Paspalum plicatulum was grown at Brisbane in boxes of sand receiving basal nutrients and frequent irrigation; weekly levels of ammonium nitrate application were varied according to growth and development stage.

The rate of tiller appearance increased to a maximum 40–50 days after sowing and almost ceased thereafter. Tiller leaf number, survival, fertility, inflorescence branching, seeds per raceme and seed size were positively related to tiller age. Young tillers were more sensitive to variations in nitrogen supply than old tillers.

Adequate nitrogen nutrition during the vegetative phase from sowing to floral initiation (93 days) increased tiller and hence inflorescence density; increased inflorescence branching was compensated by fewer seeds per raceme. Good nitrogen nutrition during the phase from floral initiation to inflorescence exsertion (142 days) increased survival of late-formed tillers and hence inflorescence density; inflorescence branching, seeds per raceme and seed size were also increased. Nitrogen stress during the final maturation phase did not affect seed yield.

Egg production and body mass changes were measured in six groups, each containing 10 single comb White Leghorn (SCWL) hens, in which each group received decreasing amounts of dry matter (D.M.) in decrements of 10%. Group 1 received 101·2 g D.M./day (100%), an amount normally offered these hens, whereas group 6 received 52·8 g D.M./day (50%). Egg production remained relatively high but body mass declined rapidly in the feed-restricted groups when compared with group 1 in the first 4 weeks (period I); in the second 4 weeks (period II), egg production declined to a great extent but body mass remained constant. Egg production and egg mass were significantly lower in period II than in period I in the feed-restricted birds. In period I egg production did not decrease significantly until the hens were restricted in feed by 30%; in period II this occurred at 20% feed restriction. Energy of eggs produced as a fraction of metabolizable energy intake (MEI) tended to increase in the feed-restricted groups when compared with group I in period I, but decreased significantly at the 40% and 50% group in period II. Maintenance energy requirements for the hens were 569·2 kJ/kg0·75 per day and the efficiency of utilization of energy for egg production was 88·2% in period I; these values were 551·6 kJ/kg0·75 per day and 74·0%, respectively, in period II. Energy yielded from the catabolism of body tissue per gram body mass loss was 23·08 kJ.

It was concluded that the hens initially maintained near-normal egg production at the expense of body energy reserves and then at the expense of egg mass. The efficiency of utilization of energy for egg production was higher when the energy source was mainly from body energy reserves than from MEI (88·2% v. 74·0%). The level of feed restriction and its length of imposition, the body energy reserves of the hen and the source of energy for egg production can explain many of the different responses reported in feed-restricted laying hens. In addition, reduction of 20 to 30 % feed intake in laying hens had little effect on egg production for a short period (4 weeks) during which time the hens mobilized body energy reserves. If these hens were to be sold, then this would add an additional option to this enterprise; that is, reduce feed cost at the expense of body mass prior to the sale of the hens.

Alley cropping is a prototype agro-forestry system practiced in many parts of the humid tropics. It is one of the established, promising and sustainable low-input soil management ventures. An improved understanding of the eco-physiological relationships between the arable and perennials in this system could contribute to solving issues of sustainability for nutrient use and system productivity. Field experiments were conducted in Alabata and Ajibode, located in the derived savannah zone of Nigeria, to evaluate the comparative effects of an alley cropping system, arbuscular mycorrhizal fungi inoculation and cassava intercropping on maize yield. These on-farms trials (research managed and farmer managed) were conducted in the 1993/94 and 1995/96 growing seasons, in Rhodic Kandiustalf soil type with low nutrients. Each trial was a split-plot factorial arranged in randomized complete blocks with three replications. Biomass productions of maize and cassava tuber yield were determined. The results obtained at Alabata indicated that the maize plants were heavily infected with AM fungi whether inoculated or not. The hedgerow trees did not have a significant effect on maize yield. The increase in yield brought about by the alley cropping system was generally less than 15%, except in one farm where increases of 34·6 and 46·5% were recorded in AM-inoculated and non-inoculated plots respectively. The introduced AM fungi did not significantly enhance maize yield at Alabata; the percentage increase was not more than 24%. This trend was also observed at Ajibode. Cassava tuber yield was found to be suppressed by the alley cropping system irrespective of the cultivar. The decrease in yield ranged from 2·6 to 150·8%. However, inoculation of the cassava with exotic AM fungi brought about an enhancement of its tuber production. The increase ranged from 20·7 to 189·8% depending on the treatment combination. It is therefore necessary to encourage adoption of the improved alley cropping system integrated with mycorrhizal technology.

