Ghavi Hossein-Zadeh Navid
Department of Animal Science, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran.
Res Vet Sci. 2019 Feb;122:111-117. doi: 10.1016/j.rvsc.2018.11.017. Epub 2018 Nov 20.
The objective of this study was to evaluate effect of twinning on the lactation curve characteristics for milk yield (MY), fat (FP) and protein (PP) percentages, fat to protein ratio (FPR) and somatic cell score (SCS) in Holstein cows. The data set consisted of 5,917,677 test day production of 643,625 first lactation cows from 3146 herds in Iran. Calvings were classified into single or twin births. Six non-linear models (Brody, Wood, Sikka, Nelder, Dijkstra and Rook) were fitted to monthly productive records of single or twin calvers. The Rook model provided the best fit of the lactation curve for MY and FP in single and twin calvers and single calvers for SCS and twin calvers for FPR. The Dijkstra model provided the best fit of the lactation curve for PP in single and twin calvers and single calvers for FP. Also, the Wood model provided the best fit of lactation curve for SCS in twin calvers. Twin calvers had greater predicted 200-day and 305-day cumulative milk yield than single calvers. Time to the peak milk yield was observed later for twin calvers (92 days in milk vs. 80 days in milk) with greater peak milk yield (32.16 kg vs. 31.70 kg) compared with single calvers. The results indicated the efficiency of different models for modelling productive performance of single or twin calvers. The application of the association between production and twinning in dairy cows is crucial because present strategies used in the dairy industry are intended to maximize production performance.
本研究的目的是评估双胞胎对荷斯坦奶牛产奶量（MY）、脂肪（FP）和蛋白质（PP）百分比、脂肪与蛋白质比率（FPR）以及体细胞评分（SCS）的泌乳曲线特征的影响。数据集包括来自伊朗3146个牛群的643625头头胎奶牛的5917677条测定日产奶记录。产犊分为单胎或双胎。六个非线性模型（Brody、Wood、Sikka、Nelder、Dijkstra和Rook）被拟合到单胎或双胎产犊的月度生产记录中。Rook模型对单胎和双胎产犊的MY和FP泌乳曲线以及单胎产犊的SCS和双胎产犊的FPR提供了最佳拟合。Dijkstra模型对单胎和双胎产犊的PP泌乳曲线以及单胎产犊的FP提供了最佳拟合。此外，Wood模型对双胎产犊的SCS泌乳曲线提供了最佳拟合。双胎产犊的预测200天和305天累计产奶量高于单胎产犊。双胎产犊达到产奶高峰的时间比单胎产犊晚（产犊后92天vs产犊后80天），且产奶高峰更高（32.16千克vs 31.70千克）。结果表明不同模型对单胎或双胎产犊生产性能建模的有效性。奶牛生产与双胞胎之间关联的应用至关重要，因为目前乳制品行业所采用的策略旨在使生产性能最大化。
