Abstract

GUERRA-GARCIA, Minerva et al. IGF-I ovarian activity of goats in divergent body condition and with a supplement of non-degradable protein in rumen. Agrociencia [online]. 2009, vol.43, n.3, pp.241-247. ISSN 2521-9766.

The influence of nutrition on ovarian function can be measured through changes in metabolic hormone levels and the superfamily of growth factors, but its relative importance and paths of action need to be determined. In the present study, 32 adult goats (7/8 Saanen-Alpina x 1/8 Criollo) were exposed to a divergent feeding period of 40 d to form two groups with low (LBC) and high (HBC) body condition (BC). The experiment included 40 d pre and 15 d post-ovulation. Goats received 70 % and 100 % of the nutritional requirements; the base diet was ground alfalfa hay plus a non-degradable protein supplement in rumen (NDPR): 0 g and 103.95 g. Both body weights in fasting and the BC were taken at the beginning of the study and every 15 d. Two applications with cloprostenol were used to synchronize the estrus of goats; 24 h after the second application, in pre-ovulatory follicular phase, 16 goats (four goats per treatment) were selected for two blood samplings and to detemine the serum concentration of the IGF-I through RIA. The total ovarian activity (TOA) was evaluated through ultrasonagraphy, registering the number of corpus luteum (CLN), total follicles (TF), antral follicles (AF), TOA-1 (CLN+TF) and TOA-2 (CLN+AF). The supplement with NDPR increased CLN and TF (p<0.01), TOA-1, TOA-2 and IGF-I (p<0.01), and there was a positive correlation (p<0.05) of IGF-I with NDPR (R = 0.53) and with BC scoring (R=0.51). For HBC there was a higher response in TOA-1 (p<0.05), TOV, CLN, AF, TOA-2 and IGF-I (p<0.01). It is concluded that in adult female goats a supplement with NDPR and a good BC in the stage prior to mating, improves the ovarian response and is positively related to an increase in the circulating levels of IGF-I.

Keywords : Ovarian activity; goats; body condition; IGF-I; non-degradable protein in rumen.