Changes in prices of the basic cereals make it necessary to have a reliable assessment of their relative nutritive values if maximum economic efficiency of pig production is to be attained. As the primary role of cereals in pig feeds is as a source of energy, it is on this basis that comparison should be made but with due allowance for any major differences in nutrient content which may necessitate differential supplementation.

Sorghum, or milo, is a cereal imported into the United Kingdom which, at times, may be competitive with other cereals for price per ton but about whose nutritive value there is some confusion. Sorghum has not often been compared with barley as a cereal for pigs, but its value relative to that of maize seems to vary widely, between 80 and 100% (Braude, Mitchell and Robinson, 1950; Hillier, MacVicar and Pond, 1954; Aubel, 1956; Loeffel, 1957; Peo and Hudman, 1958; Schruben, 1959; Vanschoubroek, Spaendonk and Nauwynck, 1964). Estimates of relative digestible energy values (DE) are equally variable; the DE value of sorghum has been assessed as 94·5% (Diggs, Becker, Terrill and Jensen, 1959) and 96·2% (Robinson and Lewis, 1962) that of maize, whereas the TDN value given by Evans (1960) is greater than that of maize. Robinson and Lewis (1962) consider the DE value of sorghum to be 140% ofthat of barley, but Evans (1960) quotes a TDN value for sorghum which is 111% of that of barley. While variation in the type of sorghum used may account for some of this discrepancy, Dammers and Djikstra (1961) found little difference between the varieties milocorn, kaffir corn, granifero and white dari, and only guinea corn differed in having a lower energy value.

Braude (1965) has recently reviewed the literature on the subject of supplementation of rations for growing pigs with copper, and concluded that as much as 0·1% copper sulphate could be added to the feed without toxic effects, and that this increased growth rate by about 8·1% and improved efficiency of feed conversion by about 5·4%. Both these values are average responses from a very large number of experiments. Similar results have been reported from the Soviet Union by Volkopjalov, Lebedjeva, Spiridonova and Matuskova (1962).

Perry (1964) has shown that piglets failed to absorb homologous Brucella abortus antibodies, whereas they absorbed homologous Salmonella pullorum antibodies much more readily. When S. pullorum antibody was used, piglets showed marked differences in their efficiency of absorption. These differences existed whether the antibodies were administered in serum or in colostrum (Perry and Watson, 1967a, b). Moreover, they could not be entirely accounted for by variation in concentration of antibody in the dose, age at dosage, genetical effects or maternal effects (Perry and Watson, 1967a).

There is little published information on the seasonal distribution of ewe mortality in hill flocks. This note presents records relating to some 1,500 Blackface and 1,000 Cheviot breeding ewes on three hill farms over a 10-year period from 1955 to 1965. The farms are Sourhope, Roxburghshire, in the Cheviot Hills, with 1,000 Cheviot and 350 Blackface ewes on predominantly Festuca-Agrostis, Nardus and Molinia pastures, subject to intermittent snow cover; Glensaugh in the East Grampians in Kincardineshire, with 550 Blackface ewes on predominantly heather (Calluna) pasture on free draining ground, subject to prolonged periods of snow which necessitate regular supplementary feeding; Lephinmore on Loch Fyne in Argyll, with over 600 Blackface ewes on mixed pastures mostly overlying peat, not liable to prolonged periods of snow. Further details are given in the H.F.R.O. report (1958).

Chromic oxide (Cr2O3) has been used for some time as an inert marker to estimate the faecal output of livestock. Although several methods of administration have been reported (Grassland Research Institute, 1961) the more widely used form would appear to be that of purchased gelatin capsules containing a suspension of Cr2O3 in maize oil. An alternative is to include the Cr2O3 in a concentrated feeding stuff. This method was widely used by early workers (e.g. Edin, Kihlén and Nordfeldt, 1944).

Diethylstilbestrol (DES) implants have consistently increased the weight gains and feed efficiency of 5 to 7 month old fattening lambs. The effects of DES on young sucking lambs is less well delineated. Twelve mg DES implants used by Perry, Andrews and Beeson (1951) and Clegg, Albaugh, Lucas and Weir (1955) and 3 mg DES implants used by Lewis, Hines and Mansfield (1966) resulted in significant increases in weight gains of 6-to 14-week-old lambs. Conversely Jordan and Dinusson (1950), Jordan (1953) and England (1959) using 3 mg implants reported no significant increase in weight gains of 2- to 4-month-old grazing sucking Iambs. Wilkinson, Carter and Copenhaver (1955) implanted 6 to 8 week old grazing, sucking lambs with 10 mg of oestradiol and 250 mg progesterone. No increase in weight gains resulted and 5 of 28 lambs treated were lost from prolapse of the rectum.