Lamb and fattening performance and carcass quality of Suffolk x local Ossimi cross-bred lambs are discussed. 1369 cross-bred lamb records over the period from 1957 to 1970 were available for the study. The lambs of 50-59% Suffolk were the best cross-bred group with an advantage of 7-7, 14-2 and 17-1 % over the native Ossimi lambs in birth weight, 120-day and yearling body weights, respectively. Generally, lamb performance declined as the Suffolk breeding was increased. However, breed groups variation was not statistically significant, except for birth weight.Seventy-one weaned male lambs, 4 months of age, from three breed groups: 70-90 % Suffolk, 35-45 % Suffolk and local Ossimi, were fattened for 16 weeks using two levels of feeding. The two Suffolk cross-bred groups gained slightly more body weight than the local Ossimi. After 8 weeks of fattening, the 35-45 % Suffolk lambs gained significantly more weight than the local lambs. However, the local lambs were more efficient in converting food to live-weight gain.The carcass quality of the Suffolk cross-bred lambs was better than the local lambs, and the advantage was greater for the high Suffolk breeding group. INTRODUCTIONcross-bred lambs produced in the years 1957-70. Total number of lambs records available for the A programme for upgrading the Ossimi local analysis was 1369. The lambs were grouped accordEgyptian sheep with imported Suffolk was estab-ing to Suffolk breeding percentage (from 40 to 99 %) lished in the 1940s by the Ministry of Agriculture, into six breeding groups. Traits studied were birth In an attempt to evaluate this early trial, several weight, lamb survival up to weaning (at 4 months of studies were carried out. The first part of the study age), 120-day weight, daily gain from birth to (Aboul-Naga, 1978) was concerned with the repro-weaning, yearling weight and daily gain from birth ductive performance of the Suffolk cross-bred ewes, to the yearling stage. The present work deals with lamb performance Fattening experiment. A fattening trial was carried traits, fattening potential and carcass quality of out over two experimental years (1972-73 and the cross-bred lambs. 1973-74) to compare fattening performance and carcass quality of the Suffolk cross-bred lambs with

Milk yield of 270 Rahmani, Ossimi and Barki subtropical Egyptian ewes rearing single lambs during three successive lambings in 2 years was estimated over 12 weeks of the lactation using a lamb-suckling technique. The ewes received either normal or high level of feeding during late pregnancy and lactation.Ossimi and Rahmani ewes showed significantly (P < 0-01) higher total milk production than the Barki. Milk yield declined sharply for the Barki ewes after the 6th week of lactation. Breed variation failed to attain statistical significance in the first 4 weeks of lactation. The highly fed ewes produced significantly (P < 0-01) more milk at different stages of lactation than the normally fed ones. High level of feeding, however, is not recommended for subtropical non-dairy ewes as it is not economic. Spring-lambing ewes produced significantly more milk during the first 8 weeks of lactation, while the summer-lambing ewes were more persistent in their milk yield in the last 4 weeks of lactation.

SummaryMilk yield of 240 single-suckled ewes from Rahmani, Ossimi and Barki subtropical non-dairy Egyptian sheep, in addition to 64 twin-suckled Rahmani ewes, was estimated over two lambing seasons using three methods of measuring, i.e. lamb-suckling (plus residual milk), oxytocin technique and hand milking.For single-suckled ewes, the oxytocin technique resulted in higher (P < 0·05) estimates of milk yield during the first 4 weeks of lactation than lamb-suckling. However, over 12 weeks of lactation the two methods showed closely similar estimates. Hand milking produced 31·6% less milk than the other two methods.For twin-suckled ewes, the lamb-suckling method produced significantly (P < 0·05) higher estimates than the oxytocin technique. Estimates obtained by hand milking were 65·2 and 50·8% less than that of the other two methods, respectively.

No abstract

1969). Ammonium salts of fatty acids for milk production 1. The effect of feeding a salt solution containing ammonium acetate on the yield and composition of milk produced by Jersey cows fed hay/concentrate diets. SUMMARY 1. Two experiments have been carried out to study the nutritive value of dilute solutions of fatty acids (consisting mainly of ammonium acetate) when incorporated in the diet of lactating Jersey cows. The first, a continuous trial, extended over a total of 17 weeks and involved five pairs of cows. One cow in each pair received the treatment and one the control diet. The second trial, of change-over design, involved four pairs of cows; one cow in each pair received one or other of the experimental diets alternately over four 28-day periods.2. The cows received basic diets comprising hay ad libitum and concentrates regulated according to milk yield. On the control treatment cows received water and a concentrate containing an appropriate percentage of groundnut cake; on treatment cows received a dilute solution of salts and an 'all-cereal' concentrate. The treatment provided cows with approximately 30% of their total DCP intake as ammonia-N and with 270 to 310 g of acetate and 43 to 49 g of propionate/day from the salt solution. 3. Solutions of salts have been offered to the cows at various concentrations in the range 0-25 to 2-6% (w/v) as a substitute for drinking water. Nineteen of the 20 cows consumed solutions of 1-4% concentration in normal quantities equivalent to water. 4. Treatment was associated with an appreciable depression in the yield of cows producing 13 to 14 kg of milk per head/day, but had little effect on the yield of cows producing 10 to U kg or less. This result has been discussed with reference to the role of the ammonia-N as a substitute for protein-N. 5. Treatment significantly increased the fat content of the milk produced by these Jersey cows above the high control level of 5-4%. Total milk fat production was also increased. This result has been discussed with reference to the role of acetate in dairy cow diets.