This study provides estimates of genetic parameters for various diseases, fertility and 305-day milk production traits in dairy cattle using data from a UK national milk recording scheme. The data set consisted of 63891 multiple lactation records on diseases (mastitis, lameness, milk fever, ketosis and tetany), fertility traits (calving interval, conception to first service, number of services ...

The objective of this research was to estimate genetic parameters of first-lactation body condition score (BCS), milk yield, fat percentage (Fat%), protein percentage (Prot%), somatic cell score (SCS), milk urea nitrogen (MUN), lactose percentage (Lact%), and fat to protein ratio (F:P) using multiple-trait random regression animal models. Changes in covariances between BCS and milk production t...

This study investigated the improvement in genetic evaluation of fertility traits by using production traits as secondary traits (MILK = 305-d milk yield, FAT = 305-d fat yield, and PROT = 305-d protein yield). Data including 471,742 records from first lactations of Denmark Holstein cows, covering the years of inseminations during first lactations from 1995 to 2004, were analyzed. Six fertility...

Phenotypic and genetic correlations were estimated between 48 type appraisal traits and first lactation milk production to determine the importance of appraisal traits in a breeding program from 5,024 records from the New York type appraisal program. Most phenotypic correlations amgng the type traits were near zero. Depth of udder was the appraisal trait having the highest correlation with firs...

The impact of polymorphism of the diacylglycerol acyltransferase (DGAT1), butyrophilin (BTN1A1), oxidized low-density lipoprotein receptor (OLR1), and signal transducer and activator of transcription 1 (STAT1) genes on milk production and reproduction traits in 419 Czech Fleckvieh cows was examined using polymerase chain reaction and restriction fragment length polymorphism. The loci DGAT1 and ...

The objective of the present study was to investigate single nucleotide polymorphisms (SNPs) located in three candidate genes previously reported to have effects on fertility and milk production traits in a population of 123 Holstein cows. The milk production traits evaluated included lifetime averages of milk yield, protein concentration, and fat concentration. Fertility traits evaluated inclu...

this experiment was aimed to study the association between the dgat1 k232a polymorphism and milk production traits and somatic cell score (scs) in iranian holstein dairy cows. the records of 408 animals from five dairy herds were randomly identified and then genomic dna was extracted from blood using the modified-salting method described by miller. rflp-pcr was performed to obtain all the polym...

Improvement of milk production traits in dairy sheep is required to increase the competitiveness of the industry and to maintain the production of high quality cheese in regions of Mediterranean countries with less favourable conditions. Additional improvement over classical selection could be reached if genes with significant effects on the relevant traits were specifically targeted by selecti...

the milk and milk fat production records of 28 holstein herds in khorasan razavi province were analyzed in this study. the records were based on 305 days of milking and were from the first to third milking periods and two times milking per day. the fixed effects of herd-year-season and age of dam at parturition as covariate were fitted in the models of analyses. the (co)variance components were...

Received: 7 March, 2014 Accepted: 21 May, 2014 Published: 20 July, 2014 The data consisted of 37118 TD milk record of 5851 primiparous Holstein cows of Tunisia. Herd-years of calving means for milk production traits were clustered in three levels using the CLUSTER procedure in SAS software. Production levels included low, medium and high levels. Genotype by environment interaction were investig...