1. Field tests indicate that sunflower seeds are suitable as a wartime substitute for cereal grains for fowls, and that eggs produced on rations containing these seeds are excellent in both flavour and quality.

2. Digestibility trials indicate that sunflower seeds are a good source of protein and energy.

3. On an energy basis, metabolizable energy determinations indicate that sunflower seeds yield more energy than cereal grains on a weight-for-weight basis, with the exception of yellow maize.

4. Under commercial conditions of management, sunflower seeds appear to be quite palatable to poultry, but not under conditions of individual cage feeding.

For highest revival rates in experiments on the deep-freezing of bull spermatozoa to – 79° C., a period of incubation of the undiluted semen at 30° C. did not eliminate the need for overnight equilibration at 5° C. The addition of 1·25% fructose or arabinose to the diluent improved revival rates of non-equilibrated spermatozoa but these rates still did not equal those of equilibrated spermatozoa.

Glycerol apparently penetrated spermatozoa rapidly and spermatozoa survived in glycerol solutions as high as 2·0m if 0·1m buffered citrate was also present. Omission of the citrate solutions caused immediate death of the spermatozoa.

A one-ninth replication of a 37 factorial experiment showed that, by all scoring criteria, 40° C. was superior to 0° C. as a thawing bath temperature. A diluent containing 8% (v/v) glycerol was superior to either 4% or 6% if activity of spermatozoa after thawing was the scoring criterion, but there was no difference in the percentage of spermatozoa stained by congo-red-nigrosin when frozen in diluents containing these levels of glycerol.

In the range of tonicity 80, 100 and 120% (0·9% NaCl = 100% tonicity), using the diluent composed of a mixture of fructose and citrate, there were more motile spermatozoa than in buffered citrate or fructose alone. Increasing tonicity had an adverse effect on revival rates of spermatozoa in the buffered citrate diluent. Spermatozoa stored chilled at 5· C. for periods up to 36 hr. prior to freezing survived best in the mixture of fructose and citrate.

The investigation of the equilibration phenomenon showed that an improvement in survival after deep-freezing occurred if diluted semen was stored for up to 12 hr. after dilution, but this was not dependent on the presence of glycerol in the diluent during this ageing process.

Ninety-eight sheep in three farm flocks were treated in July (period of late anoestrus) with intravaginal sponges impregnated with 30 mg ‘Cronolone’ (9α-fluoro-11βhydroxy 17α-acetoxy-progesterone; G. D. Searle) or ‘Cronolone’ plus 400 mg progesterone and incorporating doses of 0–800 μg diethyl stilboestrol. Treatment was for 12 days; a single dose of 500 i.u. PMS (Burroughs Wellcome) was injected at pessary withdrawal. Ten rams bred the ewes at the induced and subsequent heats.

Of the ninety-five ewes retaining pessaries, ninety-three (98%) were bred in the 3 days following treatment. Sixty-three sheep (68·5%) conceived at the controlled oestrus, producing an average of 1·54 lambs/conception. In the thirty-four ewes failing to conceive at that time, twenty-seven (80%) showed oestrus after one cycle interval; twenty of these (74%) conceived and produced 1·3 lambs/conception. Lambing outcome toservices at the controlled oestrus was lowest in sheep treated with 800 μg stilboestrol, but the reduction was not significant.

Records on growth and reproductive characteristics collected from 1993 to 2013 at the Breeding Station of Kermani sheep, south-east of Iran, were used for estimating genetic parameters related to parent-of-origin effects. The studied growth traits were birth weight (BWT), weaning weight (WWT), six-month weight (6MW), average daily gain from birth to weaning (ADG1), and average daily gain from weaning to six months of age (ADG2). The reproductive traits were litter size at birth per ewe lambing (LSB), litter size at weaning per ewe lambing (LSW), the sum of litter weight at birth per ewe lambing (LWB), and the sum of litter weight at weaning per ewe lambing (LWW). Models with and without imprinting (maternal and paternal) effects were compared by applying Akaike's information criterion (AIC). Maternal imprinting effects explained 14, 7, 24 and 5% of the phenotypic variances for BWT, WWT, 6MW and ADG1, respectively and their inclusion in the model decreased direct heritability estimates for BWT (from 0.07 to 0.05), WWT (from 0.29 to 0.23), 6MW (from 0.26 to 0.12) and ADG1 (from 0.20 to 0.17). Imprinting effects did not affect ADG2 and studied reproductive traits. The results indicated that a considerable proportion of the maternal imprinting effects overlap with direct additive genetic and maternal effects. Therefore, imprinting effects may be crucial for the genetic assessment of BWT, WWT, 6MW and ADG1 in Kermani sheep.

