Barley which had been stored after treatment with 0·8 % propionic acid was incorporated into pig diets in either the milled or the rolled form and its feeding value compared with that of barley stored dry and then ground, and of moist barley stored anaerobically and then rolled. The pigs were fed from 50 to 200 lb live weight on the four diets. Their performance was not affected by the method of storage of the barley, but those given rolled barley required 11% more dry matter per unit of live-weight gain than those given milled barley. There were no significant differences between the treatments in carcass measurements, or in apparent digestibility coefficients as measured by the chromic-oxide method.

The position of the incisor teeth in relation to the maxillary pad was examined in bulls (at approximately 10 months old). Visual gradings grouped into five classes were made on 5582 bulls of eight breeds in the course of inspection for licensing. In addition, measurements of the tooth positions (grouped into 11 classes) were made on separate samples of 1163 Galloway and 191 Ayrshire bulls.

Among the beef breeds 84·0% of all tooth positions were classed as being normal and 96·6% of those among the dairy breeds. The proportion of mouths with incisor teeth forward of the maxillary pad was higher among the beef breeds. Individual breeds within the beef and dairy types also differed significantly.

Herds of the Galloway and of the Ayrshire breeds, judged on the bulls submitted for licensing, differed in the distributions of the position at which the incisor teeth met the pad. Herds also differed when judged on the occlusion of the sons of their bulls.

Heritability was calculated for Galloways by half-sib correlation and sire-son regression, yielding estimates from 0·31 to 1·28, suggesting that at least some of the variation is inherited. The undershot and overshot conditions were found together only rarely among the male offspring of any one bull.

Twenty-eight female and 26 uncastrated male Scottish Blackface sheep were shorn and subjected to two acute cold exposures one week apart. Between exposures and for one week before the first exposure the sheep were kept either at +30°C (thermoneutral), or at +8°C (subcriticai), or at + 30°C with daily short cold shocks. Food intakes were restricted.

Females showed significantly greater resistance to body cooling than males during both acute exposures.

Both males and females showed acclimatization (increased resistance to body cooling) as a result of the first acute exposure.

Exposure to +8°C for one week did not produce significant acclimatization. Exposure to +8°C for two weeks tended, in females only, to increase acclimatization above that resulting from the first acute exposure.

Daily short cold shocks reduced cold resistance and inhibited acclimatization in females, but had little effect in males.

The male sheep lost significantly more weight during treatment and became thinner than the females. It was suggested that this, and their low cold resistance, might be related to a lesser ability of males to store fat as a subsequent source of energy.

1. Scottish Half-bred ewes carrying twin foetuses were fed individually to make live-weight gains in the last six weeks of pregnancy of (1) 20%, (2) 10% and (3) 0% of their live weight in week 14 of pregnancy. In lactation the ewes were fed ad libitum. The lambs were removed 12 to 16 hr after parturition and the ewes were machine-milked twice daily for the first six weeks of lactation.

2. Total birth weights per ewe of twin lambs from the treatments were (1) 10·10 kg, (2) 9·44 kg and (3) 8·18 kg and differed significantly.

3. The level and pattern of voluntary intake in lactation did not differ significantly between the treatments. Total dry-matter intakes in the six weeks of lactation were (1) 121·9 kg (2) 105·9 kg and (3) 109·5 kg.

4. The pregnancy treatments affected the level of milk production and the shape of lactation curves. The total yields in the first six weeks of lactation were (1) 58·8 kg, (2) 43·5 kg and (3) 26·9 kg. Higher contents of fat and protein and the lower content of lactose in the milk from treatment-3 ewes on days 1 and 3 of lactation indicated a slower onset of lactation in these ewes. Between days 7 and 35 of lactation the contents of fat and SNF were lowest on treatment 3 but the differences were not significant.

5. The live-weight changes in lactation, which were in inverse order to the gains in late pregnancy, were (1) 3·4 kg, (2) 5·5 kg and (3) 9·5 kg.

Three trials were conducted to investigate the effect of length of journey by road to the abattoir, resting and feeding before slaughter on carcass characteristics of pigs of about 200 lb live weight.

