Adaptations of mammary uptake and nutrient use to once-daily milking and feed restriction in dairy cows
| Autor: | Jocelyne Guinard-Flament, P. Lamberton, Jean-Louis Peyraud, E. Delamaire |
|---|---|
| Přispěvatelé: | Production du lait (PL), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Physiologie des Adaptations Nutritionnelles (PhAN), Institut National de la Recherche Agronomique (INRA)-Université de Nantes (UN) |
| Rok vydání: | 2007 |
| Předmět: |
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences
DAIRY COW Time Factors Glucose uptake Mammary gland chemistry.chemical_compound fluids and secretions Nutrient ONCE-DAILY MILKING Lactose ComputingMilieux_MISCELLANEOUS 2. Zero hunger chemistry.chemical_classification 0303 health sciences food and beverages 04 agricultural and veterinary sciences Dairying medicine.anatomical_structure Milk MAMMARY UPTAKE Female medicine.medical_specialty Biology Milking Feeding Methods 03 medical and health sciences Animal science Mammary Glands Animal Internal medicine Genetics medicine Animals Lactation Dairy cattle FEED RESTRICTION 030304 developmental biology Caloric Restriction 0402 animal and dairy science Fatty acid Metabolism Carbon Dioxide 040201 dairy & animal science Oxygen Endocrinology chemistry Regional Blood Flow Animal Science and Zoology Cattle Blood Chemical Analysis Food Science |
| Zdroj: | Journal of Dairy Science Journal of Dairy Science, American Dairy Science Association, 2007, 90 (11), pp.5062-5072. ⟨10.3168/jds.2007-0250⟩ |
| ISSN: | 1525-3198 0022-0302 |
| Popis: | The aim of this study was to gain a clearer understanding of the different levels of regulation involved in the reduction in milk yield in response to once-daily milking and feed restriction. The treatments were designed as a 2 x 2 factorial arrangement of 2 milking frequencies (once- or twice-daily milking) and 2 feeding levels (70 or 98% of requirements determined 1 wk before the trial). The cows were surgically prepared to study the net mammary balance of the nutrients that are precursors of milk components. Mammary efficiency in synthesizing milk components was estimated using a milk output:mammary uptake ratio. No interaction was observed between the effects of milking frequency and feeding level on milk and blood parameters except for milk protein yield, milk fatty acid profile, and nonesterified fatty acids metabolism. Once-daily milking and feed restriction reduced milk yield by 5.1 and 2.9 kg/d and fat-corrected milk yield by 4.2 and 4.1 kg/d, respectively. Both treatments induced a decrease in mammary blood flow. Once-daily milking led to a reduction in the extraction rate of glucose but no changes to the lactose output:glucose uptake ratio. Feed restriction did not change the glucose extraction rate but tended to improve the lactose output:glucose uptake ratio. Under once-daily milking, the slight increase in milk fat content (0.34 percentage units) was linked to a depressed uptake of glucose and acetate but without any variations in the uptake of beta-hydroxybutyrate and total glycerol and in the efficiency of acetate and beta-hydroxybutyrate conversion to short- and medium-chain fatty acids in milk. The decline in milk fat and protein contents (-0.43 and -0.23 percentage units, respectively) under feed restriction was associated with relatively similar reductions in the mammary uptake of all nutrients and with enhanced conversion of the glucose taken up by the mammary gland and used for lactose synthesis. As a result, once-daily milking and feed restriction seem to affect milk yield through mechanisms that may be different and relatively independent. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|