Feeding and nutrition management of heat-stressed dairy ruminants

Abstract

<p>Climate change, with a constant increase in the Earth temperature, negatively affects livestock<br>\nproduction and health. This paper will focus on the possible nutritional and feeding strategies to<br>\nmitigate the negative impact of heat stress (HS) on ruminants. The first nutrient interacting with<br>\nhot weather conditions is fibre and its digestibility. It is well recognised how fibre may affect voluntary<br>\ndry matter intake (DMI), chewing and ruminating activity. A possible dietary strategy to<br>\ncounteract the reduced DMI under hot environment is represented by the increased diet energy<br>\nconcentration, protein supply and essential aminoacids. Mineral feeding under HS condition<br>\nmust cover the supply of each nutrient as consequence of altered turnover, and the needs<br>\nrelated to buffer requirements. Particular interest is growing in the use of Se (Se-yeast), because<br>\nof its role to support the animal antioxidative defences. Water is a pivotal nutrient to cope with<br>\nHS in ruminants because it plays a role in animal thermoregulation. Recently, some vitamins and<br>\nfeed additives were studied for their action on the animal physiology to cope with HS. Among<br>\nvitamins, niacin was tested for its action on the vasodilatation in the mammalian and for its role<br>\nin lipid metabolism; among feed additives, yeasts and plant extracts may exert a positive action<br>\nin rumen metabolism as well as in regulation of body temperature.</p>