A recent paper by A. E. Brandt (1937) goes into the details of a type of design in field experimental procedure, where two or more factors are under examination, which has been much elaborated since 1928, when the first 2 × 2 × 2 experiment, involving two levels of each of three factors, nitrogen, potash and phosphate, was carried out at Woburn (Rothamst. Rep. 1927–8) with four-fold replication. Similar experiments, of the 3 × 2 × 2 type, had in fact been conducted at Rothamsted (Rep. 1925–6) two years earlier, but there was here the further complication that no differentiation was possible for two of the factors at one level (no manure) of the third. Details have been given by Fisher (1937) and Yates (1937) of, among others, experiments of the 2n and 3 × 2n types, and it may be said that the recent work has been in the direction of systematizing the lay-out and analysis of such experiments. Further features have been the device of confounding, which dates back to 1927 (Rothamst. Rep. 1927–8), i.e. it is almost contemporaneous with the first introduction by Fisher of randomized blocks and Latin square experiments, and the suggestion that replication may even be dispensed with entirely, a much more recent innovation. Confounding is a method of enlarging the number of blocks between which elimination of soil heterogeneity is possible by sacrificing information on certain of the higher-order interactions, which are considered unlikely to be real effects; with absence of replication an estimate of the experimental error is found by grouping together a number of these higher-order interactions.

In a 2-year experiment anhydrous ammonia (82% N) and an ammonium nitrate fertilizer (34·5% N) were applied at three annual rates—100, 200 and 300 lb N/acre (112, 224 and 336 kg/ha)—on an S.24 perennial ryegrass sward. At each rate the two fertilizers were applied either as a single dressing in the spring or as five equal split dressings over the season. Total yields of herbage dry matter and of crude protein were determined by cutting the herbage at approximately the same stage of growth five times each year. On the basis of total yield and seasonal distribution of yield anhydrous ammonia was best applied as a single dressing in the spring, whereas ammonium nitrate was best applied as five equal split dressings over the season. However, in both years anhydrous ammonia applied as a single dressing gave smaller yields and a poorer seasonal distribution of production than did ammonium nitrate applied as five equal split dressings. The factors contributing to the lower yield level with anhydrous ammonia applications are discussed. It is concluded that anhydrous ammonia has no marked advantages over ammonium nitrate as a nitrogen fertilizer for intensively managed grassland.

1. Digestibility trials, using sheep, were carried out on five batches of oat hay grown during 2 years; nitrogen balance experiments were made simultaneously.

2. The oat hay was not readily consumed by the sheep; this necessitated calculating the digestibility data on an ‘as consumed’ and on an ‘as offered’ basis; it also prevented a majority of the sheep from obtaining their maintenance requirements of energy or from maintaining nitrogen equilibrium.

3. Statistical analysis of the data revealed a downward drift in digestibility in the succeeding periods of the 1955 trial.

4. While stage of maturity had little consistent effect on digestibility or on the amounts of digestible nutrients present, the percentage digestible crude protein did increase with advance in maturity.

5. The amounts of digestible nutrients present in oat hay indicated that it had a nutritive value between those of oat straw and medium-quality meadow hay.

6. The data suggest that the maximum yield of digestible nutrients is obtained when the oat hay is cut at the ‘late cheesy’ stage of maturity.

Quantitative aspects of skin follicle population growth and maturation in post-natal life from birth to 16 months have been studied in four groups of N-type and non-N New Zealand Romneys. The following characters were observed on skin biopsy specimens from a standard position on the mid-side in all cases: total and primary follicle population density; ratio of secondary to primary follicles ; primary and secondary fibre diameter; primary/secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation.

No important differences were found between the genotypes examined in any of these characters except primary fibre diameter , the primary/ secondary fibre diameter ratio ; and the incidence and degree of primary and secondary fibre medullation. These characters individually, but especially in combination, appear of great diagnostic value at all post-natal ages in discriminating N-type from non-N genotypes, in terms which reduce the number of assumptions necessary on the relations between the fibre types of the staple and the follicles of origin in the skin.

In experiments at this Institute in which samples of liver were required for the estimation of mineral content, difficulty had been encountered in obtaining samples reliably, especially in pregnant animals using the technique described by Dick (1944) and Abdellatif (1968). It was decided to investigate the possibility of obtaining liver samples from sheep under direct vision using a laparoscope.

On the College of Agriculture farm in Abu-Ghraib 147 ejaculates were collected from three docked and four normal Awassi rams born during November 1962. The work covered a period from 1 April 1967 to 31 March 1968.

