Birthcoat samples from Lincoln and Welsh Mountain lambs born in an ova transfer experiment (Weiner & Slee, 1965) were examined to determine the fibre type arrays and any effect of ova transfer on manifestation of the prenatal check or the base (Dry, 1965).

In the Lincoln breed arrays were Truncated Ravine or Truncated Valley thus showing central checking. Pre-curly tip fibres were mainly confined to central primary follicles. Post-natal medullation was plentiful, especially in peak curly-tips, but kemp was absent. In the Welsh lambs all identifiable arrays were either Plateau or Saddle, with the lateral primary fibres more checked than the centrals. Pre-curly tip fibres occupied almost all the primary follicles, with only a few curly-tips in primary laterals. Post-natal medullation was strongest in pre-curly tips and their successors.

The effect of ova transfer was to decrease the manifestation of check in Lincoln-in-Welsh and increase it in Welsh-in-Lincoln, without affecting the base. Although this, in each case, changed the check of the lamb in the direction of that of the foster breed, it is suggested that this may not be due to any influence of maternal check on foetal check. The effect on pre-natal check may be due to foetal size, and in particular skin expansion, during a short period immediately following completion of primary follicle initiation. As compared to their respective controls, the Welsh transfer lambs had a higher S/P ratio at birth, whilst that of the transferred Lincolns was reduced.

If increased prenatal fibre check is associated with increased foetal growth rate at the relevant period, it may also be correlated with increased lamb size at birth and therefore have been favoured in selection for meat production, at least in some breeds.

Data were collected from 549 Barki and Merino cross sheep during 1967, 1968 and 1969 to study the relation between kemp production and body vigour. The study also included the staple length and greasy fleece weight. The results showed that:

Age had a marked effect on the traits studied. Whereas kemp frequency (score) declined slightly as age proceeded, showing a significant reduction in the seventh shearing season, the staple length and fleece weight decreased after the second shearing season.

Differences due to sex, year and breed occurred, though the pattern differed in the different traits.

Kemp showed a highly significant correlation with birth and weaning weights, as indicating the animal vigour, and was negatively correlated with fleece weight.

Staple length was negatively correlated with birth and weaning weights and positively correlated with fleece weight.

Fleece weight was positively correlated to birth and weaning weights and negatively correlated to kemp score.

Kemp score in the Barki sheep was shown to be quite repeatablo (repeatability = 0·5).

Published and unpublished results for apparent nitrogen digestibility from 107 digestibility trials with Zebu (Africander, Brahman and their crosses with British cattle) and British breeds of cattle were analysed by regression analyses to determine its relationship with dry matter intake and dietary nitrogen content.

The linear regression of apparent nitrogen digestibility on the reciprocal of dietary nitrogen content was an adequate mathematical description of the relation (r = 0·92) and the addition of the reciprocal of nitrogen intake as an independent variable improved the description (r = 0·95) particularly for diets with a low nitrogen content. Both these equations have a physiological basis.

Estimates of the true nitrogen digestibility and metabolic faecal nitrogen from the linear regression of apparent nitrogen digestibility on the reciprocal of dietary nitrogen content were 86·8% and 0·49 g/100 g dry-matter intake. Independent estimates of these parameters from a multiple regression of total faecal nitrogen on dry-matter intake and nitrogen intake were 88·7% and 0·46 g/100 g dry-matter intake. The analyses on the breeds suggested that the Zebu cattle may have a higher true digestibility and a lower metabolic faecal nitrogen than the British cattle, although the differences were small and could not be subjected to statistical tests.

In each of two experiments the comparative slaughter technique was used to compare the retention of energy by young Border Leicester × Merino wethers when the same total amount of food was offered according to two different feeding regimens. These were designed to simulate, in pens with a diet of pelleted lucerne, feeding patterns typical of continuous and intensive rotational grazing.

In the first experiment ten 9-month-old sheep that were offered the same amount of food daily (mean intake 367 g digestible organic matter) during each of 14 weeks made mean daily gains of 39 g live weight, 6·3 g body fat and 0·59 MJ (140 kcal) energy compared with a gain of 30 g live weight, a loss of 1·4 g body fat and a gain of 0·28 MJ (67 kcal) energy by a similar group that ate the same total quantity of food but in amounts that ranged, during each week, from 1·8 to 0·1 times the daily intake of the other group. This cyclic feeding pattern caused a small decrease in the digestibility of dietary organic matter.

