Abstract #W381
Section: Ruminant Nutrition
Session: Ruminant Nutrition: Dairy III
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Ruminant Nutrition: Dairy III
Format: Poster
Day/Time: Wednesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# W381
Energy expenditure in crossbred (Holstein x Gyr) calves differing in phenotypic residual feed intake.
Juliana Mergh Leão*1, Fernanda Samarini Machado2, Alexandre Lima Ferreira2, Mariana Magalhães Campos2, Juliana Campos Carneiro3, Paulo Campos Martins1, Juliana Aparecida Mello Lima2, Thierry Ribeiro Tomich2, Luiz Gustavo Ribeiro Pereira2, Rayanne Soalheiro de Souza1, Sandra Gesteira Coelho1, 1Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Minas Gerais, Brazil, 2Embrapa Dairy Cattle, Juiz de Fora, Minas Gerais, Brazil, 3Instituto de Ciências Agrárias da UFMG, Montes Claros, Minas Gerais, Brazil.
Key Words: facemask, heat production, performance
Energy expenditure in crossbred (Holstein x Gyr) calves differing in phenotypic residual feed intake.
Juliana Mergh Leão*1, Fernanda Samarini Machado2, Alexandre Lima Ferreira2, Mariana Magalhães Campos2, Juliana Campos Carneiro3, Paulo Campos Martins1, Juliana Aparecida Mello Lima2, Thierry Ribeiro Tomich2, Luiz Gustavo Ribeiro Pereira2, Rayanne Soalheiro de Souza1, Sandra Gesteira Coelho1, 1Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, Minas Gerais, Brazil, 2Embrapa Dairy Cattle, Juiz de Fora, Minas Gerais, Brazil, 3Instituto de Ciências Agrárias da UFMG, Montes Claros, Minas Gerais, Brazil.
The aim of this study was to evaluate the energy expenditure in crossbred Holstein-Gyr (F1) calves at 50 d of age with different phenotypes for residual feed intake (RFI) by measuring the respiratory gas exchanges with a face-mask. Eighteen calves were housed in individual sand bed stalls in the experimental farm of Embrapa Dairy Cattle (Coronel Pacheco, Brazil). All animals were fed 6 L/d of whole milk (TS; 11.75%), divided in 2 equal meals (7 and 15h). Solid diet consisting of 95% of pelleted calf starter (88% DM; 20% CP and 3% Fat) and 5% Tifton 85 hay (81% DM; 13.4% CP; 72.8% NDF; 32.3% ADF), and water were provided ad libitum from the first day of life. Phenotypic RFI was calculated for each animal as the difference between actual dry matter intake (DMI) and expected DMI. Expected DMI was computed for each animal by regressing average daily DMI on conceptus-adjusted mean BW0.75 and conceptus-adjusted ADG over a 60 d period. Twelve animals were ranked by RFI into low (efficient) and high (inefficient) groups. Oxygen consumption, carbon dioxide and methane production data were recorded in calves with 50 d age using Sable System (Sable Systems, Henderson, NV) attached to a facemask over a 2 d period, 3 h after morning milk supply, during 20 min. Heart rate (HR) was recorded during 20 min with Polar equine transmitter and monitor (RS800CX G3, Polar Electro Inc., Finland). Daily energy expenditure was calculated as heat production estimated from Brouwer equation (Brouwer, 1965). Methane production was not detected and urinary nitrogen was neglected in calculations. Data were analyzed as a completely randomized design by ANOVA using the GLM procedure of SAS software (version 9.4; SAS Institute Inc., Cary, NC). High RFI calves had DMI 12.39% higher (P < 0.05) than the low RFI group (1.07 and 0.941 Kg/d, respectively), but body weight was higher by 0.6% (P < 0.05) for the low RFI group. Heart rate did not differ between the groups. High RFI animals presented higher energy expenditure (177.64 kcal/kg of metabolic weight – MBW) than low RFI animals (144.40 kcal / kg of MBW).
Key Words: facemask, heat production, performance
