title: Performance, endocrine, metabolic, and reproductive responses of Nellore heifers submitted to different supplementation levels pre- and post-weaning.
abstract: The present study was conducted to evaluate the effects of high and low supplementation levels pre- and post-weaning on performance, endocrine, metabolic, and reproductive responses of Nellore heifers. Fifty Nellore heifers with 132 ± 9.9 kg average body weight (BW) and 138 ± 19 days of age were supplemented from 4 to 14 months. The heifers were distributed into five supplementation plans: HH-6 g/kg of BW of supplement pre- and post-weaning, HL-6 g/kg of BW of supplement pre-weaning and 3 g/kg post-weaning, LH-3 g/kg of BW pre-weaning and 6 g/kg of BW post-weaning, LL-3 g/kg of BW pre- and post-weaning, and CC-control, no supplementation. Interactions were not significant (P > 0.10). The level of supplement fed pre-weaning did not affect any of the performance variables evaluated at the end of the experiment (P > 0.10). There was a significant effect of supplementation and level of supplementation fed post-weaning on average daily gain (ADG) and final BW (P < 0.05). Overall ADG was also affected only by supplementation and level of supplement fed post-weaning (P < 0.05) with animals receiving 6 g/kg of BW post-weaning gaining more weight. Follicular diameter was greater in animals that received 6 g/kg of BW post-weaning (P < 0.05). In summary, performance, endocrine, metabolic, and reproductive variables evaluated in the current study were improved by the level of supplement fed post-weaning. Heifers receiving supplementation of 6 g/kg of BW post-weaning had greater responses, independent of the level received during the pre-weaning phase.
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil. alinegomesdasilva@rocketmail.com.
authors.forename: Aline Gomes
authors.initials: AG
authors.lastname: da Silva
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Mário Fonseca
authors.initials: MF
authors.lastname: Paulino
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.|Biotran - Biotecnologia e Treinamento em Reprodução Animal, Alfenas, Minas Gerais, 37130-000, Brazil.
authors.forename: Lincoln
authors.initials: L
authors.lastname: da Silva Amorim
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Luciana Navajas
authors.initials: LN
authors.lastname: Rennó
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Edenio
authors.initials: E
authors.lastname: Detmann
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Felipe Henrique
authors.initials: FH
authors.lastname: de Moura
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Marcos Rocha
authors.initials: MR
authors.lastname: Manso
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Paulo Henrique
authors.initials: PH
authors.lastname: Silva E Paiva
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Román Enrique Maza
authors.initials: RE
authors.lastname: Ortega
authors.affiliation: Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
authors.forename: Luciano Prímola
authors.initials: LP
authors.lastname: de Melo
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002417:Cattle / Q000502:physiology*; D019587:Dietary Supplements; D005260:Female; D011897:Random Allocation; D012098:Reproduction / Q000502:physiology; D014886:Weaning; D015430:Weight Gain / Q000502:physiology
keywords: Biometry; Growth hormone; Insulin; Ruminant metabolism