Twenty-four Friesian steers, initially 5 months of age, were involved in a 2 × 2 factorial experiment which spanned grazing and silage feeding periods of 22 weeks' duration. In the first period, cattle were stocked at a uniformly high density, with half of the group being fed 1·25 kg/head per day of supplementary barley. In the second period, the cattle were subdivided into four groups and fed varying levels of barley with silage. Finally all the animals received 3·65 kg/head per day of barley. Replicates of the four treatments were slaughtered at random after 5 to 11 weeks on this treatment. Whilst supplementary cereal feeding significantly increased the live-weight gains of steers at grass by 11%, this live-weight advantage was offset by their slower gains in the final weeks before slaughter. Feeding cereals to grazing cattle had little effect on carcass composition or the proportions of carcass joints, but their beef was considered, by a tasting panel, to be more tender than the meat from the control steers.

Increasing the level of barley fed with silage only increased live-weight gains by 2%, and had little effect on carcass or meat quality.

Two experiments concerning the effects, on the carcass and meat characteristics of 18-months-old Friesian steers, of variation in grazing intensity and the level of barley feeding with silage are reported.

Groups of 12 steers were grazed at different intensities over 5-month grazing periods, such that live-weight differences of 38 kg and 16 kg were recorded at housing. No compensatory growth was recorded during the subsequent winter feeding period.

Whilst the grazing treatments had little effect on carcass or meat quality, higher levels of barley feeding with silage over the winter period (710 v. 410 kg/steer) had significant effects on live-weight gain, and increased carcass weight by 21 kg at slaughter. The higher yield of carcass weight was reflected in significant differences in carcass composition, joint proportions and retail cut-out value. Sixty per cent of the carcass weight difference was removed as trim fat. Differences in carcass fatness were not associated with any differences in eating quality.

Six Hereford and Shorthorn cross steers were ultrasonically scanned in parallel planes perpendicular to the spine. Scanning was performed at the level of each vertebra and extended from the head of the 9th rib to the articulation of the 3rd and 4th lumbar vertebrae. Scans of each live animal were compared with those of its hot carcass and related to dissected sections of the frozen carcass. In general, the difference between an ultrasonic estimate and the carcass measurement was found to depend on the anatomical parameter being investigated, the location on the animal at which measurement was made and the individual interpreting the scan. Results are presented for fat thickness, Mm. longissimi thoracis et lumborum depth, ‘A’, ‘B’ and area measurements. Possible explanations for some discrepancies between the ultrasonic and carcass measurements are discussed.

Additional results showed that whilst judges are consistent within themselves, in general their interpretations of ultrasonic scans differ significantly from each other.

Length and diameter of teats were measured on first-lactation cows at Danish progeny testing stations. The cows were also classified into four groups according to shape of teat and teat tip. All traits were corrected for yield level and interval after calving and correlated with milking characteristics. The conclusions drawn were:

1. Teat length influences both average rate of milk flow and yield on hand stripping. The most satisfactory milking is obtained in cows with short teats. In Red Danish, Black and White Danish and Jersey cows, respectively, desirable length of fore teat is ≤ 6, ≤ 6, and ≤ 5 cm, and of rear teat about 1 cm shorter.

2. Teat diameter is of no significant importance to average rate of milk flow, but yield on hand stripping is most satisfactory when the diameter is ≤ 2·4 cm.

3. Teat shape must be very extreme before an adverse influence is recorded on average rate of milk flow and yield on hand stripping.

4. The milking characteristics of cows are correlated with shape of the teat tip. The highest rate of milk flow and the lowest yield on hand stripping is found in cows with flat and concave teat tips.

5. A relationship exists between teat length and the shape of the teat tip, and partial correlation coefficients show that of the teat traits investigated the most important factor affecting average rate of milk flow is the shape of the teat tip whilst teat length—similar to the effect of teat diameter—is of greater importance to the yield on hand stripping. Investigations into the possible consequences for udder health must, however, be conducted before selection for a special shape of the teat tips is introduced.

Following weaning of their first litter at 42 days post partum, 36 Landrace × (Landrace × Large White) sows were fasted for 24 hr then allocated to one of three feed levels, 1·8, 2·7 and 3·6 kg food/day, until the day after mating. During pregnancy all the sows received 1·8 kg food/day.

The incidence of infertility and anoestrus was greatest for sows fed 1·8 kg/day and least for sows fed 3·6 kg·day. Sows fed 1·8 kg/day took significantly (P < 0·01) longer (21·6 + 3·0 days) to return to oestrus than sows fed 3·6 kg/day (9·2 ± 2·2 days). The mean litter size for sows fed 1·8, 2·7 and 3·6 kg food/day was 9·4 ± 0·9, 10·1 ± 0·8 and 11·5 ± 0·6 piglets respectively, but these differences were not significant.

The availability of Ca and P in the young growing pig was determined by the use of a radioisotopic technique. Eighteen Large White barrows of 25 kg mean body weight were used in the study, 10 being fed 1·20 kg per day of a cereal-based diet and the remainder half of this amount. At the higher dietary level the intake of Ca was 9·4 g/day, and that of P was 9·7 g/day. The mean availabilities of Ca and P were 41·5% and 78·1% respectively. At the lower level of intake there was no significant change in the availability of either element, mean values being 39·6% for Ca and 82·5% for P. These values contrast markedly with the 67% for Ca and 50% for P currently used in the calculation of dietary requirements for the elements by the factorial approach.

Sows housed with free access to water were found to have urine protein levels comparable to those recorded for man, dog and sheep. However, in stalled sows with restricted access to water, urine protein levels were twice as high as those of penned sows.

