Grazing beef cows identified as efficient using a nutrition model partition more energy to lactation

Autor: P. A. Lancaster, Luis Felipe Prada e Silva, A. Saran Netto, Luis O Tedeschi, Sirley Luzia Figueiredo Silva, B. R. dos Reis
Rok vydání: 2021
Předmět:
Zdroj: Animal Production Science. 62:40-54
ISSN: 1836-5787
1836-0939
DOI: 10.1071/an20558
Popis: Context The efficiency of the cow–calf sector could be enhanced by matching cow biological type to the production environment; however, methods to estimate the biological efficiency of grazing beef cows are not available. Aims This study utilised a mathematical nutrition model for ranking beef cows for estimated biological efficiency, determining energetic efficiency and evaluate relationships with other production traits. Methods Cow live weight, calf birth and weaning weight, calf birth and weaning date, and forage nutritive value of hay and pasture were collected for 69 Brangus crossbred beef cows over a complete production cycle. The Cattle Value Discovery System for Beef Cow (CVDSbc) model was used to compute metabolisable energy required (MER) for the cow, and energy efficiency index (EEI) was computed as the ratio of MER to calf weaning weight. Pearson correlation coefficients were computed among performance traits. During late lactation and gestation, low (n = 8) and high (n = 8) EEI cows were individually fed ad libitum for 44 and 32 days, respectively, then fed 0.5× the estimated metabolisable energy required for maintenance for 7 days (gestation experiment only). Apparent nutrient digestibility, heat production, and milk yield were measured. Key results EEI was strongly negatively correlated (P 0.75) between low and high EEI cows even though low EEI cows weighed less (P
Databáze: OpenAIRE
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