1. Growth and feed conversion efficiency of pigs between weaning and 100 lb. live weight were improved by adding a vitamin B12 a supplement to simplified all-plant rations containing, principally, barley and groundnut meal. This response was obtained with less than one-third of the U.S. recommended allowance of vitamin B12 in the rations of growing pigs.

2. No such response was obtained when a vitamin B12 supplement was added to rations containing milling by-products and grass meal.

3. When pigs were fed to a scale based on live weight, those that received an all-plant ration (containing milling by-products and grass meal, and relying on groundnut meal as the main source of supplementary protein to give a total content of 18·4 to 18·8% crude protein) gave 90–93% as good growth as pigs that were fed rations of similar total digestible nutrient content containing 14·5–15·5% crude protein and 3·6 or 7·0% white fish meal. Calculations suggest that such groundnut meal rations may be slightly deficient in lysine, but probably not deficient in tryptophan or ‘cystine + methionine’.

4. When pigs were fed to appetite, those that received rations containing 3·6% white fish meal and no milling by-products or grass meal, ate significantly more than those that had either ‘milling by-products + grass meal’ or no fish meal in their rations; they grew proportionately faster, with no improvement in the efficiency of feed conversion.

5. The carcasses of pigs that had received all-plant rations from weaning to bacon weight were of good quality, and their measurements did not differ from those of pigs that had received fish meal to 100 lb. live weight.

1. Superphosphate, at two levels and three intervals of application, was applied to calcareous downland pasture grazed by sheep over a period of 3 years.

2. At the high level, total dry-matter and crudeprotein yields were higher from a single initial application and from thrice-yearly applications than from annual applications.

3. At the high level, mean herbage phosphate content and total phosphate yield were higher following a single initial application than when superphosphate was applied at shorter intervals.

4. Superphosphate increased the cover of grasses and legumes and reduced the cover of herbs.

5. Superphosphate affected the cover of individual species in the following manner:

(a) Favourably: Dactylis glomerata, Festuca rubra, Arrhenatherum elatius, Poa trivialis, Holcus lanatus, Lolium perenne and Trifolium repens.

(b) Unfavourably: Agrostis stolonifera, Leontodon spp., Prunella vulgaris, and other minor herbs.

(c) No measurable effect: Poa pratensis, Plantago lanceolata, Ranunculus bulbosus and Crepis capillaris.

1. A study was made of the performance of eight litters of pigs housed under two widely different levels of ambient temperature during the suckling period and under uniform conditions from weaning to 200 lb. live weight.

2. There was no significant treatment difference in the amount of milk suckled, but the pigs exposed to the lower temperature consumed more solid food before weaning.

3. Up to weaning those kept at the higher temperature were the more efficient converters of milk and solid food into live weight.

4. There was a highly significant correlation between milk suckled and live-weight gain.

5. Probably through excessive handling, the pigs were under weight at weaning, but the postweaning performance appeared to be unaffected by the pre-weaning treatment.

6. The average milk yield of six sows from the 3rd to the 56th day of lactation was 275 kg. 605 lb.) (variations 202–347 kg. (445–764 lb.)). Yields have been compared with others published.

7. After allowing for maintenance requirements and weight gain or loss it is estimated that the sows required 412 Calories of net energy to produce 1 lb. of milk.

Seasonal variations in the contents of organic and inorganic constituents of three East African grasses, Bothriochloa insculpta, Chloris gayana and Brachiaria dictyoneura are reported.

Protein content is closely associated with rainfall and the stage of growth of the grasses. Protein content of from 15 to 20% is maintained for a short time only, at the beginning of the rainy season. During the dry season the values fall to 4–5%.

Even in the vegetative phase the fibre contents are relatively high, 23% being the lowest figure recorded.

A common feature of the grasses is a high content of silica, which may amount to more than 10% of the dry matter.

The phosphorus content of the grasses is low, ranging from 0·65% P2O5 in young grass during the rainy season to 0·13% during the dry season.

