Effetto della durata dell’asciutta sulle concentrazioni plasmantiche di NEFA e IGF-I e sulla ripresa della ciclicità ovarica post partum nella bovina da latte

The current study was carried out to examine the effect of dry period duration on NEFA and IGF-I plasma concentrations and postpartum ovarian activity resumption in dairy cows. Twenty-five pregnant Friesian cows (second and third lactation) were randomly assigned to 1 (standard dry period 9 wk, group C n=12) of 2 (short dry period 5wk, group T n=13) treatments. Blood samples for NEFA and IGF-I analysis were collected once-a-week during the last 5 wk prepartum and the first 14 wk of lactation. Milk whey collection (2 times/wk) for progesterone analysis began 2 wk after parturition and was used to detect ovarian activity resumption. Short dry period reduced milk production (26.55 vs 27.55 kg/d; P≤0.01). The median interval to first postpartum cycle was shorter for group T than group C (34.5 vs 46.9 d, P≤0.01). No differences were found in NEFA plasma concentrations between groups before and after calving, while IGF-I circulating concentrations were higher in group T than in group C during both the dry period and the first 14 weeks of lactation (P≤0.01).