Cooling Holstein cows for 60 days prepartum in summer: effects on prepartum physiology, postpartum productivity, and calf growth.

Heat stress (HS) during the dry period of dairy cows in hot and dry conditions compromises the physiological status and mammary gland development of dairy cows, thereby negatively affecting milk component yield in the subsequent lactation. Our objective was to evaluate the effects of cooling Holstein cows under moderate or higher HS conditions (i.e.

Holstein heifers in desert climate: effect of coat color on physiological variables and prediction of rectal temperature.

Two hundred Holstein heifers were divided by hair coat color in black (n = 60), white (n = 62), and mixed (n = 78) to accomplish two objectives: (1) to compare physiological variables using an analysis of variance, and (2) to construct regression equations to predict rectal temperature. In each heifer, rectal temperature (RT), respiration frequency (RF), and body surface temperatures (obtained with infrared thermography in eye, nose, forehead, head, neck, ear, shoulder, flank, belly, leg, loin, rump, and vulva) were measured. Black heifers had more RF and RT (P < 0.

Muscle fiber morphometry and physicochemical characteristics of the Longissimus thoracis muscle of hair male lambs fed zilpaterol hydrochloride and implanted with steroids.

Muscle fiber morphometry and physicochemical characteristics were evaluated in LT muscles obtained from entire male lambs treated with zilpaterol hydrochloride (ZH, 0 and 0.15 mg/kg body weight) and/or steroidal implant (SI, with and without trenbolone acetate/estradiol). ZH and SI acted synergistically to increase LT area, type-IIb fiber cross-sectional area and soluble collagen content, likewise to decrease metmyoglobin concentration and insoluble collagen content.

Feedlot growth, carcass characteristics and meat quality of hair breed male lambs exposed to seasonal heat stress (winter vs. summer) in an arid climate.

Twenty Dorper × Katahdin male lambs (body weight = 33.9 ± 0.4 kg and age = 4.