A description is given of a double change-over, grazing trial designed to test the value of Hyparrhenia veld grazing for milk production during the rains.

Three feeds were offered to lactating cows, and the effects of qualitative differences between the feeds were measured on milk yields. The treatments were:

1. The addition of casein to the mixed lime sulphur-lead arsenate spray causes:

(a) an increase in the amount of soluble arsenic formed on the decomposition of the spray,

(b) no change in the reactions of the polysulphide sulphur.

2. The addition of lime to the spray:

(a) decreases the formation of soluble arsenical compounds,

(b) reduces the fungicidal value of the spray owing to its reaction with the sulphur liberated from the calcium sulphide.

3. The addition of lime-casein to the mixed spray is influenced by the composition of the lime-casein.

If much free lime is present:

(a) the formation of soluble arsenic is dependent on external conditions which in certain cases tend to decrease the amount of soluble arsenic formed,

(b) the fungicidal value of the spray is reduced as in 2 (b).

If slight excess of lime is present, or if the sample has badly carbonated:

(a) the amount of soluble arsenic is increased,

(b) there is little effect on the reaction of the polysulphide sulphur.

4. The addition of gelatine to the spray:

(a) increases the formation of soluble arsenic,

(b) has no effect on the reaction of the calcium sulphide.

5. The rate of decomposition of the mixed spray is retarded by the addition of casein, lime, lime-casein and gelatine.

From the agricultural point of view the amount of oxygen carried into the soil as gas dissolved in rain has considerable interest. Since all the oxygen required either for the bacterial activities of the soil or for the root aeration of growing crops must first pass into the dissolved state, the supply of this essential element in a form immediately available must exercise a proportionately beneficial effect on the manufacture of plant food or on the growing crop. Recent work on the decomposition of organic matter in the soil has shown that rainfall is one of the chief factors controlling bacterial activity, but that its influence is due to something more than the supply of water. The oxygen dissolved in the rain appears to be the missing factor. As very little systematic work seems to have been done in this direction, estimations of dissolved oxygen in rain at Rothamsted were made from time to time during the year 1915.

In the first of two experiments 45 ewes were treated on day 141 of gestation with either prostaglandin F2a or saline. Doses of 10, 15, 20 or 25 mg PGF2a failed to induce lambing earlier than in control animals. A further 50 ewes were similarly treated on day 144; neither dose level of PGF2a nor day of administration had any effect on the interval from injection to lambing compared with controls. In a second experiment 159 ewes were randomly assigned to one of four treatment groups as follows: (1) 20 mg oestradiol benzoate (ODB); (2) 16 mg dexamethasone; (3) 15 mg PGF2a; (4) 2 ml saline. Ewes were injected on either day 143 or 144 of gestation and on each of those days animals were injected either in the morning or evening. The mean times to induction of lambing were 38·6 ± 20·8; 44·2 ± 18·1; 83·5 ± 39·8 and 82·9 ± 43·1 h for the four treatments respectively. Neither day nor time of treatment had any significant effect on the interval to lambing. Both ODB and dexamethasone induced parturition earlier than PGF2a or saline (P < 005).

Two digestibility and balance experiments were carried out using 12 growing heifers to compare first and second cut silages fed alone or with supplementary barley or barley and urea, and to measure the effects of the addition of urea to silage and barley diets at three levels of dietary energy.

Digestibility of gross energy (GE), N and modified acid detergent fibre (MADF) was higher in first cut than second cut silage diets, and although D.M. intake was slightly lower, metabolizable energy (ME) intake was significantly higher. Inclusion of urea increased the apparent digestibility of N but had no effect on the intake of D.M. or ME. Nitrogen retention was significantly higher on first cut than second cut silage diets and was significantly increased by the addition of urea when N intake was low. The relationship between daily N retention (DRN), ME intake (DME) and digestible N intake (DAN) was represented by an equation of the form:

DRN = C–2·164DME+0·447DAN–0·00512DAN2+0·0487DMExDAN,

but when apparent biological value (ABV) of dietary protein was high DRN was linearly related to DAN. These equations were used to estimate requirements for digestible N. The results of rumen fermentation studies suggested that the response in DRN to urea inclusion could be partially explained by the low rumen ammonia values on silage and barley diets.

1. Analysis of spring mating data in 1955 indicated that the fall in conception rate associated with the use of older semen was a serious problem.