Trial 1 investigated feeding or no feeding on the morning of slaughter, followed by a ½-hr or 8-hr journey by lorry to the abattoir with all pigs ending their journey and being killed at the same time. Ninety-six pigs were divided equally among the four treatments and the trial was repeated with a further 108 pigs. Measurements recorded on the live pigs and their carcasses included the live weight before the imposition of treatments, weight of liver, carcass and matured sides and the composition of a sample joint. Trial 2 studied lairaging overnight with food and water after a ½-hr or 8-hr journey to the abattoir compared with these journey lengths on the morning of slaughter. Eighty pigs were divided equally among the four treatments. Similar measurements to those in trial 1 were recorded. Trial 3 involved 49 pigs applied to each of three treatments, or 7-hr journey on the day of slaughter, with all pigs finishing their journey and being slaughtered at the same time.

In trial 1, pigs which travelled for 8 hr before slaughter had carcasses averaging 0·9% less than those which travelled for ½ hr, regardless of whether or not they were fed. It could not be established where this loss occurred. Liver weights were greater for those pigs which were fed and was greatest for those pigs which were fed and had the ½-hr journey. Streak thickness was found to be decreased by feeding, but was not affected by the length of the journey. No effects of the treatments were found on pH or eye-muscle colour, but the ultimate pH of the pigs fed before the 8-hr journey was lower than for the other treatments. Trial 2 pigs showed no effect of the treatments on carcass weights. Liver weights were similar on all treatments except for the treatment involving 8-hr journey followed by lairage where the liver was about 220 g (16%) heavier. The ultimate pH value was lowest among pigs which travelled 8 hr on the morning of slaughter but was similar for pigs on the other treatments. In trial 3, loss of live weight tended to increase with increasing journey length. Pigs on the 7-hr journey treatment had about 90 g (6%) more liver than those on the shorter journeys. pH1 values increased with length of journey and the longer the journey the thinner tended to be the maximum shoulder fat thickness.

From the differences in the results from the three trials, notably with carcass weight, it may be inferred that the behaviour and handling of pigs during the journey and during loading and unloading, may play an important part in determining the result of the length of the journey, resting and feeding. Further work is considered necessary to study such factors.

One hundred and forty-four weanling Duroc barrows were individually fed to study effects of season (summer and winter), energy concentration of the diet (high and low), protein concentration (high and low), and orally administered hormones (none, diethylstilboestrol, and mefhyltestosterone) on performance and carcass characteristics of growing-finishing swine.

In summer the rate of gain of pigs was 6% slower and yielded carcasses with 19% smaller loin-eye areas but 3% more lean cuts than in winter.

Pigs fed on high-energy diets gained 13% faster, consumed 8% less feed daily and required 18% less feed per unit of weight gain than pigs fed on low-energy diets. Pigs fed on high-energy diets also had a dressing percentage 2·5 units higher and yielded carcasses 2% shorter, with 15% more backfat, than those fed on low-energy diets.

Pigs fed on low-protein diets had a dressing percentage 1·6% higher and yielded carcasses with about 7% thicker backfat than pigs fed on high-protein diets. Dietary energy and protein concentrations interacted significantly in their effect on rate of gain. Pigs fed on low-energy, low-protein diets gained weight about 7% faster than pigs fed on low-energy, high-protein diets; however, pigs fed on high-energy, high-protein diets gained weight about 3% faster than pigs fed on high-energy, low-protein diets.

The only significant effect of giving each pig about 2 mg of diethylstilboestrol (DES) per day was a 2% increase in weight of lean cuts. An average daily consumption of 20 mg methyltestosterone (MT) per pig decreased rate of gain, daily feed intake, dressing percentage and backfat thickness, but increased carcass length, area of the loin-eye and weight of lean cuts. Hormones and dietary energy levels interacted in their effects on rate of gain and feed efficiency. Pigs fed on low-energy diets with or without hormones gained weight at about the same rate, but high-energy diets increased rate of gain in pigs receiving no hormone or DES by about 17% and 21%, respectively, while having no effect in pigs receiving MT. Pigs fed on low-energy diets with MT required about 7% and 6% less feed per unit of gain than pigs fed on low-energy diets without hormone or with DES, respectively; whereas pigs fed on high-energy diets containing MT required about 10% and 14% more feed per unit of gain than did pigs fed on high-energy diets without hormone or with DES, respectively.

