Field experiments were conducted at the International Institute for Tropical Agriculture, Ibadan, Nigeria, during two cropping seasons, with two cultivars of climbing cow peas (Vigna unguiculata (L.) Walp. subspecies sesquipedalis) cv. FARV-13 and TVU-1209. The work investigated their yields when intercropped with maize, which served as live support.

The results showed that there were varietal differences in the cow-pea response to method of planting. Under the intercropped systems, highest dry-matter yield was obtained when TVU-1209 was planted on the same hill with maize while similar yields were obtained with FARV-13 planted in alternate hills with maize. TVU-1209 did not increase maize lodging except when planted in alternate hills with maize, but FARV-13 significantly increased maize lodging under all planting methods. Consequently, FARV-13 reduced maize yields more than TVU-1209.

Neither pod length nor pod weight was affected by the planting. Highest yields from both cow pea and maize combined were realized from TVU-1209 planted between rows of maize. The yield of FARV-13 cow pea intercropped with maize did not show any advantage due to intercropping over sole crop of each.

The general equation, y = 70 log x − 15, connecting y, the digestibility coefficient, to x, the percentage of crude protein in the dry matter of the feed of ruminants, which was proposed in an earlier paper, has been shown to fit all the directly determined world data for cattle, sheep and goats which have been published by Schneider (1947). It is applicable to rations composed of both single and mixed feeds for it is the total percentage of crude protein in the ration which determines its digestibility.

The equation is of general application, irrespective of climate or feed, and for the first time a link is provided between the large bulk of data from temperate regions and those hitherto neglected and apparently aberrant data from the tropics and subtropics.

The equation adequately explains a large part of the variability of results obtained by the ‘by difference’ method. In particular, attention is drawn to its value in explaining ‘associative effects’ in mixed feeds.

It would seem to have several practical applications; one being the ready determination of the average digestibility of crude protein in rapidly growing grasses and herbages at different stages of development; another being the evaluation of average crude protein digestibility of single or compound feeds in those parts of the world where adequate facilities for digestibility studies are not available. It can also be used in computing maintenance and production rations for meat and milk.

Broiler chicks reared under three environmental temperatures (7·2, 23·9 and 35 °C) in the Southeastern United States of America in 1988/89 were precision-fed to levels which were c. 70, 90, 110 and 130% of the consumption observed in ad libitum-fed controls at 23·9°C, in order to examine the limitations imposed by feed intake upon growth rate, feed efficiency and survival. Ad libitum-fed birds that were housed at 7·2, 23·9 and 35 °C consumed feed at 12·1, 9·4 and 8·5% of body weight, respectively. Liveweight gain of birds consuming feed ad libitum was depressed by 26 and 46% in the 7·2 and 35 °C environments respectively. Increasing feed intake by precision feeding exceeded ad libitum consumption in the 23·9 and 35 °C environments, but not at 7·2 °C. Consumption of feed above thermoneutral ad libitum levels failed to increase (p <0·l) liveweight of carcass gain. Ration digestibility and dressing out percentage declined (P < 0·05) at the higher feed intake levels in the 7·2 °C environment.

The carcasses of 20 Landrace, 20 Hampshire and 20 Duroc Jersey barrows were dissected in order to study the influence of the breed on tissue weight distribution.

After weaning, at 56 days of age, the animals were allocated to individual pens and fed a standard diet containing 18% crude protein and 13 MJ ME/kg, until they reached their designated slaughter weight.

The Landrace and Hampshire pigs were slaughtered between 60 and 115 kg and the Duroc Jersey ones between 40 and 115 kg live weight. The right half carcasses were completely dissected using strictly anatomical criteria. Individual muscles were classified into eight anatomical groups (Carden & Goenaga, 1977).

The results were examined by covariance analyses utilizing the allometric equation. Carcass tissue composition was studied using the weight of the dissected side as covariate. When muscle: bone ratio was examined, the weight of total side muscle was used as the independent variable. The growth of different parts of a tissue relative to the corresponding whole tissue was studied.

