1. Two series of simple nitrogen manuring trials, one on level of sulphate of ammonia applied to the seedbed at twenty-two centres and the other on the time of top dressing with ‘Nitro-Chalk’ at nineteen centres, were conducted on commercial farms in south-east Scotland during 1954 to 1957.

2. The optimum level of sulphate of ammonia varied with season and farm type. The optimum dressing was at least 0·9 cwt. N/acre in the dry season of 1955, and in the other years was estimated to be 0·9 cwt. N/acre on arable farms and about 0·-25–0·4 cwt. on ley rotation farms when the barley did not follow sheeped turnips. In the latter event no fertilizer was best.

3. The nitrogen content of the grain increased little until after the 1 cwt. sulphate of ammonia level, although the optimum yield was not obtained in many experiments without some rise in the grain nitrogen content.

1. The mean velocity ῡ and the velocity frequency distribution f(υ) of bull spermatozoa with normal motility have been determined in standardized eggyolk—citrate buffers at different pH values, ranging frompH 5·70 to 8·35.

Under assumed approximately anaerobic conditions at37·0 ± 0·1° C. the mean velocity was found to show a straight-line relationship -with pH in the physiological region pH 5·70–7·50, according to the general equation

Statistically, k was shown to be a linear function of a, namely,

Consequently, the dependence of the mean velocity of the spermatozoa from any ejaculate can be characterized by the one parameter a = dῡ/dpH. (dimension μ/sec./pH), determining the slope of the ῡ υs. pH curve.

The mean velocity of all individual spermatozoa (measurements of all ejaculates at the same pH value pooled together) could be described accurately by the equation:

For some ejaculates the linear relationship was found to hold up to pH 8·00.

2. The velocity frequency distribution curves were found to change with pH. At pH 5·70 the curves are skew with a relatively high top value. At increasing pH values both the top value and skewness decrease. The mean standard deviation of the velocity distribution f(υ) was found to be proportional to pH and could be described by the equation

This means that the variability in swimming speeds of the individual spermatozoa of any ejaculate increases proportionally with pH, indicating a strain effect of increasing alkalinity on the population, irrespective of the general stimulation of motility in the region up to pH 7·50.

3. At each pH value the mean velocity decreases with time. Under assumed approximately anaerobic conditions at 37° C. the speed of velocity decrease as a function of pH was found to differ so much between different ejaculates that no generalization could be derived from the available material. The same holds for the effect of pH on the number of normally moving spermatozoa in the diluted ejaculate.

4. The total number of spermatozoa moving normally depends on pH, but the optimum varies with the individual ejaculates.

1. Alternate husbandry systems containing 1-, 2- and 3-year grazed leys were compared with continuous arable cropping at Jealott's Hill during the period 1945–56. Kale and wheat were used as successive test crops to measure the fertility accruing from the following crop sequences: (a) 3-year ley; (b) wheat, 2-year ley; (c) wheat, barley, 1-year ley; (d) wheat, barley, barley. A study was also made of the effect on crop yields of compost, dung and N fertilizer dressings applied to kale.

2. The yields of kale and wheat were improved considerably by 1-, 2- and 3-year leys. Increments were: 5·2 tons fresh kale per acre and 8·7 cwt. wheat grain per acre from 1-year ley, 9·0 tons kale and 13·5 cwt. wheat per acre from 2-year ley and 9·2 tons kale and 15·0 cwt. wheat per acre from 3-year ley. Two- and 3-year leys were markedly superior to 1-year ley in their effects on kale and wheat. The slight benefit apparent in wheat yields from 3-year ley compared with 2-year ley was not significant and so the 2- and 3-year leys may be considered equal in their effect on the succeeding arable crops. In the third arable crop, wheat, the 2-year ley was still effective to the extent of 3·9 cwt. grain per acre but the residual effect of the 1-year ley had largely disappeared. Yields under the all-arable system were considered to have been reduced by the poor physical and nutrient status of the soil, by increased incidence of ‘take-all’ in wheat and by more weed growth.

3. The response of kale to dung averaged only 1·1 tons per acre over all four rotations but this was largely obtained in the ley systems and little after all-arable cropping. Compost was generally ineffective on kale with some signs of detrimental effect, especially in the arable system. Wheat following kale benefited equally from dung and compost applied in the previous year; the average response to organics was 1·6 cwt. grain per acre and this was unaffected by rotation. The residual value of dung on subsequent crops amounted to an average of 2·0 cwt. grain per acre per annum but compost had no significant effect.

4. The response to an additional 0·4 cwt. fertilizer N per acre to kale was greatest after continuous arable cropping and virtually nil after 3-year ley. Wheat grain yields were improved by 1·0 cwt. per acre on average by the addition of the extra 0·4 cwt. fertilizer N per acre to kale in the previous year.

