Biochemical changes during fasting or the withholding of feed for 5 day were studied in serum of camelids (dromedary camel, llama) and ruminants (sheep, steers). Camels maintained low levels of 13-hydroxybutyrate (BHB) and high levels of glucose but showed some increased levels of non-esterified fatty acid (NEFA) and urea when fasting. Sheep and steers showed a rise in serum BHB and much higher increases of NEFA than camels and llamas. Sheep showed decreased serum glucose. The llama showed some increase in BHB but NEFA was lower than the other three species. The results indicate that camelids have a unique ability to control lipolytic and gluconeogenic activity to prevent or postpone the state of ketosis. Understanding and manipulation of these metabolic mechanisms in cattle and sheep could have great benefit to the livestock industry

Some of the adaptations of ruminant livestock to climate and feed resources are discussed. 1. Physical. Various types of coat serve to protect animals from cold and from the sun’s heat. 2. Physiological. Large rumen volumes enables animals to consume large amounts of poor roughages; fat depots in distinct regions of the body allow them to withstand regulation and fluctuating supply of nutrients, seasonality of reproduction matches requirement to seasonal variation in food supply. 3. Biochemical. There are species differences in the ability to recycle N to the rumen (buffaloes) in the requirement for glucose to accommodate several days of fasting (camels), and in adaptation to low atmospheric oxygen tension (yaks). Such adaptations are important and should be considered when animals exported to areas where climates and feeds are different

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The importance of fat thickness and size and shape of eye muscle in bacon pigs has initiated much work to establish convenient routine measurements that would most reliably estimate these qualities. Measurements taken of the muscle: fat ratios in the region of the loin have been found to be the best estimate of the whole carcass and (as discussed by Harrington, 1958) have been a valuable aid in carcass competitions, where, to ensure similarity between contests, judges have used standard photographs of cut sides. The use of routine photographic records of cut sides in nutrition and breeding work has not, however, been fully explored, but was used by American and German workers (Ferguson, Brennan and Buric, 1961; and Brohmann, 1961). The advantage of using photographic records is that the measurements can be made at the most convenient time and place and form a near permanent record. They can also be used in developing correlations with measurements on live pigs which might estimate the quality of the rashers later produced.