نتایج جستجو برای: lactating dairy cows
تعداد نتایج: 64226 فیلتر نتایج به سال:
OBJECTIVE To estimate seroprevalence of Mycobacterium avium subsp paratuberculosis (MAP) infection among adult dairy cows in Colorado and determine herd-level factors associated with the risk that individual cows would be seropositive. DESIGN Cross-sectional observational study. ANIMALS 10,280 adult (> or = 2 years old) dairy cows in 15 herds in Colorado. PROCEDURE Serum samples were test...
Three-hundred and thirty-five lactating dairy cows from two herds were used to compare the effects on reproductive performance of intramuscular injections of 100 micrograms gonadotropin-releasing hormone (GnRH), 250 micrograms GnRH or saline given on day 13, 14 or 15 postpartum. The incidence of ovarian cysts or uterine infections was not reduced after GnRH injection. Culling rate for infertili...
The role of obligate anaerobic bacteria in the aetiology of mastitis of lactating dairy cows was investigated. Anaerobes were isolated from 12% of lactating mastitic cows, which were representative of 50% of the 10 dairy herds examined. Bacteroides fragilis was the most frequently isolated organism of (50%), followed by Peptococcus indolicus (33%), Eubacterium lentum (33%), E. aerofaciens (17%)...
Growth of the corn ethanol industry has created a need for alternatives to corn for lactating dairy cows. Concurrent expansion in soydiesel production is expected to increase availability and promote favorable pricing for glycerol, a primary co-product material. The objective of this study was to determine the feeding value of glycerol as a replacement for corn in diets fed to lactating dairy c...
The objective of this study was to examine the effect of an excess intake of quickly degradable nitrogen (QDN) on ovarian follicle development. Twenty lactating dairy cows were fed mixed silage and concentrates twice daily. The control diet was a typical ration for high producing dairy cows in the United Kingdom (crude protein (CP)=17.5%; metabolizable energy (ME)=11.8 MJ/kg DM). The cows were ...
Introduction Ionophores have been used extensively in the beef industry in Canada since 1977. Until recently, there has been no label indication for use of ionophores in lactating dairy cattle. Ionophores are feed additives that alter rumen microbial populations through ion transfer across cell membranes. In Canada, the label warning prohibiting the use of Rumensin premix in lactating dairy ca...
In 1996, data on management practices used on US dairy operations were collected and analyzed for association with fecal shedding of Salmonella by dairy cows. A total of 4299 fecal samples from 91 herds was cultured for Salmonella isolation. Herd-size (adjusted odds ratios (OR) = 5.8, 95% CI 1.1, 31.3), region (OR = 5.7, CI 1.4, 23.5), use of flush water systems (OR = 3.5, CI 0.9, 14.7), and fe...
Lactating dairy cows have unique reproductive responses compared to when they were heifers that result in distinctly different reproductive measurements and pregnancy outcomes that can be partially overcome with pharmacological strategies. These parameters include circulating progesterone and estradiol concentrations, ovulatory follicle and corpus luteum diameter, incidence of anovulation and d...
Controlling heat stress (HS) is a global challenge for the dairy industry. In this work, an integrated metabolomics and lipidomics approach using (1)H nuclear magnetic resonance (NMR) and ultra-fast LC-MS in combination with multivariate analyses was employed to investigate the discrimination of plasma metabolic profiles between HS-free and HS lactating dairy cows. Here we provide the informati...
Plasma samples from suckling beef calves, transport-stressed weaned calves, 500 kg feedlot cattle, and lactating dairy cows were analyzed for vitamin C, folic acid, pantothenic acid, and vitamin B12' Plasma from stressed calves also was analyzed for vitamin B6' Differences in plasma levels were detected between groups. Plasma vitamin C was highest in suckling calves, but similar for stressed ca...
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