Haemoglobin (Hb) and transferrin (Tf) types have been studied in the breeds Muturu, N'Dama, Gudali and Red Bororo of Nigeria, West Africa.

The Hb gene frequencies were: Muturu, HbA = 0·72, HbD = 0·28; Gudali, HbA = 0·60, HbB = 0·32, HbC = 0·08; Red Bororo, HbA = 0·54, HbB = 0·44, HbC = 0·02.

Transferrin studies showed six different Tf phenotypes in Muturu their distribution being in agreement with the occurrence of the alleles TfA, TfD1 and TfD2. In N'Dama nine different Tf phenotypes were observed and were explained by the alleles TfA, TfD1, TfD2 and TfE. In Gudali 15 different Tf phenotypes were found with a distribution in agreement with the occurrence of the alleles TfA, TfB, TfD1, TfD2, TfF and TfE. All alleles in this breed occurred at frequencies above 0.1. In a limited number of Red Bororo cattle nine Tf phenotypes were seen. Their distribution can be explained by the occurrence of the six genes: TfA, TfB, TfD1, TfD2, TfF and TfE.

1. A direct calorimeter is described, capable of partitioning the total heat loss from individual pigs into its evaporative and non-evaporative components; tests revealed that the instrument measured non-evaporative heat loss with a coefficient of variation of 3%, and evaporative heat loss with a coefficient of variation of 5·0% at 10° and 20°C, and 5·6% at 30°C.

2. Experiments were carried out to measure the differences between heat losses at 20° and 9°C, or at 20° and 30°C, for pigs weighing approximately 26 kg and 64 kg; each measurement lasted 20 minutes and was made after an equilibration period of 3–4 hr.

3. Heat loss was proportional to body weight raised to the power of 0·6, under the present experimental conditions, over the range 26–64 kg at 20°C.

4. Total heat loss at 9°C was significantly greater than at 20°C for pigs of both sizes; total heat loss at 30°C was smaller than at 20°C for pigs of both sizes, the decrease being significant for the heavier pigs only. Nonevaporative heat loss increased significantly with decrease in temperature. Evaporative heat loss at 30°C was significantly greater than at 20°C. The increases in total and non-evaporative heat losses at 9°C when compared with 20°C, were significantly greater for the lighter pigs than for the heavier pigs. The small decrease in total heat loss at 30°C, compared with 20°C, may have been due to non-attainment of thermal equilibrium at 30°C.

5. Values for whole body thermal conductance were calculated from the measurements of non-evaporative heat loss, and these indicated that a change in tissue conductance took place between 20° and 30°C; the mean values at 9°C were 3·78 and 3·15 kcal/°C.m2.hr for the lighter and heavier pigs respectively.

6. Evaporative heat loss at 20°C amounted to 280 and 330 kcal/m2. 24. hr for the lighter and heavier pigs respectively. This component of heat loss amounted to 8% and 13% of the total heat loss at 9° and 20°C respectively for all pigs; the corresponding values at 30°C were 32% and 25% for the lighter and heavier pigs respectively. The increased evaporative loss at 30°C was accompanied by an increase in respiratory rate.

7. These results agreed well with the results of previous work with groups of pigs, for heat loss at 20°C. Comparisons with that work indicate that the increase in heat loss at 9°C, when compared with 20°C, was greater for individual pigs than for groups of pigs, of both sizes.

1. Four groups of three litter-sister Large White gilts were given during four successive pregnancies a daily meal allowance of either 2·70 kg (High), 1·35 (Low) or 1·35 kg for 76 days followed by 2·70 kg until parturition (Low-High). During 8-week lactation periods all received the same daily allowance of 1·8 kg meal plus 0·35 kg for each piglet suckled.

2. On the 100th day of the fourth pregnancy all sows were slaughtered. The major internal organs were weighed and measurements recorded of the length of carcass and backfat thickness at shoulder, midback and loin. The carcasses were then separated into bone, skin, subcutaneous fat and muscles plus intermuscular fat. The weights of radius-ulna, tibia-fibula, humerus and femur were recorded.

3. In each of the treatment groups the live-weight changes of the sows in the fourth pregnancy were almost identical to those in the third pregnancy.

4. The mean total carcass weights for the High, Low and Low-High sows were 154, 92 and 110 kg respectively, and the mean subcutaneous fat contents of the carcasses 14, 4 and 6 kg respectively.

