The influence of age and live weight at conception on the consumption of metabolizable energy and crude protein during 6 months of pregnancy, processes of their growth and development was studied. The gain of live weight of springer heifers during the first three months of pregnancy was determined to be 67,0±3,66 kg in group I, 65,0±5,26 kg in group II and 49,0±4,40 kg in group III. Studying the growing power of the animals during 0-3 months (92 days) of pregnancy, the springer heifers of groups I and II were found to be superior to the herdmates of the group III by 196g and 174g or 26,9 and 24,4% (p<0,01) in terms of the average daily gain. Comparing the characteristics of the live weight gain at 4-6 months (92 days) of pregnancy, the springer heifers of groups I and II were found to be significantly superior to their analogues in group III by 29.0 and 28.0 kg. The springer heifers of groups I and II outweighed their herdmates of group III by 316 and 305 g or 43,4% and 47,5% (p<0,001) in terms of the average daily gain. It is necessary to underline that animals of groups I and II had higher gain of live weight during the whole experimental period by 47,0 and 43,0 kg or 58 and 53% as compared to the analogues of group III. According to the results of multicriteria analysis, for group I the objective function was determined to be lower and was 0.0359 on the examined criteria, while the objective functions of groups II and III were worse at 1.4 and 12.1 respectively. At the same time, the animals in group II were 8.6 times superior to their analogues in group III. It indicates the superiority of animals in groups I and II with a productive mating age of 14.8-15.3 months and a live weight of 373-414 kg. They had a more intensive gain of live weight during pregnancy and spent less energy and crude protein feed per kilo of gain. The linear, partial quadratic and partial quadratic regressions were developed to describe the correlation between the increase of live weight of heifers and their age and live weight at the time of conceiving and the consumed metabolizable energy and crude protein for 6 months of pregnancy. The season of the year was determined to have no significant impact on the heifers' development during the pregnancy period in the herd and their further milk productivity.
The article presents the results of studies of reproductive performance, safety and average daily milk yield of first-calf cows of the Ukrainian Red-and-White dairy breed, obtained from the Montbeliard and Holstein sire bulls in the SE "Gontarivka", Kharkiv region. It was found that the weight at the first fertilization in heifers obtained from bulls of different breeds did not practically differ, and averaged 470 kg. At the same time, the age of the first insemination and calving of the daughters obtained from the Montbeliard bulls was significantly less than of the daughters obtained from the Holstein bulls, which indicates a greater intensity of growth of crossbred heifers. The average daily milk yield of daughters of Montbeliard breed bulls for the first two months of lactation was 1.6 kg and 0.5 kg less than that of their counterparts. In the third month of lactation, the average daily milk yield of first calving cows obtained from Holstein bulls became 0.2 kg less than that of crossbred ones, and later this trend of the advantage in daily milk yield of the daughters of Holstein bulls continued. For 8 months of lactation, the milk yield of the daughters of the Montbeliard bulls was slightly less by 201.4 kg than their peers. There were no significant differences in the content of fat, protein and the somatic cells count.
Викладено результати впливу фенотипових факторів на молочну продуктивність корів та показники якості молока, зокрема вміст соматичних клітин. Встановлено вірогідний вплив віку тварини, стадії лактації, сезону року та оператора машинного доїння на фізико-хімічні показники молока та захворювання корів на мастит.Проаналізовано більше 15 тисяч проб молока та виявлено, що середній вміст соматичних клітин у молоці був досить високим -411±7 тис у см 3 За отриманими даними біля 20 % досліджених проб молока були отримані від корів, хворих на субклінічний або клінічний мастит.За результатами дисперсійного аналізу вміст соматичних клітин у корів 6 лактації і старше (634±53,1 тис у cм 3 ) був майже в два рази більшим ніж у первісток (331±9,2 тис у cм 3 ).
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