2. The fall in conception rate in 1955 was more marked in bulls of below average conception rate than in those with above average conception rate.

3. Results for groups used in two successive years indicate that this decline is highly repeatable.

4. Bulls which have ‘good keeping quality’ semen can be selected on the records of a previous season. Where there is no previous record, it has been shown that an individual can be classified as a ‘good keeper’ or a ‘poor keeper’ by measuring the fructolysis index of the semen on the day after collection. If the fructolysis index is above some minimum figure (1·05 mg. fructose/hr./109 sperm has been adopted in this case for second-day semen), the bull can be used for delayed inseminations with good prospects of success.

5. The best method of classification would appear to be: (i) initial classification by fructolysis index; (ii) subsequent rejection of bulls of low fertility in this group after fertility records are available.

An experiment was carried out over a 3-year period at two locations in the central rainlands of Sudan under rainfed conditions at one site and under supplementary irrigation at the other to study the effects of cultivars and cultural practices on growth and grain yield of sunflower. Four cultivars, namely, Manohurian, Peredovik, Hungarian-A and Hungarian-B and four intra-row spacings of 15, 30, 45 and 60 cm (in rows 60 cm apart) were tested with three sowing dates starting on 15 July and following at 15-day intervals. Manchurian outyielded the other three varieties under supplementary irrigation whereas under rainfed conditions the reverse was true. This was attributed to the relative earliness in flowering of the varieties and their moisture requirements. Manchurian was the tallest with the thickest stem and a larger head at both locations compared with the other three varieties. Under rainfed conditions, the early sowing date of 15 July gave a significantly higher grain yield than the other two sowing dates, with the last sowing date of 15 August giving significantly least. This is attributed to decreasing moisture availability with delayed sowings. But under supplementary irrigation the effect of sowing date was less marked. Contrasting effects of sowing dates on plant height and stem circumference were obtained under the two systems of production. Under rainfed conditions there was a decrease in plant height and stem circumference with delayed sowing, whereas under supplementary irrigation the reverse was true. A contrasting response of plant height to spacing was also obtained; wider intra-row spacing was associated with taller plants under rainfed conditions and shorter plants under supplementary irrigation. Wider spacing was associated with thicker stems and larger heads at both locations. On the evidence obtained, 45 cm intra-row spacing is recommended for rainfed planting and 30 cm intra-row spacing for irrigated production of sunflower.

This study was conducted in the central highlands of Ethiopia during 1990–92 to examine the effects of diet and partial suckling on lactation and reproductive performance of Boran (Bos indicus) cows. Primiparous Boran cows were allocated to dietary supplementation or no supplementation with either milking or partial suckling based on body weight at calving. All cows received grass hay ad libitum and the supplemented groups were provided with additional concentrate feed which supplied 222 g/kg DM crude protein and 10 MJ/kg DM energy. Calves were weaned at 8 weeks of age. Mean (±S.E.) dam calving and calf birth weights were 314±11·4 and 25±0·6 kg. Body weights at first postpartum oestrus and at conception were not affected by suckling. Supplemented cows however, were heavier at first oestrus (P = 0·06) and at conception (P < 0·01) than non-supplemented cows. Lactation length was longer (P < 0·01) and mean daily milk yield higher (P < 0·001) in suckled than in milked cows. Diet, however, did not influence either lactation length or daily milk yield. In suckled cows, mean daily milk yield declined sharply after weaning (week 9) and was lower by 38 and 43% of week 8 production in the supplemented and non-supplemented groups, respectively. The overall mean lactation yield was 212·4±64·6 litres; with a significant (P < 0·05) diet × suckling interaction effect. Concentrations of milk fat, total protein and total solids were not affected by either diet or suckling treatment. The postpartum anoestrus interval was longer (P < 0·01) in non-supplemented than in supplemented cows, but did not differ between suckled and milked cows. The percentage of cows cycling by 150 days postpartum was higher (P < 0·05) in supplemented than in nonsupplemented and in milked than in suckled (P > 0·05) cows. By this interval, a higher (P < 0·05) percentage of supplemented-milked (90%) cows cycled than in the other three treatment groups (48·5%). Pregnancy from the first insemination ranged from 45·5 to 63·6% in the four treatment groups. It was concluded that although partial suckling extended the postpartum anoestrus interval, lactation length and milk yield were improved. The negative effects of partial suckling on postpartum reproduction could be overcome with the appropriate dietary supplementation. The economic tradeoff between dietary supplementation, milk yield and reproduction has to be determined in partially suckled cows.