An estimate of the frequency of twin calvings was obtained from the analysis of over 38 000 calvings of Friesian cows in M.M.B. milk-recorded herds. The incidence of twinning increased from 0·54 % in the first parity to 3·37% in the fifth parity. A significant excess of cows above expected produced either more than one set of twins or no twins at all. Repeatability ranged from 0·0 for cows with three calvings to 0·063 for cows with five calvings.

Data on lactation yield and duration, butterfat percentage and calving interval showed no significant effect of twinning. However, consistent trends were noted showing that dams which calve twins have longer subsequent lactations, higher whole lactation yields and lower fat percentages than contemporary dams with single calves. The possible causes for these trends are discussed and are considered to be the lower breeding efficiency and longer calving intervals of dams of twins.

1. Three groups, each of eight steers, were fed on pelleted diets containing 30, 50 or 70% ground barley straw, maize and soya bean meal. On an air-dry basis the diets contained 12% crude protein.

2. Daily live-weight gain was 1·29, 1·19 and 1·02 kg/day for the 30, 50 and 70% straw diets respectively, and was negatively related to the percentage of crude fibre in the dry matter (r = −0·61, P < 0·05).

3. The apparent digestibility of dry matter, determined in sheep at the maintenance level of feeding was negatively related to percentage crude fibre in the dry matter (r = −0·91, P < 0·001).

4. All animals were killed at approximately the same live weight, which was reached on average in 140,153 and 163 days by the 30, 50 and 70% groups, respectively.

5. The differences in mean carcass weight between treatments were significant (P < 0·05). Killing-out percentage was significantly reduced (P < 0·05) as the proportion of ground barley straw in the diet was increased from 30 to 70%.

6. The proportion of straw in the diet had no direct effect on the composition of carcass gain.

7. The results are discussed in relation to the intake of digestible energy.

1. Three experiments are reported in which chromic oxide, administered as a component of shredded paper at 09·00 and 16·30 hr daily, was used in the estimation of the faecal output of steers fed on silage and barley.

2. Four Friesian steers of 160 kg live weight were used in experiment 1. They were fed on grass silage ad libitum with controlled allowances of concentrate supplement. ‘Absolute’ recovery of Cr2O3 in total collections was 85–91%, though it was apparent that some faeces may have been lost from the total collections. ‘Relative’ recovery in grab samples was 97%.

3. Diurnal variation in Cr2O3 excretion was investigated in experiment 2 with four yearling Friesian steers. Faeces were sampled in three 24-hr periods at each natural defaecation. A significant and consistent diurnal variation was observed, with the lowest concentration of Cr2O3 occurring during the night. Concurrent grab samples taken at 09.15 and 17.00 hr over four days gave estimates of cr2O3 in the faeces which were 16·27% higher than the mean concentration for the three 24-hr sampling periods.

4. Day-to-day variation in the Cr2O3 content of grab samples was examined in experiment 3 with eight yearling Friesian steers. Four steers received 3·63 kg/head per day of barley supplement and four received 1·81 kg. Both groups were offered silage of 25% dry matter ad libitum. Faeces were sampled per rectum twice daily at 09.15 and 17.00 hr over four-day sampling periods. The degree of day-to-day variation was small and tended to be random.

Eight hundred and ninety-eight records of the interval between calving and conception (service period) of 349 Hariana cows, the progeny of 79 sires, were analysed by fitting constants for the effects of year, month of calving, calving sequence, sex of the calf, weight of the cow at calving and weight of the calf at birth. The average service period was 272·7 days with a coefficient of variability of 50·7%.

The service period was longest after the first calving. Animals calving in the months of February to August had a longer service period than those calving during the months of September to January. Heavier cows tended to have a shorter service period. Sex of the calf, calving sequence and birth weight of the calf did not affect this trait significantly.

Heritability of service period estimated from the paternal half-sib correlation using repeated records was 0·06 ± 0·018 and repeatability was 0·250 ± 0·039. It seems likely therefore that a shortening of the service period may not be possible through direct selection.

