Physiologic responses to feeding rumen-protected glucose to lactating dairy cows

Abstract

Lactating Holstein cows were enrolled in a study beginning before first insemination. Cows were supplemented with a rumen-protected glucose (RPG) product to test the hypothesis that circulating progesterone concentrations could be increased by increasing blood glucose, which causes an increase in insulin, subsequently decreasing progesterone clearance by liver enzymes. Supplementation occurred at 0, 2.2, 4.4, or 8.8 lb per head per day to test a dose response. Treatment began 3 days before ovulation and continued until day 12 of the estrous cycle. Rumen-protected glucose did not impact serum concentration of glucose before or after feeding, but the change in insulin concentration (post-feedingpre-feeding) was greater for the control cows compared with cows that received the three doses of RPG. Crude protein (CP) intake and milk urea nitrogen (MUN) increased linearly with treatment, but dry matter intake (DMI) and milk yield were unaffected by treatment. Concentrations of progesterone were unaffected by treatment, and pregnancy risk at first insemination was reduced by treatment. Rumenprotected glucose failed to increase serum insulin or progesterone concentrations.

Milk Potential of Pantaneira Cows, a Local Breed, at Organic System

“…The TC and sugars are converted to SCFAs in the rumen. As glucose is a key nutrient required for milk synthesis and the maintenance of other body tissues, there must be de novo synthesis of glucose in cattle because of activation of the gluconeogenic metabolic pathway in the liver [ 31 ]. As a result of this mechanism, the effects of treatments on plasma glucose concentrations are normally not expected.…”

“…However, in this study, the lactose content decreased linearly with the decrease of concentrate supplementation level. The low intake of starch can decrease the rumen propionate production and intestine absorption [ 27 ], consequently reducing the glucose synthesis by gluconeogenic metabolism and subsequent uptake by the mammary gland for production of lactose [ 31 ]. Additionally, the highly negative RDP balance can reduce the number of glucogenic amino acids, which are glucose precursors [ 37 ].…”

Effects of fresh‐cow grouping strategy and rumen‐protected glucose on production performance, reproductive variables and risk of culling in Holstein cows

“…It is plausible to hypothesise that incorporation of a rumen‐protected glucose (RPG) source in the fresh‐cow diet may be a viable nutritional strategy contributing to the improvement of dairy cow performance after parturition (McCarthy et al., 2020 ). An increased glucose delivery to the small intestine in this way would reduce the need for its de novo synthesis mainly occurring through hepatic gluconeogenic pathways (Sauls‐Hiesterman et al., 2020 ). Abomasal or duodenal glucose infusion has been shown to improve energy balance, milk production, and milk protein synthesis in dairy cows (Larsen and Kristensen, 2009 ; Rigout et al., 2002a , 2002b ; Wang et al., 2020 ).…”