Effects of a dietary supplement of β-carotene given during the dry period on milk production and circulating hormones and metabolites in dairy cows

Winai W. Kaewlamun (1) , Marcel M. Okouyi (1) , Patrice P. Humblot , Dominique D. Remy (1) , Mongkol M. Techakumphu , Christine Duvaux-Ponter (2) , Andrew A. A. Ponter (1)

1 BDR - Biologie du développement et reproduction
2 MoSAR - Modélisation Systémique Appliquée aux Ruminants

The objective of this study was to investigate whether a supplement of β-carotene given during the dry period is able to 1) improve milk production and milk composition and 2) modify hormone and metabolic status in dairy cows during the dry and postpartum periods. This study was conducted using 40 Holstein, primiparous and multiparous cows. On the day of drying-off, cows were allocated to one of two dietary treatments: control diet (n=20) or control diet plus 1g/cow/d β-carotene (n=20). The β-carotene supplement was given individually to the cows until calving. Blood samples were obtained regularly and the concentrations of β-carotene in blood and circulating metabolites and hormones in plasma were measured. Live weight and body condition score (BCS) were monitored once a month. Daily milk production was recorded starting 5 days after calving. Milk composition was measured every 15 days. The dietary supplement of β-carotene increased blood concentrations of β- carotene during the dry period (P<0.05) and although the difference decreased postpartum β-carotene concentrations remained higher compared to the control group until the end of experiment. Live weight, BCS, milk production and composition: milk protein, milk fat, milk urea and somatic cell count, were unaffected by treatment (P>0.05). Plasma concentrations of insulin, insulin- like growth factor-1, glucose, non-esterified fatty acids and urea were unaffected by dietary supplementation with β-carotene (P>0.05). In conclusion, supplementation with β-carotene during the dry period increased blood concentrations of β-carotene but had no effect on milk production and milk quality nor on hormone and metabolic status.

Mots clés: β-carotène; dairy cow; supplement; vache laitière; supplémentation

Domaines: Sciences agricoles

Winai W. Kaewlamun, Marcel M. Okouyi, Patrice P. Humblot, Dominique D. Remy, Mongkol M. Techakumphu, et al.. Effects of a dietary supplement of β-carotene given during the dry period on milk production and circulating hormones and metabolites in dairy cows. Revue de Médecine Vétérinaire, 2012, 163 (5), pp.235-241. ⟨hal-01000653⟩