In the second experiment two similar feeding patterns were compared with ten pairs of 3-month-old sheep eating twice as much food each week as in the first experiment. One member of each pair was, in each of 13 weeks, offered food ad lib. for 3 days and then amounts falling to 20% of voluntary intake on the seventh day; the other one ate the same amount of food each week but in seven almost equal feeds. The latter sheep gained, on average, 132 g live weight daily and retained 58 g body fat and 2·96 MJ (707 kcal) energy compared with 124 g live weight, 49 g body fat and 2·61 MJ (624 kcal) energy by the sheep on the cyclic feeding pattern. In neither experiment was wool growth affected by feeding pattern.

The greater effect of the cyclic feeding pattern in reducing the efficiency of energy retention in the first experiment is attributed to the higher number of days each week during which these animals were estimated to be in negative energy balance. These results suggest that adverse nutritional effects of a fluctuating feeding pattern in rotational grazing are likely to be most important where sheep are being rationed near their maintenance level and only small where food is ample.

Soya beans grown on land planted the previous year with inoculated soya beans produced more nodules, lodging, seed yield, 1000 seed weight, and protein content and less seed oil concentration as compared to those grown on land that was planted with non-inoculated soya beans. Nitrogen fertilization (120kg N/ha) reduced the total number of nodules per plant. Increasing inoculation rates of the seed increased the dry weight of nodules per plant. Location, nitrogen fertilization, and inoculation increased or decreased the levels of certain amino acids but had no significant effect on the sulphur amino acids, cystine and methionine.

Forages and faeces from 28 digestibility experiments with cattle or sheep were extracted with neutral detergent solution, with and without sodium sulphite, or sequentially extracted with acid-pepsin, ethyl alcohol, diethyl ether and either ammonium oxalate or hot water. Ammonium oxalate was used to extract small amounts of non-protein material not extracted from legumes by hot water. Compared with sequential extraction the average protein-free organic residues after extraction with detergent, with and without sodium sulphite, were significantly lower in legumes and faeces, but not in grasses. The largest differences occurred in faeces from grasses for which the recoveries of cell walls as percentages of the faecal organic matter were found to be 59·2, 62·0 and 66·4 respectively, after extraction with neutral detergent plus sodium sulphite, neutral detergent alone and sequential extraction with various solvents. It was considered that the differences were due to extraction of cell-wall constituents by both detergent and sulphite.

Six fertilizer–nitrogen sources, each at three levels, together with a control of no fertilizer–nitrogen were compared in field trials in two consecutive crop seasons on a sandy soil comparatively deficient in nitrogen at Patna, Bihar. Four mathematical models were fitted to the potato yield data in order to evaluate the relative availability indices of the individual fertilizers. Data collected on final stand and ‘emergence rate’ index (Bartlett) showed that while urea applications gave rise to a comparatively low speed of emergence, with observed shoot injuries, nitrate of soda caused poor final stands. The other fertilizers had no effect on either the final stand or the speed of emergence.

Sulphate of ammonia was chosen as the standard fertilizer for the present study. Ammonium sulphate nitrate was as good as or even slightly better, while ammonium chloride and calcium ammonium nitrate were of intermediate efficiency, in that order. Urea and nitrate of soda were decidedly poor as nitrogen sources for potatoes under the conditions of the study. The concurrent Mitscherlich curves model was found to represent the behaviour of these fertilizers with a good measure of fit.

The performance of the six fertilizers is discussed in the light of the availability of NH4+ and NO3-, the phytotoxicity of urea and nitrate of soda, and the harmful effects of Cl-. It is concluded that ammonium sulphate nitrate is the best carrier of nitrogen among those studied for potatoes under the conditions set forth.

Recently developed mathematical models have been used to study the effects of plant population density and arrangement on the yield of cotton in central Uganda. Optimum density did not vary with variety, but was less with bollworm infestation, infertile soils and drought. A reasonable compromise between a population density suitable for adverse conditions and one suitable for good conditions is 7·4 plants m−2. This population is best achieved with 0·45 × 0·25 m spacing but if such rows are too close to manage then 0·2 m in rows 0·7–0·9 m apart is recommended. The mathematical models used in the study are discussed and appraised.

