Effects of incorporating wasted dates in the diet on reproductive traits and digestion of prolific D’Man ewes

Wasted dates represent an energy-rich alternative feedstuff that can be locally exploited in the south of Tunisia as a substitute to the more conventional barley grains in the sheep diets, and, in the present two experiments, we studied the use of the feed when given to prolific ewes in preparation to mating. In a first experiment, 45 ewes blocked by live weight and ovulation rate were randomly allocated to three treatment groups. All animals were fed individually 500 g concentrates/day (barley and/or wasted dates) and 800 g of oaten hay (as fed) for 90 days. In treatment B250, 250 g of the barley was replaced by dates and in treatment B0, the ewes received only dates. second experiment, 45 ewes were also allocated to three treatment groups based on their live weight, ovulation rate and previous record of litter size in a 105-day feeding trial. Ewes receiving the D25 experimental diet were daily fed 970 g of oaten hay and 320 g of wasted dates (as fed). Those in D50 group received 650 g of hay and 650 g of wasted dates, while those fed the D75 diet received 320 g of hay and 970 g of wasted dates. Daily intake of the diet ingredients was recorded on an individual basis. Rumen fermentation parameters, in vivo digestibilities of the diets, live weight variation and reproductive traits (cyclic ovarian activity, oestrous manifestation, ovulation rate and litter size) were measured. Compared to barley grains and hay, wasted dates were lower in crude protein and fibre, but higher in energy. In Experiment 1, partial and total replacement of barley grains with wasted dates had no effect on relative feed intake, organic matter digestibility, digestible organic matter intake, urinary excretion of allantoin and microbial N supply. Replacing half of the amount of barley grains with wasted dates resulted in a decrease of crude protein digestibility (P<0.05). The feeding regime had no effect on ovulation rate which dropped, for ewes in the three treatment groups, from an initial average value of approximately 2 to an average value of 1.575 ± 0.72. Number of ewes exhibiting oestrus or conception rate were also not affected by the experimental diets. In Experiment 2, the feeding regime influenced live weight (P<0.05) with a higher weight loss for ewes in D50 and D75 groups. For D75 ewes, live weight loss reached 1.87 ± 0.992 kg after 75 days of the application of the feeding regimes. The feeding regime also affected (P<0.05) ovulation rate that was lower in the D50 and D75 ewes in comparison to the D25 group. There was also a trend for prolificacy to be affected (P=0.07) by the feeding regime being 163, 166 and 130% for ewes in the D25, D50 and D75 ewes, respectively. It was concluded that when daily animals’ intake of wasted dates was equal or above 42 g dry matter/kg W0.75, reproductive performances of prolific D’Man ewes are likely to be lowered.