When linear programming is used to rank sires on daughter profits, coefficients of input are required for representative daughters of each sire. Within herdyear-season regressions of daughter's actual 305-day milk, fat percent, days open, 2-min milk yield adjusted for total yield, total milking time, and body weight at birth and first calving on sire's proofs for production, conformation, milki...

To explore the potential of cattle to produce both milk and beef, the genetic aspects of beef production among Holstein‐Friesian bulls pedigree selected for milk were studied. The data included growth records of 504 bulls (DPT) by 120 sires (SPT) pedigree selected for progeny testing by American Breeders Service, 1964 to 1971. DPT bulls with proofs had an average predicted difference for milk (...

Poor fertility has become a major reason for involuntary culling of dairy cows in the UK. Research in the UK has recently developed a Fertility Index for dairy cattle. After examining national data it was decided that fertility proofs in the UK would be based on calving interval (CI) and non-return rate after 56 days (NR56) weighted by their relative economic weights (independent of culling). S...

The use of milk sample categorization for diagnosing mastitis using Kohonen’n Self-Organizing Feature Map (SOFM) is reported. Milk traits data of 14 weeks of milking from commercial dairy cows in New Zealand was used to train and test a SOFM network to discriminate the samples into its appropriate health category. The SOFM was useful in discriminating data patterns into four separate mastitis c...

The worldwide production of sheep milk was 9,246,922 tonnes in 2009, whereas dairy cows produced 583,401,740 tonnes (FAOSTAT, at http://faostat.fao.org; accessed July 2011). The dairy sheep production is based on the utilization of local breeds of small or moderate effective and well adapted to local conditions in the different Mediterranean countries. This peculiarity contrasts with the "Holst...

Increases in milk yield from genetic selection may be accompanied by correlated increases in genetic susceptibility to clinical mastitis and somatic cells. Unlike clinical mastitis, somatic cell scores can be easily determined and recorded and are related to milk loss from subclinical mastitis. Selection against high somatic cell scores should decrease incidence of clinical mastitis and provide...

Various QTL mapping experiments led to the detection of a QTL in the centromeric region of cattle chromosome 14 that had a major effect on the fat content of milk. Recently, the gene encoding diacylglycerol O-acyltransferase (DGAT1) was proposed to be a positional and functional candidate for this trait. This study investigated the effects of a nonconservative lysine to alanine (K232A) substitu...

The use of whole-genome resequencing to obtain more information on genetic variation could produce a range of benefits for the dairy cattle industry, especially with regard to increasing milk production and improving milk composition. In this study, we sequenced the genomes of eight Holstein bulls from four half- or full-sib families, with high and low estimated breeding values (EBVs) of milk p...

We estimated the allele and genotype frequencies of IGF-I/SnaBI gene polymorphism and the concentration of this protein in Holstein dairy cows. We also examined the association with milk yield (305-day milk yield) and milk components (fat and protein percentage, and 305-day milk protein and fat yield). Blood IGF-I levels were measured and genotyping was performed on 250 Holstein cows of four di...