As part of their normal behaviour, buffaloes need to wallow in water or mud for a period of the day and, in general, show a greater affinity for water than other domestic ruminants. It has been reported (McFarlane, 1971) that buffaloes turn over more water than other domestic ruminants. This, in turn, should make them more susceptible to deprivation of water, even for short periods. Requirements for water are also known to change with the physiological state of animals. The experiment described in this paper was carried out to compare the effects on the daily turnover of body water in growing, pregnant and lactating buffaloes, under normal management, when denied wallowing and when drinking water was restricted.

Maize or lucerne silages were fed to two groups of cows in a large dairy herd. Metabolic profile tests carried out during the trial showed that abnormal blood chemistry such as might lead to production disease did not occur in either group.

The results of feed analysis and digestibility trials showed that the two silages provided equal quantities of digestible energy but that the lucerne silage provided more digestible protein than the maize silage. Blood glucose concentrations were similar in both groups of cows but serum urea and albumin concentrations were significantly higher in the cows fed lucerne silage than in those fed maize silage. There was also evidence that lucerne silage provided slightly less available phosphorus but more calcium than the maize silage.

It is concluded that maize silage, as used in these experiments, showed no tendency to lead to production disease, and furthermore the metabolic profile test provided additional information to feed analysis in making this assessment.

1. Four varieties of marrow stem kale, three of thousand headed kale, Hungry Gap Kale, Rape-Kale and five other rape varieties were sampled at two centres in mid-Wales and separate leaf and stem samples analysed for manganese, molybdenum and boron. Similar samples of four varieties of marrow stem kale, two of thousand headed kale, Hungry Gap Kale, Rape-Kale and two other varieties of rape were taken from two further centres and prepared with the most stringent precautions to prevent contamination. Iron, copper, zinc and lead were determined in these samples.

1. Individual birds have a characteristic date for the termination of the egg laying cycle.

2. The date of cessation of production at the end of the pullet year is not a reliable indication of the bird's potentiality in this respect.

3. The longer the birds are retained the greater is the chance of distinguishing the true date.

4. Individual dates for the termination of the cycle occur at so many points throughout the total range (from July to December) that this must either indicate a multiple factor situation or that the genes involved show a considerable range of expression.

Bleasdale & Nelder (1960) refer to several models which have been used in studying the relationship of yield and density in crop plants and indicate that they regard as most satisfactory the equation:

where ω = yield/plant, ρ = number of plants/unit area and A and B are constants. The estimation of the constants for any given case is a very unattractive arithmetic exercise requiring a fairly large number of observations and a tedious iterative calculation; Nelder (1961) has discussed the least squares fit with the equation in the form

which may readily be derived from (1) by the substitutions

The data in the present case do not justify attempting this process but some progress can be made by the substitutions

by means of which it is easy to derive from (1) that

Relations were developed between the carrying capacity or production of fat-corrected milk (FCM)/ha and various measures of pasture growth for six pasture treatments grown in a subtropical environment. The pasture and animal production variables were obtained from pastures grazed on a weekly rotation using stocking densities which were varied so that a target weight of leaf material remained on the pasture at the conclusion of each grazing.

Within a treatment, there was a curvilinear relation between the rate of leaf growth and carrying capacity, with the greatest efficiency of conversion at the lowest leaf growth rates. This relation generally varied between pasture treatments because of differences in grazing intensity. There was little variation in the production of FCM per cow between grazing periods within a treatment, reflecting the experimental technique of matching the stocking density to the amount of forage. Consequently FCM/ha largely mirrored the stocking density with some adjustment for differences in production per cow caused by differences in grazing intensity between treatments. Production of FCM/ha was affected more by a unit change in residue leaf yield than by a unit change in leaf yield before grazing.

Using the rate of leaf removal (intake plus grazing losses) per cow as an inverse index of grazing intensity, it was apparent that the use of variable stocking densities to obtain specified residue yields after grazing did not necessarily equalize the grazing intensity because the rate of leaf removal per cow varied according to the before-grazing leaf yield. Also soiling by dung caused differences in the acceptability of forage for grazing, resulting in differences in grazing intensity between pastures with the same yield and stocking density.