5. It was concluded that when mixed farming is practised the aim should be to have the land under grass for at least as long as it is under arable, e.g. 3 years of ley with 3 years of arable.

Soils collected from paddy fields were kept in a waterlogged condition in glass cylinders with and without drainage. After about 2 months of waterlogging soil samples were collected from each cm. depths of the cylinders, both from the bright and dark sides of the cylinders. The soil samples were analysed for iron, manganese and phosphorus. At the beginning these elements were uniformly distributed throughout the entire soil depth, but as a result of waterlogging a distribution pattern developed. More of these elements concentrated on the surface and illuminated sides of the cylinders. It is assumed that such a phenomenon also occurs in the paddy field. These elements by concentrating on the soil surface limit the feeding zones to the top 3–5 cm. of the soil.

1. The serum β-globulin phenotype of 141 bulls located at Cattle Breeding Centres in England and Wales was determined by starch-gel electrophoresis.

2. The distribution of the contemporary comparison values of these bulls with respect to β-globulin type was investigated. The great majority of the bulls were βAA, βAD, or βDD with very few βAE and βDE and no βEE types.

3. The contemporary comparison values for 130 bulls of the three types βAA, βAD and βDD each fell into a normal distribution. The mean and its standard error and the standard deviation of the mean and its standard error were calculated for each of the three curves. The mean contemporary comparison value for the βAA bulls was + 12·2 ± 5·4 gal., for the βAD bulls + 26·8 ± 5·4 gal., and for the βDD bulls + 38·2 ± 5·5 gal. The βAA and βDD means were significantly different (P < 0·01).

4. The pooled contemporary comparison values of the βAA, βAD and βDD bulls did not give a normal distribution curve, neither did the contemporary comparison values for a sample of 1028 bulls quoted by the Milk Marketing Board. However, when the contemporary comparison values of the βAA, βAD and βDD groups were superimposed around the same mean, the ensuing distribution was normal.

5. It is concluded that the β-globulin locus is concerned in the genetic control of milk yield. The estimated mean genetic value of βD over βA is approximately + 50 gal. This is about one-sixth of the total genetic variation in milk yield in the major milk breeds.

6. The distribution of butterfat percentages with respect to β-globulin phenotype in four Ayrshire and one Friesian herds was investigated. No difference between the mean first lactation butterfat percentage of the βAA, βAD, and βDD cows in each herd was found. There was an indication (not significant) that the mean butterfat percentage of the βAE and βDE cows in three of the four Ayrshire herds studied was higher than the mean of the other groups.

1. EUN and MFN excretions have been determined in goats on a N-low ration and also on a N-free ration. The values obtained were,

EUN = 0·052 g./kg. live weight and

MFN = 0·41 g./100 g. dry-matter feed intake.

2. The values so determined with the two feeding regimens, for both the EUN and MFN agreed very closely.

3. The minimum protein requirement of goats for maintenance, as calculated from the EUN value, is 0·65 lb./1000 lb. live weight.

4. The formula for calculating the utilizable protein requirement for this species is found to be P = 0·89. W0.734, and is almost identical with the one given by Mitchell.

5. The usefulness of the above formula in predicting the EUN of immature goats is discussed.

1. The crude protein requirement of goats for maintenance has been determined from balance studies. The requirement per kg., as found by three different methods of treatments of the balance data, is practically the same, viz. 2·63 g. crude protein.

2. The digestible crude protein requirement also has been calculated, again by two different methods, and is estimated at 1·12 lb./1000 lb. body weight. This value is undoubtedly very much higher than the value (0·65 lb./1000 lb.) obtained previously from the endogenous urinary nitrogen determinations alone.

3. The dry-matter requirement of goat per 100 lb. live weight has been determined. Calculated on the basis of live weight raised to the power 0·734, the requirement was found to be 2·6 lb./100 lb.

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. 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 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.

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.

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.

1. Twenty-eight experiments on sugar beet in 1956–8 compared ammonium sulphate, calcium nitrate and urea applied to the seedbed before sowing. The three fertilizers were compared at rates which supplied nil, 0·6 and 1·2 cwt. N/acre. Treatments in which 0·6 cwt. N/acre was held back until the end of June were also included.

2. Average responses in sugar yield were low, 0·6 cwt. N/acre provided virtually all the nitrogen required for maximum sugar production. The heavier nitrogen dressing, on the other hand, substantially increased the yield of tops.

3. Calcium nitrate and urea were as effective as ammonium sulphate at raising sugar yield. There was no damage to germination with any fertilizer, and when urea containing 4·5% biuret was used for topdressing in 1956, no damage was seen. Calcium nitrate and, to a lesser extent, urea produced more tops than ammonium sulphate.

4. Putting all the nitrogen into the seedbed was as effective as a split dressing in raising sugar yield. Leaching of nitrogen in a wet summer is therefore not important to sugar beet. Late nitrogen, on the other hand, never harmed sugar production if some had been given to the seedbed.

