Weather influences feed intake and feed efficiency in a temperate climate

Hill, D. L. and Wall, E. (2017) Weather influences feed intake and feed efficiency in a temperate climate. Journal of Dairy Science, 100(3), pp. 2240-2257. (doi: 10.3168/jds.2016-11047) (PMID:28109597)

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A key goal for livestock science is to ensure that food production meets the needs of an increasing global population. Climate change may heighten this challenge through increases in mean temperatures and in the intensity, duration, and spatial distribution of extreme weather events, such as heat waves. Under high ambient temperatures, livestock are expected to decrease dry matter intake (DMI) to reduce their metabolic heat production. High yielding dairy cows require high DMI to support their levels of milk production, but this may increase susceptibility to heat stress. Here, we tested how feed intake and the rate of converting dry matter to milk (feed efficiency, FE) vary in response to natural fluctuations in weather conditions in a housed experimental herd of lactating Holstein Friesians in the United Kingdom. Cows belonged to 2 lines: those selected for high genetic merit for milk traits (select) and those at the UK average (control). We predicted that (1) feed intake and FE would vary with an index of temperature and humidity (THI), wind speed, and the number of hours of sunshine, and that (2) the effects of (1) would depend on the cows' genetic merit. Animals received a mixed ration, available ad libitum, from automatic feed measurement gates. Using >73,000 daily feed intake and FE records from 328 cows over 8 yr, we found that select cows produced more fat- and protein-corrected milk, and had higher DMI and FE than controls. Cows of both lines decreased DMI and fat- and protein-corrected milk but, importantly, increased FE as THI increased. This suggests that improvements in the efficiency of converting feed to milk may partially offset the costs of reduced milk yield owing to a warmer climate, at least under conditions of mild heat stress. The rate of increase in FE with THI was steeper in select cows than in controls, which raises the possibility that select cows use more effective coping tactics. This is, to our knowledge, the first longitudinal study on the effects of weather on FE. Understanding how weather influences feed intake and efficiency can help us to develop management and selection practices that optimize productivity under unfavorable weather conditions. This will be an important aspect of climate resilience in future.

Item Type:Articles
Additional Information:Scotland's Rural College (SRUC) receives grant-in-aid from the Scottish government. This work was funded by the Scottish Government Rural Affairs and the Environment Portfolio Strategic Research Programme 2011 to 2016 (Environmental Change Programme and the Climate Change Centre of Expertise, ClimateXChange).
Glasgow Author(s) Enlighten ID:Hill, Dr Davina
Authors: Hill, D. L., and Wall, E.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Journal of Dairy Science
ISSN (Online):1525-3198
Published Online:18 January 2017
Copyright Holders:Copyright © American Dairy Science Association®, 2017.
First Published:First published in Journal of Dairy Science 110(3):2240-2257
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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