The total metabolism of the pregnant goat remains at a steady rate from the 4th to the end of the 13th week of pregnancy. It increases steadily from the 14th to the 21st week, when a value is attained about 50 per cent, above the rate at the 14th week. Just before delivery the rate drops slightly. The increased metabolism is due partly to the increase in the mass of active protoplasm and partly to the stimulus exerted by the growing ovum on the maternal tissues. This stimulus tends to fall off slightly in intensity in early pregnancy and increases markedly in late pregnancy.

Post partum the total metabolism drops suddenly and continues to fall until the end of the 5th week; but the metabolism per unit of weight increases steadily until the 4th week and then declines. This increased activity of the maternal protoplasm is due to the processes of involution and repair.

In early pregnancy the increasing intra-abdominal pressure cuts short fermentation of food and causes the R.Q. to be higher in the pregnant than in the non-pregnant animal. As the pressure increases it begins to impede slightly the evacuation of the rumen so that the food ferments more thoroughly and the R.Q. falls slightly. After parturition the low intra-abdominal pressure aggravated by the laxity of the abdominal walls allows the food to remain longer in the rumen so that fermentation is more thorough and the R.Q. lower than in late pregnancy.

Corolla colour in chickpea (Cicer arietinum L.) is white or various shades of pink or blue (Smithson, Thompson & Summerfield, 1985). Normally, a leaf axil subtends a single peduncle bearing a single flower but ‘double-flowered’ types, where a pro-portion of the peduncles subtends two flowers, are not uncommon and produce 6–11 % more seed yield than the normal single-flowered type (Sheldrake, Saxena & Krishnamurthy, 1978)

1. Selections from a cross of varieties of Triticum vulgare and T. Turgidum have been backcrossed repeatedly to the turgidum and vulgare parents and selections of turgidum and vulgare type respectively made within each series.

2. The yield and morphological stability of turgidum- and vulgare-type selections from the straight cross have been compared with those of selections backcrossed up to four times to T. turgidum and T. vulgare respectively.

3. In the case of backcrosses to T. Turgidum the highest yielding selections have been derived from the most frequently backcrossed material, but the vulgare-type selections from the straight cross have outyielded those from the material backcrossed to T. vulgare.

4. An analysis of the yield components of the parents and of the most promising selections, in terms of ears per plant, spikelets per ear, grains per spikelet and 1000-grain weight, has shown no evidence of a combination of the characters determining the high yield of the parents in these high yielding selections.

An account is given of artificial insemination of 733 grade cows in Kenya from January 1936 to August 1939. 76·8% of the cows inseminated calved, with an average of 1·88 inseminations per conception. The different doses and dilution of sperm used gave very similar results, as did two inseminations, compared with one insemination, in a single heat period.

In field drainage waters, Fe(II) can be oxidized to Fe(III), which is precipitated as iron ochre. At a farm near Aberdeen, Scotland, ochre is precipitated both chemically and biologically. The precipitation was delayed using the antibiotic D-threo-chloramphenicol and Cu(II) ions. Iron deposition was delayed on glass slides coated with copper filings. It is suggested that the incorporation and slow release of substances which inhibit ochre formation, from drainage pipe material, would be a valuable method of controlling the ochre problem.

In Morocco, sugar-beet seed production represents a new challenge to meet the main breeding programme goals. The identification of a suitable zone for plant vernalization represents a bottleneck for seed production. This study aimed chiefly at evaluating the vernalization aptitude of 18 sugar beet half-sib progenies. Trials were conducted during three selection cycles in a specifically chosen environment. The experimental site of Merchouch is 40 km south-east of Rabat city. Field trials design is according to an open-pollinated experimental block. Yield components and five phenological traits were recorded during the growing cycle and at the plant maturation. The variance analysis showed a significant effect of the selection cycle on the phenological traits and grain yield. The plant cycle duration increased by 10.7 days between the first and the third selection cycles. According to the principal component analysis and the hierarchical clustering, F2, F5, F6, F9, F10, F11, F14 and F15 half-sib progenies are described as long cycle and high grain yield families. Grain yield reached 257.3 g per plant, the duration to maturity 350.6 days and the germination rate 93%. The three selection cycles and the suitability of the site vernalization conditions are potentially effective for seed production progress. Our results are relevant as they established an adequate site for the sugar beet seed production. The half-sib selection is a valuable method for sugar beet germplasm enhancement.

