The effect of prepartum feeding and lying space on metabolic health and immune function.

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

Short communication: The effect of calcium supplementation at calving on neutrophil function.

Low total blood calcium concentration after calving has been demonstrated to be a risk factor for reduced neutrophil function. The objective of this study was to evaluate whether administration of an injectable calcium supplement product soon after calving increased neutrophil oxidative burst or phagocytosis capacity. Cows (n = 27) from 4 farms were blocked by parity and randomly assigned to receive either calcium gluconate (35% wt/vol) in combination with calcium glucoheptonate (10% wt/vol; Theracalcium, Vétoquinol Canada Inc., Lavaltrie, Quebec, Canada) or a placebo within 12 h after calving and again 24 h later. Each dose of 120 mL was injected subcutaneously over 2 sites. Total serum calcium concentration, neutrophil oxidative burst, and neutrophil phagocytosis capacity were measured from coccygeal blood samples before (time 0) and 72 h after first treatment. There was no difference between treatment groups in lactation number, total calcium concentration, oxidative burst, or phagocytosis at time of enrollment. There was no effect of treatment on oxidative burst or phagocytosis by neutrophils. This preliminary study does not support an effect of supplemental calcium to improve neutrophil oxidative burst or phagocytosis capacity of low-parity parturient cows.

Effects of local anesthetic or systemic analgesia on pain associated with cautery disbudding in calves: A systematic review and meta-analysis.

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. This may in part be due to the lack of a consistent recommendations of treatment protocols between studies examining pain control methods for disbudding. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding, cautery, on outcomes associated with disbudding pain in calves. The outcomes were plasma cortisol concentrations, pressure sensitivity of the horn bud area, and validated pain behaviors (ear flick, head shake, head rub, foot stamp, and vocalization). Intervention studies describing cautery disbudding in calves 12 wk of age or younger were eligible, provided they compared local anesthesia, nonsteroidal anti-inflammatory drug (NSAID), or local anesthesia and NSAID to 1 or more of local anesthesia, NSAID, or no pain control. The search strategy used the Agricola, Medline (via OvidSP), and Web of Science databases, as well as the Searchable Proceedings of Animal Conferences (S-PAC), ProQuest Dissertations and Theses Database, and Open Access Theses and Dissertations. Meta-analysis was performed for all outcomes measured at similar time points with more than 2 studies. Local anesthetic was associated with reduced plasma cortisol until 2 h postdisbudding; however, a rise in cortisol was observed in the meta-analysis of studies reporting at 4 h postdisbudding. Heterogeneity was present in several of the analyses for this comparison. The addition of NSAID to local anesthetic showed reduction in plasma cortisol at 4 h, and a reduction in pressure sensitivity and pain behaviors in some analyses between 3 and 6 h postdisbudding. Heterogeneity was present in some meta-analyses, including several using pain behavior outcomes. This may reflect the variation in measurement time periods for behavioral measures between studies, as well as differences among NSAID treatments. Overall, a protective effect of local anesthetic was seen for the acute pain of cautery disbudding, and the delayed rise in cortisol was mitigated by the addition of an NSAID, which also reduced other signs of pain, including pressure sensitivity and pain behaviors. Based on these findings, we recommend use of local anesthetic and an NSAID as best practices for pain mitigation for cautery disbudding of calves 12 wk of age or less. The magnitude and duration of the effect of NSAID treatment was not possible to deduce from the literature because wide variation existed between studies. We recommend consideration of more standardized outcome measurements, especially for pain behaviors. Adherence to reporting guidelines by authors would help ensure more transparent and complete information is available to end users.

Randomized clinical trial of a calcium supplement for improvement of health in dairy cows in early lactation.

Prophylactic Ca supplementation immediately after calving is a common strategy to prevent clinical and subclinical hypocalcemia in parturient dairy cows. The objective of this study was to evaluate the effect of prophylactic administration of an injected Ca supplement on blood Ca concentration at 24 and 48h after treatment, incidence risk of clinical disease and culling, milk production in early lactation, and probability of pregnancy at first insemination. Cows without signs of visible milk fever (n=984) from 7 farms were blocked by parity and randomly assigned to receive either Ca gluconate (35% wt/vol) in combination with Ca glucoheptonate (10% wt/vol; TheraCalcium, Vétoquinol Canada Inc., Lavaltrie, Quebec) or a placebo (medication vehicle solution with no Ca) at first contact with each cow after calving and again 12 to 24h later. Each dose was 120mL injected subcutaneously over 2 sites. Total serum Ca concentration (tCa) was measured from coccygeal blood samples before (time 0) and 24 and 48h after first treatment in a subsample of cows (n=129). Blood ß-hydroxybutyrate concentrations were measured from all cows twice between 3 and 16d in milk at weekly visits and cows were evaluated for vaginal discharge once between 28 and 42d in milk. Disease events, production data from the first 3 Dairy Herd Improvement milk tests, reproduction, and culling data were collected from each herd. For cows that had received 1 injection of Ca before the blood sample at 24h (n=95), tCa was significantly higher in the treated cows: mean ± standard error, 2.03±0.03 versus 1.90±0.03mmol/L, accounting for tCa at time of enrollment and a treatment by tCa at enrollment interaction. At 48h, no significant difference was found in tCa between treatment and control (mean ± SE, 2.12±0.02 and 2.10±0.03mmol/L, respectively). Cows treated with the Ca product were significantly less likely to have received intravenous, subcutaneous, or oral supplemental Ca for exhibiting clinical signs of hypocalcemia than control cows (5.0 vs. 8.4%). No effect was found of treatment on retained placenta, metritis, hyperketonemia, prevalence of purulent vaginal discharge, culling from the herd, early lactation production, probability of pregnancy to first artificial insemination, or time to pregnancy. With this subcutaneous prophylactic Ca treatment regimen, blood Ca levels were temporarily increased at 24h after treatment, but no effect was observed of supplemental Ca on the risk of disease or culling, milk production, or reproductive performance.