Influence of various environmental factors on dairy production and adaptability of Holstein cattle maintained under tropical and subtropical conditions.

In near future global warming is assumedto beeven more disastrous to the dairy animals in tropics; therefore, selection for genetic merit of both production andadaptability should be of concern. Breeding systems, which include proxy indicators for adaptability and geneticmarkers in the evaluation program to assist the selection for higher accuracy and efficiency, are proposed toimprove both milk yield and adaptability of dairy cattle under tropical and sub-tropical conditions.The futurechallenge is to maintain high producing dairy cattle performance in hot and humid climatic conditions. To avoidthis alarm,considering integrated approach by improving cooling capability, efficient ration formulation andimproved genetic potential for heat resistance through genetic manipulation are supposed to be promisingapproachestoimprove the production and survivability of lactating Holstein under these conditions.Milk yield and adaptability of Holstein are factors of major concern under tropical and subtropicalconditions. Under these conditions the focus had always been on milk production and the adaptability andsurvival are often overlooked. Genotype by environment interactions pose a potential challenge for Holstein-Friesian cattle raised in tropical and subtropical environments by hampering the production and adaptability andpredispose the cattle forinvoluntary culling.The present review was aimed at comparing milk yield, influence ofvarious non-genetic factors and adaptability of Holstein dairy cattle under different environmental conditionswith special focus on tropical and sub-tropical conditions. The milk production in tropical and subtropicalconditions was 40% to 60% lower than the temperate conditions. This wide discrepancy in the milk productionin different environmental conditionswasmainly the outcome of influence of non-genetic factors and mostimportantly the management of the farm under which the animals were kept. The management role was obviousin tropical and subtropical conditions, the more the country was technologically advance the better was themanagement and the higher was the production.Noticeably, in tropics and sub-tropics milk yield wassignificantly higher in cooler part of the year than the hotone. Environmental and physiological adaptability ofHolstein needs considerable attentionin tropics and sub-tropics.