Samples of a Colombian criollo breed of cattle, the Blanco Orejinegro, and contemporary onequarter Jersey crossbreds were kept on a farm in the Andes. Records were included of all calvings which occurred over an 8-year period, giving totals of 1357 lactations from 514 purebreds and 424 lactations from 137 crossbreds.

Age at first calving was about 41 months for both breed groups. Cattle were milked twice daily by hand without calf at foot. Mean lactation yields were 220 kg (purebreds) and 612 kg (crossbreds). The repeatability and heritability of milk yield are estimated. Statistics are also given for lactation length, daily yield, calving interval and butterfat percentage. The effects on yield of age at first calving and calving year were negligible, but month of calving was important.

It is concluded that the low level of performance was partly due to failure to eject milk without calf at foot, at least in the case of the purebreds, and that this was itself mainly due to genetic causes. The improvement in yield due to crossbreeding was not accompanied by a loss of other desirable traits. The development of the local cattle industry is discussed in the light of these results and the general characteristics of the region.

1. Dressings of 12–100 lb. borax per acre resulted in marked temporary ‘yellowing’ of bean seedlings. Dressings of 25 lb. or more depressed the stand and reduced the yield.

2. Determinations were made to ascertain the distribution of boron within the treated plants and to measure the uptake of boron from the soil. The relevant figures are quoted in the text.

Experiments were conducted to determine the effects of zinc (Zn) supplementation on the performance and mineral metabolism of lambs fed forage-based diets containing 15–23 mg Zn/kg. In Expt 1, 20 lambs were fed a good-quality orchardgrass (21·4 mg Zn/kg) or a low-quality tall fescue (14·7 mg Zn/kg) hay and supplemental Zn (as ZnO) at 0 or 30 mg/day in a 2 x 2 factorial arrangement of treatments. Forage was fed ad libitum and all lambs received 92 g dry matter/day of a corn-based supplement which served as the carrier of the supplemental Zn. Lambs fed orchardgrass hay had a greater (P < 0·01) dry matter intake and average daily gain for the 42-day study. Zinc supplementation did not affect performance of lambs fed tall fescue but tended to improve performance in those fed orchardgrass hay. At the end of the 42-day growth phase, lambs were placed in metabolism crates for a 7-day total collection of urine and faeces. Supplemental Zn increased intake (P <0·01) and faecal excretion (P <0·01) of Zn. Absorbed Zn was greater (P < 0·05) for lambs fed supplemental Zn. There was a tendency for a forage × Zn interaction (P < 0·10) for urinary Zn excretion and retention. Urinary Zn excretion was highest in lambs fed tall fescue hay supplemented with Zn. In Expt 2, 24 lambs were fed diets consisting of ad libitum chopped tall fescue hay (23 mg Zn/kg) and 176 g/day of a corn and mineral supplement which served as the carrier of the Zn treatments. Treatments were no supplemental Zn or 30 mg/day supplemental Zn as ZnO, ZnSO4 or Zn methionine. Zinc oxide and ZnSO4 supplementation increased average daily gain (P < 0·10) and decreased feed/gain (P < 0·10) for the 56-day study when compared to control and Zn methionine-supplemented lambs.

The experiment reported here involved thirty-two pigs from birth to bacon weight. During the 9 weeks before weaning sixteen pigs were reared on damp cold floors in a cold building and sixteen were reared on dry cold floors in the same building. After weaning all the floors were kept dry.

Before weaning four out of the sixteen pigs in each treatment died, but only one, which was in the wet cold floor group, was suspected of having a liver disease which has been described by Naftalin & Howie (1949). A greater incidence of this disease was expected to occur under the cold environmental conditions of the experiment.

After weaning one deformed pig was killed and three other pigs were killed at 40 weeks old. The latter three all had the liver disease. There was evidence that the disease had developed after the pigs were weaned and this indicated that it cannot necessarily be prevented by the provision of dry conditions in a cold house. The growth curves of two of the three pigs fitted the hypothesis that the disease is associated with cold environmental conditions, but the growth curve of the third suggested that it might have contracted the disease during the summer when the minimum air temperature was 54° F.