In a trial to investigate an ill-thrift problem in lambs on an Exmoor farm frequent oral drenching with cobalt sulphate was compared with pasture spraying. There were two groups of twin lambs reared respectively on sprayed and unsprayed pasture. One partner from each twin set was drenched with cobalt sulphate every two weeks. There were no significant differences in live-weight gain up to weaning time. Thereafter there was little difference in the progress of the twins on sprayed pasture. On the unsprayed pasture, however, the drenched lambs had gained an average of 9 lb live weight more than their partners over a period of 15 weeks but were still about 7 lb lighter than the lambs on sprayed pasture.

Blood vitamin B12 concentration, assayed with Lactobacillus leichmannii, was not well correlated with the treatment of the groups and all values were above commonly accepted critical levels.

Fifty weaned store lambs approximately 7-month-old were used in an experiment designed to assess their protein requirements and utilization. At the beginning of the experiment a random sample of 10 animals were slaughtered and their loin joints analysed. The remaining 40 were allocated at random to four dietary treatments (T1, T2, T3, T4) comprising four crude protein intakes at a constant energy intake. The experiment was divided into two periods. During period 1 (48 days) the dietary crude protein intakes were 58 (T1), 111 (T2), 170 (T3), and 198 (T4) g/day with a mean digestible organic matter intake (DOMI) of 578 g/day. During period 2 (55 days) the corresponding crude protein intakes were 89, 157, 215, 251 and the DOMI was 678 g/day.

Digestibility and nitrogen balance trials were carried out on two animals from each treatment in period 1 and on six animals on each treatment in period 2. At slaughter the loin joints from five animals on each dietary treatment were chemically analysed.

The only significant effect on live-weight gain of varying protein intake was a lower gain on the lowest protein intake (T1) in period 1. It was estimated that the optimum ratio of digestible protein intake (g) to digestible energy intake (meals) for live-weight gain in period 1 was approximately 30 : 1 and in period 2 approximately 21 : 1. There was a significant increase in killing-out percentage with increasing crude protein intake. The digestibility of dry matter and nitrogen increased with increasing crude protein intake. There was a significant quadratic relationship between the apparently digested nitrogen intake in g/day (X) and nitrogen retained in g/day (Y). The regression equation was

Y = −0·008X2 + 0·537X + 0·682

Liver copper levels decreased with increasing crude protein con-centration in the diets.

Daylengths of 13 or 20 hr were applied to six groups of nine ewes during the 2nd to 8th, 8th to 14th and 14th to 20th week of pregnancy. Two groups of nine non-pregnant ewes received a constant 13- or 20-hr daylength during the above experimental period. A group of 10 non-pregnant ewes which initially received a 20-hr daylength were subjected to a 13-hr daylength in the last 14 to 20 weeks of the experimental period. After parturition (26 March) all the ewes received increasing natural daylength.

The mean number of days from the onset of the experimental light treatments (17 November) to the cessation of oestrous activity did not vary significantly between the three non-pregnant groups of ewes and was on average 89 days.

Only two of the 82 ewes, both non-pregnant, exhibited oestrus prior to the longest day (22 June). The various light treatments did not significantly affect the mean dates of occurrence of the natural breeding season of the groups of ewes.

In six light-proofed buildings experiments were conducted with Clun Forest ewes to determine whether the date of first oestrus was affected by the absolute size of reduction in the case of an abrupt decrease in daylength and by the rate of reduction in the case of a given total decrease in daylength.

The mean number of days from the onset of the light treatments to first oestrus (the reaction interval) for ewes receiving gradual decreases in daylength of 3·5, 7·2 or 10·9 min/day from 1 July were 66·4, 53·7 or 33·6 days, respectively. The reaction interval for ewes receiving abrupt decreases in daylength of 3·75, 7·75 or 11·75 hr on 1 July were 59·5, 44·8 or 33·6 days, respectively. A control group of ewes at pasture on natural daylength had a mean reaction interval of 66·2 days.

It is concluded that the various light treatments applied significantly affected the date of onset of oestrus in Clun Forest ewes.

