Data/hora: 23/06/2024 03:48:03

Biblioteca(s): 	Embrapa Gado de Leite.	
Tipo da produção científica: 	Nota Técnica/Nota Científica	
Data corrente: 	14/02/2017	
Data da última atualização: 	30/01/2023	
Autoria: 	OSS, D. B.; MARCONDES, M. I.; MACHADO, F. S.; TOMICH, T. R.; CHIZZOTTI, M. L.; CAMPOS, M. M.; PEREIRA, L. G. R.	
Afiliação: 	D. B. OSS, UFV; CAPES; M. I. MARCONDES, UFV; FERNANDA SAMARINI MACHADO, CNPGL; THIERRY RIBEIRO TOMICH, CNPGL; M. L. CHIZZOTTI, UFV; MARIANA MAGALHAES CAMPOS, CNPGL; LUIZ GUSTAVO RIBEIRO PEREIRA, CNPGL.	
Título: 	Technical note: Assessment of the oxygen pulse and heart rate method using respiration chambers and comparative slaughter for measuring heat production of cattle.	
Ano de publicação: 	2016	
Fonte/Imprenta: 	Journal of Dairy Science, v. 99, n. 11, p. 8885-8890, 2016.	
Idioma: 	Inglês	
Conteúdo: 	Abstract The objective of this study was to assess the oxygen pulse and heart rate (O2P-HR) technique using the respiration chamber (RC) and comparative slaughter (CS) methods for measuring the heat production (HP) of crossbred (Holstein × Gyr) yearling bulls. Twenty-four bulls were used. Six bulls were slaughtered at the beginning of the experiment as a reference group to estimate the initial empty body weight (BW) and energy content of the remaining animals. The remaining bulls were assigned to a completely randomized design with 3 levels of dry matter intake, with 6 replicates. The levels of dry matter intake were 1.2% of BW, 1.8% of BW and ad libitum, with target orts of 5%. The bulls were fed a diet consisting of 59.6% corn silage and 40.4% concentrate on a dry matter basis. The HP (kcal/BW0.75) was measured using 3 techniques, first using O2P-HR, followed by the RC and CS methods. The HP did not differ among assessed techniques, averaging 162.7kcal/BW0.75. The intercepts of the linear regressions (mean ± SE) were 64.82±25.515 (H0: intercept=0; P=0.024), 33.77±13.418 (H0: intercept=0), and 50.02±27.495 (H0: intercept=0) for O2P-HR versus RC, CS versus RC, and O2P-HR versus CS, respectively. The slopes of the linear regressions were 0.59±0.153 (H0: slope=1), 0.88±0.081 (H0: slope=1), and 0.62±0.155 (H0: slope=1) for O2P-HR versus RC, CS versus RC, and O2P-HR versus CS, respectively. The coefficients of determination were 0.52, 0.90, and 0.52 for O2P-HR versus RC, CS versus RC, and O2P-HR versus CS, respectively. The concordance correlation coefficients, 0.70 and 0.68, were moderate for O2P-HR versus RC and O2P-HR versus CS, respectively, but high, 0.90, for CS versus RC. The between-animal coefficient of variation was greater for the O2P-HR method (16.6%) compared with RC (7.7%) or CS (6.7%). We conclude that there was an agreement among the HP measurements detected using the assessed methods and that O2P-HR is able to predict HP in cattle with great accuracy but only moderate precision. Therefore, the O2P-HR method may have limitations in terms of assessing HP in low numbers of replications due to greater between-animal coefficient of variation than either the RC or CS methods.	
Palavras-Chave: 	Oxygen pulse.	
Thesaurus Nal: 	heart rate; heat production.	
Categoria do assunto: 	L Ciência Animal e Produtos de Origem Animal	
Registro original: 	Embrapa Gado de Leite (CNPGL)	
Exemplares: 	CNPGL - (23278-1) - UPC - AP - DD -  -  -  - DIS