5. The relative proportions of the weights of the organs to carcass weight, weight of bone to weight of muscle plus intermuscular fat, and the weight of individual bones to total bone weight were relatively unaffected by the treatments after allowance had been made for total carcass weight.

6. The implications of the changes in body composition on the lifetime reproductive performance of sows are discussed.

The relationship between mature weights of domestic species and the times they take to mature in live weight is extended to breeds and strains within a species and to sex differences within a breed or strain. Results based on the Gompertz growth curve are found to be essentially the same as those based on Brody's growth curve. Both confirm the relationship of proportionality between the time a species takes to mature in live weight and its mature weight raised to the power 0·27 or some power close to this. The overall weighted average coefficient was 0·273 ± 0·029 for Brody's (1945) growth curve data and 0·276 ± 0·030 for the Gompertz growth curve data of Laird (1966). The weighted average coefficients of 0·358 ± 0·098 for strains within a species and 0·343 ± 0·049 for sexes within a strain, although not significantly greater than 0·27, suggest that a coefficient of ⅓ might be a better value to adopt when the relationship is confined within species.

Birds as a class matured significantly more rapidly than expected from their mature weight and mammals significantly more slowly. Body temperature could account for this class difference in maturing time but not for deviations of individual species or strains. Relative to their mature weight, some species appeared to take much less time to mature than others, with possibly a 2- to 3-fold genetic difference between extremes of the range.

The main use of the relationship obtained lies in providing a ‘metabolic’ age scale on which animals or species can be examined for differences in immature physiological characteristics such as maturing time, body composition or efficiency of food utilization independently of differences in adult size.

In three trials, two with suckler cows and one with lambs, supplementary forms of dietary nitrogen and/or energy were added to a basal diet of barley straw offered ad libitum. The nitrogenous supplements appeared to have a small effect on the intake of straw but only when they were available for frequent consumption. The addition of cereals to the diet did not affect the intake or digestibility of the straw but reduced the live-weight losses.

Blood samples were taken from 472 dead lambs on hill farms in Peeblesshire and their serum proteins fractionated by paper electrophoresis. No y-globulin was detected in 84% of the lambs dying on the day of birth, or in 43% of all other lambs aged 9 days or less. Most of these lambs had not fed. But a substantial minority, including 24·5% of all lambs dying, after walking, on the first or second days, i.e. when the gut is normally permeable to protein, had not absorbed γ-globulin despite having food in the gut. This could be due to a failure of colostral proteins to pass from the stomach into the small intestine, γ-globulin being detected relatively more often in lambs with food in their intestines than in lambs with food only in their stomachs; insufficient time between the arrival of food in the small intestine and death; or a premature loss of gut permeability.

The mean γ-globulin levels in lambs aged up to 6 days, excluding those with none, were significantly lower than in live lambs. Differences between older lambs were slight. Lambs aged up to 9 days and recorded as dying of starvation because they had no visceral fat, had significantly lower levels than lambs dying from other causes. The levels in older lambs were not correlated with the reasons for death.

This report gives an account of the paternal half-sib analysis of carcass quality, based on commercial joint dissection, on Down cross sheep collected in the four years 1962–65 inclusive. It also includes a discussion of the multiplicative correction factors used, and the phenotypic and genetic correlations between all the traits, estimated from the pooled within-farm, within-year analysis. It shows that there is very little genetic variation for many of the characters but that the percentage leg, percentage best end, age at slaughter and eye-muscle area have much additive genetic variation remaining for worthwhile response to be expected from selection. These three carcass traits are also the most important characters in determining the commercial value and saleability of lamb. From the results obtained it is argued that there is still much genetic variation for fat development in sheep.

Thirty-two yearling Friesian steers were used in a 2 × 2 factorial experiment. The treatment variables were source of supplementary nitrogen and physical form of the diet. The diets contained 30% ground barley straw, ground maize, a nitrogen supplement, and minerals and vitamins. Urea was compared with soya bean meal as the nitrogen supplement and both diets were given as cubes or meal. There was no significant difference between treatments in daily live-weight gain, feed intake or commercial carcass acceptability.

