Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 28

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
EN
The average relationship between bulls qualified to reproduction (selected) and cows in insemination region is the basic task of the system. The chief point of applied method is to evaluate numbers of daughters, granddaughters and great granddaughters of assumed bull, which live in consecutive years. These numbers (precisely fraction) are astimated on the ground of such characteristics of population as distributions of age at first calving and calving period, and survival rate to consecutive ages. After multiplication those fractions by number of semen portions of particular bulls used earlier in the region, one estimate real numbers of female descendants in actual year. These descendant numbers in conection with relationship coefficients between the bull qualified to reproduction (proband) and all bulls used earlier in the region give basis to evaluation of the average relatioship between the proband and all cows „living" in the region.
RU
Основная задача системы вычисления среднего родства быков отобранных для воспроизводства и коров в районах осеменения. Существом метода является определение, на основе актуальных параметров популяции, фракции дочерей и дальнейших женских потомков гипотетического быка проживающих к очередным годам. Исходная точка это число порции спермы быка использованных в районе осеменения во время 1 года. Для вычисления числа женских потомков быка используется распределения возрастов первого отела, межотельных интервалов и выживаемости коров до очередных возрастов в реальной популяции. На основе этих данных определяется предусматриванные распределения коров в возрасте очередных отелов и помещает их во времени (с 1 января года использования спермы быка). Затем считается родство между быками предусматриваными для возпроизводства и быками ранее используемыми в районе осеменения и на этой основе вычисляется среднее родство быков и всех „живущих" коров в районе.
EN
The effect of inbreeding on milk and fat yield and fat content in milk in the first three lactation periods of red-white cows was determined by means of linear and parabolic regression. The calculations were made within the group of sires for low, medium and high production levels and irrespective of the herd's productivity. Inbreeding led to a slight depression in milk and fat yield -7.5 kg and -0.3 kg per 1% of Inbred, respectively - but it dit not affect fat content in milk. The most significant depression in milk and fat yield was observed at the level of medium productivity. It ranged from 11.5 to 17.7 kg of milk and from 0.31 to 0.51 kg of fat according to the lactation, with the Increase in the inbred by 1%. The highest inbreeding lactation; depression in milk and fat yield however remained rectilinear.
EN
The effect of inbreeding on the age of the first calving and on the length of the first and second intercalving periods in red-white cows was determined by means of linear and parabolic regression. To eliminate the effect of sires on the evaluation of inbreeding depression, the linear and parabolic regression coefficients were calculated within the groups of sires. All the calculations were made for the herds of low, medium and high production levels as well as for all three levels togetheri In the population studied, considerable frequency of inbreeding resulted: 9,5% of all the heifers and 15,7% of the older cows were offsprings of related parents. The average inbreeding coefficient for 14743 cows was 0,8% and 6,9% in the inbred group. The inbred cows calved 0,4 month later and their first and second intercalving periods were 0,24 and 0,16 longer than in the outbred group. The inbreeding depression was observed mainly in the low productivity of herds; this tendency proved to be curvilinear. The survival rate of the inbred group was - until the end of the second and third lactation - considerably higher than in the non-inbred group.
EN
13476 pairs of mothers and daughters from 165 herds of red-white cattle used In 1963-1983, in Low Silesia and Opole region were studied. The values of all the traits analysed /milk and fat yield, fat content in milk/ were expressed as deviations of the means for the herd-year. Corrections were made for age and the season of calving. The evaluations were based upon the data referred to above; heritability, phenotyplc, genetic and environmental correlations were calculated in pairs of mothers and daughters. The values of heritability, phenotyplc correlations, particularly environmental correlations, were higher than those in the same breed estimated by similarities in half-sib groups. Incomplete elimination of parts of some common environmental influences for daughter and mothers could have caused that effect, in particular, the Influence of maternal environment.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.