| Title: | Milk metabolites as noninvasive indicators of nutritional status of mid-lactation Holstein and Montbeliarde cows |
| Author(s): | Billa PA; Faulconnier Y; Larsen T; Leroux C; Pires JAA; |
| Address: | "INRAE, Universite Clermont Auvergne, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genes-Champanelle, France. Department of Animal Science, Aarhus University, DK-8830 Tjele, Denmark. INRAE, Universite Clermont Auvergne, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genes-Champanelle, France. Electronic address: jose.pires@inrae.fr" |
| ISSN/ISBN: | 1525-3198 (Electronic) 0022-0302 (Linking) |
| Abstract: | "The objective was to investigate the effects of feed restriction on concentrations of selected milk metabolites in mid-lactation Holstein and Montbeliarde cows and to explore their correlations with energy balance and classic plasma and milk indicators of nutritional status. Eight Holstein and 10 Montbeliarde cows (165 +/- 21 d in milk) underwent 6 d of feed restriction during which feed allowance was reduced to meet 50% of their net energy for lactation (NE(L)) requirements. The experiment was divided in 4 periods: control (CON; d -3 to -1), restriction (RES; d 1 to 6), wk 1 (W1; d 7 to 13), and wk 2 (W2; d 14 to 18) after refeeding at ad libitum intake. Intake, milk production, energy balance and plasma metabolites were used to validate the feed restriction model. Concentrations of 7 milk metabolites: beta-hydroxybutyrate (BHB), glucose, glucose-6-phosphate, isocitrate, glutamate, uric acid, and free amino groups were measured in morning milk samples, and fatty acids were measured in pooled p.m. and a.m. samples. Feed restriction induced a negative energy balance (-42.5 +/- 4.4 MJ/d), increased plasma nonesterified fatty acids and BHB, and decreased plasma glucose concentrations. Feed restriction increased milk glucose-6-phosphate and isocitrate (+38% and +39%, respectively) and decreased milk BHB, glucose, glutamate, uric acid and free amino group concentrations (-20%, -57%, -65%, -42%, and -14%, respectively), compared with pre- restriction. Milk concentrations of medium-chain fatty acids (e.g., sum of C10 to C15) decreased and those of long chain (e.g., 18:0, cis-9 18:1) increased during restriction. Breed differences were not detected for the majority of variables. All studied milk metabolites were significantly correlated with energy balance (Spearman correlation = 0.48, 0.63, -0.31, -0.45, and 0.61 for BHB, glucose, glucose-6-phosphate, isocitrate, and glutamate, respectively). Milk glucose and glutamate showed the strongest correlations with plasma metabolites and milk FA associated with lipomobilization. These results suggest that milk metabolites may be used as noninvasive indicators of negative energy balance and metabolic status of dairy cows" |
| Keywords: | "3-Hydroxybutyric Acid/blood Animal Feed/*analysis Animals Cattle/*physiology Diet/veterinary *Energy Metabolism Fatty Acids, Nonesterified/blood Female Glucose/metabolism Humans Lactation Milk/*metabolism Nutritional Status feed restriction lipomobilizati;" |
| Notes: | "MedlineBilla, P A Faulconnier, Y Larsen, T Leroux, C Pires, J A A eng 2020/02/16 J Dairy Sci. 2020 Apr; 103(4):3133-3146. doi: 10.3168/jds.2019-17466. Epub 2020 Feb 12" |
