Genetic aspects of body weight, body condition score, scrotal circumference and reproductive performance in Italian Holstein young bulls

Abstract

Apart from all the issues regarding health and undesirable recessive genes, which are determining factors to identify bulls not suitable for AI, there are other aspects which can be considered. The principal aims of AI studs are the selection of the best animals from a genetic point of view and the production of semen in a very short time, in order to start progeny testing as soon as possible. In Italy progeny testing starts when 1200 straws for each young bull are available. This requirement implies that bulls should be in good physical condition. According to this, the genetic centre of the Italian Holstein Breeder Association (ANAFI) has been paying growing attention to animal welfare and fitness, recording routinely some biometrical indicators. Body weight (BW), scrotal circumference (SC), body condition score (BCS) are some examples of this policy and could be helpful and easy predictors of reproductive performance for a young progeny testing dairy bull. The objective of this report was to conduct a preliminary analysis on the genetic aspects of BW, BCS, SC, age at the 1st usable straw (AGE1) and age at the 1200th straw (AGE1200) in Italian Holstein young bulls.