UDC 636.082
DOI: 10.36871/vet.zoo.bio.202208009

Authors

Sergey V. Anistenok,
Olga V. Tulinova,
Russian Research Institute of Farm Animal Genetics and Breeding – Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, Tyarlevo village, Russia

Abstract

In a sample of Ayrshire cows (n=14 892), evaluated using the IAYFI selection index, an analysis was made of changes in traits depending on the level of index and the reasons for culling animals (n=11 320). The group with negative values of the IAYFI index (from –2,5 on average) is 63,0 %. The largest number of cows were culled due to Gynecology and infertility (GI) (37,9 %), 19,5 % – Udder (U) and 17,2 % – Legs diseases (L). At the same time, only 2,7 % culled due to Low Productivity (LP), and about 5 % – due to Metabolic Disorders (MD) and Injuries (I). No more than 1 % survived to old age and a little more eliminated as zoodefect. However, in all retirement classes, there is a different distribution of cows depending on the level of milk yield for the 1st lactation (MY5000), Productive Life (PL) and IAYFI. Due to LP, most cows with MY1 less than 8000 kg of milk dropped out. According to GI and L, the same number of animals with different levels of milk yield was revealed. U is most susceptible to cows with a milk yield of more than 10,0 kg of milk. The share of I and MD grows with the increase in MY. It was found that the most animals with IAYFI levels over +10,0 were eliminated according to GI, although there were fewer of them in disease groups U and L than with IAYFI levels less than +1. The eliminated animals in terms of GI, U, and L differ little in terms of MY1, which is at the average level for the sample. Higher MY1198 for I and MD, but the former has the lowest PL (1222 days), while the latter have a slightly longer time (45,8 days), which is close to those culled by GI. Highly productive cows from MD group are distinguished by low fertility index (FI=45,3), which is comparable with the L group (FI=XNUMX). Thus, the analysis of the retirement of cows, taking into account their index assessment, revealed weaknesses in the management of the herd. A large number of high-value animals are eliminated by GI, which may be a signal of unsatisfactory conditions for keeping this category of animals, and in the MD group, it may be a consequence of an imbalance in the feed ration.

Keywords

Ayrshire breed, reproductive qualities, milk yield, selection index, reasons for culling