1. An investigation is reported in which the relationship was examined between body size and muscle fibre size of nineteen newborn lambs and including twelve males and seven females. Body size was measured in terms of the dead body weight and that of the dressed carcass, while muscle fibre size was estimated on the basis of the mean crossdiameter of 150 fibres per lamb.

2. It was shown that the dressing (or carcass) percentage tends to increase with an increase in body weight, from 42·26% at a body weight of 2000 g. to 49·04% at 7000 g.

3. Of the 2850 cross-diameters recorded, the majority (33·8%) of the fibres measured between 8·0 and 9·6 μ, while individual fibres varied in size from 1·6 to 22·4 μ.

4. Highly significant, positive correlations were shown to exist between both body (r = 0·996) and carcass (r = 0·946) weight, and mean muscle fibre diameter, indicating that differences in size between the lambs may be accounted for largely by corresponding variations in the size of individual muscle fibres.

5. Of the three muscles sampled m. gastrocnemius had the largest mean fibre diameter (10·38μ), followed in decreasing order by m. rectus femoris (9·72 μ) and m. longissimus dorsi (9·09 μ). These inter-muscle differences were significant at the 1% level of probability.

6. Ram lambs had significantly thicker muscle fibres (10·32 μ) than ewe lambs (8·72 μ), but also weighed the heavier and produced heavier dressed carcasses. Some evidence was produced, however, in support of the theory that at comparable weights males possess thinner individual, and therefore a greater number of fibres than females.

1. The relationship existing between the gross digestible energy content and the chemical composition of twenty-four silages has been studied with nine Cheviot wether lambs over a period of 8 months.

2. Silages were made from grassland herbage and varied widely in the chemical composition of the ingoing material.

3. Each silage was fed to a group of three lambs for a 10-day preliminary- and a 9-day collectionperiod. Faeces and urine were collected in metabolism crates.

4. The silages were analysed for volatile acids and bases, for proximate nutrients and for some of the more precise chemical constituents as suggested in the scheme of analysis of Ferguson (1948).

5. A close relationship existed between the gross digestible energy contents of the silages and the lignin (Ellis) content.

6. The most accurate prediction of gross digestible energy was obtained by taking into account the content of lignin (Ellis), cellulose (Crampton & Maynard) and crude protein, in the silage.

7. In the case of hays (Walker & Hepburn, 1955) no increase in the accuracy of predicting gross digestible energy was obtained by estimating the lignin and cellulose content, rather than crude fibre alone. However, with silages the results give support to the opinion of Mitchell (1942) and Schneider et al. (1951) that analysis for more precise chemical constituents will increase the accuracy of predicting digestibility.

8. Crude fibre and cellulose were not related in any fixed way with the digestibility of energy. Crude fibre itself was digested to some 80% compared with 62% in hays.

9. Metabolizable energy was closely related to digestible energy.

10. The starch equivalents of the silages were calculated by conventional methods and also from the content of gross digestible energy.

1. The results of nine digestibility trials on three East African grasses, using sheep as experimental animals, are reported.

2. In five of the trials Bothriochloa insculpta, at various stages of growth during the season, was used. Chloris gayana (Rhodes grass) was used in two trials, as was Pennisetum clandestinum (Kikuyu grass).

3. The results are discussed and are compared with other results from East Africa.

4. P. clandestinum has a high digestible protein content and is highly digestible in the early stages of growth, and maintains its high protein content when 9 to 12 in. in height.

5. Bothriochloa insculpta and Chloris gayana are moderately highly digestible in the-young stages but are relatively low in digestible protein. As growth ceases during the dry season the digestible protein content falls more rapidly than the starch equivalent with consequent widening of the nutritive ratio.

6. It is suggested that the differences between Pennisetum clandestinum and the other grasses may be due to its predominantly vegetative habit.

1. The information analysed in this report is taken from records of the Compton herd of Large White pigs over a period of about 4 years.

2. Length of gestation period: close concentration about the mean of 114·17 days; no apparent relationship between litter size and extremely long or short gestation period. There was no difference in the average duration of pregnancy as between old and young sows, nor was there any evidence of a characteristic tendency to long or short pregnancies in individuals. The incidence of stillbirths appears to be independent of the length of the gestation period.

