From the standpoint of modern ideas, the normal functioning of the poultry body and full implementation her of the genetic potential is impossible without the presence of selenium in the diet. The biochemical diversity of selenium puts it in a number of priority trace elements. Scientists who were studying the effects of selenium on poultry body and paid relatively little attention to the quality of the meat. In scientific experiment are studied the effect of additives different doses of selenium in compound feed on the chemical composition, energy and biological value of meat of the cross chickens-broilers COBB 500. Introduction of selenium into the feed for broiler chickens in the doses which are studied (0.3 mg/kg, 0.4 and 0.5 mg/kg) did not significantly affect to the quality of their muscle tissue although it positively affected on some indicators that characterizing its chemical composition, nutritional and biological value. Among the experimental groups, the best meat quality indicators were in the second group of chickens for which was introduced into the feed selenium from the calculation of 0.3 mg/kg. When feeding mixed feeds with selenium additives to broiler chickens it was found that it is likely to increase the concentration of this trace element in muscle tissue by 60.6-100% (P?0.001), which does not exceed the maximum permissible level (MPL). Consumption of selenium-enriched meat of broiler chickens within the limits of the physiological norms recommended in Ukraine will ensure the daily requirement of an adult in this trace element by 23.6-29.4%. This meat product can be especially useful for people who live in regions with low levels of selenium in the natural environment.
The major components of economically useful traits in cattle dairy productivity, which conducted the selection is milk productivity and reproductive ability of cows. Studies conducted on animals Ukrainian black and white dairy cattle in the «Milk River» farm in the Sokal and Brody offices breeding reproducers «Breeder» Lviv region and plant breeding «Yamnytsya» Ivano–Frankivsk region. Ukrainian black and white dairy breed in the western region of Ukraine is characterized by good reproductive ability. Depending on the husbandry and lactation duration, service period lasted within 87.4 – 121.5 day, intercalving period – within 364 – 402.6 day, dry period within – 47.3 – 72.9 day, the fertility index was 46.3 – 48.0, coefficient of reproductive ability – within 0.92–0.99, output of calves per 100 cows – within 91.8 – 98.8. The duration of pregnancy in cows of different farms and lactations were in range 277 – 283.5 day and meet the requirements of the physiological norm. It has been shown that the milk yield of cows depends on the parameters of reproductive capacity. The correlation between duration of service–period and intercalving period, and milk yield, milk fat in most cases was positive. Correlation dry period duration and parameters of milk yield changed from negative to positive. Depending on the husbandry, lactation and index the impact share of service–period duration on milk yield was 7.0 – 29.7, for intercalving period – 8.8 – 31.8, for dry period – 9.2 – 23.8% respectively.
A fundamental genetic improvement of domestic dairy breeds is carried out by using the gene pool of the best foreign breeds, in particular Holstein. This approach has greatly improved the milk productivity of cows, but has led to a significant deterioration in reproduction, longevity, product quality, general animal health etc. Taking into account that the increase of the milk productivity of cows leads to a shortening of their use, this problem will only become aggravated over time. Therefore, it is now necessary to direct scientific research into a comprehensive assessment of animals taking into account the signs of lifelong productivity. In view of the above, the purpose of our research was to study the economic utility signs of dairy cows and their relationship with productive longevity. The research was conducted on cows of Holstein (n = 2902), Ukrainian Black- (n = 14876) and Red-and-White (n = 2176) dairy breeds. To characterize the economic useful signs of animals of the studied breeds based on the materials of the primary zootechnical and breeding records, weighed growth of animals, reproductive capacity, milk productivity and duration and efficiency of lifetime use were studied. It was established that heifers of investigated dairy breeds were characterized by a moderate intensity of growth of live weight, as evidenced by average daily increments from birth to 18 months of age: in animals of Holstein breed – 644, Ukrainian Black-and-White milk breed – 641 and Ukrainian Red-and-White dairy breed 692 g. The first fruitful insemination of heifers of the Holstein breed occurred on average at the age of 19.1, Ukrainian Black and Red-and-White dairy breeds - 20.4 and 20.8 months, while their live weight at that was 405.3; 414.3 and 438.5 kg respectively. The milk yield of the Holstein breed cows, depending on the lactation, was 4846–7920 kg, the fat content in milk was 3.63–3.74% and the amount of milk fat was 181.2–279.7 kg, the Ukrainian Black-and-White milk breed was 4008–6317 kg, 3.63–3.70% and 148.6–228.8 kg respectively, while Ukrainian Red-and-White milk is 4578–6592 kg, 3.74–3.87% and 177.2–245.9 kg. The cows of the given breeds were used in herds only 2.32–2.50 lactation. The highest life milk yield was noted in animals of the Holstein