Silage as a feed for pregnant ewes

Abstract

1. Four experiments are described in which silages or kale were given to groups of ewes in the later stages of pregnancy and their voluntary intake recorded. A concentrate supplement was given in the last few weeks of pregnancy in each experiment. In experiments 1, 3 and 4 the ewes were housed in a semi-covered yard.2. In the first experiment, three groups of 10 Scottish Halfbred ewes were offered one of three silages. A fourth group was offered all three in equal amounts. The silage with a low DM content, low crude-protein content, low pH and high crude-fibre content was eaten in smaller quantities than the other two silages. The ewes fed on this poor silage gained less weight during the latter half of pregnancy.3. In a second experiment four groups of 15 ewes were offered either silage or kale and housed in a Dutch barn or left in a small paddock. There was no difference between the results from the two silage-fed groups in any respect. The ewes offered kale outside ate less than those offered it inside; they gained less weight and produced lighter lambs.4. There were two groups of 13 ewes in experiment 3a, one group lambing 5 weeks before the other. Both were fed on the sanie silage; intake was higher in the late lambing group but there was no difference in lamb birth weights.5. Experiment 3 was repeated with 15 ewes per group; the silage was of much poorer quality, intake being low and the ewes gaining very little weight. Lamb birth weights and growth rates were low.6. Groups of 15 Scottish Halfbred (90 kg. live-weight) and 15 Speckle-faced Welsh (45 kg.) ewes were fed on yet another silage. The Specklefaced ewes ate more silage DM per unit weight than did the Halfbred ewes and gained in weight, whereas the Halfbreds did not gain.7. In all experiments there was a decline in silage intake in the last few weeks of pregnancy. This decline did not always coincide with the start of concentrate feeding.8. The results are discussed and comparisons made between experiments. Suggestions are made for the feeding and management of ewes fed on silage, including the recommendation that a silage for pregnant ewes should have at least 20% DM and 14% crude protein in the DM, but not more than 32% crude fibre in the DM.