RESUMO
The effect of duckweed (DW) supplementation was evaluated on dry matter intake (DMI), presence and duration of estrus, percentage of ewes repeating estrus and pregnancy rate, as well as the concentration of progesterone (P4) in multiparous crossbred ewes from Pelibuey, Dorper, and Katahdin breeds, fed with Taiwan grass hay (TWH). Eighteen ewes with 39.7±4 kg mean body weight, kept in individual pens, were randomly assigned to one of the following treatments: T1: TWH, T2: TWH plus 200 g DW, T3: TWH plus 300 g DW. The ewes were synchronized with 40 mg fluorogestone acetate (FGA) and 400 UI equine chorionic gonadotropin (eCG). Data were analyzed as a completely randomized design using the GLM procedure. DW supplementation had no effect on dry matter intake (p>0.05); however, a slight decrease of TWH intake was observed as DW supplementation increased. No differences (p>0.05) were found in the beginning of estrus, percentage of ewes presenting it, its duration, or pregnancy rate. There were no differences (p>0.05) on P4 concentration among treatments, or treatmentxperiod interaction (p>0.05). However the period was significant (p<0.01), since the P4 levels increased as time increased after the removal of the FGA device and eCG application.
RESUMO
In Guadeloupe, small ruminants are reared for meat production under pasture conditions. Intensive rotative grazing systems (irrigated, fertilized and high-stocked tropical pastures) allow satisfactory levels of production but generate high post-grazing residues. Experiments were designed to control these. A system in which residuals were mown (RM) was tested in comparison to the control system (residuals remained, RR). The same design was carried out over two years with Creole goats and Martinik sheep. An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year (dry, intermediate and rainy seasons). Each group was composed of 20 goats (36.0+/-2.5 kg) or 20 ewes (46.8+/-2.4 kg). The systems exhibited high levels of productivity in both species compared to other results in the tropics: more than 50 and 30 offspring born alive per hectare and per reproductive season for the goat and ewe flocks, respectively. The annual production at birth was 110 kg kids/ha per year and 133 kg lambs/ha per year (i.e. 21% more). Corresponding values at weaning were 630 kg kids/ha per year and 785 kg lambs/ha per year (i.e. 25% more). The RM system produced 10% more than the RR system in Creole goats, while it produced 35% more in Martinik sheep. Seasonal effects and other factors of variation are discussed.