MILK PRODUCTIVITY OF THE FOURTH LACTATION COWS DEPENDING ON LACTATION AGE OF MOTHER-COWS

Abstract

Studying the realization of the genetic potential of milk productivity of the Holstein daughter cows of the
fourth lactation, born by mothers in the first, second, third, and fourth lactations was carried out. The re-
search was conducted at the industrial complex for maintaining purebred Holstein cows of the “Agro-
Soyuz” Private Joint-Stock Partnership in Synelnykove district of Dnipropetrovsk region. Milking at the
complex was conducted three times a day (two times before drying), on the milking installation of the “Par-
allel” type. The animals were provided with a passive motion, they were kept in easy-disassembled cow
barns with boxes for having rest, and sand served as litter. The maintenance technology at the industrial
complex provided the feeding of animals with generally mixed rations of conserved and concentrated feeds
being distributed twice a day on the feeding table. It was established that milk yield indices during the full
lactation period, the duration of the productive period, qualitative characteristics of dairy products were
better and more stable in Holstein daughter cows of the fourth-lactation born by the third-lactating mothers,
in which milk fat index was 644.3 kg and milk protein index – 540.3 kg, while daughter cows of the fourth
lactation born by the fourth-lactating mothers, were distinguished by the best indicators of the organism
functional activity, such as the highest daily milk yield during the full lactation period – 49.4 kg, which indi-
cated the cows’ considerably high potential for milk synthesis and secretion. The indicator of physical fitness
was also high considering the estimated 4 % milk obtained during one day for 305 days of lactation (kg),
which made 39.4 and 38.5, correspondingly. As for the amount of milk obtained per 1 kg of live weight cal-
culated for 4 % milk during the adjusted lactation period (305 days), it was 18.5 kg. In this case live weight
of animals did not affect the indices of milk productivity and functional activity of lactating organism direct-
ly. So, the experimental daughter cows of four groups were characterized by a rather high live weight, which
was approximately 626.9 kg. The fourth-lactating daughter cows, born by mothers of the second lactation
had the maximum live weight and their productive indices were also at a rather high level making 635.1 kg.