نتایج جستجو برای: holstein dairy herds
تعداد نتایج: 56478 فیلتر نتایج به سال:
BACKGROUND Infection with Coxiella burnetii, the cause of Q-fever, has never been detected in Norwegian animals. Recognising the increasing prevalence of the infection in neighbouring countries, the aim of the study was to perform a survey of Norwegian farmed ruminants for the prevalence of C. burnetii infection. RESULTS Milk and blood samples from more than 3450 Norwegian dairy cattle herds,...
A University of Wisconsin-Madison lameness survey was carried out on 30 well recorded dairy herds – 15 stanchion/tie-stall and 15 free-stall, with a variety of stall bases. Each herd was visited twice – once in the spring/summer of 2000 and once in the winter of 2001. On both occasions, all milking cows were locomotion scored 1 through 4 with cows scoring 3 or 4 classified as lame. The proporti...
Genetic relationship between milk urea nitrogen and reproductive performance in Holstein dairy cows.
The objective of this study was to describe the genetic and phenotypic relationship between milk urea nitrogen (MUN) and reproductive traits in Iranian Holstein dairy cows. Test-day MUN data obtained from 57 301 dairy cows on 20 large dairy herds in Iran between January 2005 and June 2009. Genetic parameters for MUN and reproductive traits were estimated with a five-trait model using ASREML pro...
BACKGROUND Urban/peri-urban dairy production and sales has evolved as an adjustment to cope with food security and economic needs for urban dwellers in low-income countries and created an opportunity to transform from subsistence rural lifestyles of dairy farming to commercial engagement in towns. However, urban/peri-urban dairy farms differ in challenges from rural dairy farms and reproduction...
background: cardiovascular system is a very importantorgan that plays a vital role in tissue function. in farm animals,the growth and high milk production depends on function ofcardiovascular system. objectives: cardiovascular health inhigh and low-yielding dairy cows was investigated. methods:fifty 4-year-old high- yielding holstein dairy cows and fifty 4-year-old low- yielding holstein dairy ...
Progeny-test (PT) programs of US artificial-insemination (AI) organizations were examined to determine timeliness of sampling, PT daughter distribution, rate of return of PT bulls to widespread service, and genetic merit of PT bulls compared with AI-proven and natural-service (NS) bulls. Bull age at semen release and at birth and calving of PT daughters was documented by breed (Ayrshire, Brown ...
to estimate the prevalence of subacute ruminal acidosis (sara) in dairy cows, a total of 196 ruminalfluid samples were drawn by rumenocentesis from 10 dairy herds of khorasan razavi province, northeast ofiran. two groups of 12 cows, early lactation and mid-lactation cows were sampled in each dairy herd andruminal ph was determined immediately using a portable ph-meter. a total of 54 cows (27.6%...
Complex vertebral malformation (CVM) is a recently described monogenic autosomal recessive hereditary defect of Holstein dairy cattle that causes premature birth, aborted fetuses and stillborn calves. Guanine is substituted by thymine (G>T) in the solute carrier family 35 member A3 gene (SLC35A3). A valine is changed to a phenylalanine at position 180 of uridine 5'-diphosphate-N-acetyl-glu...
Invasions of gastrointestinal nematodes in dairy cows may affect animals productivity. The most frequently detected internal parasite of dairy cattle is Ostertagia ostertagi. The objective of this study was to determine O. ostertagi invasion extensiveness in selected herds of dairy cattle, with special consideration to cows being in the first lactation, and to analyze the milk yield and content...
In November 2008, a total of 19,910 bulk tank milk (BTM) samples were obtained from dairy farms from all over Germany, corresponding to about 20% of all German dairy herds, and analysed for antibodies against the bovine lungworm Dictyocaulus viviparus by use of the recombinant MSP-ELISA. A total number of 3,397 (17.1%; n = 19,910) BTM samples tested seropositive. The prevalences in individual G...
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