In our study of the origins of domestic horses, published in 1998, my colleagues and I examined sequence data of the mitochondrial DNA control region from 29 individuals, including Przewalski's horse and 14 domestic breeds (1). We found virtual genetic constancy within Przewalski's horse, unsurprising considering its severe historical bottlenecking, but a great deal of variation within and amon...

ICAR Technical Series No 3 Not more than a third of a century ago, a comprehensive theory of systematic cross-breeding in farm animals was fully developed (Smith, 1974; Moav, 1966; Dickerson, 1969; Dickerson, 1973). Since then many experiments have been conducted to provide information about the effect of crossing breeds or strains within farm animal species. Based on these results, efficient i...

Losses caused by parasitic disease varies considerably from death to that of a minor annoyance. The differences may be due to geographic, genetic, or husbandry variability. Genetic differences between breeds and among individuals within breeds may greatly determine the effect the parasites have on their hosts. More important is the system of management which will lead to a greater or lesser exp...

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with a...

Inherited kidney diseases have been recognized in several breeds or kindreds of dogs and cats, and more examples of such conditions are likely to be identified as renal diseases that occur in a familial pattern are investigated thoroughly. In affected breeds/kindreds, accurate diagnosis of familial nephropathies is especially important because of the potential health and selective breeding impl...

The aim of the current study was to explore growth performance and carcass traits using ultrasound measurements calves different cattle breeds under pasture concentration feeding system. A total 25 male between ages 6 7 months with an average body weight 162.37 ± 7.7 kg were fed two separate fattening trials for seven (pasture finishing period). Animals divided into five groups (five each breed...

The number of breeds of domesticated animals, especially livestock, have declined rapidly. The proximate causes and processes involved in loss of breeds are outlined. Also the path-dependent effect and Swanson’s dominance-effect are discussed in relation to lock-in of breed selection. While these effects help to explain genetic erosion, they need to be supplemented to provide further explanatio...

Records for birth and subsequent, monthly weights until weaning on beef calves of two breeds in a selection experiment were analysed fitting random regression models. Independent variables were orthogonal (Legendre) polynomials of age at weighing in days, and orders of polynomial fit up to 10 were considered. Analyses were carried out on a phenotypic and genetic scale, fitting sets of random re...

Artificial insemination (AI) and embryo transfer (ET) are not just reproductive techniques, but indispensable tools for genetic improvement. In this sense, they play an effective part in propagating improved breeds. Analysis of the development of insemination of French cattle breeds since 1960 shows how breeders can alter their genetic choices to meet economic needs. AI and ET also have their p...

The paper studies indices of lipid metabolism, immunoglobulins in blood serum heifers different breeds. Black-and-white, Simmental, Aberdeen-Angus, mongrel cattle was selected for this study. Each breed the group consisted 10 heads. study lipids dynamics experimental showed, concentration gradually increased and by 5th month reached maximum values. By end pregnancy on 9th month, a decrease all ...