The application of a mechanistic model to analyze the factors that affect the lactation curve parameters of dairy sheep in Mexico

Angeles-Hernandez, J C; Pollott, G E; Albarran-Portillo, B; Ramírz-Perez, A H; Lizarazo-Chaparro, A; Castelan Ortega, O; Gonzalez Ronzuillo, M

Abstract

Pollott́s mechanistic model has been designed to describe lactation curve parameters based on the known biology of milk production and can be useful for analyzing the factors that affect this process. A total of 553 lactations (9956 weekly test-day records) of crossbred dairy sheep from four commercial farms located in Mexico, were analyzed to investigate environmental factors that influenced lactation curve parameters, using Pollott’s 5-parameter additive model. This model was fitted to each lactation using an iterative nonlinear procedure. The estimated parameters were maximum milk secretion potential (MSmax), relative rate of increase in cell differentiation (GR), maximum secretion loss (MSLmax), relative rate of decline in cell numbers (DR) and the proportion of parenchyma cells dead at parturition. A general linear model procedure was used to determine the effect of type of lambing, lambing number, flock and lambing season on total lactation milk yield (TMY), lactation length and estimated parameters of the Pollott model. Ewes had an average milk yield of 74.4 L with an average lactation length of 140 days. Flock had a significant (P 

Citation

Angeles-Hernandez, J. C., Pollott, G. E., Albarran-Portillo, B., Ramírz-Perez, A. H., Lizarazo-Chaparro, A., Castelan Ortega, O., & Gonzalez Ronzuillo, M. (2018). The application of a mechanistic model to analyze the factors that affect the lactation curve parameters of dairy sheep in Mexico. Small Ruminant Research, 164, 58-63. https://doi.org/10.1016/j.smallrumres.2018.05.003

• Journal Article Type: Article
• Acceptance Date: May 4, 2018
• Publication Date: May 18, 2018
• Deposit Date: Jun 28, 2018
• Publicly Available Date: May 20, 2019
• Journal: SMALL RUMINANT RESEARCH
• Print ISSN: 0921-4488
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 164
• Pages: 58-63
• DOI: https://doi.org/10.1016/j.smallrumres.2018.05.003
• Public URL: https://rvc-repository.worktribe.com/output/1387201