Dietary cation-anion difference and day length have an effect on milk calcium content and bone accretion of dairy cows
| Autor: | Agnès Narcy, Anne Boudon, Philippe Lamberton, Marion Boutinaud, Catherine Hurtaud, Muriel Johan |
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| Přispěvatelé: | Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage [Rennes] (PEGASE), AGROCAMPUS OUEST-Institut National de la Recherche Agronomique (INRA), Recherches Avicoles (SRA), Institut National de la Recherche Agronomique (INRA), 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), Unité de Recherches Avicoles (URA) |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Anions
0301 basic medicine Silage Animal feed Photoperiod [SDV]Life Sciences [q-bio] chemistry.chemical_element Urine Calcium Poaceae Zea mays 03 medical and health sciences Latin square Cations Casein Genetics medicine Animals Dry matter Food science Udder 2. Zero hunger Chemistry 0402 animal and dairy science food and beverages 04 agricultural and veterinary sciences Animal Feed 040201 dairy & animal science Diet Milk 030104 developmental biology medicine.anatomical_structure Sunlight Cattle Female Animal Science and Zoology France Food Science |
| Zdroj: | Journal of Dairy Science Journal of Dairy Science, American Dairy Science Association, 2016, 99 (2), pp.1527-1538. ⟨10.3168/jds.2015-9664⟩ |
| ISSN: | 0022-0302 |
| Popis: | International audience; Milk and dairy products are an important source of Ca for humans. Recent studies have shown fluctuations in cow milk Ca content during the year in France, with high values in winter and with corn silage diets, and a decrease during May and June and with grass diets. The aim of this study was to identify the reasons for this seasonal decrease in milk Ca content by testing the effect of 2 levels of dietary cation-anion differences (DCAD; 0 mEq/kg of dry matter for DCAD 0 and 400 mEq/kg for DCAD 400) and 2 day lengths (8 h of light/d for short days: SD; and 16 h/d for long days: LD) on the Ca balances of dairy cows. The DCAD treatments were designed to mimic diets based either on corn silage or on herbage. The cows were only illuminated by solarium lights providing UVA and UVB. The trial was conducted according to 2 simultaneous replicates of a 4 × 4 Latin square design using 8 dairy cows averaging 103 ± 44 d in milk with 4 periods of 14 d. Data were analyzed by ANOVA with a model including treatment, cow, and period effects. No significant interaction was found between day length and DCAD treatments. With DCAD 400 compared with DCAD 0, blood pH increased and plasma ionized Ca content decreased, whereas the plasma total Ca content did not differ between treatments. Milk Ca content, however, increased with DCAD 400 compared with DCAD 0, in relation to a decrease in the amount of Ca excreted in urine. The DCAD had no significant effect on protein and casein contents and DCAD 400 tended to decrease milk yield. This illustrates that the udder did not decrease Ca uptake from the blood at high DCAD even though DCAD 400 decreased the mammary availability of Ca by decreasing the proportion of blood ionized Ca. Milk Ca and casein contents were significantly lower with LD compared with SD, whereas day length had no effect on milk yield after 14 d of treatment. Bone accretion of cows increased when the Ca content of milk increased (i.e., with DCAD 400 compared with DCAD 0 and with SD compared with LD). This work suggests that long and sunny days could explain part of the seasonal decrease in milk Ca content in summer and refutes the hypothesis that low milk Ca contents at grazing could be due to the high DCAD of herbage. |
| Databáze: | OpenAIRE |
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