Swarm preparations are leas frequent (at least during July and August in southern England) among colonies with queens reared in the current year than among those with queens of the previous year (Simpson, 1957). Queens which had survived one and two winters are now considered; they are described as 1- and 2-year-old, respectively.

1. Statistics of several measured parameters are reported. They show that fermentation rates of rumen contents from zebu and European-type cattle in East Africa differ due to time of feeding, to individual animals, and to differences between zebu and grade.

2. The fermentation products were determined as acid, CO2 and methane. The proportion of methane showed an inverse correlation with the rate of fermentation.

3. The mean fermentation rate showed a trend in the direction expected from the weight gains of the animals.

1. Comparisons were made between the two sexes and the various treatments of kids at the 16 lb. stage and the 30 lb. stage. Kids were killed in such a manner that their fatless empty body weights were as uniform as possible at each dissection stage. This was achieved by slaughtering fat H-plane kids at somewhat heavier live weights than the less fatty L-plane kids. The experiment was successful in achieving uniformity of fatless empty dead weights at 16 lb., but not so successful at 30 lb. where significant differences existed between certain subclasses in the male series, the HH and LH having heavier fatless empty body weights than L.L and HL.

2. The dry-matter percentages were in all cases highest for kids on H or eventual H planes of nutrition. On the basis of the total fatty bodies the differences were highly significant at both dissection stages, chiefly due to the larger amounts of fat, with very high dry-matter percentages, in the H-plane kids. On the basis of fatless bodies the differences were only significant at the 30 lb. stage. There were no differences in dry-matter percentages between the two sexes. The order of treatments with increasing dry-matter percentage was LL, HL, LH and HH.

3. The proportions of the joints of the body were very uniform between sexes and the treatments. Male heads were larger than female heads, the difference being just significant at the 16 lb. stage only. Conversely, female hindlegs were significantly larger than male hindlegs at both stages studied. The effect of treatment on body proportions was that H kids had larger hindlegs than L kids, and significantly smaller heads. The female kids thus differed from male kids in body form in a similar fashion to the way H kids differed in body proportions from L kids.

4. The effect of treatment on the carcass composition was greatest for the fatty tissues, H-plane kids in all cases having significantly larger amounts of fat. The treatment effect on all other tissues, that is on the fatless body, was very slight. H kids had slightly more muscle than L kids, but this difference was only statistically significant at the 16 lb. stage. This slightly larger amount of muscle in H-plane kids was offset by smaller amounts of bone, the differences in this case not being statistically significant at either dissection stage, and by smaller weights of alimentary canal, the difference again being significant only at the 16 lb. stage.

The overall picture was one of great similarity in body composition between all the treatments employed in the experiment. The small differences which existed were only statistically significant at the 16 lb. stage when the heterogonic changes in body composition were most apparent. This picture of the effect of plane of nutrition on the body composition is very dissimilar to that claimed by other workers analysing their results on the basis of equal total weight of animal. The results confirm the provisional findings of the present writer using the chicken as the experimental material, and using a different design of experiment.

5. The sex differences in body composition were larger and of greater statistical significance than the treatment differences discussed above. The females contained greater amounts of fat than males, the difference being greatest at the 30 lb. stage. In regard to the composition of the fatless body, the females differed from males in similar manner to the way H-plane kids differed from L kids. Females contained 2% more muscle and 1·5% less bone than males at 30 lb. Males possessed a greater proportion of skin, and a smaller proportion of visceral organs. The males had a much greater percentage of urinogenital organs, due to the basic differences in these structures between the sexes.

6. The division of the body into total saleable percentage and non-saleable percentage showed that the only statistical differences existed between H and L treatments at 16 lb., when H kids had higher total saleable percentages than L kids at this stage, the difference being as great as 8%. Females tended to have a higher total edible carcass percentage than males, due to the larger amount of meat and edible offals in the female sex, but this difference was never statistically significant. The treatment difference demonstrated at 16 lb. is of no agronomic importance, since kids would not normally be slaughtered at this immature stage. By the time maturity was reached, the carcasses of the four treatments were remarkably uniform with regard to their economic composition.

7. Sex and treatment differences were demonstrated by certain of the bone measurements. Male kids possessed thicker leg bones than females, and H kids had larger leg-bone diameters than L. At the 30 lb. stage the order of increasing minimum bone diameters was LL, HL, LH and HH. An identical picture was revealed by the series of data for bone volumes, but statistical differences could not be demonstrated for bone lengths or weights.

