Department of Veterinary Population Medicine, University of Minnesota, St. Paul 55108, USA.
J Dairy Sci. 2013 Jul;96(7):4436-46. doi: 10.3168/jds.2012-6464. Epub 2013 May 6.
The objectives of the current experiment were to determine the effect of 2 prepartum grouping strategies on the health, metabolic, reproductive, and productive parameters of dairy cows. Jersey cows enrolled in the experiment at 253±3 d of gestation (d 0=calving) were balanced for parity and projected 305-d mature equivalent and assigned to 1 of 2 treatments. Cows assigned to the traditional (TRD; n=6 replicates with a total of 308 cows) treatment were moved to the study pen as a group of 44 cows and weekly thereafter groups of 2 to 15 cows were moved to the study pen to reestablish stocking density. Cows assigned to the all-in-all-out (AIAO; n=6 replicates with a total of 259 cows) treatment were moved to the study pen in groups of 44 cows, but no new cows entered the AIAO pen until the end of the replicate. At the end of each replicate, a new TRD and AIAO group started but pens were switched. Cows were milked thrice daily and monthly milk yield, fat and protein contents, and somatic cell count data were recorded up to 305 d postpartum. Plasma nonesterified fatty acid concentration was measured weekly from d -18±3 to 24±3 and plasma β-hydroxybutyrate was measured weekly from d 3±3 to 24±3. Cows were examined on d 1, 4±1, 7±1, 10±1, and 13±1 for diagnosis of uterine diseases and had their ovaries scanned by ultrasound on d 39±3 and 53±3 to determine resumption of ovarian cycles. Average stocking density was reduced for the AIAO (71.9%) treatment compared with the TRD (86.9%) treatment. Treatment did not affect the incidences of retained fetal membranes (TRD=10.9, AIAO=11.6%), metritis (TRD=16.7, AIAO=19.8%), and acute metritis (TRD=1.7, AIAO=3.6%). Concentrations of nonesterified fatty acids (TRD=80.4±8.2, AIAO=62.9±8.5 µmol/L) and β-hydroxybutyrate (TRD=454.4±10.9, AIAO=446.1±11.1 µmol/L) were not different between treatments. Percentages of cows that resumed ovarian cycles by d 39±3 (TRD=70.8, AIAO=63.1%) and 53±3 (TRD=90.1, AIAO=90.2%) were not different between treatments. Similarly, treatment had no effect on rate of removal from the herd {TRD=referent, AIAO [(adjusted hazard ratio (95% confidence interval)]=0.85 (0.63, 1.15)} or rate of pregnancy [TRD=referent, AIAO=1.07 (0.88, 1.30)]. Finally, treatment did not affect energy-corrected milk yield (TRD=34.4±0.6, AIAO=34.3±0.7 kg/d). In conditions of adequate feed bunk space, the AIAO treatment did not improve health, metabolic, reproductive, or productive parameters compared with the TRD treatment.
本实验的目的是确定两种产前分组策略对奶牛健康、代谢、繁殖和生产性能参数的影响。253±3 天妊娠（分娩）的荷斯坦奶牛进入实验，按胎次和预计 305 天产奶量进行平衡，然后分为 2 种处理之一。传统处理（TRD；6 个重复，共 308 头奶牛）的奶牛以 44 头奶牛为一组转移到研究栏，此后每周将 2 至 15 头奶牛转移到研究栏以重新建立畜群密度。全进全出处理（AIAO；6 个重复，共 259 头奶牛）的奶牛以 44 头奶牛为一组转移到研究栏，但直到重复结束才允许新奶牛进入 AIAO 栏。每个重复结束时，开始新的 TRD 和 AIAO 组，但更换栏。奶牛每天挤奶 3 次，记录产后 305 天的每月产奶量、脂肪和蛋白质含量以及体细胞计数数据。从-18±3 天到 24±3 天每周测量非酯化脂肪酸浓度，从 3±3 天到 24±3 天每周测量β-羟丁酸浓度。奶牛在第 1、4±1、7±1、10±1 和 13±1 天进行子宫疾病诊断，并在第 39±3 和 53±3 天进行超声卵巢扫描，以确定卵巢周期的恢复情况。与 TRD（86.9%）处理相比，AIAO（71.9%）处理的平均畜群密度降低。处理方式不影响胎衣不下（TRD=10.9%，AIAO=11.6%）、子宫炎（TRD=16.7%，AIAO=19.8%）和急性子宫炎（TRD=1.7%，AIAO=3.6%）的发生率。非酯化脂肪酸（TRD=80.4±8.2，AIAO=62.9±8.5 μmol/L）和β-羟丁酸（TRD=454.4±10.9，AIAO=446.1±11.1 μmol/L）浓度在处理间无差异。第 39±3 天（TRD=70.8%，AIAO=63.1%）和第 53±3 天（TRD=90.1%，AIAO=90.2%）恢复卵巢周期的奶牛比例在处理间无差异。同样，处理方式对淘汰率（TRD=参考，AIAO[调整后的风险比（95%置信区间）]=0.85（0.63，1.15））或妊娠率（TRD=参考，AIAO=1.07（0.88，1.30））没有影响。最后，处理方式对能量校正奶产量（TRD=34.4±0.6，AIAO=34.3±0.7 kg/d）没有影响。在有足够饲料槽空间的情况下，与 TRD 处理相比，AIAO 处理并没有改善奶牛的健康、代谢、繁殖或生产性能参数。
