1Instituto de Ciencias Agrícolas, Universidad Autónoma de Baja California, Blvd. Delta s/n, Ejido Nuevo León, Baja California, México, 21705.
2Animal Sciences Department, University of California, Davis, CA 95616, USA.
3Cooperative Extension, University of California, Davis, CA 95616, USA.
*For correspondence: Tel: (686)52300-88; Fax: (686)523302-17; E-mail: lar62@hotmail.com
1Research supported by the Consejo Nacional de Ciencia y Tecnología, México (Project Number I33476-B), and the Coordinación de Posgrado e Investigación of the Universidad, Autónoma de Baja California, Mexicali, Baja California, México.
In order to determine the effect of a cooling system on prepartum physiological parameters and postpartum productivity, forty multiparous Holstein cows were assigned to one of two treatments 60 days prior to their expected calving date: cooled (soaking for 2 min twice daily) and non-cooled. The highest ambient temperature registered during the study was 49.5C and the average daily temperature humidity index was higher than 72. Cooled cows showed a trend (P=0.08) to reduce their respiration rate, however, rectal temperature, body condition score and body weight were not affected at all (P>0.05). Postpartum milk yield, milk fat and milk energy output did not show significant differences, nor reproduction parameters postpartum (P>0.05). Thus soaking Holstein cows during the prepartum period had no advantage on postpartum productivity under hot and dry conditions.
Dairy cattle, milk production, heat stress, cooling system, reproduction
