Department of Animal Sciences, Colorado State University, Fort Collins, CO, 80523-1171, USA.
Aurora Organic Farms, Platteville, CO, 80651-9009, USA.
BMC Vet Res. 2021 Apr 29;17(1):178. doi: 10.1186/s12917-021-02881-2.
Hypocalcemia has detrimental effects on health and performance of dairy cows. As hypocalcemic cows show reduced feed intake, we hypothesized that cows with reduced combined rumination and eating time (CRET) may benefit from Ca supplementation. The objective was to evaluate the effect of postpartum oral Ca administration on metabolic status (Calcium [Ca], fatty acids [FA], and β-Hydroxybutyrate [BHB] serum concentrations) and incidence of puerperal metritis (PM) in dairy cows with reduced postpartum CRET. Cows in an organic-certified dairy, diagnosed with reduced CRET (< 489 min/d; n = 88) during the first day postpartum were assigned into 1 of 2 treatments: i) Calcium administration (CA; n = 45) that received 1 Ca oral capsule (Bovikalc bolus, Boehringer Ingelheim, St. Joseph, MO) containing CaCl2 and CaSO4 (43 g of Ca) once per day, for 3 consecutive days, starting at d 1 postpartum; and ii) Control (CON; n = 43) that did not receive oral Ca. A convenience group consisting of cows with CRET ≥489 min/d was used for comparison and did not receive oral Ca (NOR; n = 96).
At day 1 postpartum cows with reduced CRET had lower Ca serum concentrations (CA = 2.08 mmol/L; CON = 2.06 mmol/L) compared with NOR cows (2.17 mmol/L). Calcium concentrations at d 3, 5, and 12 postpartum were not different among the three groups. Serum FA concentrations at d 1, 3 and 5 postpartum were higher in both CA and CON cows compared with NOR. At d 12, only CA cows had higher FA concentrations than NOR cows. Serum BHB concentrations at d 3 were highest in CA, with no difference between CON and NOR. At d 5, BHB concentrations were higher in CA, followed by CON, and NOR. No effect was observed for Ca administration on incidence of PM and reproductive performance. CON cows had lower survival at 30 DIM (86.5%) than NOR cows (97.9%).
The use of remote sensor technology identified cows with reduced rumination and eating time that had lower postpartum serum concentrations of calcium and altered metabolic status. However, oral calcium administration to cows with reduced CRET did not affect incidence of metabolic disorders nor reproductive health and subsequent pregnancy. Although survival at 30 days postpartum was lower for non-Ca supplemented cows, the identification of effective interventions in cows with reduced CRET requires further consideration.
低钙血症会对奶牛的健康和生产性能产生不利影响。由于低钙血症的奶牛采食量减少，我们假设减少反刍和进食时间（CRET）的奶牛可能受益于钙补充。本研究旨在评估产后口服补钙对奶牛代谢状态（钙、脂肪酸[FA]和β-羟丁酸[BHB]血清浓度）和产后子宫炎（PM）发病率的影响，这些奶牛在产后第一天被诊断为 CRET 减少（<489 分钟/天；n=88）。产后第一天被诊断为 CRET 减少（<489 分钟/天；n=88）的奶牛，被分配到以下 2 种处理之一：i）钙处理（CA；n=45），每天口服 1 个含有 CaCl2 和 CaSO4（43g 钙）的 Bovikalc 丸（Boehringer Ingelheim，圣约瑟夫，密苏里州），连续 3 天，从产后第 1 天开始；ii）对照组（CON；n=43），不接受口服钙。使用方便组（CRET≥489 分钟/天）的奶牛作为对照，且不接受口服钙（NOR；n=96）。
产后第 1 天，与 NOR 组（2.17mmol/L）相比，CRET 减少的奶牛血清钙浓度较低（CA=2.08mmol/L；CON=2.06mmol/L）。产后第 3、5 和 12 天，三组间血清 FA 浓度无差异。产后第 1、3 和 5 天，CA 和 CON 组的血清 FA 浓度均高于 NOR 组。产后第 12 天，只有 CA 组的 FA 浓度高于 NOR 组。产后第 3 天，CA 组的血清 BHB 浓度最高，CON 和 NOR 组之间没有差异。产后第 5 天，CA 组的 BHB 浓度最高，其次是 CON 组和 NOR 组。钙补充对 PM 和生殖性能的发生率没有影响。CON 组奶牛在 30 天 DIM（86.5%）的存活率低于 NOR 组（97.9%）。
使用远程传感器技术可以识别出反刍和进食时间减少的奶牛，这些奶牛产后血清钙浓度较低，代谢状态发生改变。然而，对 CRET 减少的奶牛进行口服补钙并不能影响代谢紊乱或生殖健康及随后的妊娠发生率。尽管未补充钙的奶牛在 30 天产后的存活率较低，但仍需进一步考虑针对 CRET 减少的奶牛进行有效的干预措施。
