| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 University of Florida, Gainesville 32611
Follicular growth, lifespan of the corpus luteum, and antioxidant status of lactating Holsteins that experienced heat stress were monitored. Eleven multiparous cows, 60 to 110 d in milk, were maintained from 0800 to 1800 h daily in environmental chambers from d 11 to 21 of the estrous cycle. Cows were randomly assigned to a heat stress (mean dry bulb temperature peaked at 38.3°C) or control treatment (mean dry bulb temperatures varied from 20.8 to 25.6°C). Rectal temperature and respiration rates of heat-stressed cows were higher at 1600 h than were those of control cows. The length of the estrous cycle and the interval from estrus until luteolysis were not different between treatments. Two of 6 control cows and 1 of 5 heat-stressed cows had extended cycles (>24 d). Heat-stressed cows had more class 1 (2 to 5 mm) follicles from d 11 to 15 of the estrous cycle. Numbers of class 2 (6 to 9 mm) and class 3 (
9 mm) follicles were similar between treatments. Plasma progesterone concentrations were higher for heatstressed cows until d 19 of the estrous cycle. Treatment did not affect concentrations of a-tocopherol, ß-carotene, retinol, retinyl palmitate, or total protein in plasma or concentrations of malondialdehyde in muscle. In conclusion, heat stress did not extend luteal function or the length of the estrous cycle of lactating Holstein cows but did affect follicular growth and progesterone concentrations in plasma. Heat stress did not appear to increase lipid peroxidation or decrease lipid-soluble antioxidant concentrations in blood.
Key Words: free radical • length of estrous cycle • heat stress • lactating Holstein cows
Submitted on April 21, 1997
Accepted on January 9, 1998
This article has been cited by other articles:
|
|
 |
|
  N. C. Burke, G. Scaglia, K. E. Saker, D. J. Blodgett, and W. S. Swecker Jr Influence of endophyte consumption and heat stress on intravaginal temperatures, plasma lipid oxidation, blood selenium, and glutathione redox of mononuclear cells in heifers grazing tall fescue J Anim Sci, November 1, 2007; 85(11): 2932 - 2940. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M Ozawa, D Tabayashi, T A Latief, T Shimizu, I Oshima, and Y Kanai Alterations in follicular dynamics and steroidogenic abilities induced by heat stress during follicular recruitment in goats Reproduction, May 1, 2005; 129(5): 621 - 630. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Sartori, J. M. Haughian, R. D. Shaver, G. J. M. Rosa, and M. C. Wiltbank Comparison of Ovarian Function and Circulating Steroids in Estrous Cycles of Holstein Heifers and Lactating Cows J Dairy Sci, April 1, 2004; 87(4): 905 - 920. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. J. White, R. P. Wettemann, M. L. Looper, T. M. Prado, and G. L. Morgan Seasonal effects on estrous behavior and time of ovulation in nonlactating beef cows J Anim Sci, December 1, 2002; 80(12): 3053 - 3059. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Bernabucci, B. Ronchi, N. Lacetera, and A. Nardone Markers of Oxidative Status in Plasma and Erythrocytes of Transition Dairy Cows During Hot Season J Dairy Sci, September 1, 2002; 85(9): 2173 - 2179. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.M. Burke, D.E. Spiers, F.N. Kojima, G.A. Perry, B.E. Salfen, S.L. Wood, D.J. Patterson, M.F. Smith, M.C. Lucy, W.G. Jackson, et al. Interaction of Endophyte-Infected Fescue and Heat Stress on Ovarian Function in the Beef Heifer Biol Reprod, July 1, 2001; 65(1): 260 - 268. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
