Abomasal infusion of glucose and fat--effect on digestion, production, and ovarian and uterine functions of cows.
Four ruminally cannulated lactating dairy cows, arranged in a 4 x 4 Latin square design, were infused abomasally with 1) water (control), 2) 1 kg/d of glucose, 3) 0.45 kg/d of tallow, and 4) 0.45 kg/d of yellow grease. Cows were synchronized for estrus within each 35-d period by injection of a GnRH agonist followed 7 d later by an injection of PGF2 alpha. Dry matter intake was not affected by infusates. Apparent digestibility of total fatty acids was greater for cows receiving the fat infusions relative to those receiving the glucose infusion and tended to increase for cows receiving the yellow grease infusion compared with those receiving the tallow infusion. Energy infusions decreased apparent acid detergent fiber digestibility compared with effects of the control infusion. Fat infusions tended to increase milk fat percentage and decrease the energy status of cows relative to the glucose infusion. The feed efficiency was greater for cows receiving fat infusions than for those receiving the glucose infusion and was greater for cows receiving the yellow grease infusion than for those receiving the tallow infusion. Plasma progesterone concentration peaked higher during the estrous cycle for cows infused with fat than for those infused with glucose. Mean growth rate and maximum size of the first wave dominant follicle were greater with tallow than with yellow grease. During the period of infusion of yellow grease and afterward, release of 13,14-dihydro-15-keto-PGF2 alpha in response to an injection of oxytocin on d 15 of the estrous cycle was attenuated.
Oldick
B S
BS
Department of Dairy and Poultry Sciences, University of Florida, Gainesville 32611, USA.
Staples
C R
CR
Thatcher
W W
WW
Gyawu
P
P
D000018:Abomasum / Q000187:drug effects* / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D004041:Dietary Fats / Q000008:administration & dosage* / Q000494:pharmacology; D004063:Digestion / Q000187:drug effects*; D004734:Energy Metabolism; D004958:Estradiol / Q000097:blood; D004971:Estrus; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005947:Glucose / Q000008:administration & dosage* / Q000494:pharmacology; D007328:Insulin / Q000097:blood; D007774:Lactation / Q000187:drug effects*; D008892:Milk / Q000737:chemistry; D010053:Ovary / Q000187:drug effects / Q000502:physiology; D011374:Progesterone / Q000097:blood; D014599:Uterus / Q000187:drug effects / Q000502:physiology
D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D011374:Progesterone; D004958:Estradiol; D005947:Glucose