The relative concentration of the fatty acid components of the total intramuscular lipids from six muscle locations of pigs at 1·5 to 54 months of age were assessed by gas liquid chromatography. Although the pattern was generally similar at each location, differences between locations in the concentrations of oleic and arachidonic acids in particular were noted.

Differences between animals in the relative concentration of fatty acids (other than linoleic) could not be accounted for by the pattern of dietary intake.

The stage of ossification of various, normally visible, bones were examined by two independent observers on 134 sides of beef from cattle of known dates of birth. These examinations failed to produce sufficiently consistent values to allow the ages of these cattle at slaughter to be determined from their skeletal characteristics within an accuracy of 3 months.

Data on the protein content of the empty body were obtained for 44 young Polish Black-and-White Lowland bulls ranging from 10-day- old calves to bulls more than 400 kg live weight. The percentage of protein of the empty body was found to be practically constant (19–19·5%) over the weight range investigated. Less than a half (up to 48 %) of the total protein content was found in the edible parts of the carcass.

The macroscopically measured thickness of the skin of bacon-weight pigs has been found to differ between entire boars and castrates. The histological analysis showed that this difference can be attributed to a significantly stronger development of the dermis in the boars compared with the castrates.

Records on lamb survival were available for 757 lambs, the progeny of 33 rams. Purebred lambs were of the Nali and Lohi breeds and crossbred lambs were produced by mating Nali ewes to Nellore or Mandya rams, and Lohi ewes to Nellore rams. For the flock as a whole 93% of those born survived to 14 days of age and 86% to weaning. A least-squares analysis of variance showed that among the factors investigated only lamb's weight at birth significantly affected survival to 14 days of age, and lamb's weight at birth, ewe's weight at lambing and the year of birth had significant effects on lamb survival from 15 days to weaning. Heritability estimates for lamb survival were based on half sib correlations. For the period from birth to 14 days of age the estimates were 0·08 for pure Nali lambs and 0·03 for the whole flock, and for the period from 15 days to weaning the estimates were 0·10 and 0·26 for the two groups respectively.

A control diet was compared with a diet containing 2 mg diethylstil-boestrol (DES) plus 2 mg methyltestosterone (MT) per kg air-dry feed, the hormone treatment extending either from 20 to 84 kg live weight or from 50 to 84 kg live weight. The experiment contained 20 blocks, each of 3 littermate castrated male pigs individually penned and fed to a restricted scale. Hormone supplementation had no effect on growth performance and significantly affected car-cass characteristics only when given for the longer period. Killing-out percentage, backfat thickness and percentage subcutaneous fat plus skin in the gammon joint were reduced and carcass length, percentage bone and percentage lean in the gammon joint were increased when the supplement was given over the longer period.

Eighty pregnant ewes, housed in December approximately 14 weeks before lambing, were offered grass silage to appetite. The factors considered were breed (Greyface or North Country Cheviot), concentrate level during the final 7 weeks of pregnancy (‘normal’ or ‘high’) and clipping (clipped at housing or left undipped at housing). Silage intakes were affected by level of concentrate supplementation, the higher level tending to reduce intakes during the final weeks of pregnancy but no effect of clipping on silage intakes was detected. Level of concentrate had no effect on lambing performance, but ewes clipped at housing produced lambs which were 1 kg heavier (P<0·05) at birth than lambs from undipped ewes. Time of clipping had a significant effect on wool yields but no effect on wool grades.

Some aspects of sexual development and mating behaviour in Clun Forest ram lambs having a wide range of birth dates were studied during two seasons. The 61 ram lambs studied were introduced individually to Clun ewes in oestrus, for short periods at fortnightly intervals during late summer and autumn. Complete matings, i.e. intromission and ejaculation, were first achieved at a mean age of 6 months (range 142–223 days) and a mean body weight of 35 kg (range 24–49 kg). The attainment of physiological puberty preceded the first copulation, often by several weeks. A few individuals had abnormal testes and were partly or completely sterile, but exhibited normal mating behaviour. Early-born lambs tended to complete their first matings at a higher age and heavier body weight than late-born lambs, which suggests a possible seasonal influence on the development of breeding activity in the ram lamb.

The fatness of 34 non-pregnant Scottish Blackface ewes was estimated subjectively by lumbar palpation. The sheep were separated into groups of ‘fat’ (more than 27 % body fat) and ‘thin’ animals (less than 20% body fat). The voluntary intake of dried grass by these sheep was measured over a 6-week period.

The mean daily dry-matter intake by the thin sheep was 1·9 kg or 106 g/kg W0·73 and by the fat sheep was 1·4 kg or 68 g/kg W0·73.