| Grant number: | 15/02066-4 |
| Support type: | Regular Research Grants |
| Duration: | October 01, 2016 - September 30, 2018 |
| Field of knowledge: | Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals |
| Principal researcher: | Maria Eugênia Zerlotti Mercadante |
| Grantee: | Maria Eugênia Zerlotti Mercadante |
| Home Institution: | Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Nova Odessa , SP, Brazil |
| Assoc. researchers: | Claudia Cristina Paro de Paz ; Fabio Morato Monteiro ; Joslaine Noely dos Santos Goncalves Cyrillo ; Lenira El Faro Zadra ; Renata Helena Branco Arnandes ; Roberta Carrilho Canesin ; Sarah Figueiredo Martins Bonilha |
Abstract
The evaluation of phenotypic variation of feed efficiency in beef cows is essential to increase the knowledge of the impact of more efficient animal on reproduction and productivity of the cow herd. The objective of this project is to quantify the phenotypic variation in feed efficiency traits of cows during lactation in order to elucidate the effect of residual feed intake (RFI) class on production and reproduction traits. Sixty Nelore heifers (30 per year) will be assessed during the first production (up to weaning of the first calf), for determining feed efficiency (RFIC-100 and RFI100-200) and associations with the skeletal size, body composition (obtained by ultrasound), feeding behavior (recorded by the intelligent feeder system), skin surface temperature (obtained by infrared thermography), production (weight-suckle-weight technique) and composition of milk (fat, protein and lactose), and calf growth in the pre-weaning period, and endocrine, energy, protein and mineral metabolism through metabolic indicators. Cows will remain for 228 days (28 days adaptation + 200 days birth to weaning) on paddock equipped with intelligent feeder banks (Intergado, Contagem, Minas Gerais, Brazil) for the assessment of dry matter intake (in 200 days after calving), and other variables. The association between genomic breeding value of RFI obtained in the post-weaning phase (RFIyear) and RFIC-100 and RFI100-200 will also be determined. Moreover, with the historical database, the relationship between feed efficiency (RFIYEAR) and subsequent reproductive efficiency will be evaluate, through comparisons of means and by estimating phenotypic and genetic correlations between RFIYEAR and reproductive traits (days to calving and scrotal circumference of males). The results will be important to promote the evaluation, selection and use of more efficient animals for meat production. (AU)