Concerning carcass composition, there were significant breed differences in muscle and fat contents and in the muscle:bone ratio.

Breed differences were found in muscle distribution. The 6 values of muscle groups 1 (proximal hind limb), 2 (distal hind limb), 6 (distal forelimb) and 7 (muscles connecting forelimb to thorax) were statistically different as were the adjusted means of groups 3 (spinal column), 5 (proximal forelimb) and 8 (muscles connecting forelimb to neck and intrinsic muscles of neck and thorax).

Significant differences were also found in bone weight distribution. Slope values of the tarsals, os coxae, scapula and sternum were statistically different. Adjusted means of tibia-fibula, sacrum, spinal column, radius-ulna, carpals and ribs were also significantly different.

Finally, there were breed effects in the distribution of fat, the relative weight of subcutaneous and of intermuscular fat being statistically different.

Part I. The changes in amount and composition of the mammary secretions of a heifer in its first pregnancy are recorded.

The most striking feature is the abrupt appearance at half-way through pregnancy of a viscous secretion consisting largely of globulin.

These results are extended to the primiparous and to the multiparous “dry” goat.

Colostrum is shown to be normal milk admixed with the globulin secretion.

The significance of the globulin is discussed. Reasons are advanced indicating that it may be an excretion of the cell when it changes from the growth phase to the secretory phase of life.

The stimulus to mammary growth is briefly discussed.

A partial analysis is given of the secretion from the tubercular udder of a cow. This secretion resembles somewhat the secretions of mid-pregnancy.

Part II. Instances are given of cases of premature lactation in the goat, and analyses are recorded of these secretions.

These cases are discussed in the light of Part I of this paper, and their bearing on the corpus luteum theory of mammary development is considered. The sexual precocity of the goat is such that the mammary growth may in all cases have been due to luteal influences.

A few cases of premature lactation in the cow are also reported.

The theory that the foetus produces a hormone inhibiting lactation is shown to be unnecessary.

Characterization of plant varieties is traditionally based on phenotypic observation. However, some varieties have very similar morphological characteristics, which make it difficult to distinguish between them. The present study employed 15 microsatellite markers distributed across all linkage groups (LG) of the chickpea genetic map to characterize 32 commercial chickpea cultivars and determine the usefulness of these markers for cultivar identification. These markers showed a high level of polymorphism; a total of 154 different alleles were detected, with a mean of 10·3 alleles per locus. The polymorphic information content (PIC) value ranged from 0·455 to 0·897. All the markers, with the exception of TA130, TA135 and TA144, were considered to be informative (PIC>0·7), indicating their potential usefulness for cultivar identification. A subset of markers (TA186, TA200, TA106, TA113, TA117 and TA30) was sufficient to identify all the cultivars studied. In order to confirm their discriminatory power, 16 unreleased chickpea cultivars (V1–V16) were screened and all of them presented different patterns. Therefore, these microsatellites can be regarded as a reference set for chickpea cultivar identification and their profiles can be used as a DNA fingerprint for each registered cultivar, avoiding redundancy of identical cultivars as well as to protect breeders' rights.

Laboratory studies were conducted on four soils to ascertain the effect of P content and texture on the capacity factor (P buffering capacity) of soils and in turn the effect of these factors combined with moisture content of soil on the diffusion coefficient of P (Dp). A glasshouse experiment was conducted to study the relationship of Dp with P uptake by maize and wheat. The buffer capacity decreased by the application of P in all four soils. There was a significant negative correlation between buffer capacity and Olsen's extractable P but positive correlation with other soil factors. The relative influence of different soil variables on the buffer capacity was in the order: free iron > percentage clay > exchangeable aluminium. The Dp value increased significantly with applied P, the maximum (3·2-fold over control) being in Tolewal loamy sand. The increase in clay and moisture content of soil also increased the Dp value. The drymatter yield and P uptake was significantly correlated with Dp, the r value being higher at later stages of growth of maize and wheat.

