Nutritional and net energy value of fermented olive wastes in rations of lactating ewes

In an experiment with 18 lactating Chios ewes, the replacement of barley grain, wheat grain, sugar beet pulp and lucerne meal with fermented olive wastes (FOW), maize grain and soybean meal was used to formulate diets that allowed the net energy (NE) for lactation (NEl) density of FOW to be calculated. In the experiment, which lasted 8 weeks, ewes were allocated, after equal distribution for milk yield, body weight (BW) and lactation number, into three treatments of 6 ewes each in a Youden square experimental design with 4 consecutive periods of 14 days. Ewes in all groups were offered a concentrate mixture ad libitum (1.12 kg/ewe/day, dry matter (DM) basis) and lucerne hay (0.90 kg/ewe/day, DM basis). FOW were added to the concentrate mixture at inclusion levels (on an as-fed basis) of 0, 100 and 200 kg/t for treatments FOW0, FOW100 and FOW200, respectively. There were no differences among groups in milk protein (60.0 g/kg), lactose (53.0 g/kg) or ash (9.6 g/kg) contents, but milk fat content increased linearly (P < 0.01) with increasing dietary levels of FOW. Average milk yield (1 137 g/day) and yields of components tended (P < 0.10) to decrease with increased FOW feeding. The best estimate of the NEl density of FOW was 2.55 MJ/kg DM at 2.7×M NE intake, a value only slightly lower than that of 2.62 at 2.7×M based upon a Van Soest et al. (1984) discount from equations of Van Es (1978), who suggested 3.00 MJ/kg DM at 1.1×M of NE intake. FOW is a low protein, high fibre and low NEl feedstuff that will be of limited value in rations of high producing lactating ewes.