نتایج جستجو برای: respectively acceptable genetic improvement for milk yield
تعداد نتایج: 10821085 فیلتر نتایج به سال:
Selection of genotypes based on high value of heritability and forecasted genetic conditions would be an effective method for improvement of wheat cultivars. The present investigation was carried out to estimate the genetic variability of agro-physiological characters using biometrical genetic techniques in 20 bread wheat genotypes under irrigated condition. For this purpose an experiment was c...
Seventy six high and low producer cows were selected to determine the composition of the blood and milk parameters, and their interrelationships to determine the indices which could be useful to improve the milk yield. The highest mean blood concentrations were found in high producer cows. Mean values for blood urea nitrogen (BUN), serum protein (SPtn), creatinine, triglycerides (TGs), choleste...
The traits particularly important for milk production include milk yield, protein percentage, fat percentage, and the somatic cell score. Alpha-lactalbumin (α-LA) is an important whey protein of cow milk, and is also present in the milk of many other mammalian species. In this study, we analyzed the genetic polymorphisms of the α-LA gene and their relationship to milk production traits (milk yi...
The aim of this research was to investigate the calving season effect on some of the productive traits including milk production, fat percentage and some of reproductive traits including pregnancy period and calf birth weight and also estimation of genetic parameters of studied traits too. In this study the data of 22360 Holestein dairy cows form Tehran province’s 65 herds of between 2012 ...
using monthly test day records the genetic parameters of iranian holstein cattle in first lactation were studied. data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. the model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) ...
Breed additive and non-additive effects, and genetic parameters of lactation milk yield (LYD), 305-day milk yield (305YD), lactation length (LL), milk yield per day of lactation (DM) and lifetime milk yield (LTYD) were estimated in Ethiopian Boran cattle and their crosses with Holstein in central Ethiopia. The data analyzed included 2360 lactation records spread over 15 years. Ethiopian Boran c...
A spline animal model was fitted to 152,103 test-day milk, fat, and protein yield records from 14,423 first-lactation cows. The models included age at calving and the herd-test-month as fixed effects. Model fitting was carried out using Restricted Maximum Likelihood with ASREML. For milk yield, the heritability at 18 d in milk was 0.19, which increased to the maximum estimated value of 0.23 at ...
The objectives of this study were to estimate genetic correlations among body condition score (BCS), dairy form, milk yield, and days open in US Holsteins and investigate the potential of using BCS or dairy form evaluations as early indicators of days open. Dairy form and BCS obtained from the Holstein Association USA, Inc., were merged with mature equivalents (ME) for milk yields and days open...
The Reggiana population is a dairy cattle breed reared in the province of Reggio Emilia, located in the Italian Po Valley. Milk from this breed has been mainly used for the production of Parmigiano Reggiano cheese. The Reggiana breed has shrunk from 84,000 cows in 1940 to 200 animals in 1984, having being replaced by much more productive HolsteinFriesian cows. Thanks to government support the b...
this research used the test day data of the milk production of holstein cows from golestan, mazandaran and guilan provinces collected by animal breeding center of iran between the years of 1988-2011. permanent effects of model, including cattle blend, breeding year and season, also percent of holstein gene and age during recording, were used as a secondary variable. all data obtained in this re...
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