8. Significant treatment differences were found in the weights of the rumen, reticulum, omasum, abomasum and in the lengths, but not the weights, of the small intestine. H-plane kids had larger abomasums than L, and L-plane kids had very much larger rumens, reticulums, omasums and bigger large intestines at the 16 lb. stage. These differences were related to the functional requirements of kids on different diets at the 16 lb. stage.

9. Treatment differences were shown to exist in the weights of the heart, pancreas, kidneys and spleen at the 16 lb. stage, and in the liver weights at the 30 lb. stage. In all cases the H-plane kids contained larger visceral organs than L. Sex differences were significant for the heart, spleen and the pancreas. Females had larger hearts and smaller pancreas at 16 lb. than males, and females had bigger spleens at 30 lb. than males. It is suggested that these apparent sex differences may be due to greater amounts of fat contained in the structures of the female viscera.

10. The only head structures to reveal sex and treatment differences were the eyes and tongue, which, like the total weight of the head itself, were larger in the L plane and the male sex.

11. Male kids had significantly heavier skins than female kids at the 30 lb. stage. There were no treatment differences in the weight of the skin, and skins from all treatments alike were placed in the first grade by an experienced dealer.

12. The thymus and abdominal lymphatic glands were significantly heavier in the female than in the male, and treatment exerted a significant effect in favour of the H-plane kids at the 16 lb. stage.

13. The treatments exerted no effect on the early maturing ovaries or female genitalia, but the male kids which were initially on the L plane of nutrition had significantly heavier testes and penes than those which commenced growth on the H plane. The male gonads were the only organs studied in which the effect of initial plane of nutrition persisted at the 30 lb. dissection stage. In all other cases, the effect of initial plane of nutrition was masked or reversed by the nutritional level followed prior to sexual maturity.

Phosphate responses of wheat in a number of soil types have been correlated with the amounts of phosphate extracted by ten different methods. Of these only total organic phosphorus, and inorganic phosphorus extracted with hot 0·1N caustic soda, were significantly related to phosphate response, the former at the 1% level and the latter at the 5% level. The amount of organic phosphorus in the soil was also found to be significantly related, in each instance at the 5% level, to phosphate responses of grass and the percentage phosphate in the grass. When the amount of organic phosphorus was considered together with the phosphate retention capacity of the soil, to give a measure of available mineralized phosphate, the relationships to response (and uptake of phosphorus by grasses) was more significant than with organic phosphorus alone.

The organic phosphorus fraction accounted for about 86% of the total soil phosphorus. Measurable amounts of water-soluble organic phosphorus were found with all the soils. The amounts were, however, not significantly related to phosphate response. Moreover, it was found that while the soil extract containing organic phosphorus decomposed, it did so without the production of mineral phosphate. From this, and further evidence in the literature, it is considered that the organic complex in the soil, rather than the water soluble phosphorus, is the main source for the plant.

1. The penises of five bull calves were examined during the first year of life, using epidural anaesthesia or sedation with chlorpromazine hydrochloride.

2. The process of separation between penis and sheath is described and data on age and weight of the calves are given.

3. There was considerable variation in times and rates of development, but in general terms the penis began to separate from the sheath at about 4 months of age, and the process was completed at about 10 months.

4. From the second to the sixth or seventh month of life the penises of these calves were short, and not manually protrusible.

1. A factorial experiment on wether hoggs was carried out to examine the effects on bone growth and composition and on blood composition of four dietary factors. The factors were extra calcium, phosphorus, vitamin D, and energy in the form of starch, and each was fed in all possible combinations, so that there were sixteen dietary treatment groups in all. Each group consisted of three animals.

2. Serum calcium and blood inorganic phosphorus concentrations were determined monthly, and radiographs of most parts of the skeleton were taken at the beginning and end of the experiment. After about 6 months on the experimental diets the animals were killed and the ash weights and percentage of ash of different parts of the skeleton and of the whole skeleton were determined. Live-weight changes and food intakes were also measured.

A long-term calcium and phosphorus balance experiment with laying hens is described.

The cumulative balances of calcium and phosphorus over a whole year were seen to be physiologically impossible.

Results from other workers using short term balances could be equally impossible and a similar situation has recently been noted in balance experiments with ruminants.

The techniques employed in the experiment were, therefore, investigated in detail.

Only systematic errors could be responsible and it was found that the most likely source of such errors was (a) the spilling of food on to the floor or into the water bowl, and (b) failure to collect all the droppings.