In this paper the results are described of experiments on bull sperm cells with the photo-electric device for measuring the ‘motility’, as developed by Rikmenspoel, van Herpen & van Dam (1956).

It was found that the velocity distribution of sperm samples differs only slightly from a Gaussian one. The form of the distribution curve, which is a bit skew, is rather constant between ejaculates. This means that generally the ‘motility’ of a sperm sample can be characterized by the mean velocity of the sperms, the standard deviation of the velocity distribution and the number of cells moving normally. The mean ratio of velocity and frequency of rotation (the ‘speed’ of the screwing movement of the head of the sperm cell) was found to be a less important motility characteristic for most experiments.

The scattering of the above-mentioned properties in various ejaculates were measured, while the sperm samples were all kept in the same conditions. It was found that the mean velocity has a rather constant value.

A linear relationship between the mean velocity of the sperms of a sample and the viscosity of the diluent is found. This holds also for the dependence of the ‘speed’ of the head movement and the viscosity.

The mean velocity of sperm cells was found to increase approximately in a straight-line relationship with the temperature in the range 33–41° C. There were indications that the mean velocity may reach a maximum in the region of 42–45° C.

If sperm samples are stored at 4° C, the mean velocity and the number of cells moving normally is found to decrease exponentially. The decrease of the number of cells moving normally is three to four times faster than that of the mean velocity. Some evidence was obtained that the characteristic time for the decrease of the number of cells moving normally is bull-specific.

The influence of various night- and day-temperature regimes on inflorescence initiation and earing in vernalized and unvernalized Lolium temulentum, L. multiflorum, short-rotation ryegrass, and two varieties of L. perenne, and also in the Athabasca strain of Poa pratensis, is described.

Vernalization response curves for the ryegrasses, when grown under controlled conditions, are presented, and are consonant with the operation of a first-order reaction as the rate-limiting step in the vernalization ofLolium perenne. Velocity coefficients for the rate of vernalization in various conditions are deduced, and are shown to be higher in seedlings than in seeds, and higher in short days at 10° C. than at 4° C. The Q 10 for the velocity of vernalization over this range is about 2·7.

Low-temperature vernalization in L. perenne can occur when low night temperatures are combined with moderately high day temperatures, and it can take place during abundant vegetative growth. In short days and in continuous light mean temperatures up to 10° C, at least, are fully effective, but in 16 hr. photoperiods even 7° C. was not a fully effective vernalizing temperature. The requirement of perennial ryegrass plants for cold treatment may be replaced by short-day induction if light intensities are low and if the plants are continually divided.

1. Experiments are described in which retention time of digesta in the reticulo-rumen, fermentation rates of rumen contents, and dry-matter digestibilities were studied simultaneously in four grade European and three zebu steers.

2. Fermentation rates and rumen retentions were significantly negatively correlated.

3. Correlations between digestibility and the other two factors were not significant at a high level.

4. The multiple regressions calculated for retention time and fermentation rate were significant at the 5% level and that for digestibility approached this level.

5. While only fermentation rates show significant differences for the two types of cattle, the results suggest that grades and zebus differ also in the rate of passage of digesta through the rumen.

6. The loss in weight of substrate per unit of fermentation products was measured in in vitro experiments.

7. Using certain assumptions, estimates are made of the extent to which the measured fermentation rates could account for the loss in weight of dry matter during digestion, and are compared with the loss actually found.

1. There were many distinct, consistent, individual differences in the thyroid activity of several of the animals used in this study. Graphic indications of breed differences were present at several high temperatures, and statistical analyses supported differences between the Jerseys raised at each temperature and the other two corresponding breeds. The Jerseys displayed higher rates. In no instances were there thyroid 131I release rate differences between Holsteins and Brown Swiss.

2. There was a negative correlation between thyroid 131I release rate and temperature for each breed raised at each temperature. Correlations for the 50° F. animals were statistically significant below the 0·05 level of probability and for the 80° F. animals they were significant below the 0·01 level. As the environmental temperature increased from 35° to 80° F. there was a gradual decrease in thyroid 131I release rate. Above 80° F. there was a sharp decline in thyroid 131I activity.

3. Within the range of environmental temperatures from 35° to 70° F. the animals raised at 80° F. displayed thyroid release rates higher than those of the animals raised at 50° F. At 80° and 90° F. the 50° F. Jerseys exhibited higher activity. The Jersey differences approached statistical significance. At the lower temperatures graphic differences between the Brown Swiss and the Holsteins raised at the two temperatures appeared to be present, but they were not generally supported by statistical analysis.

4. At temperatures of 80° F. and above, when regulatory mechanisms could not control body temperature, both groups showed considerable rises in body temperature concomitant with decreases in thyroid 131I activity and TDN consumption. The 80° F. group showed a rise less sharp than that of the 50° F. group.