Fecha/hora: 08/06/2024 01:16:03

Biblioteca(s): 	INIA Treinta y Tres.	
Tipo de la producción científica: 	Artículos en Revistas Indexadas Internacionales	
Circulación/Nivel: 	-- - --	
Fecha corriente: 	30/07/2020	
Fecha de la última actualización: 	22/04/2021	
Autoria: 	IEWDIUKOW, M.; LEMA, O.M.; VELAZCO, J.I.; QUINTANS, G.	
Afiliación: 	MARÍA IEWDIUKOW, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; OSCAR MARIO LEMA QUEIJO, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; JOSÉ IGNACIO VELAZCO DE LOS REYES, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; GRACIELA QUINTANS ILARIA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay.	
Título: 	Is it possible to accurately estimate lactation curve parameters in extensive beef production systems?	
Año de publicación: 	2020	
Fuente/Imprenta: 	Applied Animal Science, August 2020, v. 36 (4), p. 509-514. Open Access. Doi: https://doi.org/10.15232/aas.2019-01965	
DOI: 	10.15232/aas.2019-01965	
Idioma: 	Inglés	
Notas: 	Article history: Received 2 December 2019, Accepted 13 April 2020, Available online 25 July 2020.	
Contenido: 	Objective
The objective was to characterize the lactation curve applying 3 different models using multiparous grazing beef cows.
Materials and Methods
Milk production data from 99 British crossbred multiparous cows grazing native pastures were analyzed. Lactation was assessed 15 d postpartum and then monthly until weaning (180 d postpartum) using a milking machine after an oxytocin injection. Total milk production and lactation curve were characterized using Wood (WD) and Wilmink (WIL) models, and both were compared with spline functions. Comparison was made applying adjusted coefficient of determination (R2adj) and MSE.
Results and Discussion
Cubic splines with 5 equally spaced knots (CS5) presented the best adjustment (lowest Akaike information criterion and Bayesian information criterion). The R2adj values were 0.55, 0.54, and 0.53 (the greater the better) and MSE values were 2.54, 2.59, and 2.47 (the lower the better) for WD, WIL, and CS5, respectively. Estimated milk production for the lactation period was 1,277, 1,255, and 1,195 kg for WD, WIL, and CS5, respectively. Milk peak was predicted to happen at 32, 25, and 36 d postpartum, with a production of 8.74, 8.21, and 8.40 kg for WD, WIL, and CS5, respectively. No differences were evident in the lactation curves (95% CI).
Implications and Applications
The proposed method and frequency used to assess grazing beef cattle milk production accurately estimate the lactation curve. The Wood model, used worldwide, was a precise estimator of the lactation curve, which in our case was verified applying splines. These results provide key information to calculate grazing beef cow requirements.	
Palabras-Clave: 	BEEF CATTLE; ENERGY REQUIREMENTS; MILK PRODUCTION; NATIVE PASTURES; REQUERIMIENTOS ENERGÉTICOS; WOOD MODEL.	
Thesagro: 	PASTURAS NATURALES; PRODUCCION ANIMAL; PRODUCCIÓN DE LECHE.	
Categoría del tema: 	L01 Ganadería	
URL: 	http://www.ainfo.inia.uy/digital/bitstream/item/14574/1/Iewdiukow-2020.pdf
https://www.sciencedirect.com/science/article/pii/S2590286520300896?via%3Dihub	
Registro original: 	INIA Treinta y Tres (TT)	
Ejemplares: 	TT - (103120-1) - PXI - AP - DD - Applied Animal Science/2020/Iewdiukow -  -  - DIS