Desempenhos produtivo e reprodutivo de um rebanho F1 Holandês x Gir em Minas Gerais

Abstract

RESUMOObjetivou-se avaliar os desempenhos produtivo e reprodutivo de vacas F1 Holandês x Gir Minas Gerais, as quais foram mantidas em sistema de produção a pasto no verão, com suplementação de concentrado, e, no inverno, alimentadas com cana-de-açúcar, polpa de citros e concentrado. As características avaliadas foram: idade ao primeiro parto, intervalo parto-primeiro serviço, período de serviço, intervalo de partos, permanência da matriz no rebanho, produção de leite total por lactação, duração da lactação, produção média diária, produções ajustadas a 280 dias e a 305 dias de lactação, produção de leite por intervalo de partos e curvas de lactação conforme ordem de partos, época de partos e período de serviço. A função gama incompleta foi utilizada para estimação dos parâmetros das curvas de lactação. As demais características foram analisadas utilizando-se modelos lineares mistos. O rebanho apresentou ótimo desempenho (6271,56kg de leite por lactação). As fêmeas F1 Holandês x Gir são boa alternativa para a produção de leite, desde que garantidas boas condições de manejo, alimentação do rebanho e utilização de matrizes oriundas de programas de cruzamento direcionados empregando-se critérios de melhoramento genético.Palavras-chave: bovinos de leite, curva de lactação, rebanho mestiço, produção de leite ABSTRACT

Influence of age and weight of Girolando heifers on uterine and ovarian development

“…This result fits within the average described by Radostits et al (1994), 60-70%, as being the ideal for pregnancy rate at the first service of heifers. The average age at first delivery was 42.82 months old, equaling the national average according to Ribeiro et al (2017). These same authors used 176 F1 crossbred heifers (Holstein × Gir) and obtained an average of 33.36 months for the first calving, while Balancin Júnior et al 2014found 30.71 months for 1435 F1 Holstein versus Gir heifers, 32.73 months for 1412 ¾ heifers and 33.85 months of age for 372 ⅞ animals.…”

“…In the work by Ribeiro et al (2017), heifers were kept in batches in continuous grazing with pasture of Brachiaria sp., and in the periods of drought, they received a complete mineral-protein mixture (35% crude protein) and in the rainy season, a complete mineral-energy mixture (20% crude protein) with a small proportion of urea. However, in the work carried out by Balancin Júnior et al (2014), the animals were kept in pasture formed by grasses such as Brachiaria brizantha cv Marandu, Panicum maximum cv Tanzania, Cynodon dactylon × Cynodon nlenfuensis and Cynodon plectostachyus; and during the drought period, they received corn silage and sugar cane as a bulk supplement.…”

Identification and phenotypic characterization of genetic groups of the girolando breed in dairy herds of the state of Roraima

“…The frequency of genetic groups in the dairy herds is in agreement with Madalena et al (2012), who stated that there is a plurality of blood compositions, making management more difficult. A higher frequency of the ½ Hol + ½ Gir (25.20%) genetic group was noted, as these are animals adapted to the tropical environment (RIBEIRO et al, 2017) and have a higher degree of heterosis, since they further express traits of productive and economical interest. Consequently, they are more efficient in production systems with low management levels, as reported by Ribeiro et al (2017) and Pires et al (2012).…”

“…Production systems under tropical conditions have largely relied on the crossing of Zebu breeds, of excellent adaptability, with breeds of European origin, specialized in milk production (RIBEIRO et al, 2017). In general, this is due to serious problems of adaptation in pure animals of specialized breeds, to tropical conditions.…”

Curvas de crescimento e consumo de alimentos em novilhas leiteiras de reposição

“…Moreover, the random effect of the farm was considered in all models to adjust for factors such as the effects of management, genetics, and other possible factors causing variation among farms. Data on HH and WH were modeled up to the age of 30 months for heifers that had not calved, comprising the recommended age of 22 to 24 months for average at first calving (AFC) for European cattle Pietersma et al, 2006) plus 6 months for late puberty genetic groups such as H×G heifers (Facó et al, 2005;McManus et al, 2008;Delgado et al, 2012;Ribeiro et al, 2017;Canaza-Cayo et al, 2018;Azevedo et al, 2020). BW data for all cows and heifers were used without an age limit.…”