3. The number of pigs born, alive or dead, ranged from 3 to 24, the average being 13·12. The average number of pigs born alive was 12·4 and the average number weaned was 8·1.

4. The average number of pigs born rose with successive pregnancies to a maximum of more than 15 in the 6th and 7th litter and declined thereafter. The average number born alive reached a maximum of more than 14 in the 5th litter and declined thereafter, the decline being less marked among pigs born alive than among all pigs including stillbirths, apparently because embryonic mortality (before parturition) bears more heavily on the litters of older sows, whereas the incidence of stillbirths is not related to age (or to the ordinal number of the litter).

5. The incidence of stillbirths was studied in relation to litter size, the data being compared with similar data recorded elsewhere. The proportion of stillbirths was higher among female piglets than among males. The reverse was true in litters of less than average size, and the possible significance of this difference between smaller and larger litters is discussed.

6. The foetal sex ratio appears to bear no relation to the ordinal number of the litter or to its size.

7. The reasons for discard of sows which have been culled during the period under review have been recorded and are briefly discussed.

An examination was made of wool and skin samples from sheep being dosed with sodium fluoride, and from other sheep acting as controls, from March 1953 to March 1954. It was evident that the sodium fluoride caused the wool to grow shorter, finer, less crimped and to become less lustrous; less wool grease was produced, and it seemed that in certain samples from one sheep tenderness of the fibres had been caused. There was a greater occurrence of capsules associated with follicles in skin samples from the dosed sheep, suggesting that the sodium fluoride might have been the cause of these. The number of capsules in one sample was large enough for the details of possible stages in their development to be described. There were apparently no other abnormalities in the skin and follicles, and follicle counts suggested that the sodium fluoride had not influenced the percentage of shedding fibres. Information was gained about the normal changes in the percentage of shedding fibres through the year.

The present investigation is concerned with the influence of procaine penicillin and aureomycin on digestion. In particular, the effect of antibiotics, in amounts generally included in feeding-stuffs, on the bacterial digestion of cellulose in the large intestine of the pig, was investigated.

The digestibility of a basal diet composed of fine bran, maize meal, dried lucerne meal and whitefish meal was determined with and without the addition of antibiotic. No effect was noted on the digestibility of any food constituent.

The diet fed in four digestion trials contained 500 g. of shredded fodder cellulose. The digestion coefficient for the crude fibre, in these diets rich in cellulose, was 76·2% when 18 mg. of procaine penicillin was added per lb. of meal and 76·8% when no antibiotic was added.

The nitrogen-free extractives in the fodder cellulose are mainly if not entirely composed of xylan. If the nitrogen-free extractives and crude fibre are combined to give ‘cellulose’ as defined by Norman & Jenkins, the digestion coefficients for the cellulose were 85·7, 83·4, 85·7 and 87·2%, respectively, thus showing little difference between treatments.

There is no warrant for assuming that the antibiotics had any bactericidal or bacteriostatic effect on the cellulose-splitting organisms.

1. The partition of the egg into shell, yolk, thick and thin albumen has been determined for eggs from pullets, 1-year-old hens and hens aged 6–10 years.

2. The proportion of thick albumen increased, and that of the thin albumen decreased, with advancing age of the hen.

3. It is suggested that these observations may be explained by the action of one or more of the following agencies: an increase in the amount of ovomucin relative to the amount of albumen; an impairment of the adrenal function; and a reduction of the period of time spent by the egg in the shell gland.

1. Two digestibility trials were carried out to determine the s.e. and t.d.n. of swedes, fodder beet and grass silage when fed alone and when each kind of root was fed with silage at separate feeds. In addition, fodder beet and silage were fed together at the same feed.

2. The results were examined to determine if the feeding of roots and silage together in the diet, but at separate feeds, had led to any complementary effect.

3. No complementary effect was found when swedes and silage were fed at separate feeds.

4. A negative complementary effect was found when fodder beet and silage were fed at separate feeds.

5. The s.e. and t.d.n. values of the fodder beet plus silage at each feed were significantly higher than when the two foods were given at separate feed times.