These errors only become apparent in long-term experiments and are more pronounced when diets containing high levels of calcium and/or phosphorus are fed.

An experiment on the use of wheat straw (ploughed in or composted at the rate of 53⅓ cwt./acre every second year) and NPK fertilizers in the maintenance of fertility was carried out at Rothamsted between 1933 and 1958. The effects of these treatments on the yields of the crops of the rotation used in the experiment—barley, sugar beet, potatoes—are discussed in the present paper.

The treatments appear to have had no effect on crop yields through improvements to the soil caused by better structure or increased organic matter content. All the effects obtained can be attributed to changes in the supplies of available nutrients. The most important of these changes appear to have been: (1) nitrogen deficiencies due to the immobilization of soil nitrogen or nitrogen fertilizer by the straw: there is some evidence that this added to the store of slowly available nitrogen; (2) additions to potassium supplies from potassium in the straw. Factor (1) affected all three crops. Factor (2) affected potatoes, the only crop of the three to give good responses to potassium.

It was found that when the straw was ploughed in directly about 0·08 ewt. N fertilizer applied to the crops for each ton of straw was sufficient to overcome losses in yield due to nitrogen deficiencies. The straw improved the yields of potatoes in the first and second years after application. Provided that allowance was made for losses of available nitrogen the yields of potatoes from ploughed-in straw were about the same as the yields obtained by adding K fertilizer to the crop, equal in amount to the potassium in the straw. When part of the fertilizers was ploughed in with the straw instead of being given directly to the crop the yields of potatoes were reduced.

Compost made with NT fertilizers and straw and ploughed in with K fertilizer gave much poorer yields than were obtained by ploughing the straw in directly and applying the fertilizers to the crops. Losses of available nitrogen were severe, all the N fertilizer used in making the compost (0·15 cwt. N for each ton of straw) being either lost through drainage or immobilized by the straw. In addition, more than one half of the potassium in the straw was lost in composting.

There was no evidence that any of the nitrogen immobilized in the decomposition of the straw became available in the first or second years after application. Residues from repeated applications of straw every second year over 18 years increased the yields of potatoes and sugar beet in the last 6 years of the experiment. The increases may have been due to the release of previously immobilized nitrogen.

1. Thirty-two single lambs were grazed together on pasture. At weekly intervals, from birth to 112 days of age, two lambs were slaughtered and various organs weighed immediately after death. Also the alimentary tracts of seven adult sheep were obtained immediately after death.

2. The rumen had the fastest growth rate of the four stomachs, followed by the reticulum, omasum, and abomasum, in that order.

3. Immediately after birth the four stomachs altered rapidly in their relative proportions, but by about 66 days of age they had reached approximately adult proportions.

4. The weights of the liver, heart and kidneys, relative to live weight, decreased during the first few weeks of life, and thereafter remained constant.

5. The weight of the spleen, relative to live weight, increased during the first week of life and thereafter remained constant.

1. Milk yields of grazing ewes with single lambs were estimated using two methods—the traditional lamb-suckling technique, and a technique involving hand-milking following stimulated let-down by intravenous injection of posterior pituitary gland extract (known as the oxytocin technique).

2. The oxytocin technique gave significantly higher figures for milk production than did the lamb-suckling technique (P < 0·01), and this persisted throughout lactation. Variation between ewes was similar for both techniques.

3. The two techniques are discussed in relation to the errors involved, and their accuracy and convenience of application to field conditions.

4. Differences in milk yield between Border Leicester x Merino ewes, and Romney Marsh x Merino ewes, estimated by either technique, were not significant. Correlation coefficients between lamb growth rate and milk yield of the ewe, measured by either technique, were high up to 7 weeks of age.

5. Where the ewes were under the same nutritional conditions before and after lambing, milk yield was not related to the live weight of the ewe, or birth weight of the lamb.

1. The ratios of water drunk:hay eaten were studied for groups of Zebu and grade Hereford steers.

2. In all comparable conditions the ratio was significantly smaller for the Zebus.

3. Restricting water availability to about half significantly reduced the ratios for both types of steers.

4. The decrease in hay eaten resulting from restriction of water was less for the Zebus.

5. Restricting the hay intake to approximately half significantly increased the ratios for both groups.

6. The Zebus drank significantly less water than did the grades in relation to body weight.

7. It is concluded that the results of water restriction may not be as disastrous as would have appeared likely from the constant ratio relationship of water and food intakes previously suggested, particularly in the case of the Zebu steers who have been shown to be better adapted to dry conditions.

