located across the United States and Canada were visited weekly for blood sample collection from 2,365 cows. For each week of sampling (from wk -1 through wk 3 relative to calving) and for each metabolite, serum concentrations were dichotomized at various thresholds to identify the thresholds with the best negative associations with milk production and pregnancy at first AI. These thresholds were used to categorize the serum concentrations into higher and lower risk categories. Repeated-measures ANOVA and multivariable logistic regression were conducted for milk production and pregnancy at the first AI data, respectively, considering cow as the experimental unit and herd as a random effect. In the week before calving, serum NEFA ≥ 0.5 mEq/L, BHBA ≥ 600 μmol/L, and calcium ≤ 2.1 mmol/L were associated with 1.6 to 3.2 kg/d milk loss across the first 4 Dairy Herd Improvement Association (DHIA) milk tests. High levels of NEFA and BHBA in wk 1 and 2 after calving (≥ 0.7 and ≥ 1.0 mEq/L for NEFA, and ≥ 1,400 and ≥ 1,200 μmol/L for BHBA), and low levels of calcium (≤ 2.1 mmol/L) in wk 1, 2 and 3 after calving were associated with milk loss at the first DHIA milk test. Serum concentrations of NEFA and BHBA were not associated with pregnancy at first AI in any sampling week, whereas calcium <2.2 to 2.4 mmol/L from wk 1 through wk 3 postpartum were associated with reduced pregnancy at first AI. In conclusion, high serum concentrations of NEFA, BHBA, and low concentrations of calcium around parturition were associated with early lactation milk loss, and low calcium concentration around parturition was associated with impaired early lactation reproduction.

Prepartum feeding behavior is an early indicator of subclinical ketosis

Cows diagnosed with subclinical ketosis (SCK) after calving are at increased risk of developing other diseases and compromised reproductive performance. The objective of this study was to determine whether changes in feeding and social behaviors during the transition period were associated with SCK during the week after calving. Feeding behaviors of 101 Holstein dairy cows were monitored from 3 wk before to 3 wk after calving. Ten otherwise healthy animals were identified as having SCK by serum beta-hydroxybutyrate levels >or=1,000 micromol/L taken during wk +1. These animals were matched by parity with 10 healthy animals. During the week before calving and the 2 wk after calving, animals with SCK had lower dry matter intake, had fewer visits to the feeder, and spent less time at the feeder than healthy animals. For every 10-min decrease in average daily time spent at the feeder during the week before calving, the risk of SCK increased by 1.9 times. During the same week, a 1-kg decrease in average daily dry matter intake increased the risk of SCK by 2.2 times. The largest increase in risk of SCK was associated with a 1-kg increase in the change in average daily intake from wk -2 to -1. During the week before calving, animals with SCK initiated fewer displacements at the feed bunk compared with animals that remained healthy after calving. The results of this study provide evidence that time spent feeding, dry matter intake, and social behavior play an important role in transition cow health. These results indicate that special consideration should be given to management and social factors that can negatively affect dry matter intake and feed bunk attendance during the transition period.

Metabolic parameters in transition cows as indicators for early-lactation culling risk

