Open AccessEffect of Hot and Humid Conditions on Cortisol Levels m Lactating Dairy Cows
Author(s) -
Muhammad Younas,
J. W. Fuquayz,
A.B. Moorez,
Shahid Hussain
Publication year - 1997
Publication title -
journal of agricultural and marine sciences
Language(s) - English
Resource type - Journals
eISSN - 2410-1079
pISSN - 2410-1060
DOI - 10.24200/jams.vol2iss0pp21-25
Subject(s) - estrous cycle , zoology , barn , luteal phase , rectal temperature , blood sampling , endocrinology , medicine , biology , hormone , civil engineering , engineering
Fourteen lactating, non-pregnant Holstein cows were heat synchronized for estrus and assigned randomly to pens in a free stall barn with (Fan) or without (Control) a fan to observe the effect of forced ventilation on cortisol concentrations. After a 21-day adjustment period, Jugular cannulae were inserted for blood sampling before PGF2a injection. All animals were in their luteal phase at the time of injection as determined by previous observations for estrus and palpation. After PGFZa, blood samples were collected at 6-h intervals from 0 to 36h, 4-h intervals from 36 to 88h and 3 times weekly for three weeks thereafter. Blood samples were assayed for cortisol. Daily rectal temperatures and ambient data were recorded. Average daily rectal temperatures were lower (P 0.05) between treatment groups.