Gyr Cattle
A collection of papers and internet publications on the subject of Bos indicus I have found in my search for information on Gyr cattle.
An FAO Study prepared by N. R. JOSHI Animal Breeding Specialist, Animal Production Branch and
RALPH W. PHILLIPS, Deputy Director, Agriculture Division
FOOD AND AGRICULTURE ORGANIZATION Of THE UNITED NATIONS ROME, ITALY – MARCH, 1953
The present study was conducted to examine genetic diversity, genetic differentiation and genetic relationship among Gir, Deoni and Kankrej cattle breeds using microsatellite markers. The number of alleles observed at different loci ranged from 5 (HEL5) to 8 (CSRM60) with a total of 46 alleles across three breeds. The overall heterozygosity and polymorphic information content (PIC) values were 0.730 and 0.749, respectively. Nei’s standard genetic distance was least between Gir and Kankrej and highest between Deoni and Kankrej. In the analyzed loci, an overall significant deficit of heterozygotes across these breeds was found and it could be due to inbreeding within breeds. The overall genetic differentiation (F ST ) among breeds was moderate, but significantly different. All loci, except INRA035, contributed significantly to the overall differentiation. The highest F ST values were found in HEL5 and lowest in INRA035. The overall N e m value indicated a high rate of genetic flow between the breeds, which is in agreement with their origin of close proximity in the geographical area.
Abstract
During their separate evolution from Bos taurus, zebu cattle (Bos indicus) have acquired genes that confer thermo-tolerance at the physiological and cellular levels. Cattle from zebu breeds are better able to regulate body temperature in response to heat stress than are cattle from a variety of B. taurus breeds of European origin. Moreover, exposure to elevated temperature has less deleterious effects on cells from zebu cattle than on cells from European breeds. Superior ability for regulation of body temperature during heat stress is the result of lower metabolic rates as well as increased capacity for heat loss. As compared to European breeds, tissue resistance to heat flow from the body core to the skin is lower for zebu cattle while sweat glands are larger. Properties of the hair coat in zebu cattle enhance conductive and convective heat loss and reduce absorption of solar radiation. At the cellular level, genetic adaptations to resist deleterious effects of elevated temperature result in pre-implantation embryos from zebu being less likely to be inhibited in development by elevated temperature than are embryos from European breeds. The zebu genotype has been utilised in crossbreeding systems to develop cattle for beef and dairy production systems in hot climates but success has been limited by other unfavourable genetic characteristics of these cattle. An alternative scheme is to incorporate specific thermo-tolerance genes from zebu cattle into European breeds while avoiding undesirable genes. Once specific genes responsible for thermo-tolerance in zebu have been identified or mapped, breeding strategies such as marker-assisted selection and transgenics can be applied to further the exploitation of the zebu genotype for cattle production systems.
Sustainable Utilization of Indigenous Animal Genetic Resources of India
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