The possibility was discussed that the liver disease is caused by a virus or low nutritional status interacting with the effects of cold environmental conditions.

The two pre-weaning treatments had no dissimilar effects upon the piglets' weaning weights, blood haemoglobin levels and appetites for solid food, nor did they have any differential effect upon the growth rates and efficiencies of conversion of food to flesh of the pigs which survived to bacon weight. The bacon carcasses from the pigs born and reared to weaning on wet cold floors were shorter and fatter than those from pigs born and reared on dry cold floors. No explanation could be offered for this difference in carcass conformation.

The rates of heat loss from a constant temperature water-bath to an uninsulated concrete floor upon which pigs had not lain were halved by the provision of ½ in. depth of chopped straw bedding. They were also halved if the measurements were taken after pigs had recently been lying on the bare floor, and under these circumstances the provision of ½ in. depth of chopped straw bedding cut the heat losses even further.

The objective of the current experiment was to determine the effects of high-concentration phytase (5000 FTU/kg) feeding to diverse lines of chickens fed phosphorus (P) adequate maize–soybean meal diets (4.5 g/kg non-phytate P) on the performance and intestinal immune function. Performance was measured for outbred broiler (Ross 308) and inbred Fayoumi lines over 0–21 days, and duodenum and ileum were harvested for the determination of mucin-2, interleukin (IL)-1β and IgA mRNA by quantitative reverse transcription polymerase chain reaction. Over the 0–7-day period, there was a significant line × diet interaction, as high phytase supplementation increased broiler average daily gain (ADG), but had no effect on Fayoumi ADG. Treatment of diets with phytase increased expression of the mucin-2 gene in the duodenum mucosa. There were significant interactions between line and age, and line, diet and age on duodenal expression of the IL-1β gene as phytase supplementation of the broiler line reduced IL-1β in comparison to control fed broilers without change in the Fayoumi line. Overall, the addition of a high concentration of phytase to broilers fed adequate concentrations of non-phytate P resulted in improved growth performance early with a reduction in this effect over time. Mucosal mucin-2 expression was increased with high-concentration phytase feeding across both lines, but IL-1β mRNA expression was reduced in the duodenum of broilers fed high concentrations of phytase, suggesting that the increased performance noted might be related to decreased inflammation.

On the feeding regimes examined, i.e. hay ad libitum restricted hay and restricted hay with supplementary glucose, the quantities of extracellular water-soluble polysaccharides in rumen liquor were small (3·6–9·0 mg/100 ml) and could have originated from the diet or the saliva as well as from microbes. The polysaccharides extracted with hot water (fraction B) and acetate buffer (fraction C) were also small in amount in the rumen liquor from sheep on any of these diets (less than 56 mg/100 ml) and were composed of rhamnose—containing polysaccharides, starch-like polysaccharides and xylose polymers. Syntheses of these B and C polysaccharides were found with the hay and glucose diet but the quantities involved were small (12·27 mg/100 ml rumen liquor). Degradation of the polysaccharides occurred at 4–6 h after feeding. The consistently high ratios of rhamnose to hexose in the B and C polysaccharides from rumen liquor suggest that these were microbial in origin. Iodine-staining organisms in the rumen liquor were a small proportion of the total and showed no increases after feeding.

Muscle growth was studied for 64 female, 64 castrated male and 64 intact male indigenous Nigerian pigs at 16 ages between birth and 672 days of age. Highly significant (P < 0·001) age differences were obtained for the proportion of total muscle, each muscle group and the 13 individually dissected (seven hind limb, two spinal column and four fore limb) muscles. Sex differences were significant (P < 0·05) for the proportion of total muscle and some of the individually dissected muscles.

A highly significant (P < 0·01) increase in the rate of muscle deposition for each muscle group occurred between 56 and 112 days. Muscle deposition continued at the same rate up till 224 days of age before the peak was attained between 280 and 392 days when the average body weight was between 40·8 and 61·2 kg. A continuously significant (P < 0·05) decline in the rate of muscle deposition was obtained beyond 392 days of age. Growth coefficients b calculated from the linearly transformed allometric equation Y = aXb were generally higher in the early phase of growth (0–168 days) than in later phases considered. However, growth coefficients obtained for the whole period revealed that apart from M. gastrocnemius, the other hind limb and spinal column muscles exhibited either ‘high’ or ‘average’ growth impetus. The fore limb muscles had growth coefficients significantly (P < 0·05) less than 1·00 and were therefore classified as having ‘low’ growth impetus. Generally, the intact male pigs showed superiority to the female and castrated male pigs in muscle growth and development.