6. The s.e. and t.d.n. of the swede dry matter were higher than the standard figures published. An explanation is given.

7. The nutritive value of the fodder-beet dry matter was not higher than that of swede dry matter.

8. The results of the digestibility trials are compared with some calculated results from a cattle feeding trial.

Synthetic soil crumbs stabilized by the addition of small quantities of a polymer, and natural soil crumbs from old grassland, have been extracted with neutral sodium pyrophosphate and alkali and the strengths of the crumbs compared before and after extraction, using the sodium saturation technique. Three polymers were used: polyvinyl alcohol (a non-ionic polymer), sodium alginate, and a vinyl acetate-maleic anhydride co-polymer (Vama), the latter both carboxylated polymers. Pyrophosphate was able to displace the carboxylated polymers from the synthetic crumbs, but not the stabilizing fraction of the organic matter from the grassland crumbs. 0·5N-NaOH produced a much greater reduction on the strength of the alginate treated crumbs compared with Vama crumbs, which is attributed to the weaker hydrogen bonds formed by the former. Prolonged leaching with alkali removed a considerable part of the stabilizing organic matter in the grassland crumbs. Neither method of extraction affected the stability of the polyvinyl alcohol crumbs.

It is concluded that the grassland crumbs are stabilized by the formation of inter-lamellar complexes with the clay in the crumbs, and probably that the substance forming the complexes is a polymer and contains amino-groups.

Evidence is also given that phosphate ions and the carboxylated polymers are attached in the same manner to the edges of the clay crystals.

Semen samples were collected from buffalo bulls by a.v. at intervals of 24, 12, 8 and 2 hr., four consecutive ejaculates being collected for each bull in every treatment. Semen qualities were measured in fresh and stored ejaculate at 4° C. for 48 hr.

1. (a) In fresh semen, the average initial values were 3·12 ml. for volume, 645 × 103 for concentration per cubic millimetre, 2134 × 106 per ejaculate, 7·25 for motility, 80·1% for live spermatozoa and 21·1% for abnormals.

(b) Volume, concentration and percentage of live sperm were not affected by successive ejaculations.

(c) Motility started to decrease after the third collection in most cases.

(d) Percentage of abnormals was highly affected irrespective of interval of collection.

(e) When the interval of collection was short, enlarged middle piece of spermatozoa and detached galea capitis were observed.

2. (a) In stored semen, the average values were for motility 3·12%, for live sperm 64·5%, and for abnormals 27·4%.

(b) Storage caused a decrease in motility and an increase in percentage of abnormals, while it had no effect on percentage of live sperm.

(c) The rupture of head membrane of spermatozoa was observed in stored semen.

The results of 8 days' observations with ten animals, under both free-grazing and night-paddock systems, are given. These results are discussed in relation to changes in the food consumption of the animals. The indications are that when the animals are on rough grazing, the pattern of behaviour is not influenced by the night-paddocking system, but that the food consumption of the animals is affected by the relative abundance of herbage in the day and night enclosures. In this trial one comparison shows a significant reduction in average ruminating times by 1 hr. without any effect on the grazing time, when the herbage was scarce in the night paddock; and in the other comparison, when there was more herbage in the night paddock than in the day paddock, the food consumption, as indicated by the ruminating times, was unaffected, but at the same time the animals needed to graze 1 hr. more under the free-grazing conditions than under the night-paddocking system.

The yields of cotton from five three-course rotations are given; they show marked seasonal variations, the variations of the different rotations being in close accord with one another. The average yields of the rotations are related fairly closely to the average soil nitrates; in individual years this is not so, though considerable responses to nitrogenous manuring are always obtained on Gezira soil.

The distribution of nitrate in Gezira soil shows an unusual accumulation at depth; though cotton roots can reach the zone of accumulation, the variability of nitrate at these depths renders it impossible to relate changes to uptake. The figures show that under growing cotton the whole of the upper 4 ft. of soil can have low nitrates (of the order of 1 p.p.m.). Unless the roots obtain nitrate from the fifth and sixth feet accumulations the plants must be taking up nitrate as fast as it is formed, and the nitrate-supplying power of the soil must be of first importance. Figures are given showing differences in nitrification in soil from the different rotations.