Catchment basins were prepared within bunded fields from 1986 to 1988, with ratios of catchment area to cropped area of 1:1 or 2:1. Annual rainfall varied from 102 to 282 mm.

Run-off from the catchment basins increased water storage in the cropped areas by 55 and 43% of the rain falling on the catchments in the 1:1 and 2:1 treatments, respectively. Yields increased considerably on a cropped area basis by water harvesting, but not always sufficiently to compensate for the loss of cropped land. Averaged over all trials, yields from the 1:1 treatment were 95% of the control yields. Yields-in the 2:1 treatments were reduced by waterlogging damage.

The cost of catchment set-up was low compared with the reduced seed and ploughing costs in the water-harvesting treatments, resulting in 18 and 31% reductions in overall costs for the 1:1 and 2:1 treatments, respectively. Net benefits for the 1:1 treatment equalled or exceeded those of the control, but were 32% lower for the 2:1 treatment. Within-field water harvesting with a 1:1 crop: catchment ratio thus reduced risk by reducing investments in seed and animal draught power, whilst maintaining yields and net benefits, suggesting that it could be of considerable benefit to farmers in an environment with a high risk of crop failure. Catchment preparation on unused land adjacent to cropped land, and further research aimed at reducing waterlogging damage, could both lead to improvements in farmers' circumstances in upland Balochistan.

A simple mathematical model is shown to provide reasonably good predictions of time series data on ammonia loss from three experiments on slurry stores. The model produces predictions of changes in the distribution of ammonia with depth. Experimental evidence suggests that ammonia concentrations above a critical value appear to destroy the viability of Cryptosporidium oocysts. Using this criterion, the model predicts that, even under the most favourable circumstances, oocysts are unlikely to remain viable in slurry stores except in the top few centimetres. The effect of stirring the slurry is considered.

Data on ovulation rate and numbers of ova and transferable embryos recovered from superovulated cattle and sheep were analysed using generalized linear models, quasi-likelihood, restricted maximum likelihood (REML) and generalized linear mixed models (GLMMS). The data pertained to the operation of nucleus breeding schemes in cattle and the commercial application of embryo transfer in sheep.

Results of the analyses showed that generalized linear models involving Poisson and Binomial distributions were inappropriate because of over-dispersion, and that analyses using quasi-likelihood to model negative binomial and β-binomial distributions were more suitable. Factors identified as important in determining the results in cattle were the number of previous superovulations (a higher proportion of transferable embryos were obtained in the initial flush compared to subsequent recoveries in two out of three sets of data), the donor (significant in all analyses with repeated recoveries) and its mate (significant in some analyses). In sheep, the use of pFSH or hMG for superovulation increased embryo yields above those obtained with PMSG + GnRH. Analyses of a further data set for sheep showed the effect of breed was ambiguous.

The effects of donors and their mates were treated as random effects in analyses involving REML and GLMMS. Results showed that the repeatability of the number of transferable embryos produced per donor ranged between 0·13 and 0·23 in three sets of data and was significant in all cases. In these analyses the variance among mates was not significantly different from zero.

The results of analyses were used to develop a random generator to simulate the numbers of ova and embryos recovered from a cow following superovulation. By sampling from negative binomial distributions where the scale factor used for each cow was a normally distributed deviate, distributions were obtained which had the same mean, variance and repeatability as those observed.

Statistical analyses were carried out on the data obtained under strictly controlled conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2–6 months earlier and whose daily milk production ranged from 11 to 20 kg.

The authors have calculated and studied the correlations between faecal and urinary sodium losses, sodium excretion in the milk, digestible sodium and sodium balance and the 75 other nutritive factors which were analysedfor each of the 55 above mentioned experimental diets.

The most important factor in the fate of sodium is the amount of dietary sodium. Sodium digestibility is neither total nor constant: faecal losses and digestible amounts are enhanced when sodium intake is increased and faecal losses are also positively correlated with dry matter and nitrogen intakes. An increase in digestible sodium benefits both urinary excretion and balance, the latter being reduced by an increase in dry matter and nitrogen intake.

