Chebel Ricardo C, Gonzalez Tomas, Montevecchio Ana B, Galvão Klibs N, de Vries Albert, Bisinotto Rafael S
Department of Large Animal Clinical Sciences, University of Florida, Gainesville, FL 32610; Department of Animal Sciences, University of Florida, Gainesville, FL 32610.
Department of Large Animal Clinical Sciences, University of Florida, Gainesville, FL 32610.
J Dairy Sci. 2025 Feb;108(2):1584-1601. doi: 10.3168/jds.2024-25525. Epub 2024 Nov 8.
Targeted reproductive management (TRM), employing automated monitoring devices (AMD), is as an alternative to the blanket adoption of ovulation synchronization protocols (OvSP) for first postpartum AI and a means of reducing the use of OvSP for re-insemination of nonpregnant cows. We hypothesized that a TRM that relies heavily on AI of cows on AMD-detected estrus improves reproductive performance and economic return. Early-postpartum estrus characteristics (EPEC) of multiparous (n = 941) cows were evaluated at 40 and 41 DIM (herds 1 and 2, respectively) and EPEC of primiparous (n = 539) cows were evaluated at 54 and 55 DIM (herds 1 and 2, respectively). Cows in the control treatment were enrolled in the Double-Ovsynch protocol and AI at a fixed time (TAI) at 82 and 83 DIM (primiparous cows in herds 1 and 2, respectively) and 68 and 69 DIM (multiparous in herds 1 and 2, respectively). Cows enrolled in the TRM treatment were managed according to EPEC as follows: (1) cows with ≥1 intense estrus (heat index ≥70; 0 = minimum, 100 = maximum) were AI upon AMD-detected estrus starting at 64 (primiparous) and 50 (multiparous) DIM and, if not AI, were enrolled in the Double-Ovsynch, (2) cows without an intense estrus were enrolled in the Double-Ovsynch at the same time as cows in the control treatment. Control cows were re-inseminated based on visual or patch-aided detection of estrus, whereas TRM cows were re-inseminated as described for control cows with the aid of the AMD. All cows received a GnRH injection 27 ± 3 d after AI and, if diagnosed as nonpregnant, completed the 5-d CoSynch protocol and received TAI 35 ± 3 d after insemination. The hazard of pregnancy was greater for cows in the TRM treatment (adjusted hazard ratio = 1.17, 95% CI = 1.05, 1.32), resulting in more cows from the TRM treatment starting a new lactation (82.6% vs. 77.2%) and fewer of them sold (15.5% vs. 20.8%). Treatments did not differ regarding total milk yield (control = 12,782.1 ± 130.6 kg, TRM = 13,054.7 ± 136.1 kg). The gross profit [(milk income + sale value + subsequent lactation calf value) - (feed cost + replacement cost + fixed cost + reproductive management cost)] of cows in the TRM treatment was $108 greater than the control treatment ($3,061.6 ± $45.9 vs. $2,953.8 ± $45.2). According to a Monte Carlo stochastic simulation, the mean (±SD) difference in gross profit was $87.8 ± 12.6/cow in favor of the TRM treatment, and 95% of the scenarios ranged from $67.2/cow to $108.5/cow (minimum = $30.2/cow, maximum = $141.1/cow). Under the conditions of the current experiment, the TRM treatment improved the gross profit of Holstein cows because the increased hazard of pregnancy changed culling dynamics, reducing replacement cost and cow sales and increasing calf value. The findings of the current experiment emphasize the importance of efficient reproductive management and its substantial economic implications, particularly in the context of high-producing Holstein cows.
采用自动监测设备（AMD）的靶向生殖管理（TRM），可替代首次产后人工授精时全面采用的排卵同步方案（OvSP），并减少未怀孕母牛再次输精时OvSP的使用。我们假设，严重依赖于对AMD检测到发情的母牛进行人工授精的TRM可提高繁殖性能和经济回报。对经产母牛（n = 941）产后早期发情特征（EPEC）在产后40天和41天进行评估（分别为牛群1和牛群2），对初产母牛（n = 539）的EPEC在产后54天和55天进行评估（分别为牛群1和牛群2）。对照处理的母牛采用双同期发情方案，并在固定时间进行人工授精（定时人工授精，TAI），初产母牛分别在产后82天和83天（分别为牛群1和牛群2），经产母牛在产后68天和69天（分别为牛群1和牛群2）。纳入TRM处理的母牛根据EPEC进行如下管理：（1）有≥1次强烈发情（热指数≥70；0 = 最低，100 = 最高）的母牛，在AMD检测到发情时进行人工授精，初产母牛从产后64天开始，经产母牛从产后50天开始，如果未进行人工授精，则纳入双同期发情方案；（2）没有强烈发情的母牛与对照处理的母牛同时纳入双同期发情方案。对照母牛根据发情的视觉或贴片辅助检测进行再次输精，而TRM母牛在AMD辅助下按照对照母牛的描述进行再次输精。所有母牛在人工授精后27±3天接受促性腺激素释放激素（GnRH）注射，如果诊断为未怀孕，则完成5天同步发情方案，并在输精后35±3天接受定时人工授精。TRM处理的母牛怀孕风险更高（调整后的风险比 = 1.17，95%置信区间 = 1.05，1.32），导致TRM处理中有更多母牛开始新的泌乳期（82.6%对77.2%），且出售的母牛更少（15.5%对20.8%）。处理组间总产奶量无差异（对照 = 12,782.1±130.6千克，TRM = 13,054.7±136.1千克）。TRM处理的母牛总利润[（牛奶收入 + 销售价值 + 后续泌乳期犊牛价值） - （饲料成本 + 替换成本 + 固定成本 + 繁殖管理成本）]比对照处理高108美元（3,061.6±45.9美元对2,953.8±45.2美元）。根据蒙特卡洛随机模拟，总利润的平均（±标准差）差异为87.8±12.6美元/头，有利于TRM处理，95%的情况范围为67.2美元/头至108.5美元/头（最小值 = 30.2美元/头，最大值 = 141.1美元/头）。在当前实验条件下，TRM处理提高了荷斯坦奶牛的总利润，因为怀孕风险增加改变了淘汰动态，降低了替换成本和母牛销售数量，并增加了犊牛价值。当前实验的结果强调了高效繁殖管理的重要性及其重大经济影响，特别是在高产荷斯坦奶牛的背景下。
