Zebu cattle

Aschaffenburg, R., Sen, A. and Thompson, M. P. 1968. Genetic variants of casein in Indian and African zebu cattle. Comp. Biochem. Physiol. 25, 177-184. 

Some races of domestic cattle may be descended in part from the golden ox or aurochs (Bos primigenius) of Europe, which became extinct in the wild in the seventeenth century. Domestic cows are also partly descended from the zebu (B. indicus) and the Indian ox (B. na-madicus). 

As reviewed before," differences in results obtained in IVEP systems are caused by various factors such as time taken to transport ovaries to lab after collection, temperature changes during ovary collection and transport to the laboratory, cow breed, oocyte quality and follicular, maturation, fertilization and embryo culture environments. In particular, cattle breed has been shown to influence developmental competence of oocytes and blastocyst rates. The effect of breed on oocyte quality is amplified by environmental conditions. For example, although Holstein cows Bos taurus) have bigger ovaries, they produce oocytes of lower quality compared to Brahman cows Bos indicus) However, for both cases, the in-vitro-fertilized embryos at the 4- and 8-celI stage when subjected to heat stress results in decreased blastocyst rate but the effect is more severe in Holstein embryos compared to zebu embyros. ... 

The results obtained so far clearly demonstrate that in-vitro oocyte maturation (TVM) of embryos obtained from ovaries of slaughtered cows, subsequent in-vitro fertilization (IVF) of these, in-vitro embryo culture (IVC) and embryo transfer process is a possible option for generating specific cattle genotypes for specific production systems in Eastern Afiica. However, there is need for fine tuning of the IVM, IVF and IVC protocols for the local zebu breeds. Planned application of combinations of these technologies would deliver the desired genotypes and commercial business approaches are needed to deliver this technology beyond the current laboratory trial. Ovum pick up (OPU), if embraced, would even make the process much more economically and ethically attractive. 

The milk of Western cattle contains only a-la B but Zebu and Droughtmas-ter cattle secrete two variants, A and B. a-La A contains no arginine, the one Arg residue of a-la B being replaced by glutamic acid. 

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