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) ...

The objective of this study was to analyze the correlation between Holstein body conformation traits and milk production traits in the Shanghai region. In total, 871 Holstein cows were randomly chosen from 28 dairy farms in Shanghai at second stage of lactation as the object of our study. Five milk production traits, including 305-d milk yield, butter fat percentage, milk protein percentage, pe...

Our objectives were to test differences in protein synthesis and secretion by cultured oviducts and endomemum from Brahman and Holstein cows and the response of those tissues to in vitro heat shock. Explants of oviductal tissue obtained at estrus from Holstein (n = 5 ) and Brahman (n = 6 ) cows were cultured at a homeothermic (39°C) or heat shock (43°C) temperature. At 6 h, cultures were pulse-...

Dystocia (DYS) is an important problem in Holstein cattle and imposes important economic losses on cattle producers. The etiologies and types of DYS are various and different factors can influence its incidence. In the present study, incidence of different types of dystocia was investigated in different seasons and parities in Holstein cows. One hundred and eighty two primiand multiparous cows ...

Some production parameters of seropositive cows (age, first calving age, 305 day mature equivalent last milk yield production, lifetime mature equivalent milk yield production, lifetime total milk production, lifetime total milking period, lifetime monthly milk production, lifetime daily milk production, lifetime total days of milking, number of inseminations per pregnancy (for last pregnancy),...

Merit of service sires for Holstein cows designated as genetically elite for yield in January 1990 was calculated to determine the contribution of these cows to genetic progress. Service sires were determined from sires of registered female progeny because male progeny were selectively registered. Primary data were 1295 elite cows (top 1%) that had a daughter produced from a mating in the 6 mo ...

To develop an efficient DNA typing system for Chinese Holstein cattle, 17 microsatellites, which were amplified in four fluorescent multiplex reactions and genotyped by two capillary electrophoresis injections, were evaluated for parentage verification and identity test. These markers were highly polymorphic with a mean of 8.35 alleles per locus and an average expected heterozygosity of 0.711 i...

Background: Information regarding the metabolic hormones in different metabolic states of high producing dairy cows can aid high producing herds to manage and resolve the metabolic and production problems. Furthermore, it can be considered as a tool to evaluate metabolic status of dairy cows. Herd managers can also evaluate the energy input-output relationships by assessing the metabolic profil...

In the present research, molecular detection of bovine leukocyte adhesion deficiency (BLAD) and complex vertebral malformation (CVM)in a population of Iranian Holstein cows has been carried outusing milk somatic cells by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). The BLAD and CVM are monogenic and autosomal recessive heredity lethal syndrome in Holstein-Friesi...

Lifetime dairy production, reproduction and growth traits of 75 females sired by Holstein, Jersey or Brown Swiss bulls and Holstein-Friesian x Gir dams of 1/2 to 3/4 Holstein-Friesian fractions were compared. The animals were in a single herd under the same management. Milk, fat and protein yields, concentrates fed, reproduction, and weights were recorded throughout the lifetime of the cows. Th...