Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression

In sheep, diet-induced milk fat depression (MFD) results from ruminal alterations when ewes are fed marine lipids to modulate milk fatty acid profile and secretion. However, there is little available information on the relationship between characteristics existing before the consumption of MFD-induc...

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Main Authors: A. Della Badia, K.J. Harvatine, P.G. Toral, C. Matamoros, P. Frutos, G. Hervás
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Animal
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Online Access:http://www.sciencedirect.com/science/article/pii/S1751731125001004
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author A. Della Badia
K.J. Harvatine
P.G. Toral
C. Matamoros
P. Frutos
G. Hervás
author_facet A. Della Badia
K.J. Harvatine
P.G. Toral
C. Matamoros
P. Frutos
G. Hervás
author_sort A. Della Badia
collection DOAJ
description In sheep, diet-induced milk fat depression (MFD) results from ruminal alterations when ewes are fed marine lipids to modulate milk fatty acid profile and secretion. However, there is little available information on the relationship between characteristics existing before the consumption of MFD-inducing diets and response to those diets. Understanding predisposing factors for this condition may provide additional insight into the mechanisms of MFD and allow better predictions of its occurrence. Thus, a meta-analytical approach was used to identify traits that may predetermine the extent of marine lipid-induced MFD in individual Assaf sheep (a dairy breed with high genetic potential for milk production). Data were collected from 10 trials in which 160 ewes were fed 16 diets that included fish oil or marine algae until sustained MFD was observed. The decrease in milk fat concentration and yield was calculated using three approaches: absolute change (final – initial), relative change as a percent of pre-trial value, and potential change relative to the maximal expected MFD (assuming a maximal decrease to 3% milk fat). First, using bivariate analyses, there was a relationship between initial milk fat concentration and the absolute (R2 = 0.46; partial R2 of 0.08), relative (R2 = 0.39; partial R2 of 0.06), and potential changes in milk fat concentration during MFD (R2 = 0.17; partial R2 = 0.03). This finding was supported by a second approach that categorised ewes by initial milk fat concentration and yield and additionally by multivariate analyses. In addition, bivariate and multivariate analyses suggested that high MFD responsiveness in Assaf ewes was related to pre-trial milk yield and protein concentration, and to milk concentrations of candidate antilipogenic metabolites and the sum of preformed fatty acids. However, relationships were weaker than for initial milk fat concentration. Overall, when Assaf ewes were fed marine lipids, the higher the initial milk fat concentration, the greater the extent of MFD. The role of other performance traits and milk fatty acids as predisposing factors for marine lipid-induced MFD remains unclear.
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spelling doaj-art-af609532ca974602a327f205f67e1d162025-08-20T02:32:54ZengElsevierAnimal1751-73112025-06-0119610151710.1016/j.animal.2025.101517Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depressionA. Della Badia0K.J. Harvatine1P.G. Toral2C. Matamoros3P. Frutos4G. Hervás5Instituto de Ganadería de Montaña (CSIC-Universidad de León), 24346 Grulleros (León), Spain; Department of Animal Science, The Pennsylvania State University, University Park 16802, USADepartment of Animal Science, The Pennsylvania State University, University Park 16802, USAInstituto de Ganadería de Montaña (CSIC-Universidad de León), 24346 Grulleros (León), Spain; Corresponding author.Department of Animal Science, The Pennsylvania State University, University Park 16802, USA; Center for Molecular Toxicology and Carcinogenesis, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park 16802, USAInstituto de Ganadería de Montaña (CSIC-Universidad de León), 24346 Grulleros (León), SpainInstituto de Ganadería de Montaña (CSIC-Universidad de León), 24346 Grulleros (León), SpainIn sheep, diet-induced milk fat depression (MFD) results from ruminal alterations when ewes are fed marine lipids to modulate milk fatty acid profile and secretion. However, there is little available information on the relationship between characteristics existing before the consumption of MFD-inducing diets and response to those diets. Understanding predisposing factors for this condition may provide additional insight into the mechanisms of MFD and allow better predictions of its occurrence. Thus, a meta-analytical approach was used to identify traits that may predetermine the extent of marine lipid-induced MFD in individual Assaf sheep (a dairy breed with high genetic potential for milk production). Data were collected from 10 trials in which 160 ewes were fed 16 diets that included fish oil or marine algae until sustained MFD was observed. The decrease in milk fat concentration and yield was calculated using three approaches: absolute change (final – initial), relative change as a percent of pre-trial value, and potential change relative to the maximal expected MFD (assuming a maximal decrease to 3% milk fat). First, using bivariate analyses, there was a relationship between initial milk fat concentration and the absolute (R2 = 0.46; partial R2 of 0.08), relative (R2 = 0.39; partial R2 of 0.06), and potential changes in milk fat concentration during MFD (R2 = 0.17; partial R2 = 0.03). This finding was supported by a second approach that categorised ewes by initial milk fat concentration and yield and additionally by multivariate analyses. In addition, bivariate and multivariate analyses suggested that high MFD responsiveness in Assaf ewes was related to pre-trial milk yield and protein concentration, and to milk concentrations of candidate antilipogenic metabolites and the sum of preformed fatty acids. However, relationships were weaker than for initial milk fat concentration. Overall, when Assaf ewes were fed marine lipids, the higher the initial milk fat concentration, the greater the extent of MFD. The role of other performance traits and milk fatty acids as predisposing factors for marine lipid-induced MFD remains unclear.http://www.sciencedirect.com/science/article/pii/S1751731125001004Fish oilLow-fat milk syndromeMarine lipidMeta-analysisSheep
spellingShingle A. Della Badia
K.J. Harvatine
P.G. Toral
C. Matamoros
P. Frutos
G. Hervás
Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
Animal
Fish oil
Low-fat milk syndrome
Marine lipid
Meta-analysis
Sheep
title Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
title_full Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
title_fullStr Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
title_full_unstemmed Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
title_short Analysis of factors predisposing dairy Assaf ewes to marine lipid-induced milk fat depression
title_sort analysis of factors predisposing dairy assaf ewes to marine lipid induced milk fat depression
topic Fish oil
Low-fat milk syndrome
Marine lipid
Meta-analysis
Sheep
url http://www.sciencedirect.com/science/article/pii/S1751731125001004
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