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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #260568
Title: Effect of supplemental protein source during the winter on pre- and postpartum glucose metabolism

Author
item HARRELSON, F - New Mexico State University
item IVEY, S - New Mexico State University
item COX, S - New Mexico State University
item DUNLAP II, R - New Mexico State University
item MULLINIKS, J - New Mexico State University
item CARTER, B - New Mexico State University
item LOEST, C - New Mexico State University
item Petersen, Mark

Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/10/2010
Publication Date: 6/20/2010
Citation: Harrelson, F.W., Ivey, S.L., Cox, S.H., Dunlap Ii, R.L., Mulliniks, J.T., Carter, B.H., Loest, C.A., and Petersen, M.K. 2010. Effect of supplemental protein source during the winter on pre- and postpartum glucose metabolism. Western Section of Animal Science Proceedings 61:262-265.

Interpretive Summary: Circulating serum glucose concentrations as well as glucose utilization have been shown to be affected by forage quality. Supplemental protein provided to grazing range cows while consuming low quality forage may improve glucose metabolism. The objective of our study was to determine the effects of winter protein supplement strategy on serum glucose half-life, insulin response, as well as identify the effects of previous gestational protein supplementation on mid lactation milk yield. The study was conducted two consecutive calving seasons utilizing 5-yr old Angus and Angus crossbred cows (n = 8/trt each yr, 530 kg average BW). Cows were supplemented until calving with 1) a control 36% CP (35% UIP of CP) cottonseed meal based cube (CON), hand-fed at 454 g/d delivered 3d/wk ($16/45.4 kg), or 2) a self-fed 50:50 loose mineral and fishmeal 33% CP (60% UIP of CP) small supplement (SSP), formulated for a targeted consumption of 113g/d ($52/45.4 kg). After calving, cows were supplemented similarly (CON at 908 g/d offered 3 d/wk). Supplemental protein source affected (P = 0.03) glucose half-life, whereby the SSP cows had a lower half-life compared to CON (62 and 85 min respectively). Supplement also influenced insulin area under the curve (AUC; P < 0.01) with CON having a larger area compared to the SSP treatment (95.18 ± 4.9 and 75.02 ± 4.8 respectively). Prepartum glucose AUC (P = 0.10) and insulin half-life (P = 0.75) were unaffected by supplement treatment. Milk yield or components was not affected (P > 0.05) by supplement; however year showed a significant (P < 0.05) effect on these parameters. Milk yield was decreased from 7531 g ± 299 in yr 1 to 4328 g ± 293 in yr 2, possibly due to lower forage quality (~3% CP vs. ~8% CP in yr 1). These results suggest that supplemental undegradable intake protein, during times of low quality forage, may improve glucose clearance.

Technical Abstract: Circulating serum glucose concentrations as well as glucose utilization have been shown to be affected by forage quality. Supplemental protein provided to grazing range cows while consuming low quality forage may improve glucose metabolism. The objective of our study was to determine the effects of winter protein supplement strategy on serum glucose half-life, insulin response, as well as identify the effects of previous gestational protein supplementation on mid lactation milk yield. The study was conducted two consecutive calving seasons utilizing 5-yr old Angus and Angus crossbred cows (n = 8/trt each yr, 530 kg average BW). Cows were supplemented until calving with 1) a control 36% CP (35% UIP of CP) cottonseed meal based cube (CON), hand-fed at 454 g/d delivered 3d/wk ($16/45.4 kg), or 2) a self-fed 50:50 loose mineral and fishmeal 33% CP (60% UIP of CP) small supplement (SSP), formulated for a targeted consumption of 113g/d ($52/45.4 kg). After calving, cows were supplemented similarly (CON at 908 g/d offered 3 d/wk). Supplemental protein source affected (P = 0.03) glucose half-life, whereby the SSP cows had a lower half-life compared to CON (62 and 85 min respectively). Supplement also influenced insulin area under the curve (AUC; P < 0.01) with CON having a larger area compared to the SSP treatment (95.18 ± 4.9 and 75.02 ± 4.8 respectively). Prepartum glucose AUC (P = 0.10) and insulin half-life (P = 0.75) were unaffected by supplement treatment. Milk yield or components was not affected (P > 0.05) by supplement; however year showed a significant (P < 0.05) effect on these parameters. Milk yield was decreased from 7531 g ± 299 in yr 1 to 4328 g ± 293 in yr 2, possibly due to lower forage quality (~3% CP vs. ~8% CP in yr 1). These results suggest that supplemental undegradable intake protein, during times of low quality forage, may improve glucose clearance.