Digestibility trials with wethers showed the apparent digestibility of nitrogen and dry matter of the diet containing urea to be significantly lower than that of the diet containing soya bean meal (nitrogen 72·8 ν. 76·3, P < 0·001; dry matter 70·2 ν. 75·3, P < 0·01). The results are discussed in relation to the digestibility of the diets used, the source of supplementary nitrogen and the physical form of the diet.

An investigation of milking ability in three dairy breeds has shown that selection for superior productive performance would contribute little to the improvement of milking time. The heritability of both average rate of flow and milking time was reasonably high in all three breeds, however, and direct selection should result in effective improvements.

The problem of slow milking was more acute in the Danish Red breed, in which almost one cow in ten needed more than six minutes to milk out, than in the Black Pied or Danish Jersey breeds.

A comparison of the average rate of flow and milking time as criteria of selection for milking ability indicated that both measures were equally effective in the Black Pied and Jersey breeds, but that rate of flow was considerably more (40%) effective than milking time in the Danish Reds. This was largely because the heritability of milking time in this breed was only one-third that of milking rate.

It was concluded that the average rate of flow was to be preferred to milking time as a criterion of selection for milking ability in the Danish station testing programme.

The analysis was concerned with selective advantage as a possible cause of differences between breeds and individual animals in the relative proportions of milk obtained from the fore and rear quarters of the udder.

Danish Jersey cattle were found to yield a significantly higher proportion of milk from the fore quarters than Danish Red and Danish Black Pied cattle (47% ν. 45% and 44% respectively).

Very strong genetic relationships between the proportion of milk obtained from the fore quarters and lactation yields of milk and butterfat (rg = 0·92, 0·85) in the Jerseys, and correspondingly weak genetic relationships in the other two breeds, suggest that breed differences have arisen as a result of selection for productive performance operative upon different genetic relationships between production and the process controlling the partition of milk in the udder. It is suggested that differences between the breeds are likely to increase in the future.

An exceptionally high incidence of difficult birth (29% of ewes giving birth to single lambs) in a Cheviot sub-flock in 1957 was reported by Gunn and Robinson (1963). To analyse some of the factors contributing to variation in the incidence of difficult births, observations were made on three farms over a seven-year period from 1958 to 1964. The farms are Sourhope, Roxburghshire, in the Cheviot Hills, with 1000 Cheviot and 350 Blackface ewes on predominantly Festuca-Agrostis, Nardus and Molinia pastures, with no regular provision of supplementary feed; Glensaugh in the East Grampians in Kincardineshire, with 550 Blackface ewes on predominantly heather (Calluna) pasture on free draining ground, with regular provision of supplementary feed during winter and spring; Lephinmore on Loch Fyne in Argyll, with over 600 Blackface ewes on mixed pasture mostly overlying peat, with limited provision of supplementary feed during winter and spring. Further details are given in the H.F.R.O. report (1958).

Two trials were undertaken to test the effect of different levels of diethylstilboestrol (DES) on the performance of Egyptian castrated male (wether), male (uncastrated) and female lambs. Ninety crossbred lambs in groups of 10, comprising 30 wethers, 30 male and 30 female lambs were used.

Electrophoretic variants of certain red cell esterases of rabbits (Oryctolagus cuniculus) have been shown to be under the control of two co-dominant autosomal alleles (Grunder, Sartore and Stormont, 1965). Each allele controls two zones of esterase; those controlled by EsA migrated ahead of those controlled by EsB. The heterozygote manifests not only the zones of both homozygotes but also a ‘hybrid’ zone which appears between the A and B zones.

Many observations have been made on the metabolic effects of urea (see reviews by Reid, 1953; McLaren, 1964) and on the problem of urea poisoning (Repp, Hale and Burroughs, 1955), but little information is available on the use of urea for fattening beef cattle under conventional intensive systems. There has been considerable interest shown in the use of biuret as a source of non-protein nitrogen (NPN) as it has been found to be less poisonous than urea when consumed in large quantities (Berry, Riggs and Kunkel, 1956).

Attention has recently been focussed on the possibility of supplementing cattle diets with nutrient solutions containing ammonium salts of short chain fatty-acids (Kay, Preston, Walker, Macleod, 1965; Prescott, Shobokshy and Armstrong, 1967). This method of supplementation requires the liquid feed to be as acceptable to the cow as water or, if less acceptable, to be the only source of liquid intake. In both these circumstances there is a possibility that consumption of such liquids likely to be hypertonie will lead to water imbalance in the animal body.