School of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand; Department of Animal Science, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Badulla 90000, Sri Lanka.
School of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand.
J Dairy Sci. 2022 Nov;105(11):8911-8923. doi: 10.3168/jds.2021-20946. Epub 2022 Sep 22.
The objective of this study was to evaluate the reproductive performance of New Zealand dairy cows with different milking regimens. A total of 2,562 herds calving in 2017 met the criteria for inclusion in this study. The herds were classified into 5 different milking regimens: 260 herds with cows milked once daily (OAD) during the entire lactation, 1,206 herds with cows milked twice daily (TAD) during the entire lactation, 94 herds that were switched to OAD milking from TAD milking during the mating period (OAD-M), 700 herds that were switched to OAD milking from TAD milking after peak lactation (OAD-P), and 302 herds that switched to OAD milking from TAD milking at end of the lactation (OAD-E). Time from the start of mating to first service (SMFS), start of mating to conception (SMCO) and first service to conception (FSCO) were analyzed using survival analysis. Time from SMFS, SMCO and FSCO was significantly shorter in cows milked OAD compared with cows milked TAD. Also, cows milked OAD had fewer services per conception and higher mean 3-wk submission (SR21), in calf by 3 wk (PR21), in calf by 6 wk (PR42), conception to the first service (PRFS), 3-wk calving (CR21) and 6-wk calving (CR42), and lower not in calf (NIC) than herds with TAD, OAD-M, OAD-P, OAD-E milking cows. Fertility performance differed with parity; first-parity cows had lower SR21, 6-wk submission (SR42), PR21, PR42, PRFS, CR21, and CR42 values, and higher NIC values than second-parity cows. Third parity cows had the highest values for SR42, PR21, PR42, PRFS, CR21, and CR42, and lowest value for NIC compared with cows of other parities. Significant but minor interactions between milking regimen and parity existed for SMFS, SMCO, FSCO, SR21, SR42, PR21, PR42, PRFS, NIC, and CR21.
本研究旨在评估不同挤奶方案对新西兰奶牛繁殖性能的影响。共有 2017 年 2562 个分娩牛群符合纳入本研究的标准。这些牛群被分为 5 种不同的挤奶方案：260 个在整个泌乳期内每天挤奶 1 次（OAD）的牛群，1206 个在整个泌乳期内每天挤奶 2 次（TAD）的牛群，94 个在配种期间从 TAD 挤奶转为 OAD 挤奶的牛群（OAD-M），700 个在泌乳高峰期后从 TAD 挤奶转为 OAD 挤奶的牛群（OAD-P），302 个在泌乳期末从 TAD 挤奶转为 OAD 挤奶的牛群（OAD-E）。使用生存分析对从配种开始到第一次输精（SMFS）、从配种开始到受胎（SMCO）和从第一次输精到受胎（FSCO）的时间进行分析。与 TAD 相比，OAD 挤奶的奶牛从 SMFS、SMCO 和 FSCO 的时间显著缩短。此外，OAD 挤奶的奶牛每头受胎的输精次数更少，3 周内配种率（SR21）、21 天内怀孕率（PR21）、6 周内怀孕率（PR42）、配种至第一次输精（PRFS）、3 周分娩率（CR21）和 6 周分娩率（CR42）更高，未配种率（NIC）更低，与 TAD、OAD-M、OAD-P 和 OAD-E 挤奶的奶牛相比。繁殖性能因胎次而异；初产奶牛的 SR21、6 周内配种率（SR42）、PR21、PR42、PRFS、CR21 和 CR42 值较低，NIC 值较高，二产奶牛的这些值较高。与其他胎次的奶牛相比，三产奶牛的 SR42、PR21、PR42、PRFS、CR21 和 CR42 值最高，NIC 值最低。SMFS、SMCO、FSCO、SR21、SR42、PR21、PR42、PRFS、NIC 和 CR21 之间存在挤奶方案和胎次的显著但微小的互作效应。
