Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 73

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The objective of this research was to estimate phenotypic and genetic correlations between fertility and milk production traits. The following traits characterizing cow reproduction were studied: non-return rates till 56 and 72 days, age at first insemination, age at conception, calving interval, days open, days to first service, and service period. Data included reproductive traits of 42 283 first-parity Black-and-White cows. Days open and calving interval were calculated for 25 013 cows. The highest phenotypic correlation obtained between protein yield and days open amounted to 0.22; non-return rates showed the lowest phenotypic correlations with yield traits. All genetic correlations between reproductive traits and yield traits were unfavourable. The largest were found between yield traits and days open and calving interval (0.35-0.48), and the smallest for age at first insemination and non-return rate until day 72 (less than 0.1). Fat and protein content showed very small correlations with fertility traits; genetic correlations were also low except for non-return rates, which ranged from -0.55 (between fat content and non-return rate until day 56) to -0.24 (between protein content and non-return rate until day 72). The antagonistic genetic correlations between milk production and fertility traits show that selection for fertility is needed.
Phenotypic and genetic correlations between fertility measures and conformation traits were estimated. Data were records of 38,274 cows; the records consisted of eight fertility traits, five descriptive type traits, height and rump and fourteen linearly scored conformation traits. The correlations were estimated using REML based on linear animal model. The phenotypic correlations between fertility and descriptive type traits were in general low or close to zero. The largest were obtained for non-return rates with central ligament (0.055), body depth (-0.066), chest width (-0.079) and rump width (-0.082). The genetic correlations of age at first insemination and age at conception with descriptive type traits, height at rump, and linearly scored udder traits were negative and ranged from -0.014 to -0.224. Age at first insemination and age at conception correlated positively with rump width and chest width. The genetic correlations between non-return rates and most of the conformation traits were low. The largest correlations between descriptive type traits and interval fertility measures were obtained for conformation and dairy character with service period (0.361) and days open (0.313). Among linearly scored type traits, large correlations were found for rear udder height, udder width, and central ligament with service period and days open (from 0.225 to 0.422). All interval traits showed negative correlations with fore udder attachment, and small correlations with rump traits, body depth and chest width.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.