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Evaluation of sweet potato flour addition partially replacing corn on milk yield and metabolism of dairy cows.

M. A. Ollé




Evaluation of sweet potato flour addition partially replacing corn on milk yield and metabolism of dairy cows.
M. A. Ollé*1, C. F. Demarco1, L. Oliveira2, C. A. Oliveira1, J. B. Cardoso1, A. E. Anjos1, A. D. C. Matos1, A. A. Barbosa1, J. O. Feijó1, V. R. Rabassa1, E. Schmitt1, M. N. Corrêa1, F. A. B. Del Pino1, C. C. Brauner1. 1Núcleo de Pesquisa, Ensino e Extensão em Pecuária (NUPEEC), Universidade Federal de Pelotas (UFPel) Pelotas, RS, Brazil, 2IFSul Campus Visconde da Graça (CAVG) Pelotas, RS, Brazil.

Sweet potato (Ipomoea batatas) is a high source of starch feed (75.7%). This crops usually generate up to 30% of discards that are not marketing, becoming a potential ingredient as a coproduct to be added in a ruminant ration. Therefore, the objective of this study was to evaluate sweet potato flour addition on concentrate, partially replacing corn, on milk yield and metabolism of dairy cows. Twenty lactating multiparous Holstein cows 45 ± 15 DIM were randomly enrolled into 2 groups: cows receiving a standard diet with corn as an energy source (n = 20) and cows receiving a concentrate with 40% of sweet potato flour replacing corn (n = 20). Milk production was obtained daily by the sum of the morning and afternoon milkings throughout the experiment. Serum and plasma samples were collected every 3 d from all animals after morning milking through a coccygeal vein puncture, and analyzed for glucose, nonesterified fatty acid (NEFA), gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), total protein (TP), albumin and urea concentrations. The experiment lasted 70 d, divided into 2 periods of 35 d each, 14 d for adaptation to diet and 21 d for collection, adopting the crossover design (2 treatment groups and 2 periods) and data were analyzed using NCSS software. There was no effect (P > 0.05) of carry-over on the treatments in any variables. The average daily milk production was similar (P = 0.62) between groups, 38.95 and 38.67 kg/day, respectively for control and sweet potato groups. Metabolic evaluations were all within the physiologic ranges and they were similar (P > 0.05) between groups glucose (P = 0.11); NEFA (P = 0.58); GGT (P = 0.19); AST (P = 0.48); TP (P = 0.21); albumin (P = 0.14). The concentration of urea was greater (P = 0.001) in the sweet potato flour group, 38.63 mg/dL as compared with 34.96 mg/dL to the control. In conclusion, corn substitution by sweet potato flour at 40% in lactating cow diets, did not affect milk yield and metabolism. Therefore, sweet potato flour can be a potential ingredient to be used for lactating diets of dairy cows.

Keywords: milk production, ruminant nutrition, starch.

Biography: Michelle Ollé is a PhD student at the Federal University of Pelotas, Brazil. She received a B.S. degree in Animal Sciences (2014) and an M.S. degree in Animal Sciences (2018) from the Federal University of Pelotas, Brazil. His research experience is focused on the study of non-structural carbohydrate metabolism in dairy cows.