Abomasal Infusion of Glucose and Fat—Effect on Digestion, Production, and Ovarian and Uterine Functions of Cows

Abstract

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.

Effect of dietary energy source on energy balance, production, metabolic disorders and reproduction in lactating dairy cattle

“…In addition, liver triglyceride [78], and plasma triglyceride [66] concentrations were elevated after feeding extra lipogenic nutrients, in contrast to a study that found a decrease in liver triglyceride after feeding more non-fermentable carbohydrates [72] and studies that reported a decrease in plasma triglyceride levels after abomasal glucose infusion [66,73]. Two studies found a positive effect of feeding extra glycogenic nutrients on liver glycogen content [70,72], as a representative of stored carbohydrates.…”

“…Concerning plasma NEFA levels, 13 [9, [60][61][62][63][64][65][66][67][68] out of 15 studies found an increase after feeding extra lipogenic nutrients. In contrast to studies where extra glycogenic nutrients were fed, 13 [60,61,66,[68][69][70][71][72][73] out of 14 reported studies found a decrease in plasma NEFA levels. Plasma BHBA levels increased after feeding extra lipogenic nutrients in five out of eight studies [68,69,74,75].…”

“…Figure 5 further supports these hypotheses, by presenting 18 studies on either feeding more lipogenic or glycogenic nutrients on the calculated EB. Eight of the 12 studies reported an increase in EB after feeding extra lipogenic nutrients [8, 9, 12, 15, 64,66,106]. In contrast to feeding extra glycogenic nutrients where 12 out of 13 studies were able to improve, not-significantly, the calculated EB [66,69,71,72,77,107,108,110,112,116,120].…”

“…Figure 6 illustrates the effects of feeding supplemental lipogenic or glycogenic nutrients on days to first ovulation, conception rate following first insemination, services per conception and number of days open. Increasing glycogenic nutrients was reached by supplying extra dietary starch [118], maize gluten [109,124], ground shelled corn [109,124], abomasal glucose infusion [66] or propylene glycol supplementation [77]. Days postpartum (pp) till first ovulation [66,77,109,114] [77,118] found the number of services per conception to be reduced after propylene glycol supplementation.…”

Effect of a supplement rich in linolenic acid added to the diet of post partum dairy cows on ovarian follicle growth, and milk and plasma fatty acid compositions

“…However, due to the varied nature of the fats used and variable rates of ruminal hydrogenation it is difficult to formulate a general theory to describe their mode of action. Improvements in pregnancy rate at 45 d post insemination [5], ovarian follicle growth [6] and steroidogenesis [7] have all been reported. It has been suggested that the mechanism involves enhanced ovarian activity through the following: improved energy status [8], increased availability of cholesterol for steroid synthesis [9] and increased circulating insulin concentrations [10].…”