A retrospective cohort study was performed with the objective of determining whether the serum concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), or calcium were associated with the risk of culling within 60 d in milk (DIM) in Holstein cows, and to establish thresholds for each metabolite that were predictive of increased culling risk. Data from 5,979 cows in Ontario (Canada) and several US states were obtained from 4 previously reported studies. For each metabolite and each of 3 sampling weeks (-1, +1, and +2 relative to calving), an optimal threshold was calculated based on having the maximum combined sensitivity (Se) and specificity (Sp) and used to categorize the serum concentrations into high and low risk groups. Logistic regression models were built for each metabolite and each week of sampling, as well as considering together all metabolites in wk -1 and wk +1 relative to calving. Cow was considered the experimental unit and herd as a random effect. Considered separately, precalving NEFA ≥ 0.4 mmol/L [odds ratio (OR)=1.8; 95% confidence interval (CI)=1.4 to 2.2], NEFA ≥ 0.8 mmol/L in wk +1 relative to calving (OR=2.0; 95% CI=1.5 to 2.6) and NEFA ≥ 0.8 mmol/L in wk +2 (OR=4.2; 95% CI=1.9 to 9.4 for cows in lactation 2; OR=2.1; 95% CI=1.4 to 3.3 for cows in lactation ≥ 3) were each associated with an increased risk of culling within the first 60 DIM. Similarly, BHBA ≥ 0.7 mmol/L in wk -1 (OR=1.8; 95% CI=1.3 to 2.5), BHBA ≥ 1.2 mmol/L in wk +1 (OR=1.8; 95% CI=1.4 to 2.2), and BHBA ≥ 1.6 mmol/L in wk +2 (OR=3.2; 95% CI=1.6 to 6.4 for cows in lactation 2; OR=2.3; 95% CI=1.6 to 3.3 for cows in lactation ≥ 3) were each associated with an increased risk of culling within the first 60 DIM. Likewise, calcium ≤ 2.3 mmol/L in wk -1 (OR=1.6; 95% CI=1.2 to 2.2), calcium ≤ 2.2 mmol/L in wk +1 (OR=1.5; 95% CI=1.2 to 1.9), and calcium ≤ 2.3 mmol/L in wk +2 (OR=2.3; 95% CI=1.1 to 3.1) were each associated with an increased risk of culling within the first 60 DIM. When all metabolites were analyzed together, serum NEFA and calcium concentrations in wk -1 and serum NEFA concentration in wk +1 remained in the models. In conclusion, elevated serum NEFA and BHBA concentrations and lower serum calcium concentrations within 1 wk before calving through 2 wk after calving were associated with an increased risk of culling in early lactation. Measuring the concentration of selected metabolites around parturition may help to develop monitoring and intervention strategies to prevent early culling in transition dairy cows.

Short-term effects of regrouping on behavior of prepartum dairy cows

The objectives were to determine the effect of regrouping during the dry period on feeding, social, rumination, and lying behavior for cows that were moved to a new pen and cows that remained in their home pen but had new cows introduced. Forty-eight prepartum Holstein dairy cows were housed in groups of 6 and regrouped in groups of 3 (16 triads) with 1 triad moving to another pen and 1 triad staying in the same pen; the triad was considered the experimental unit. For 7 d before and 8 d after regrouping, cows were continuously monitored for feeding, rumination, and lying behavior by means of an electronic feeding system, a rumination logger on each cows neck, and a data logger attached to 1 of the hind legs, respectively. Video recording was used to monitor displacements at the feeder for 3h following the afternoon fresh feed delivery before regrouping and for the 2 subsequent afternoon feed deliveries after regrouping. Cows that were moved to a new pen after regrouping decreased DMI by approximately 9% on the day of regrouping compared with baseline values, but cows that remained in their home pen showed no significant decrease in intake after regrouping. Feeding rate decreased in both treatments by 10% after regrouping. Rumination times also decreased by approximately 9% in both treatments, reaching the lowest values on the day of regrouping for cows that stayed in the home pen and on the day after regrouping for the moved cows. Cows that were moved to a new pen displaced other cows at the feeder twice as frequently after regrouping, but no such effect of regrouping on cows that stayed in the home pen was observed. These results indicate that regrouping can affect behavior of prepartum dairy cows, especially those cows that are moved to a new pen.

Herd-level association of serum metabolites in the transition period with disease, milk production, and early lactation reproductive performance