1. The bacteria and protozoa from the rumen of the sheep have been examined for their invertase activity.

2. Washed suspensions of protozoal fractions obtained from the rumen were rich in invertase, and the greater part of the total activity in the rumen could be ascribed to the holotrich protozoa.

3. Rumen streptococci capable of fermenting sucrose and fructan were isolated in pure culture. Their invertase was found to be an adaptive enzyme.

4. Fermentation of the soluble carbohydrates of grass was studied in an ‘artificial rumen’. The micro-organisms converted 30% of the substrates into storage starch.

5. Rumen contents from a grass-fed sheep were twice as active towards grass carbohydrates as those from hay-fed sheep.

6. The hay and grass fed to the sheep contained invertase activity.

Two groups of Single Comb White Leghorn pullets, 4 months of age, were fed 1·85 and 2·70% calcium in the diet, respectively, for twelve consecutive periods, each consisting of 4 weeks.

Records of egg production and egg weight were kept throughout the entire experiment for each hen. Calcium balance and egg-shell quality studies were conducted with 16 pullets for 5 consecutive days out of each 28-day period.

A highly significant difference between the lots favouring the high-calcium birds was found in egg production, shell weight, and calcium retention. There were no significant differences between the lots in percentage calcium retention, food consumption, and body weight. The high-calcium group was shown to retain more calcium from the feed and excrete more calcium through eggs. Calcium retention and percentage calcium retention increased upon commencement of egg production to reach a maximum at the second period of production. Both remained fairly constant thereafter.

The hens went into negative balance early in production and returned to positive balance during the later part of the first laying year. The return to positive balance could be explained by an increase in calcium retention and a decrease in egg production. There was no reduction in shell weight, or shell weight per unit surface area during the period covered by this trial.

Studies have been made on calcium and inorganic phosphorus in pasture grass and their relationship to blood levels in Zebu cattle.

Excitement, adrenaline injections and fatigue were investigated as possible causes of variations in the inorganic-phosphorus levels of the blood of Zebu cattle.

Sudden rainfall appeared to cause alterations in the inorganic phosphorus levels of blood. This hypothesis, when tested on two separate batches of cattle on two occasions, showed that there was a highly significant relationship between water intake and the level of inorganic phosphorus of Zebu cattle blood.

Water starvation caused a steady increase in the level of inorganic phosphorus and when water was available for the cattle to drink the inorganic phosphorus level fell rapidly to a subnormal level before returning to normal. These results are discussed in the light of the available literature.

In a cross-breeding experiment involving all types of matings among Friesian, Ayrshire and Jersey cattle, the effect of maternal size has been investigated, based on various comparisons of reciprocal crosses, using data on weight and body size from birth to 2 years of age. Among the thirteen characters analysed, there was a close relationship at I month old between the relative maturity of the characters and the relative extent of their maternal effects. This relationship showed that the more mature characters were the least affected by the maternal environment. Cross-bred calves out of a mother of the larger breed were larger at birth than the reciprocal crosses but in all cases this difference disappeared during the first year's growth.

The early expression of the offspring's genotype for body size depended on whether prenatal growth had been favoured or restricted by the maternal environment within limits. Maternal retardation of growth resulted in neonatal phenotypes closely related to their genetic ranking for mature body size, whereas early expression of the genotype is obscured by lavish prenatal conditions.

A mammalian growth model is presented and the results are interpreted in terms of this model. The explanation assumes that temporary advantage is taken, during growth, of variations in the environment, when the latter exceeds a minimal level demanded by the genotype for stable development to normal mature size. This supply and demand hypothesis of growth is discussed in terms of its implications for genetic selection of different types of body characters. The main conclusion is that an understanding of the early environment, particularly the maternal one, may permit selection for some adult characteristics to be carried out at an early age.

1. An experiment was carried out over 2 years to study the effect of stocking rate on the efficiency of pasture utilization by dairy cows on irrigated perennial pasture.

2. Two matched groups of milking cows grazed throughout the experiment on two unequal areas of pasture at stocking rates of 1·0 and 1·7 cows/acre during the first season and 1·2 and 2·0 cows/acre during the second season (L and H groups, respectively). The same rotational grazing technique was used on both areas.

3. In each season the experimental period lasted 249 days. During the first 200 days and 215 days of this period in the first and second seasons, respectively, pasture, grazed or conserved (from the same proportion of both areas), comprised the entire ration.