Sodium balance is always negative when sodium content of the diet is lower than 0.1% in the dry cows and 0.2% in the lactating cows. In our experimental conditions, the sodium requirements for milk production do not influence sodium digestibility, but are met above all to the detriment of urinary losses.

Red clover (Trifolium pratense L.) silage usually contains lower contents of non-protein nitrogen (NPN) compared with other forage legumes. This is often attributed to the polyphenol oxidase (PPO) activity in red clover, although in most field studies the PPO activity was not measured. Therefore, a laboratory ensiling experiment with three red clover cultivars and one white clover cultivar as control grown in two management systems (with and without mechanical stress) over 2 consecutive years was conducted. Fresh, wilted and ensiled clover herbage was sampled at four cutting dates per year to determine the crude protein (CP) fractions according to the Cornell Net Carbohydrate and Protein System. The specific PPO activity was measured photometrically in fresh clover leaves. The content of CP fraction A (NPN) increased from fresh over wilted to ensiled clover herbage at the expense of the content of CP fraction B (true protein), irrespective of species, cultivar and year. The most important source of variation for all CP fractions and the calculated rumen-undegradable protein contents was generally the herbage condition, except for CP fraction C (unavailable protein). White clover silage consisted of higher contents of CP fraction A and lower contents of CP fraction B3 in CP compared with red clover silage. As a result, the calculated rumen-undegradable protein content of white clover silage was lower than that of all red clover cultivars. In conclusion, the extent of proteolysis during ensiling among the silages made from the herbage of different red clover cultivars was primarily influenced by the stage of maturity at harvesting and the degree of wilting at ensiling. The variation in specific PPO activity could not be related to the extent of proteolysis.

1. From 1960 to 1964 an experiment at Woburn, Bedfordshire, measured yields and the amounts of N, P and K removed by five arable crops (barley, grass-clover ley, potatoes, oats and sugar beet) and by a long ley; each was manured with all combinations of N, P and K fertilizers and with farmyard manure (D) and with both fertilizers and farmyard manure (DN1PK and DN2PK).

Crops of potatoes grown on 0·2–0·3 ha in each of the years 1971–8 at Stockbridge House Experimental Horticulture Station achieved total tuber yields of 70–94 t/ha. Yield was determined by the period and rate of tuber growth. The observed period of growth varied from 96 to 132 days and the rate from 0·55 to 0·90 t/ha/day. Rate of growth had the greater influence on variability of yield between the years. The number of tubers produced per unit area had little influence on their total weight, but had marked effect on their size. Adequate water supply was essential for very high yields. Experiments indicated that current recommendations for potash fertilizer can be adequate but that nitrogen and phosphate fertilizer use may need to be enhanced for very high yields. For high yields, the number of seeds planted per hectare may need to be higher than normally recommended in order to avoid the production of large tubers unsuitable for the ware market.

Blood and liver samples were taken from four fasted pregnant and five fasted non-pregnant Finnish Landrace × Dorset Horn ewes. The following metabolites were measured: adenine monophosphate (AMP), adenine diphosphate (ADP), adenine triphosphate (ATP), citrate, 2-oxoglutarate, phosphoenolpyruvate, pyruvate, lactate, 2-phosphoglycerate, 3-phosphoglycerate, α-glycerophosphate, malate, β-hydroxybutyrate, acetoacetate, glutamate, alanine and NAD+.

The effects of a 6-day fast on non-pregnant ewes were shown as significant reductions in the hepatic concentrations of 2-phosphoglycerate, alanine, NAD+ and ADP, together with significant increases in the hepatic concentrations of 3-hydroxybutyrate, malate and the ratio of 3-hydroxybutyrate:acetoacetate. In the blood there were significant reductions in the concentrations of urea, citrate and in the ratio of 3-hydroxybutyrate: acetoacetate.

