Data/hora: 22/06/2024 07:19:55

Biblioteca(s): 	Embrapa Gado de Leite.	
Data corrente: 	12/08/2021	
Data da última atualização: 	12/08/2021	
Autoria: 	SGUIZZATO, A. L. L.; MARCONDES, M. I.; DIJKSTRA, J.; VALADARES FILHO, S. de C.; CAMPOS, M. M.; MACHADO, F. S.; SILVA, B. C.; ROTTA, P. P.	
Afiliação: 	ANNA LUIZA LACERDA SGUIZZATO, Universidade Federal de Viçosa; MARCOS INÁCIO MARCONDES, Universidade Federal de Viçosa; JAN DIJKSTRAI, Wageningen University; SEBASTIÃO DE CAMPOS VALADARES FILHO, Universidade Federal de Viçosa; MARIANA MAGALHAES CAMPOS, CNPGL; FERNANDA SAMARINI MACHADO, CNPGL; BRENO CASTRO SILVA, Universidade Federal de Viçosa; POLYANA PIZZI ROTTA, Universidade Federal de Viçosa.	
Título: 	Energy requirements for pregnant dairy cows.	
Ano de publicação: 	2020	
Fonte/Imprenta: 	PLoS One, v. 15, n. 7, e0235619, 2020.	
DOI: 	https://doi.org/ 10.1371/journal.pone.0235619	
Idioma: 	Inglês	
Conteúdo: 	This study aimed to estimate energy requirements of pregnant Holstein × Gyr cows. Different planes of nutrition were established by two feeding regimens: ad libitum or maintenance. Sixty-two nonlactating cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. Cows were divided into three groups: pregnant (n = 44), non-pregnant (n=12), and baseline reference (n = 6). The 56 pregnant and non-pregnant cows were randomly allocated into a feeding regimen: ad libitum or maintenance. To evaluate the effects of days of pregnancy, pregnant and non-pregnant animals were slaughtered at 140, 200, 240, and 270 days of pregnancy. Energy requirements for maintenance differed between pregnant and non-pregnant cows, thus two equations were developed. Net energy and metabolizable energy requirements for maintenance of non-pregnant cows were 82 kcal/kg empty body weight0.75/day and 132 kcal/kg empty body weight0.75/day, respectively. The efficiency of use of metabolizable energy for maintenance of non-pregnant cows was 62.4%. Net energy and metabolizable energy for maintenance of pregnant cows were 86 kcal/kg empty body weight0.75/day and 137 kcal/kg empty body weight0.75/day, respectively. Efficiency of use of metabolizable energy for maintenance of pregnant cows was 62.5%. The efficiency of use of metabolizable energy for gain was 41.9%. The efficiency of use of metabolizable energy for pregnancy was 14.1%. Furthermore, net energy requirement for pregnancy was different from zero from day 70 of pregnancy onwards. In conclusion, net energy and metabolizable energy requirements for maintenance of non-pregnant cows are different from pregnant cows. Furthermore, we believe that the proposed non-linear equations to estimate net energy requirements for pregnancy are more adequate than current NRC equation, and should be recommended for Holstein × Gyr cows.	
Thesagro: 	Gado Leiteiro.	
Categoria do assunto: 	--	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/225095/1/Energy-requirements.pdf	
Registro original: 	Embrapa Gado de Leite (CNPGL)	
Exemplares: 	CNPGL - (25190-1) - UPC - AP - DD -  -  -  - DIS