4. The H group produced 57 and 59% more milk per acre than the L group during the first and second seasons, respectively. Milk production per cow in the H group was not significantly depressed. The solids-not-fat content of the milk in both seasons, and the butterfat content in the first season, were significantly depressed at the higher stocking rate.

5. The body-weight gain of the cowa in the H group, relative to those in the L group, was depressed by 68% (from 170 to 55 lb./cow) and 88% (from 172 to 20 lb./cow) in the first and second seasons, respectively.

6. The yield per acre of utilized pasture, based on the nutrient requirements of the cows, was 39 and 38% higher at the higher stocking rate in the first and second seasons, respectively. The estimated individual intake of these cows in the two seasons was depressed by 14 and 20%, respectively. The estimated yield per acre of utilized pasture ranged from 4092 lb. s.e. at 1·0 cows/acre to 6519 lb. s.e. at 2·0 cows/acre.

7. The mean daily herbage intake during the second season, estimated by a herbage clipping technique, was 29·5 and 22·9 lb. dry matter per cow for the L and H treatments, respectively. The cows in the H group ate, at each grazing, all the herbage that had grown since the previous grazing, whereas the estimated intake of the L group was equivalent to only 80% of this regrowth. However, the estimated rate of regrowth of the swards on the two treatments was the same.

8. Herbage intake estimates derived from a faecal-indicator technique, and observations of the grazing behaviour of the cows provided more detailed information on the pattern of herbage availability on successive days during the grazing of paddocks at each stocking rate.

9. The results of this experiment are discussed in relation to the design of grazing experiments and to farming practice.

Factors affecting the grazing habits of ruminants are discussed in relation to the attractiveness and nutritive value of herbages and the observed preferences of cattle and sheep at different times.

Methods of measuring stock preferences are considered and it is concluded that, while frequent eye estimates of the quantity of each species appear to provide an adequate method, continuous observations and herbage sampling are useful adjuncts to it.

The results of five experiments are given. Four were carried out in 3 years' winter grazing and one on spring, summer and autumn grazing over 2 years. In the latter experiment herbage samples were chemically analysed and a relationship with the observed preferences was calculated.

In the winter grazing trials the greener grasses tended to be selected first, i.e. timothy, white clover, rough-stalked meadow grass, perennial and Italian rye-grass. Cocksfoot, Phalaris, red fescue and meadow fescue were not generally relished. Meadow foxtail, smooth-stalked meadow grass, tall fescue and sometimes the different varieties of rye-grass and timothy varied in rank from year to year as a result of differential frost damage and fungal attacks.

In the summer grazing trials lucerne and white clover were found palatable in all the 1956 trials; in 1957 lucerne remained so, but white clover was less well liked, especially in June and July. The amount of grass growing with the clover seemed to affect attractiveness, mixtures being preferred to either species by itself. Meadow fescue and timothy were always ranked high, perennial rye-grass and cocksfoot usually next. Agrostis and red fescue were lowest. For the grasses, preference rank was positively correlated in 1957 with water-soluble dry matter, water-soluble ash, water-soluble carbohydrate and negatively correlated with lignin content.

Results are compared with those of other investigators and they show a marked degree of similarity. Variability in the data for sheep is possibly due to limitations in technique. The results for sheep and for cattle are compared; and it was generally found that cattle were fonder of meadow fescue than sheep, and less fond of cocksfoot.

Stock appear to graze those plants which will most readily supply their requirements for salts and energy (carbohydrates). Factors like dung, fungal attack, accessibility, density and toughness may interfere with this relationship.

Observations in the shed were made for 3 years on groups of cattle and buffaloes of both sexes for pulse rate, respiration rate, rectal temperature and haemoglobin level during the summer months under low and high humid conditions.

The average figures for these physiological reactions were always less for buffaloes than for cattle under both dry and humid conditions.

Under high humidity conditions cattle cows showed a significant increase in the pulse rate and decrease in rectal temperature whereas respiration rate remained unchanged. In the buffalo cows these physiological reactions showed less change. In both the haemoglobin level was significantly lower during the rainy season.

On exposure to direct sun, the buffalo reacted very badly; the Iberia index was 88 for cattle and 61 for buffalo.

Because of the smaller variation in the physiological reactions due to increase in humidity at higher temperature in buffaloes (85–93° F.), this species may be considered a better dairy animal than cattle in humid tropical zones if they are protected from direct sun, which can be easily done by altering the time of grazing from day to night.