Similar but more marked changes occurred in the late pregnant ewes, with additional significant reductions in the hepatic concentrations of citrate, ATP and the level of cell energy, and additional increases in the blood of the ratio of lactate: pyruvate and the concentrations of 3-hydroxybutyrate and 2-oxoglutarate. However, unlike the non-pregnant ewes no significant changes in either the plasma concentration of urea or the hepatic concentration of ADP were observed in the late pregnant ewes.

Lolium multiflorum, one of the most important temperate forage grasses in the world, is used in integrated crop-livestock systems and as a cover crop. However, it is also one of the main weeds in winter crops. The continuous use of glyphosate to manage this species has led to the selection of resistant biotypes (LOLMU-R), making it important to prevent the dispersal of these seeds. This study aimed to assess the recovery and germination of LOLMU-R that have passed through the digestive system of cattle. The experiments were carried out in metabolism cages, using a completely randomized design with six replications. The animals were given 12 112 seeds each, which were recovered from their faeces over a period of 6 days. Germination of the recovered seeds was assessed in a germination chamber and compared against a control (no animal passage). After germination, a glyphosate dose-response curve was constructed. The results obtained showed a total recovery of 1109 seeds (9.1%), with maximum recovery 2 days after ingestion, decreasing to almost zero on day 6. Germination declined linearly as a function of recovery time; however, 4 days after ingestion, germination potential was 18%. The dose-response curve proved the resistance of the recovered seeds. Cattle is a dispersal agent for LOLMU-R seeds, with animals requiring 7 days of quarantine before moving from one infested area to another.

Forage cactus is an important dry-season feed source for livestock in semi-arid regions, but in north-eastern Brazil, its contribution is limited by susceptibility to the carmine cochineal [Dactylopius opuntiae (Cockerell)] insect. New cactus germplasm shows superior agronomic performance, but the nutritive value of this material has not been adequately described. The objective of the current study was to assess the divergence in chemical composition and rate and extent of in vitro degradation of these genotypes. The treatments were 13 spineless cactus genotypes, eight of which were insect resistant types, two semi-resistant and three susceptible to the carmine cochineal. Treatments were arranged in a randomized complete block design and were replicated three times. Nutritional divergence was assessed using canonical variate analysis and hierarchical agglomerative clustering, using the variables: crude protein, total and non-fibrous carbohydrates, degradation rate and potential dry matter degradation. Five distinct nutritional groups were identified: Group I (OO), Group II (F-13 and F-15), Group III (OEA, OEM, COP, IPA 20 and GG), Group IV (V-16 and F-08) and Group V (Miuda, IS and F-21). Group II (F-13 and F-15; resistant genotypes) showed a chemical composition degradability in vitro suggesting it may have the greatest nutritive value as ruminant feed, while Group I had the least. Spineless cactus genotypes resistant to the carmine cochineal showed nutritional characteristics similar to or better than traditionally used cactus genotypes, such as Gigante and IPA 20, which can expand the range of options for using this forage.

Maize (Zea mays L.) is a major staple food and cash crop in sub-Saharan Africa (SSA). However, its production and productivity are severely constrained by drought. A total of 120 single-cross hybrids and an open-pollinated control variety were evaluated for 2 years at two locations under managed drought and rain-fed conditions in Nigeria. The objective of the present study was to assess their performance, classify them into distinct heterotic groups and identify promising hybrids for commercialization in the West and Central Africa sub-region. General combining ability and specific combining ability mean squares were highly significant for grain yield and other traits under the research environments. However, there was a preponderance of additive gene action over non-additive. Only six out of 39 inbreds were classified into distinct heterotic groups by the testers. The highest-yielding drought-tolerant hybrid, TZEEI 102 × TZEEI 95, out-yielded the open-pollinated control variety by 43·70%. The average yield reduction under drought was 54·90% of the yield under rain-fed conditions. The hybrids TZEEI 81 × TZEE1 79, TZEEI 100 × TZEEI 63 and TZEEI 64 × TZEEI 79 were the highest-yielding and most stable across environments. These outstanding drought-tolerant hybrids, which are also resistant to Striga, have the potential to contribute to food security and increased incomes in SSA and should be tested extensively on-farm and commercialized.