The objective was to identify herd-level indicators expressed as a proportion of sampled animals with increased nonesterified fatty acids (NEFA) or β-hydroxybutyric acid (BHBA), or decreased calcium in wk -1 and wk +1 relative to calving that were associated with herd-level incidence of retained placenta, metritis and displaced abomasum, milk production, and probability of pregnancy at the first artificial insemination (AI). Fifty-five Holstein freestall dairy herds in the United States and Canada were visited weekly. Blood was collected from 2,365 cows around parturition, and serum concentrations of NEFA, BHBA, and calcium were determined. Different cow-level metabolite thresholds associated with detrimental health or productivity in previous studies were used to classify animals into high- and low-risk metabolite concentration groups. For wk -1 and wk +1 relative to calving, a herd-level threshold was determined as the proportion of sampled animals in the high-risk metabolite concentration groups with the strongest association with increased incidence of disease, milk loss, or decreased pregnancy at the first AI. The odds of displaced abomasum after calving were higher in herds that had ≥ 25% of the animals with BHBA ≥ 1,400 μmol/L in wk +1 [odds ratio (OR)=2.1; 95% confidence interval (CI)=1.0-4.2)] or ≥ 35% of the animals with calcium ≤ 2.1 mmol/L in wk +1 (OR=2.4; CI=1.3-4.3). Herd-level thresholds of ≥15% of the cows with BHBA ≥ 800 μmol/L in wk -1 and ≥ 15% of the cows with calcium ≤2.1mmol/L in wk +1 were associated with milk loss (±SE) of 4.4±1.7 and 3.8 ± 1.4 kg/d per cow, respectively. When only multiparous cows were considered, herds with ≥30% of the multiparous cows with NEFA ≥0.5 mEq/L in wk -1 were associated with a 3.0 ± 1.5 kg/d per cow milk loss. The odds of pregnancy at first AI were lower in herds that had ≥ 5% of the cows with calcium ≤ 2.1 mmol/L in wk -1 (OR=0.7; CI=0.5-1.0), or ≥ 30% of the cows with NEFA ≥ 1.0 mEq/L (OR=0.6; CI=0.4-0.9) or ≥ 25% of the cows with calcium ≤2.1 mmol/L in wk +1 (OR=0.7; CI=0.5-0.9). When only multiparous cows were considered, the odds of pregnancy at first AI were lower in herds that had ≥50% of multiparous cows with NEFA ≥0.5 mEq/L in wk -1 (OR=0.5; CI=0.2-0.9). In conclusion, several herd-level thresholds for the proportion of cows with increased NEFA or BHBA, or decreased calcium in the week before and after calving were associated with higher risk of displaced abomasum, milk loss at the first Dairy Herd Improvement Association test, and decreased pregnancy at first AI. The association found between precalving BHBA and milk production is promising due to the availability of several cow-side tests for measuring BHBA. Some of the herd-level associations differed from the previously described cow-level associations, suggesting the potential of interpreting periparturient metabolic challenges at the herd level, where changes in diet and management are generally implemented.

Rumination and its relationship to feeding and lying behavior in Holstein dairy cows

The objective of this study was to describe the relationship between rumination and feeding and lying behavior in dairy cows. Rumination time was monitored electronically using HR-Tags (SCR Engineers Ltd., Netanya, Israel). Feeding time and dry matter intake (DMI) were monitored using Insentec feed bins (Insentec BV, Marknesse, the Netherlands). All measures were collected in 2-h periods for 42 mature Holstein cows for a minimum of 9 d in the early dry period. Pearson correlation was used to describe associations, among 2-h periods within cow, first examining the relationship within a single period, and then modeling how this relationship changes when a lag of 2, 4, or 6h was imposed. Periods when cows spent more time ruminating were associated with lower feeding times and lower DMI (r = -0.71 and r = -0.72, respectively), likely because cows were unable to feed and ruminate simultaneously. The correlations with rumination time changed from negative to positive when lags of 2, 4, and 6h were modeled (r = -0.09, 0.24, and 0.15, and r = -0.16, 0.23, and 0.17 for feeding time and DMI at lags of 2, 4, and 6h, respectively). These results indicate that following periods of high feeding times and intakes, cows spent more time ruminating. This relationship peaks at approximately 4h after feeding. Periods of rumination were also associated with time spent lying down. Cows that spent more time ruminating per day, spent less time feeding (r = -0.34) and rumination times did not relate to DMI (r = 0.11). These data indicate that rumination time can be used to estimate within-cow variation in feeding behavior and intake, but daily summaries of rumination behavior are a poor indicator of DMI.

Herd-level risk factors for lameness in freestall farms in the northeastern United States and California