Grasses and legumes comprising poor to good quality temperate and tropical species were fed to either cattle or sheep in 36 digestibility experiments. Cell wall in these forages was the ash-free and protein-free residue after sequential extraction with acidpepsin, organic solvents and either water for grasses or ammonium oxalate for legumes. The average amount of cell wall digested per 100 g forage OM was 40·0±0·59 g in grasses and 19·8±1·85 g in legumes. It was considered that within grasses and within legumes the physiology of ruminant digestion, rather than forage quality, was the main determinant of the average amount of cell wall digested and the difference between grasses and legumes was due to interaction of the ruminant digestion process with the physical structure of the cell wall. Of forage factors governing variation about the physiological average, the total cell wall had some effect on the amount of cell wall digested, but the lignin concentration in the cell wall had no effect.

Among grasses and legumes the average, apparently undigested, protein-free non-cell-wall component was 6·2±0·13 g per 100 g forage OM. This component and digestible protein relative to total protein varied among different sets of data. It was concluded that only the component of digestible organic matter which was governed by the relative proportions of cell walls and cellular contents was predictable from chemical composition. It was considered that selection in plant breeding should be based on both digestible cell wall and cell-wall content instead of digestible organic matter.

Early stages in the development of reproductive tillers of S. 24 and S. 23 perennial ryegrass are described. The pattern of development of the stem apex and of the unemerged leaves present at the time of floral initiation is traced up to the time when internode extension results in the elevation of the stem apices above the level of defoliation. If tillers with stems about 10 cm long, or more, escape damage to the stem apex during defoliation, the regrowth may be expected to deteriorate rapidly in leafiness, since at this stage there are few or no unemerged leaves. Tillers with 3–4 cm stems generally bear 1–2 unemerged leaves, and hence the regrowth is more leafy.

For a given stem length apical development was slightly more advanced in S. 24 than in S. 23. Consideration is given to selection methods to be used in breeding for leafy regrowths in springtime.

Survival of buffalo sperm in glycine-yolk extenders stored at 5°C was investigated. Eight glycine-yolk extenders containing variable levels of glycine (1·7 and 3·8%), glycerol (0 and 7%), fructose (0 and 1%) and 20% egg yolk, were compared with the conventional 4% glycine–50% egg yolk (control 1) and a 0·2 mol Tris-yolk extender (control 2). The highest rate of sperm survival in glycine extenders occurred in the one containing 1·7% glycine, 7% glycerol, 1% fructose and 20% egg yolk. All glycine extenders however, including control 1, were statistically (P < 0·01) inferior to the Tris-yolk. Sperm survival at the 4th day of storage for the glycine extenders ranged between 30 and 63% but it was 83% for the Tris-yolk.

Adjusting the pH of the glycine extender to 6·5 increased the percentage of sperm survival but it was still below that occurring in the Tris-yolk. Sperm survival in glycine yolk adjusted to pH values of 5·9, 6·5 and 7·1 were 55, 65 and 60% compared with 75% for the Tris-yolk control.

A hand injector was used to inject ammonia into soils in pots in which ryegrass was subsequently grown and under grass in the field; the spacing was varied.

Injecting ammonia or applying ammonium nitrate at one point or three points in the middle of a clay-loam and a sandy-loam soil in pots did not affect the growth of grass or its uptake of N. Grass with ammonium nitrate grew slightly better than with ammonia on the sandy loam and slightly worse on the clay loam.

Best yields of dry matter and most uptake of N were obtained from grass swards having ammonia injected in lines 23 and 30 cm apart and the injection points from onequarter to one-half of the distance between rows. Increasing the distance between lines from 30 to 45 cm diminished total yield and uptake because the strip 15·2 to 22·8 cm from the line of injection grew less than grass nearer to the line of injection.

With grass grown in rows 12·1 cm apart, yields were greatest with the lines of injection perpendicular to the rows of grass and least with the ammonia injected along and into the rows. The yield of dry matter of the row with ammonia injected into it was usually less than of the adjacent row and the percentage N in the grass was usually more, so that the weight of N in the grass sometimes increased and sometimes decreased with distance from the line of injection depending on the relative changes in yield of dry matter and of percentage N.

