RESULTS OF CROSSBREEDING OF AYRSHIRE CATTLE

Abstract

The dynamics of growth and development of crossbred heifers obtained from bulls of Montbeliarde and Norwegian Red breeds, in comparison with purebred Ayrshire, have been studied. The highest influence of the father's breed on the bodyweight of daughters was found at 18 months of age (29.7%). Heifers were born as a result of crossing the Ayrshire breed with the Montbeliarde breed and had a higher body weight compared to the daughters of the Ayrshire bulls. The daughters of Montbeliarde bulls at 3 months weighed 2.9 kg more, at 6 months - by 4.0, at 9 months - by 6.3, at 12 months - by 20.1, in 15 months - by 41.3 and at 18 months by 49.8 kg (p <0.001). Heifers obtained as a result of crossing Ayrshires with a Norwegian Red breed were distinguished by even greater body weight than purebred Ayrshire. The advantage in body weight was: at 3 months of age 7.6 kg, at 6 months - 19.5, at 9 months - 38.9, at 12 months - 56.3, at 15 months - 70.1 and at 18 months - 70.9 kg. By the age of 9 months, the average daily gains of heifers obtained from Montbeliarde bulls were almost the same. During the period from 9 to 18 months, the daughters of Montbeliarde bulls prevailed over their peers in this indicator by 85-217 g (P <0.001), and daughters bulls of the Norwegian Red breed in the period from birth to 15 months of age - by 82-216 g (p <0.00). The average daily gain from birth to fruitful fertilization in purebred animals was 711 ± 5.4 g, in daughters of Montbeliarde bulls 799 ± 28.9 g, and in descendants of Norwegian Red bulls - 874 ± 12.1 (p <0.001). The age of first fertilization in purebred Ayrshire animals was 18.9 months, in the daughters of the Montbeliarde bulls - 17.0 months, and in the descendants of Norwegian Red bulls - 14.7 months. The age of first calving, respectively: 27.8 months, 25.8 months, and 23.7 months. The daughters of the Montbeliarde breed bulls at different ages had a greater survival rate by 7.3-10.1%, and the descendants of the Norwegian Red bulls by 3.7-9.2% compared to purebred Ayrshire (p>0.1). The dairy strength was better expressed in the first-calf heifers of the Ayrshire breed in comparison with the crossbred animals, and the corpus and udder - in the daughters of the Norwegian Red bulls.