Nine semen characters, namely, volume, mass activity, individual motility, sperm concentration, sperm number, pH, methylene blue reduction time and the percentages of abnormal and dead sperms, were studied. The effect of season and docking on these characters was investigated.

Seasonal variation was observed in all traits studied. On the whole, semen quality was poorest during winter and best during summer. The effect of docking was more pronounced on sperm concentration, sperm number and percentage of abnormal sperms. Docking appeared to increase sperm production and reduce sperm abnormality.

Previous studies have indicated that improved artificial drainage increases yields of winter wheat by as much as 1 t/ha (Armstrong 1978), and suggested that an important component of this improved yield was the more effective utilization of nitrogenous fertilizer. Further data to support this hypothesis are here presented from the longterm drainage economics experiment at the Drayton Experimental Husbandry Farm, Warwickshire, England (Trafford & Oliphant, 1977; Bee, Dennis & Marks, 1978; Armstrong, 1978). The soil of this site is a non-calcareous pelo-stagnogley of the Denchworth series, and the mean annual rainfall is 617 mm. Both the soil and the climate are typical of much of the English midlands. The results presented here are, however, restricted to a single site, and are consequently tentative.

Data from three dairy-cow nutrition experiments have been analysed in terms of the yields of milk, lactose, fat and protein. Yields of the three constituents varied linearly with milk yield. However, yields of fat from individual cows were much more variable at high milk yields than were the other two constituents. Patterns of feeding had relatively little effect on the pattern of protein yield in cows fed to their production potential but could be important in influencing yields of fat.

Predicted responses of protein and fat yields to increments of feed were generally small in cows being fed according to their predicted yield potential and the conversion of metabolizable energy to milk constituents was of a low biological efficiency.

1. In the summer of 1945 samples of the growing crop were taken from eight Broadbalk plots. On all the plots the concentrations of nutrients in all parts of the plants decreased during growth. The compositions of the roots and stems and leaves varied with fertilizer treatment at all times of the season. The nutrient composition of the ears was only slightly affected by fertilizer treatment.

2. The total uptake of nutrients by the crop increased to a maximum and then decreased. The losses of potassium and magnesium from the stems and leaves were particularly large, due to translocation into the ear but there were also net losses of potassium and calcium from the whole plant.

3. The changes which occurred were similar on all plots and the effect of fertilizer treatment on plant composition was always related to the effect at harvest. There was no evidence that the composition of the crop at harvest differed radically from the composition earlier in the season.

The phenology of anthesis, anther dehiscence, fertilization and petal fall in the linseed cultivar Antares and its response to supplementary pollination when grown in a glasshouse were investigated. Anthesis commenced 15–30 min after the onset of the photophase and was complete within 2 h. Anthers dehisced when buds were in the tube stage of opening and produced a mean of c. 4·5 × 103 pollen grains per flower. Most ovules were fertilized within 6 h of the onset of the photophase. Flowers self pollinated naturally and, although supplementary pollination increased the percentage of flowers that produced capsules and the number of seeds per capsule, it decreased flower production and individual seed weight and conferred no increase in seed yield. Flowers retained their petals for at least 2 h after the onset of the photophase but, by 10 h, 97% of hand-pollinated flowers had shed their petals; those naturally self pollinated or shaken retained their petals for longer.

The effect of pregnancy on hair growth and shedding in the short-haired guinea-pig has been studied. It is shown that during pregnancy the amount of hair produced on defined areas of skin decreases until at the time of parturition and for 2 weeks afterwards practically no hair growth is taking place. This is followed by an increased output of hair substance, and hair production returns to its normal level after 11 weeks.

Field experiments were conducted in two wet and two dry seasons in 1984–86 to evaluate efficiencies of different urea-based fertilizers, and methods of application, for irrigated rice. Response to applied N was significant in all seasons. In the wet season, use of dhaincha (Sesbania aculeata) green manure and urea (Dh + U), reduced zone placement of urea supergranules (USG), surface application of laccoated urea (LCU) and prilled urea in three split doses (PU-split) gave similar results, and all were better than basal broadcast application of urea coated with neem (Azadirachta indica) cake (NCU) or prilled urea (PU-basal). In the dry season, USG was significantly superior to PU-basal, NCU and (Dh + U). Nitrogen uptake by rice was greatest 15–30 days after transplanting (DAT), followed by a second peak during the reproductive phase of the crop. Ammonium-N in the soil decreased sharply up to 30 DAT, more slowly up to 60 DAT and then increased slightly. Ammonium-N in the soil was higher with USG, (Dh + U) and PU split than with other treatments, especially in uncropped conditions.