Two chickpea pure lines, one being short and wide in stature and the other tall and narrow, were crossed. Parents, F1 and F2 generations were grown in the field to study the inheritance of plant dimensions, as well as their correlation with seed yield. Heritability, in broad sense, for plant height and width was 36 and 20% respectively. Estimated minimum number of genes for plant height was two and for plant width was three pairs of genes. Plant height showed correlation values of 0·43 and -0·67 with yield of seed and 1000 seed weight respectively. There were no significant correlations between plant width and the same two yield components.

The relationship between body weight, testes volume and circumference as computed for 42 slaughterhouse buffalo bulls (Bos bubalis). Animals ranged in body weight from 290 to 610 kg, testes volume (testes plus epididymides without scrota) from 102·5 to 296·7 ml and testes circumference (testes with scrota intact) from 21·31 cm. Relationships between body weight and testes volume, body weight and testes circumference, testes circumference and testes volume were all linear and correlations (r) were, 0·986, 0·932, 0·951 and were highly significant. Regression equations were calculated and it was clearly shown that buffalo bull testes volume is a function of body weight and could be easily predicted either from body weight or from testes circumference.

Comparisons between the testicular size of the buffalo bull (B. bubalis) and domestic bull (B. taurus) based on calculations from prediction equations showed that the testes size of the buffalo bull was half that of a domestic bull of similar body weight.

Milk yields determined by a lamb-suckling and an oxytocin technique were compared using a control group of four ewes. Both methods showed a similar linear decrease in yield with advancing lactation, but the oxytocin method gave 23% more milk presumably because residual milk was included.

When the diet of lactating ewes was changed so that the amounts of hay and commercial concentrates were reduced in favour of flaked maize, such severe acidosis developed when 39·5% of this food was introduced abruptly or 53% more gradually over one week, that the trials were discontinued.

Rolled barley, which probably ferments more slowly, was therefore used instead of flaked maize. Levels up to 62·9%, gradually introduced over a period of 3 weeks, also produced acidosis whose severity varied greatly in individual ewes.

Milk yield was also determined by the oxytocin technique for ewes receiving normal diets followed by those rich in rolled barley, and the milk was analysed for fat, protein and lactose. The composition of the milk was extremely variable during rolled barley feeding, but there was an indication of an increase in the percentage of crude protein and also fat, after a marked fall in the latter in the milk of two ewes with the change to the low-fibre diet.

Diet had little effect on yields of milk and its components but, on the rolled barley diets, the rate of decrease of these yields was arrested (or even reversed in the case of fat), with a high degree of significance (milk yield P < 0·05, fat yield P < 0·01, protein yield P < 0·01). These observations are discussed, in the light of knowledge on the effect of diet on molar proportions of volatile fatty acids in the rumen.

Certain aspects of puberal development and reproductive performance in Clun Forest ewe lambs with a wide range of birth dates were investigated during the two seasons 1969–71. Of 33 ewe lambs born in the spring of 1969, 26 exhibited their first oestrus at a mean date of 8 November 1969 ± 2·5 days, the mean age being 228·3 ± 2·4 days and the mean body weight 36·3 ± 0·9 kg. The lambs which failed to breed in their first year, together with lambs born in the autumn of 1969, attained puberty during the autumn of 1970. Twenty-three ewe lambs carried foetuses to term in the spring of 1970 and had a mean lambing rate of 113·0 ± 7%. Of 84 ewe lambs born in the spring of 1970, 73 attained puberty in the first year of life at a mean date of 11 November 1970 ± 2·7 days, the mean age being 223·7 ± 3·0 days and the mean body weight 32·2 ± 0·5 kg. Cyclic activity of ewe lambs born in 1970 was recorded throughout their first breeding season. They experienced their last oestrus of the season at a mean date of 24 January 1971 ± 2·2 days, the mean age being 296·9 ±3·9 days and the mean body weight 32·4 ± 0·6 kg. The mid-breeding season was 18 December 1970, coinciding with the shortest days, and the mean number of heats exhibited throughout the season was 5·15 ± 0·24 per lamb.

Marked individual variation existed in age and body weight at puberty and in breeding activity, largely due to differences in date of birth and growth rate during rearing. Ewe lambs born early tended to experience their first oestrus earlier in the season than late born lambs but they did so at a higher age and heavier body weight. Fast growth rate and earliness of puberty were associated with extended duration and enhanced regularity of cyclic activity. Time of birth was clearly of fundamental importance in relation to the onset and duration of breeding activity in the ewe lambs included in the present study.