breed (18,669 kg), and the lowest (14,940 kg) in the cows of the Ukrainian Red-and-White breed. Correlation analysis of economic characteristics of dairy cows with indicators of their productive longevity confirms the possibility of conducting an indirect predictive selection of animals in order to form high-yielding herds with long-term economic use. Among the studied features, the greatest predictive value (P < 0.001) for the indicators of life expectancy, productive use, lactation, the number of lactation per life, life yield and lifetime of milk fat have yield of cows for the first (r = -0.217 – +0.205) and the best lactation (r = +0.061 – +0.609). An intermediary predictive selection of animals can also be carried out according to the duration of their first service period (r = -0.462 – +0.106) and live weight during growing season (r = -0.286 – +0.126). It was established that live weight at the first insemination and the first calving significantly influenced the indicators of life yields, economic use and lactation of animals, as evidenced mainly by higher and reliable values of correlation coefficients between these indices. It should also be noted that the correlation coefficients between the live weight of cows in the first calving and the duration of life, productive use, lactation and the number of lactations in life were somewhat higher but negative values (r = -0,130 – -0,070), compared with the between live weight at the time of first insemination and the above indicators of longevity of animals (r = -0,037 – +0,094). This suggests that the effect of live weight on the first calving of animals on their longevity was somewhat higher than the effect of live weight at the first insemination. Our data show that the selection of cows by the age of the first calving and the duration of the first lactation is not significant, since there is practically no link between these features and the indicators of productive longevity.
There are indicators data of body weight, body parts measurements, reproductive ability, milk production, morphological and functional properties of udder, the duration of use and economic reasons of disposal of Simmental cows in terms of Lviv oblast. It was established that the experimental cows by live weight during their growth in all ages have been prevailing minimum requirements of breed standard. They are marked by peculiar to combined breed type of body structure with well–defined not only milk but also meat forms, they had strong skeleton and were quite tall (withers height – 131.1 cm). However, the width of the breast in most cows, that is not enough for combined breed (on an average 41.4 cm). Simmentals age at the moment of the 1st insemination was 19.7, while during the 1st calving – 29.0 months, the duration of the service–period, depending on lactation, was within 96.8 – 112.0, of inter–calving period – within 381.6 – 396.9 day. They were characterized by an average fertility and high adaptablity. Simmentals milk yield, depending on lactation, was 3026,4–3810,2 kg, fat content in milk – 3.76 – 3.81% and quantity of milk fat 113.6 – 145.0 kg. Cows after the 4th calving had the highest milk productivity. During the all studied lactations cows milk yield and quantity of milk fat predominated breed standard. They had a well developed udder. 68.2% cows after the first calving had cupped udder, 25.9% – wash–tub and 6.9% – round udder. Their intensity of milk yield was 1.53 kg/min. Simmental cows duration of economic use in the conditions of Lviv oblast was 1.904.1 day or 5.3 lactations, lifetime yield – 18011, lifetime quantity of milk fat – 688 kg. Most reasons for dropped out of the herd was dysfunction of reproduction (35.7%) and low productivity (21.3%).
There are shown data on the impact of live weight of Holstein cows on the duration and effectiveness of their lifetime use during the period of breeding. It was established that the animals which are not reached to the body breed standard of their weight at some period of age had lower rates and duration of lifetime use and productivity. Animals with live weight at 6 months – 181–220, 12 months – 311–340, 18 months – 411–440, at the first insemination – 411–440 and at first calving – 511–540 kg had the longest life duration, productive use, quantity of lactations during all life and highest lifetime productivity. The highest positive correlation coefficients were established between body weight of cows at different periods of their growth (exception – live weight at first calving) and lifetime milk yield (r = 0.072–0.106), the average lifetime fat milk (r = 0.062–0.126), lifetime quantity of milk fat (r = 0.077–0.112), milk yield per day of life (r = 0.077–0.165) and productive use (r = 0.077–0.112). These links were much weaker between live weight and life duration in the studied ages of animals (r = -0.009 – +0.062), productive use (r=-0.125 – +0.094), lactation (r = -0.093 – +0.038) and the number of lactations during life (r = -0.134 – +0.029). The lowest correlation coefficients were between body weight at first calving of cows and the studied parameters of duration and effectiveness of their lifelong use. The impact of the live weight of animals during growing period on the duration of their economic use was the highest (23.34–31,30%), the number of lactations for life (13.79–28.08%), lifetime milk yield (11.89–15.68%) and lifetime amount of milk fat (11.42–15.16%).
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