The objective was to investigate the association between herd-level management and facility design factors and the prevalence of lameness in high-producing dairy cows in freestall herds in the northeastern United States (NE; Vermont, New York, Pennsylvania) and California (CA). Housing and management measures such as pen space, stall design, bedding type, and milking routine were collected for the high-producing pen in 40 farms in NE and 39 farms in CA. All cows in the pen were gait scored using a 1-to-5 scale and classified as clinically lame (score ≥3) or severely lame (score ≥4). Measures associated with the (logit-transformed) proportion of clinically or severely lame cows at the univariable level were submitted to multivariable general linear models. In NE, lameness increased on farms that used sawdust bedding [odds ratio (OR)=1.71; 95% confidence interval (CI)=1.06-2.76] and decreased with herd size (OR=0.94; CI=0.90-0.97, for a 100-cow increase), use of deep bedding (OR=0.48; CI=0.29-0.79), and access to pasture (OR=0.52; CI=0.32-0.85). The multivariable model included herd size, access to pasture, and provision of deep bedding, and explained 50% of the variation in clinical lameness. Severe lameness increased with the percentage of stalls with fecal contamination (OR=1.15; CI=1.06-1.25, for a 10% increase) and with use of sawdust bedding (OR=2.13; CI=1.31-3.47), and decreased with use of deep bedding (OR=0.31; CI=0.19-0.50), sand bedding (OR=0.32; CI=0.19-0.53), herd size (OR=0.93; CI=-0.89-0.97, for a 100-cow increase), and rearing replacement heifers on site (OR=0.57; CI=0.32-0.99). The multivariable model included deep bedding and herd size, and explained 59% of the variation of severe lameness. In CA, clinical lameness increased with the percentage of stalls containing fecal contamination (OR=1.15; CI=1.05-1.26, for a 10% increase), and decreased with herd size (OR=0.96; CI=0.94-0.99, for a 100-cow increase), presence of rubber in the alley to the milking parlor (OR=0.46; CI=0.28-0.76), distance of the neck rail from the rear curb (OR=0.97; CI=0.95-0.99, for a 1-cm increase), water space per cow (OR=0.92; CI=0.85-0.99, for a 1-cm increase), and increased frequency of footbaths per week (OR=0.90; CI=081-0.99, for a 1-unit increase). The multivariable model included herd size, percentage of stalls containing fecal contamination, and presence of rubber in the alley to the milking parlor, and explained 44% of the variation of clinical lameness. Severe lameness increased with the percentage of stalls containing fecal contamination (OR=1.23; CI=1.06-1.42, for a 10% increase) and decreased with frequency of manure removal in the pen per day (OR=0.72; CI=0.53-0.97, for a 1-unit increase). The final model included both variables and explained 28% of the variation in severe lameness. In conclusion, changes in housing and management may help decrease the prevalence of lameness on dairy farms, but key risk factors vary across regions.

Temporal feed restriction and overstocking increase competition for feed by dairy cattle

Dairy cows are often overstocked. Some managers are now using slick bunk (i.e., feeding for 0% orts) management to save on feed costs, but this reduces the time that cows have access to feed. Both practices may increase competition and affect feeding behavior in dairy cows. The aim was to determine the effects of temporal and spatial restrictions on the feeding and competitive behavior of group-housed cows. Treatments were 2 levels of stocking (2:1 versus 1:1 cows:feed bin) and 2 levels of feed access time (14 versus 24h/d access). Eight groups (each of 6 cows) were tested on each of the 4 treatment combinations for 1 wk, with treatment order assigned using a replicated 4×4 Latin square design. Dry matter intake (DMI), feeding time, and feeding rate were measured for the last 4d of each week, and data were summarized daily and for the 2-h period immediately after the morning feeding. Displacements were recorded for 2h after the delivery of morning feed (peak feeding period) and 2h following the afternoon milking. The DMI did not decline when temporal access was restricted (27.0 vs. 25.7±0.5 kg/d), and was not affected by overstocking (26.4±1.9, mean ± SD). Cows with restricted temporal access spent less time feeding (190.9 vs. 207.9±6.1 min). Overstocked cows that were temporally restricted had greater feeding rates during the day (156 vs. 137±4 g/min) and especially during the peak feeding period (175 vs. 146±4 g/min) compared with cows that were not restricted. In the peak feeding period, overstocked cows had reduced DMI (3.0 vs. 3.4±0.1 kg/h) and feeding times (20.8 vs. 25.8±1.0 min/h) and increased feeding rates (161 vs. 138±4 g/min). Cows with restricted temporal access had greater DMI (3.9 vs. 2.6±0.2 kg/h) and time spent feeding (27.3 vs. 19.2±1.3 min/h) during the peak feeding period compared with cows that had continuous access to feed. Restricting temporal access in conjunction with overstocking resulted in the greatest increase in daily displacements (15.0 vs. 3.8±1.4 displacements/d); the majority of these occurred during the peak feeding period. Adequate space and time to access feed is essential to minimize feed bunk competition in indoor group housing systems.