The effect of heavy nitrogenous manuring on soil nitrate is shown to be largely confined to the year of application, and no accumulations could be demonstrated. The average recovery of added nitrogen in this experiment is only of the order of 10%. The yields of the heavily manured treatments show the same violent fluctuations as do the unmanured treatments.

In the three-course rotation experiment surface nitrates in August and September in the wider rotations are strongly negatively correlated with the rainfall of the period 1 July to 15 August. Over the period July to September the distribution of nitrates in the upper 2 ft. of the profile changes; there are differences between the rotations in this respect.

1. The digestibility of samples of heather of 3, 7 and 14 years of age has been determined.

2. The experimental technique was the same as that used in the previous digestibility studies of heather.

3. The digestibility of the organic matter, and of all its components other than crude fibre and ether extractives, was found to decline with advancing age. This decline became apparent in heather of 7 years of age.

4. Gross digestible energy values were determined for the three ages of heather under investigation. Starch equivalents derived from these values proved to be lower than starch equivalents calculated in the usual way.

5. Confirmation of earlier conclusions concerning the value of heather as a source of energy has been obtained.

A method for measuring the rate of passage of meal through the alimentary tract of pigs by feeding a stained marker is described. The results are given of sixty-four experiments made under standardized conditions on four fattening pigs with live weights ranging from 49·9 to 185·5 lb. and six experiments on a sow weighing 500 lb.

Results were expressed by means of excretion curves. These were sigmoid in shape and from them a value termed R, the mean retention time (hr.) of all the stained particles in the alimentary tract, directly proportional to the area to the left of the curve, was calculated.

In the fattening piga the first appearance of the marker in the faeces occurred 10–24 hr. after feeding, and the mean 5 and 95% excretion times were 21 and 53 hr. respectively. The marker was completely excreted after approximately 80–90 hr. The R value averaged 34·2 hr.

A marker fed at the morning feed (9 a.m.) had earlier 5 and 95% excretion times and the R value was significantly smaller.

There was no statistically significant relationship between the R values and live weight, digestibility of the dry matter of the ration or the dry-matter content of the faeces.

In the sow the 5 and 95% excretion times were 38 and 68 hr. respectively, and the R value averaged 51·1 hr.

Counts of stained particles in the intestines of two of the pigs after slaughter showed that food was delayed mainly in the large intestine.

1. An experiment comparing the growth and productivity of six varieties of lucerne representing a wide diversity of ecological conditions grown in association with S 37 Cocksfoot, S143 Cocksfoot and a commercial cocksfoot/timothy mixture is described and the results discussed.

2. Variety of lucerne had a marked effect on establishment, persistence, recovery from defoliation, early spring growth, yield of total dried produce, proportion of lucerne in that produce and on yield of nitrogen.

3. There was no evidence of differing degrees of compatibility of varieties of lucerne with the three strains of grass used.

The failure of a high proportion of fertile eggs to hatch still remains a major cause of financial loss to the poultry industry. Payne (1919) pointed out the consistent manner in which embryonic mortality manifested peak periods at the fourth day and the nineteenth day of incubation, and he drew attention to the fact that the latter period of susoeptibility showed an increased level of mortality with artificial incubation compared with natural methods. Romanoff (1949) summarized the explanations put forward to account for these two peaks of embryonic mortality. Riddle (1930) suggested that the first period was caused by respiratory maladjustments, and he, and others, considered that the failure of the developing embryo to make the fine adjustments at this time and to deal effectively with the excretion of various toxic substances may be a major cause of death. The second peak period of mortality occurs at the transition from allantoic to pulmonary respiration. Failure to achieve this change, with the consequent death of the chick in the last stages of development, may be greatly influenced by the cumulative effect of all the unfavourable conditions to which the hatching egg has been subjected. Not the least of these will be environmental conditions in the incubator and the incubator house adversely affecting the oxygen supply and the relative humidity.