Adult rams of three breeds were found to vary consistently in the proportion of ewe lambs which they detected in oestrus, rams of the lambs' own breed being most efficient.

Two 16-week experiments with lactating Ayrshire cows were conducted to study the effect on milk production of replacing barley with dried molassed sugar-beet pulp on an equal dry-matter basis. The cows on all treatments received equal weights of hay, groundnut cake and minerals but the contents of barley and of sugar-beet pulp each varied from 0 to 80% in the different concentrate mixtures. The total daily intake of dry matter expressed as a percentage of live weight averaged 2·64 and 2·72 in the two experiments.

The average yield of milk in the two experiments was 18·8 kg/cow per day, and, within each experiment, the mean yields of milk and the contents of solids-not-fat and crude protein were not significantly different on the contrasting feeding treatments. The intake of water was significantly increased as the dried beet pulp replaced the barley but no major changes occurred in the proportions of V.F.A.S in the rumen liquor.

It is concluded that barley and dried molassed sugar-beet pulp had the same feeding value on a dry-matter basis when used in the production ration of milking cows. It is suggested that for most purposes barley and dried sugar-beet pulp are interchangeable on an equal weight basis, but for more precise feeding the two feeds should replace each other on an equal dry-weight basis.

The effects of seed size and spacing on growth, development and yield of lesser yam and the relationship between growth, development and yield in this yam variety were investigated in the 1967 and 1968 growing seasons. Larger seeds outyielded smaller ones both in the total and ware tuber yields. The seed size effect was associated with a difference in tuber number, leaf area duration and bulking rate. Mean tuber weight at harvest, decreased with the decrease in seed size. Total and ware tuber yields increased with the decrease in spacing distance. The spacing effect was associated with differences in leaf area duration and bulking rate per unit area. Final total dry matter produced per plant increased with the increase in both seed size and spacing distance but the dry matter produced per unit area decreased with the increase in spacing distance. Leaf area index and leaf area duration increased with an increase in seed size and decreased with increase in spacing distance. There was a greater positive relationship between total tuber yield and leaf area duration between tuber initiation and the final sampling period than that between it and absolute leaf area duration.

Live weights of 8764 calves born in seven herds in Cuba during the years 1966–8 were measured at birth and at approximately 3 months of age. Over 2600 were pure bred: Zebu (2002), Santa Gertrudis (435) and Charolais (212); the remainder were crossbred Holstein x Zebu (4955) and Brown Swiss x Zebu (1160).

Year, season of birth, herd and sex were associated with variation in mean birth weight in all breeds and crosses except Charolais in which no seasonal effect was apparent and in Brown Swiss x Zebu cross-breeds in which herd and sex effects were absent.

At 90 days there was a general tendency for calves born in late spring and summer to be heavier than those bom at other times. By this age, herd variation had subsided among Brown Swiss x Zebu cross-breds, and variation due to sex had ceased to be important among Charolais calves.

Estimates of heritability of birth weight ranged from 0·09 in Holstein crosses to 0·62 in Brown Swiss crosses, and of weight at 90 days from 0·05 in Brown Swiss crosses to 0·44 in the Charolais breed. Phenotypic correlations between birth and 90 days weights were of the order of + 0·25 while genetic correlations were positive for pure breeds and negative for cross-breeds.

In a survey of soils in South Central England matric suctions were measured frequently during 1962 and 1963. Results for the period October to May are given for sites lying above the influence of the regional ground water table and show the matric suctions to which the soils drain. Sandy soils drain within 2 or 3 days to a definite field capacity at about 50 mbar suction. Loams and clay loams, though from profile appearance regarded as freely drained, take up to about 1 week to drain to a fairly constant suction of 40–50 mbar, which can also be regarded as field capacity. However, suctions prevailing during this time are less – about 20 mbar. The prevailing suctions in clay soils are about 10 mbar in the topsoil (13 cm) and – 10 mbar in the subsoil (38 cm). These soils drain slowly but steadily when rain ceases and no definite field capacity is evident. For the sandy soils, loams and clay loams, the matric suctions characterize the upper limit of the available water capacity (AWC) of the soil. The values are less than almost all previous estimates or assumed values. For the clays the upper limit of AWC remains best estimated by field sampling at the time of interest.