Nutritional planning for Nellore heifers post-weaning to conception at 15 months of age: performance and nutritional, metabolic, and reproductive responses
The objective of this study was to evaluate the effects of strategic supplementation in the dry period and dry/rainy transition period on the performance and nutritional, metabolic, and reproductive responses of Nellore heifers grazing Urochloa decumbens. Forty-eight Nellore heifers with age and body weight (BW) of eight months and 235 ± 3.3 kg, respectively, were used. The experimental design was a completely randomized design, with four treatments, all with 12 replications. The evaluated strategies were as follows: low supplementation (LOHI; 0.2% of BW/heifer/day) in the first 90 days and high supplementation (0.6% of BW/heifer/day) in the 90 days thereafter; average supplementation (AVER) with 0.4% of BW/heifer/day for 180 days; high supplementation (HILO; 0.6% of BW/heifer/day) in the first 90 days and low supplementation (0.2% of BW/heifer/day) in the 90 days thereafter; only mineral mix (MM) ad libitum during the 180 days. Data were evaluated using orthogonal contrasts. Supplementation improved the performance of the animals during of dry period (P < 0.05) and dry/rainy transition period (P < 0.05). Supplemented animals had higher longissimus muscle area (LMA) and subcutaneous fat thickness (SFT) at the end of the experiment (P < 0.05). Multiple supplementation increased intake of dry matter (DM), organic matter (OM), and crude protein (CP) in kg/day throughout the experiment. The supplementation increased the digestibility of DM, OM, CP, apNDF, and TDN (P < 0.05). Serum urea nitrogen (SUN), glucose (GLUC), insulin (INS), and progesterone (PROG) were higher in supplemented heifers (P < 0.05). Supplementation reduced the concentrations of non-esterified fatty acids (NEFA) (P < 0.05) and increased conception rate (P < 0.05). In summary, the supplementation strategies adopted in this study improve the performance, metabolic status, and carcass traits of heifers under grazing, allowing an improvement in the conception rate of 15-month-old Nellore heifers.
KeywordsAnimal nutrition Beef cattle Heifers Supplementation Tropical pastures
We are grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) for supporting this study.
Compliance with ethical standards
All animal care and handling procedures were approved by the Animal Care and Use Committee of the Universidade Federal de Viçosa, Brazil (protocol CEUAP-UFV 0008).
Conflict of interest
The authors declare that they have no conflict of interest.
- Batista, E.D., Detmann, E., Gomes, D.I., Rufino, L.M.A., Paulino, M.F., Valadares Filho, S.C., 2016. Effect of protein supplementation in the rumen, abomasum, or both on intake, digestibility, and nitrogen utilisation in cattle fed high-quality tropical forage, Animal Production Science, 57, 1993–2000CrossRefGoogle Scholar
- Detmann, E., Souza, M.A., Valadares Filho, S.C., Queiroz, A.C., Berchielli, T.T., Saliba, E.O.S., Cabral, L.S., Pina, D.S., Ladeira, M.M., Azevedo, J.A.G., 2012. Métodos para análise de alimentos, (Suprema, Visconde do Rio Branco)Google Scholar
- Franco, M.O., Detmann, E., Valadares Filho, S.C., Batista, E.D., Rufino, L.M.A., Barbosa, M.M., Lopes, A.R., 2017. Intake, digestibility, and rumen and metabolic characteristics of cattle fed low-quality tropical forage and supplemented with nitrogen and different levels of starch, Asian-Australasian Journal of Animal Sciences, 30, 797–803CrossRefGoogle Scholar
- Hafez, E.S.E., Hafez, B., 2004. Reprodução animal, (Manole, São Paulo)Google Scholar
- Paulino, M.F., Figueiredo, D.M., Moraes, E.H.B.K., 2004. Suplementação de bovinos em pastagens: uma visão sistêmica. In: Symposium of beef cattle production, Viçosa, 2004, (Federal University of Viçosa, Viçosa), 93–139Google Scholar
- Paulino, M.F., Detmann, E., Valadares Filho, S.C., 2008. Bovinocultura funcional nos trópicos. In: Symposium of beef cattle production, Viçosa, 2008, (Federal University of Viçosa, Viçosa), 275–305Google Scholar
- Pires, A.V., Ribeiro, C.V.M., Susin, I., 2010. Aspectos Nutricionais na Reprodução de Bovinos de Corte. In: Bovinocultura de Corte, Piracicaba, 2010, (FEALQ, Piracicaba), 585–610Google Scholar
- Silva, A.G., Paulino, M.F., Amorim, L.S., Rennó, L.N., Detmann, E., Moura, F.H., Manso, M.R., Paiva, P.H.S., Ortega, R.E.M., Melo, L.P., 2017. Performance, endocrine, metabolic, and reproductive responses of Nellore heifers submitted to different supplementation levels pre- and post-weaning, Tropical Animal Health and Production, 49, 707–715CrossRefPubMedGoogle Scholar