Physiological proteinuria has been found to occur in the piglet, in which respect it is similar to the ruminant and the dog. Proteinuria reaches a peak within 20 hr of birth and lasts for approximately 48 hr. The rapid decline in urine protein levels after this period coincides with gut closure. Proteinuria did not occur in piglets fed on glucose saline, only in those receiving colostrum; however, the continued feeding of colostrum did not prolong the period of proteinuria. In piglets fed varying levels of colostral protein there was a direct correlation between serum protein levels and mean urinary protein concentration during the period of proteinuria, but there was no direct correlation between the amounts of colostral protein ingested and the serum protein level.

Lambs weaned from the ewe at 2 days of age were fed liberally or on a restricted level in each of three periods of growth according to a factorial design. In the first period restriction was achieved by giving less milk (5 as against 9 kg of milk replacer) and in the later periods by diluting one of the diets with 40% oat husks.

Milk restriction had no effect on performance from 15 to 35 kg or on the carcass composition as determined by dissection into fat, lean and bone. However, in the separate stages, 15·25 kg and 25·35 kg there was some indication that previous restriction of milk affected subsequent dry-matter intake and growth, particularly in the middle period of growth in lambs given the low energy diet.

Restriction after 15 kg, particularly from 15 to 25 kg, reduced overall performance to slaughter at 35 kg but had little effect on dissected carcass components. Restriction in the middle period affected performance in the final period and reduced food conversion efficiency. It is calculated that milk allowances for artificially reared lambs can be reduced without much effect on subsequent performance particularly where good diets are self-fed after 15 kg.

Restriction after 15 kg can be achieved by diet dilution but it has no apparently beneficial effect on carcass quality, as in pigs, and particularly if applied soon after 15 kg has been reached, can severely reduce growth and efficiency of feed conversion.

Lambs weaned from the ewe at 2 days of age were fed ad libitum or restricted in each of three periods of growth to a slaughter weight of 35 kg according to a factorial design. Restriction in the milk-feeding period was achieved by reducing the milk allowance (6·4 kg v. 13·6 kg of milk replacer) and after weaning, by restricting the daily allowance of feed.

Restriction of the milk allowance reduced early growth but the effect was partly offset by the higher concentrate consumption of restricted lambs. There was also a tendency for lambs restricted in the milk period to eat more and grow faster when subsequently fed ad libitum. Performance after 15 kg on a diet containing no protein of animal origin was poor and the level of restriction was severe. Overall growth and efficiency from 15 to 35 kg were considerably reduced by any degree of restriction. However, there was no evidence that restriction in the middle period of growth had any effect on the performance of lambs fed ad libitum in the final period. Although carcass weight was not affected by treatment at any stage, restriction in the milk-feeding period and feeding ad libitum from 15 to 25 kg resulted in a greater weight of head, liver, heart and lungs (weighed together). Chemical analysis of the whole minced carcass showed that restriction of milk intake had a significant effect in reducing the carcass dry-matter content. There was also a trend towards a higher energy and fat content of the dry matter. Restriction in the final period increased the protein content of the carcass.

Seven Scottish Blackface and seven Finnish Landrace wether lambs were slaughtered over the weight range 26 to 41 kg. Total chemical fat deposition in relation to fleece-free empty body weight was found to be similar for both breeds, pooled data giving the significant relationship y = 1·28+0·46x, where y was the percentage chemical fat in the fleece-free empty body and x the fleece-free empty body weight.

Statistically significant differences in the rate of chemical fat deposition in different depots were found between breeds. The Scottish Blackface was found to deposit relatively more fat in muscular plus associated fatty tissue than the Finnish Landrace while the reverse situation occurred in respect of fat deposition in omental plus mesenteric fatty tissues and perirenal fatty tissues.

No breed differences were found in the rate of deposition of subcutaneous fat or fat in bone or in the remainder (head, skin and viscera).

The water intake of individually penned ewes has been determined during the last 21 days of pregnancy and the first 21 days of lactation. Pregnant ewes carrying one lamb had lower water intakes than ewes carrying twins. Water intake per unit dry-matter intake increased as dry-matter intake declined.

Lactating ewes suckling twin lambs consumed more water than ewes suckling singles although both groups had similar dry-matter intakes.

In 1971 the attainment of puberty in 30 early-born and 30 late-born Chin Forest female lambs was studied. The early-born lambs showed their first oestrus at a mean age of 265·4 days and a mean body weight of 41·4 kg; the late-born lambs at 222·0 days and 36·8 kg.

Marked individual variation existed in both age and body weight at puberty within the groups, largely because of differences in growth rate during rearing. Early-born singles showed their first oestrus on average 3·4 days earlier than twins while this difference between lateborn singles and twins was 17·9 days. Since early-born lambs attained puberty at a considerably higher mean age and heavier mean body weight than late-born lambs with similar growth rates it is suggested that the daylight environment experienced by the lamb may be a critical factor in regulating the onset of breeding activity.

Whole milk was given once daily to three groups each of 18 Friesian heifer calves and concentrates and hay were also available. Calves in one group received 2·4 kg milk/day and in a second 3·0 kg milk/day and in both of these groups individual calves were weaned when their daily intake of concentrates reached 400 g. In the third group the calves received 3·0 kg milk/day and were weaned after 28 days. Concentrate and hay intakes were not significantly affected by the treatments. Mean growth rate over 56 days increased with increasing quantity of whole milk offered but the differences between treatments were not significant. The performance of calves given whole milk was compared with the performance achieved in previous experiments where milk substitute was given. It was estimated that 1 kg whole milk gave the same live-weight gain as 170 g milk-substitute powder. From this estimate price/cost relationships were determined to indicate when whole milk or milk substitute should be fed to calves.