Effects of Heifer Age and Liveweight at the Final Stage of Puberty and the First Service Conception on Cow Productivity and Welfare

Abstract

The effects of the optimal liveweight values for heifers at the final stage of puberty and the first service conception on the cow lifespan, milk yield, and welfare status over three lactations was estimated. The survey was performed with domestic Black-and-White mature cows (n = 7171) born at the farm enterprise, Belgorod oblast, in 2010–2014. The milk yield of 7746–8570 kg per cow per indicated period was recorded; the milk fat and protein contents comprised 3.82–3.81 and 3.37–3.30%, respectively. In order to improve the cow welfare, to increase the lifespan, and to produce 20 400–31 800 kg milk over three entire lactations, the insemination of 15–16-month-old heifers of no less than 412 kg liveweight and 17–18-month-old heifers of 426 kg liveweight, taking into account their 12-month weights of 327–347 kg and 316–344 kg, respectively, should be reasonable.