Physiological Responses in Thermal Stressed Jersey Cows Subjected to Different Management Strategies

The effects of cooling and recombinant bovine somatotropin (rbST) on milk yield, reproductive performance, and health of Jersey cattle during summer thermal stress were measured for 2 yr. Cows were assigned to one of two groups based upon days in milk (DIM), parity, and genetic index. Year 1 and yea...

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Bibliographic Details
Published in:Journal of dairy science 2002-12, Vol.85 (12), p.3217-3224
Main Authors: Keister, Z.O., Moss, K.D., Zhang, H.M., Teegerstrom, T., Edling, R.A., Collier, R.J., Ax, R.L.
Format: Article
Language:English
Subjects:
Animal productions
Animals
Biological and medical sciences
bovine somatotropin
Cattle
Cattle Diseases - physiopathology
Cold Temperature
cooling
Dairying - methods
Female
Fundamental and applied biological sciences. Psychology
Growth Hormone - administration & dosage
Hot Temperature
Humidity
Jersey
Lactation
Physiological responses
Pregnancy
Reproduction
Seasons
Stress, Physiological - physiopathology
Stress, Physiological - veterinary
Temperature
Terrestrial animal productions
thermal stress
Vertebrates
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Summary:The effects of cooling and recombinant bovine somatotropin (rbST) on milk yield, reproductive performance, and health of Jersey cattle during summer thermal stress were measured for 2 yr. Cows were assigned to one of two groups based upon days in milk (DIM), parity, and genetic index. Year 1 and year 2 control cows (n=143, n=183, respectively) were housed in a pen with only shades. Cooled treatment cows each year (n=142, n=180) were housed with a spray and fan system for evaporative cooling. Cows were assigned at various days postpartum, not before d 63, coincident with commencement of rbST injections. One half of cows in each group received rbST on d 63 postpartum. Cows were assigned to the shade trial ranging from d 63 to 190. Cooled versus noncooled DIM were similar at the start of the trial. Trials began on July 1, 1999, and July 1, 2000, and concluded on September 30, 1999, and September 25, 2000. The ANOVA of daily milk weight data was conducted utilizing a 2×2 factorial design with cooling and rbST treatments as main effects. Cooling in combination with rbST increased milk yield compared with no cooling and no rbST for 1999 and 2000 (25.5 versus 21.8 kg/d, and 23.7 versus 20.5 kg/d, respectively). In general, cooling improved health and reproductive performance.
ISSN:0022-0302
1525-3198
DOI:10.3168/jds.S0022-0302(02)74410-X