In the article the analysis of bulls-producers used in the republic, depending on polymorphism on k-casein is carried out and the influence of genetic resources on the level of milk productivity, quality of milk and its dampness is determined. It has been revealed that 56 % of bulls in the republic have AA-genotype, 40 % have AB and only 4 % have BB-genotype. The highest yield for 305 days of lactation in cows with BB- and AB-genotypes 6018 and 5985 kg, respectively. Protein content in BB-cow milk was 3.15 %, which is 0.14 % higher in comparison with AA-cows (P ≥ 0.95) and AA-cows – 0.06 % higher. More than a half of all milk examined in the group of cows with BB- and AB-genotype on k-casein (90 and 85 %, respectively) had on rennet and fermentation sample I and II class. In the Udmurt Republic β-asein contains only 26 %, which also affects the quality and yield of finished products, in particular, rennet cheeses.
This study was conducted at breeding farms in the Udmurt Republic, Russia, Agricultural production cooperative "Kolos", Agricultural production cooperative (Kolkhoz) "Udmurtia", Agricultural production cooperative named after Michurin of the Vavozhsky district. Heifers of the Russian black pied breed born in 2013 and 2014 were used
Summary. Practical interest at the present stage in feeding highly productive cows is the use of fl axseed and rapeseed press cakes, which are sources of energy, high-grade protein and polyunsaturated fatty acids. Rapeseed and linseed press cakes are excellent protein feed for cattle. In concentrates for this animal species they may be the only high-protein components. The purpose of the work was to carry out comprehensive research on fi rst-calf heifers productivity traits, milk quality and its technological properties when using linseed and rapeseed press cakes in their rations. The research has been carried out in JSC “Uchkhoz Iyulskoe of Izhevsk State Agricultural Academy”. The object of research was fi rst-calf heifers of Black-and-White breed. In order to conduct research, four groups of fi rst-calf heifers have been formed – a control group and three experimental groups of 12 animals in each group. A comprehensive evaluation of productive traits, milk quality, its technological properties, as well as the quality of dairy products (cheese, cottage cheese, yogurt) when used in fi rst-calf heifers feeding various cakes (linseed and rapeseed). The lowest prime-cost of 1 kg of milk has been obtained with the simultaneous use of linseed and rapeseed cakes of 14,0 rubles, which was less than in the control group by 2,1 rubles, the 1st experimental group by 1,7 rubles and the 2nd experimental group by 0,7 rubles. The largest gross profi t from milk sales has been received in the 3rd and 2nd experimental groups of 55 744 and 48 202 rubles, respectively. The level of profi tability in all groups was high and ranged from 36,6 % in the control group and up to 57,1 % in the 3rd experimental group. The result of the conducted researches has proved the effi ciency when feeding lactating fi rst-calf heifers of Black-and-White breed of rapeseed press cake and a mixture of rapeseed and linseed press cake in 1 : 1 ratio when replacing 30 % (on crude protein content) of sunfl ower press cake in their rations.
Изучено влияние возраста и живой массы при первом осеменении на воспроизводительные качества коровпервотелок чернопестрой породы в племенных заводах Удмуртской Республики. Исследования проводились в период с 2015 по 2018 гг. Для проведения исследований были сформированы 6 групп животных в зависимости от возраста первого осеменения. В I группу вошли коровы с возрастом первого осеменения до 13 мес, во II от 13,1 до 15 мес, в III от 15,1 до 17, в IV от 17,1 до 19, в V от 19,1 до 21 и в VI группу от 21 мес и старше. При этом живая масса телок в I группе в среднем составила 349,5 кг, во II 370,9, в III 387,7, в IV 400,2, в V 420,7 и в VI группе 440,2 кг. Анализ возраста первого осеменения в племенных хозяйствах республики показал, что средний возраст плодотворного осеменения в 2018 году составил 17,0 мес. с живой массой 394 кг. По результатам экспериментальных исследований нами получено, что лучшие воспроизводительные показатели и молочная продуктивность выявлена у коровпервотелок, которых осеменяли в возрасте 14,6 мес. В данной группе продолжительность сервиспериода составила 127,3 дня, коэффициент воспроизводительной способности 0,90, выход телят на 100 коров составил более 85,3. Удой за 305 дней лактации, у коровпервотелок второй опытной группы составил 6332,3 кг с массовой долей жира 3,65 и белка 3,15 .The influence of age and live weight at the first insemination on reproductive qualities of cowsborn black and white breed in breeding farms of the Udmurt Republic was studied. The studies were conducted between 2015 and 2018. For the research 6 groups of animals were formed depending on the age of the first insemination. Group I included cows with the age of first insemination up to 13 months, in group II from 13.1 to 15 months, in III group from 15.1 to 17 months, in group IV from 17.1 to 19 months, in group V from 19.1 to 21 months and in VI group from 21 months and more. At the same time, the live weight of heifers in group I averaged 349.5 kg, in group II370.9 kg, in group III 387.7 kg, in group IV 400.2 kg, in group V 420.7 kg and in group VI 440.2 kg. The analysis of the age of the first insemination in breeding farms of the Republic showed that the average age of fruitful insemination in 2018 was 17.0 months with a live weight of 394 kg. According to the results of experimental studies, we obtained that the best reproductive performance and milk productivity was revealed in cows, which were inseminated at the age of 14.6 months. In this group, the duration of the service period was 127.3 days, the coefficient of reproductive capacity 0.90, yield of calves per 100 cows. Milk yield for 305 days of lactation, in cows of the second experimental group was 6332.3 kg with a mass fraction of fat 3.65 and protein 3.15.
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