A method that allows the effect of temperature treatments on plant quality to be quantified is described. The proposed method is based on the analysis of temperature regions for plant quality characteristics and enables an easier and more precise analysis of the influence of day and night temperature on plant growth and development. Plant quality may be evaluated by the combination of any number of plant characteristics. The proposed method can assist growers in determining what temperature regimes are necessary to produce acceptable-quality crops on specified days.

In tropical regions, water stress is one of the main causes of the reduction in forage productivity, and irrigation strategies can mitigate the problem, especially for highly productive species. The objective of this study was to evaluate the effects of irrigation, genotype and plant size on productive responses and water use efficiency (WUE) of elephant grass (Cenchrus purpureus [Schumach.] Morrone), in the rainy and dry season. The experimental design was randomized in blocks, arranged in split plots, the main plots were established based on the use of irrigation and the subplots were the tall-sized genotypes (IRI 381 and Elephant B) and dwarfs (Taiwan A-146 2.37 and Mott). The genotypes were evaluated for two years and harvested every 60 days. Water use efficiency, total forage accumulation per year and harvest, forage accumulation rate and forage density were evaluated. There was a significant difference between the genotypes in terms of total forage accumulated (P < 0.05). The most productive genotype was IRI 381, which showed the greatest total forage accumulation (42 168 kg of DM/ha in two years) in the irrigated plots. During the rainy seasons, IRI 381 stood out in terms of forage accumulated (24 667 kg of DM/ha). Irrigation favoured increases in forage accumulation around 60%, in both years of evaluation. Irrigation and plant size influenced the productivity and WUE of elephant grass harvested in 60-day intervals. Tall genotypes and Taiwan A-146 2.37 (dwarf size) stood out in most of the productive traits analysed, while Mott was highlighted by its forage density.

1. ‘Wet’ soil plants had greater tiller and leaf number, and were also taller than ‘dry’ soil plants.

2. The straw and grain dry weight, and grain weight as percentage of straw weight, were greater in ‘wet’ soil plants than in ‘dry’ soil ones.

3. Wet soil hastened the time of ear emergence.

4. Increasing the phosphate supply, on the whole, tended to increase the tiller and leaf number, weight of straw and grain and also hastened time of ear emergence.

5. Under ‘wet’ soil conditions high phosphate application is not necessary.

6. The yield of grain at high phosphate level of plants grown on ‘dry’ soil is significantly lower than the yield from those grown on ‘wet’ soil with low phosphate application. This suggested that under ‘dry’ soil conditions availability of nitrogen, as well as of phosphorus, is a limiting factor.

The phenological development from sowing to flowering of the eaxly maize hybrid INRA 200 is related to the weather conditions. Plot trial data from Wytham, near Oxford, England, and weather information from that and nearby sites formed the basic data.

The mean rate of development per day from sowing to emergence is related by linear correlation analysis to the mean values of soil temperature at 5 cm depth and soil moisture deficit. A range of temperature thresholds for emergence development exist, which depend upon the soil moisture, and which differ from the true physiological threshold.

Between omergence and flowering the mean rate of development per day is related by linear correlation analysis to mean air temperature, solar radiation and potential transpiration estimated from weather data. All correlations are significant, but the parameters which combine radiation and temperature are statistically better.

Copper deficiency in cattle is a world-wide problem. A deterministic digital computer simulation of copper metabolism was applied to cattle and especially to their response to dietary copper. This simulation was verified by comparison with published data on copper metabolism of cattle. Copper loss under conditions of dietary deficiency was governed largely by the rate of hepatic loss of copper. Copper stores were replenished gradually when the animal was returned to a normal diet. The increased copper consumption associated with increased total digestible nutrients (TDN) during lactation compensated for loss of copper in milk. Cattle have a very efficient mechanism for extrahepatic copper homeostasis by storage of excess copper in the liver, which can then be withdrawn in future deficiencies.

1. The age of 210 days was selected for calf weight standardization. In general this is a preweaning weight under prevailing Jamaican conditions, and it represents a compromise between a very early age (90–120 days) which would reflect closely the milking ability of the dam, and the actual weaning age (approximately 260 days) when the grazing management of the herd would constitute a major unpredictable variable.

2. Either one or two weighings taken between the fourth and the ninth months of life was used to standardize calf weights to 210 days of age. In either instance for groups of calves, a mean estimate was derived which was very close to the actual mean 210-day weight, and which was suitable for data relating to groups of animals.