نتایج جستجو برای: calving month

تعداد نتایج: 145034  

Journal: :Acta Veterinaria Scandinavica 2004
GE Meglia K Holtenius L Petersson P Öhagen K Persson Waller

Vitamins A and E, and the trace elements selenium (Se) and zinc (Zn) are essential for the health and performance of dairy cows. Their concentrations often decrease around calving and extra supplementation is sometimes recommended at that time. However, the need for this varies, for example depending on quantity and quality of feedstuffs in the diet. The aim of this study was to measure the con...

Journal: :Acta Veterinaria Scandinavica 2001
GE Meglia A Johannisson L Petersson K Persson Waller

Dairy cows are highly susceptible to infectious diseases, like mastitis, during the period around calving. Although factors contributing to increased susceptibility to infection have not been fully elucidated, impaired neutrophil recruitment to the site of infection and changes in the concentrations of some micronutrients related with the function of the immune defence has been implicated. Most...

Journal: :Journal of dairy science 1992
P J Boettcher L B Hansen P M VanRaden C A Ernst

Lactational means of somatic cell score from sample days of primiparous DHI cows were analyzed to compare dairy records processing centers for data properties, to examine effects of age at calving and month of calving on somatic cell score, and to calculate preliminary PTA of sires for somatic cell scores. Five processing centers contributed data but differed substantially with respect to avail...

2014
Godfrey Bernard Nyamushamba Tinyiko Edward Halimani Venancio Edward Imbayarwo-Chikosi Bruce Tavirimirwa

A study was carried out to evaluate non genetic factors affecting milk yield and milk composition in Zimbabwean Red Dane and Jersey cattle cattle. A total of 1004 and 10 986 unedited Red Dane and Jersey 305-day lactation records respectively, were obtained from Livestock Identification Trust (LIT) containing 22 herds (1 Red Dane herd and 21 Jersey herds), with Red Dane calving in the period 200...

Journal: :The Journal of veterinary medical science 2006
Masayuki Kohiruimaki Hiromichi Ohtsuka Tomohito Hayashi Kayoko Kimura Machiko Masui Takaaki Ando Daisaku Watanabe Seiichi Kawamura

The purpose of this study was to clarify whether weight change rate (WCR) is useful in evaluating herd health. Five herds (A, B, C, D, and E) were examined monthly for approximately 1 year to measure both WCR and BCS. WCR was calculated using the following equation: WCR (%) = (body weight of current month-body weight of the preceding month)/body weight of current month x 100. In addition, blood...

Journal: :علوم دامی ایران 0
حسین مهربان دکتری ژنتیک و اصلاح نژاد دام، گروه علوم دامی، دانشگاه شهرکرد سید مهدی اسماعیلی فرد دانشجوی دکتری ژنتیک و اصلاح نژاد دام، گروه علوم دامی، دانشگاه علوم کشاورزی و منابع طبیعی ساری مجتبی نجفی دانشجوی دکتری ژنتیک و اصلاح نژاد دام، گروه علوم دامی، علوم کشاورزی و منابع طبیعی ساری بیتا عباسی مشائی دانشجوی دکتری ژنتیک و اصلاح نژاد دام، گروه علوم دامی، علوم کشاورزی و منابع طبیعی ساری ابراهیم اسدی خشوئی دکتری ژنتیک و اصلاح نژاد دام، گروه علوم دامی، دانشگاه شهرکرد

a data file containing 607662 (317608) milk (open days) records belonging 294417 (177838) holstein cows that were calved from 1983 to 2008 was used. the bivariate repeatability model was used for data analyzing so that herd, calving year, calving month, days in milk (only for milk trait) and calving age for each parity, were assumed as fixed effects and additive genetics and permanent environme...

Journal: :Journal of animal science 1997
A J Lee

Weight gain of young dairy replacement heifers, even over several months, is highly variable, lowly heritable, and a poor indicator of either weight at calving or first lactation milk yield. Voluntary forage consumption is much less variable, more heritable, and a better predictor of weight at calving and milk yield. Weight at calving is highly heritable but not correlated genetically with milk...

Journal: :Journal of dairy science 2005
E Carlén M del P Schneider E Strandberg

Clinical mastitis was analyzed with mixed linear models (LM) and survival analysis (SA) using data from the first 3 lactations of >200,000 Swedish Holstein cows having their first calving between 1995 and 2000. The model for both methods included fixed effects of year-month and age at calving, fixed regressions of proportions of heterosis and North American Holstein genes, and random effects of...

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