INCREASING THE LENGTH OF PRODUCTIVE LIFE OF COWS OF SIBIRYACHKA BREED

Abstract

Results are given from studies on increasing production performance and productive life of cows of Sibiryachka breed. The studies were carried out based on zootechnic recordings for 254 cows born in 2000–2005 at a breed originator farm in Novosibirsk Region. There were studied paratypic factors influencing their life-time productivity and longevity: age, live weights of heifers at the first fertile insemination, first lactation milk yield. The best parameters of productive life were observed in cows, firstly calving at the age of 30–32 months: life span of 3193.7 days, life-time milk yield of 30283.9 kg, milk fat and protein yields of 1189.26 and 928.07 kg, respectively. As the age of first-calf cows increased, their life span decreased by 437.9 days and life-time milk yield by 5951.9 kg. With increasing the live weight of first-calf cows from 450 to 540 kg, their life span increased by 816 days (32.6%) and life-time milk yield by 11389.6 kg. The further increase in live weight of first-calf cows result in reducing their life span by 422.2 days and lifetime milk yield by 5839 kg. It was observed that life span of cows increased with increasing first lactation milk yield. The maximum productive life of a cow in a herd (3.44 lactations) was recorded in cows milking 6000 kg for the first lactation. With increasing first lactation milk yield from 4000 to 6000 kg and more, the life-time milk yield increased by 12096.3 kg. The milk fat content reduced with increased milk yield by 0.13% at the same milk protein content. These findings on the effects of first-calving age, live weight and first lactation milk yield on productive life and production performance of cows are very important to planning breeding work.