Each of seven diets containing different proportions of separated milk and barley meal, supplemented with minerals and vitamins, was given to five groups of four pigs. The ratios of barley to milk solids were such that the crude protein of the dry matter given to pigs of 20 to 40 kg live weight ranged from approximately 15 to 21%. Within each treatment, the proportion of milk was gradually adjusted so that the crude protein level was reduced by 3% over the live-weight range 40 to 91 kg. Daily energy allowances of all pigs were governed by the same scale.

The total dry matter consumed by the pigs had mean total lysine levels of from 0·52 to 1·18% (approximately 0·1% lysine between successive treatments).

Pigs on the lowest level of milk grew more slowly and had poorer feed conversion than other animals.

Percentage dissectable lean in the trimmed side was highly correlated with lysine level. Within the range studied, each 0·1% increase in lysine increased lean by 0·69% and caused decreases in fat thickness. The performance of the milk-fed pigs was compared to controls given a standard all-meal diet.

Nitrogen metabolism trials were carried out on the milk diets. Beneficial responses in terms of nitrogen retention were found up to the highest level of milk given to pigs between 16 and 90 kg live weight.

1. An experiment was conducted in which the effects on growth rate, food conversion efficiency, digestibility and rate of passage through the gut of diets containing 85% of differently processed barley, fed to growing pigs, were studied. Five different processing treatments were compared with the inclusion of the grain in the whole (unground) form (diet W). The processing treatments were: grinding through (1·56 mm), (4·68 mm) and (9·36 mm) screens (diets O, T and S respectively); cold rolling (diet R) and coarse crimping (diet C).

2. Differences in growth rate and food conversion efficiency between diets O, T, S and R were small and not significant with a slight overall superiority evidenced for diet R over the other three. Compared with these results those of diets C and W were inferior, significantly so for both diets in growth rate but for diet W only in food conversion efficiency. Diet C was superior to diet W in both of these parameters (significantly so for growth rate).

3. The overall digestibility of diet W was significantly poorer and the rate of passage through the gut faster than for any of the other diets. Diet O was retained in the gut significantly longer than any of the other diets and gave the highest coefficient of apparent digestibility for both the ether extract and crude fibre fractions of the diet.

1. In vivo gastric pH changes were studied, in 6 pigs fitted with permanent gastric cannulae, under ‘basal conditions’ (i.e. when no food was given) and when diets containing 85% of differently processed barley were given either twice daily or at frequent intervals of time in an attempt to simulate ad libitum feeding systems. Before inclusion in the diet the 85% of barley had either received no processing (i.e. was given as the whole grain) or had been processed in one of the five following ways: (a) ground through a (1·56 mm) screen (b) ground through a (4·68 mm) screen (c) ground through a (9·36 mm) screen (d) coarsely crimped (e) cold rolled.

2. Relative to the ‘basal’ determinations the systems of feeding which gave food at frequent intervals of time induced higher overall mean pH values than did those which gave food twice daily, while between the six differently processed diets those containing the smaller particles of barley tended to give higher overall mean pH values than did those containing the coarser particles.

3. The validity of the results is discussed in the context of the techniques used and some possible implications in terms of animal health are briefly discussed.

Mating trials were conducted to test the fertility of rams having a range of scrotal wool cover. These revealed that rams with heavier scrotal wool cover had reduced fertility in comparison with those having lighter scrotal wool cover.

Fertility of rams was studied following their exposure to heat for 1 or 3 days in a hot room. Eight to 16 days later exposed rams showed significantly lower fertility as judged by lambing rate of ewes compared with unheated control rams. From 25 to 36 days after exposure treated rams were not significantly less fertile than controls. There were no significant differences in fertility between rams exposed 1 day or 3 days to heat.

Groups of Clun Forest ewes, in which oestrus had been synchronized following the removal of progestogen-impregnated pessaries, were introduced into a small enclosure containing tethered Hampshire, Suffolk and Clun rams. The ewes exhibited a clear preference for the ram of their own breed. The Suffolk ram appeared to be a very poor second choice. When the Clun ram was replaced by a Kerry more ewes went to the Suffolk than to either the Hampshire or the Kerry. When Clun ewes were introduced to 3 tethered Clun rams there was no obvious preference for an individual ram.