Two strains of commercial layers, 42 weeks old, were fed ad libitum, 85 and 70% of ad libitum for five 28-day periods to study the effects of feed restriction on body weight, carcass characteristics, laying performance and mortality. There were highly significant strain effects on all traits (P < 0·01) except dressing percentage. Period differences were also observed for egg production, egg weight and feed efficiency. In addition, in all cases the relationship between period and these traits was non-linear and was affected by strain or treatment.

Feed restriction had significant effects (P < 0·01) on all traits except dressing percentage and mortality. Feed restriction to 70% of ad libitum reduced egg production, egg weight, body weight and feed consumption and improved feed efficiency. However, in most cases there was no difference between ad libitum feeding and 15% feed restriction.

Strain × treatment interaction had significant effects on egg production and feed efficiency.

An analysis of pig carcass composition was carried out, using data for 11 genetic source populations in the Meat and Livestock Commission's Commercial Pig Evaluation (CPE). The data were from years 3–5 of CPE and a total of 720 carcasses were involved. Weights of dissected tissues and parts were considered simultaneously, and the effects of growth, source population, sex, feeding regimen and time period were incorporated into an integrated model, the multivariate allometric development model.

Canonical variates were constructed for each of the classifying factors except time period, and the residual variation in carcass composition was analysed by principal component analysis. The first canonical variate for source populations was interpreted as a tissue distribution characteristic associated with the distribution of lean between joints in the dorso-cranial and ventro-caudal regions of the carcass. It accounted for 39% of the variation between source populations. The second canonical variate was associated with the ratio of subcutaneous fat to lean in the carcass, and accounted for 20% of the variation between source populations. The results explain the bias found in predicting the proportion of lean tissue in a carcass from subcutaneous fat thickness (P2).

In a graphical display of differences between source populations, nine were shown to be distinct, with only two intermediate and not clearly differentiated from some others. The interpretation of canonical variates and the relative positions of the populations were closely related to those obtained from the analysis of production and grading characteristics in the first paper of the series.

The physical wool characteristics of 268 Iraqi Awassi ewes were studied in 1963, as well as the relationship between some of these traits. The overall average grease fleece weight, clean wool percentage, staple length, fibre length, fibre diameter and degree of crimp were 3·77 lb., 84·85%, 16·47 cm., 17·37 cm., 33·32/t and 4·18 crimps per 2 cm. respectively. These attributes class the Awassi wool as a carpet wool.

Age proved to have no significant effect on any ofthe traits examined. Significant positive correlations were found between grease fleece weight and fibre length and between number of crimps and fibre diameter, while a significant negative correlation was found between clean wool percentage and fibre length.

Seed extracts prepared by soaking ryegrass seed in water were tested for their ability to suppress germination. The tests were carried out by sowing seed on to sand-filled basins moistened with seed extract.

Extracts prepared from the two diploid varieties, S. 24 and Hora and the tetraploid variety Terhoy were able to reduce both the rate of germination and the final percentage germination when applied to the sown seed. The details were as follows, (i) When S. 24 perennial ryegrass seed was used to obtain the extract inhibition was found to be related to the concentration of the extract, (ii) The final germination of diploid seed was reduced by 16% in the presence of its own seed extract and by 27% when tetraploid seed extract was applied, (iii) The final germination percentage of the tetraploid seed was reduced by 14% in the presence of either its own extract or that prepared from the diploid seed, (iv) Simple chemical tests carried out on the seed extract, although not conclusive, gave some indication that the inhibitory substance may have been a member of the alkaloid group.

The nutritional importance of a foodstuff in a diet depends on the composition of the raw foodstuff, the amount that is usually consumed and the extent to which nutrients are destroyed or lost during preparation of the diet.

Most Nigerian foods have to be prepared and cooked before they can be eaten. A lot of food preparation in Nigeria involves soaking, steeping, boiling, frying and roasting; at each stage of the preparation, some of the nutrients may be discarded or destroyed, while in some cases toxic substances may be discarded (Oke, 1968)