bluuebunny/crossref_metadata_2025 huggingface dataset:
A uniformity trial on groundnuts
Authors: Hodnett G. E.
Published: March 2009

A uniformity trial on groundnuts has been analysed and the results discussed. Plant number is less variable than yield and less sensitive to shape of plot and of block. For yield, long narrow plots are more efficient than shorter and wider plots, in all shapes and sizes of blocks and in Latin squares. The plots should not be arranged end to end along the contours, but side by side, either singly or in pairs, forming compact blocks.

The regression of the plot variance of the mean yield per unit area on size of plot approximately follows a linear logarithmic relationship. A similar relationship holds for plant number. The value of the regression coefficient b′ is low and it has been shown that, as expected, there is considerable gain from the use of small blocks. The efficiencies of various confounded and incomplete block designs relative to designs in larger blocks have been determined for some particular layouts, and values for other layouts, ignoring shape of plots and of blocks, have been obtained by interpolation.

The field used for this uniformity trial appears equally variable in all directions.
The availability of calcium in three herbs of grassland
Authors: Armstrong R. H. , Thomas Brynmor , Horner K.
Published: March 2009

1. The availability of the calcium in three common herbs, viz. narrow-leaved plantain, chicory and burnet, has been investigated using the rat as the experimental animal.

2. Parallel methods used for the determination of calcium balance involved (a) the analysis of feed, faeces and urine, and (b) carcass analysis.

3. The availability of the calcium, while high in all three species, was in the order plantain, chicory and burnet. All differences between means were significant atP= 0·05.

4. There was shown to be some evidence of inverse relationships between fibre content and calcium availability, and between oxalic acid content and calcium availability.
The effect of under-feeding on the genital functions of a bull
Authors: Mann T. , Walton A.
Published: March 2009

1. A study was made of the effect of underfeeding on the genital functions in the bull. Regular weekly collections of semen were made during (1) a 5-week pre-experimental period of normal feeding, (2) a 23-week experimental period of under-feeding, and (3) a 25-week post-experimental period of recovery.

2. Although the food intake was reduced to such an extent that the bull began to lose weight at a rate of 6·5 kg. (1 stone) per week, the volume and density of semen and the motility and morphology of the spermatozoa were not significantly changed.

3. In contrast to the testes, the secretory function of the male accessory glands was markedly affected by under-feeding. The concentration of fructose and citric acid in semen decreased to about 30 and 60% respectively of the original levels. During the recovery period the values for fructose and citric acid gradually returned to normal.
Chemical fat in the musculature of the sheep carcass
Authors: Pryor W. J. , Warren G. H.
Published: March 2009

Forty merino sheep of mixed ages including lambs, ewes, wethers and rams were slaughtered and dissected. The chemical fat content often muscle groups in each sheep was measured directly and the mean value for the musculature of the whole carcass calculated.

A characteristic pattern of chemical fat deposition was shown with the intercostal muscle group and the abdominal group being consistently highest in fat content, the shin and hind-limb muscles lowest and other intermediate. The pattern of growth of intramviscular fat was consistent with differences in activity of the muscle groups in the maintenance of posture. It was postulated that variations in fat content in muscle groups are affected by differences in blood flow.

A highly significant relationship was established between dry matter and chemical fat content for each of the muscle groups. The regression was characteristic for each muscle group, and differed for most groups.

Regressions between individual muscle group fat and that of total musculature fat revealed that no group was consistently the best predictor of the total carcass musculature fat though there was considerable difference between the groups. It was concluded there is no group which could be used for prediction purposes commercially.

In a group of 14 other ewes subjected to weight loss up to 30%, and half of which were implanted with resorcylic acid lactone, no discernible effects on muscle group fat content were revealed.
Oestrous cycle synchronization in Zebu cattle and its use in cattle production and management in the tropics
Authors: Jöchle W. , Hidalgo M. A. , Giménez T. , R. Garcia C.
Published: March 2009

Between March and August 1968 to 1970, Chlormadinone acetate (CAP), 10 mg/head/ day, was administered to 668 Zebu cows and heifers for oestrous cycle synchronization for 14, 12, or 9 days, the latter schedule supported by an injection of 5 mg estradiol valerate on day 2 to achieve luteolysis. Applied orally over a period of 14 days, CAP provided a reliable method for cycle synchronization. The severe anoestrous rate experienced in all herds reduced the overall percentage of synchronized animals. Fertility from insemination during the first synchronization period (day 2 to 10 after treatment) was slightly, yet insignificantly reduced, but was completely restored during the second synchronization period (day 20–30). Insemination only during this second synchronization period resulted in conception and pregnancy rates similar to those combined from the first and second synchronization period.

Of factors tested for influencing synchronization and fertility, presence or absence of penis-deviated teaser bulls (psycho-stimulation) had no effect on the percentage of animals synchronized, or on post-treatment fertility. In well-managed herds, the percentage of animals responding to treatment was predetermined by the number of animals already cycling, reflecting their phase of reproductive life. Levels of management had an important impact on the success of cycle synchronization combined with artificial insemination. Both methods are managerial tools for improvement of already good management. Their failure under insufficient management conditions has diagnostic value.

Possibilities and limits shown for oestrous cycle synchronization in Zebu cattle were similar to those reported in European cattle. Within these limits, CAP can be employed successfully as a means for cycle synchronization, providing sufficient synchronization and acceptable fertility and allowing economical use of artificial insemination.
The nutrient requirements of herbage on deep acid peat
Authors: Reith J. W. S. , Robertson R. A. , Inkson R. H. E.
Published: March 2009

A mixed sward of grasses and clovers, previously established with adequate Ca, N, P and K on deep acid peat, was used for a factorial experiment to determine the amounts of nutrients required to produce herbage for conservation. The treatments consisted of all combinations of 0, 117and 234 kg N, 0, 29 and 58 kg P and 0, 156 and 312 kg K/ha, and their effects on the botanical composition of the sward, the yield and mineral composition of the herbage, and the nutrient status of the peat were measured over a period of five years. Three cuts were taken annually, one third of the N dressings being applied for each cut.

Tall fescue became the dominant grass species while cocksfoot persisted much better than either ryegrass or timothy. The proportion of clover in the sward was reduced to practically zero by applying N, but without N it was maintained at about 20% by applying K.

Yields of dry matter were greatly increased both by N and by K and there was a marked positive interaction between these two nutrients. Due to the marked suppression of clover by applied N there was no response to the first increment of N in 1959, but with this exception, 1 kg N/ha with adequate P and K produced between 15 and 30 kg dry matter/ha. The effect of K increased from 1958 to 1962, the first increment consistently producing most of the response. Applying P had little effect on yield until the fifth year when a significant response was obtained.

The mineral composition of the herbage varied during the season; the percentages of N, Ca, Na and Mg were generally higher in autumn than in early summer whereas the percentage of K showed the opposite effect.

The N, P and K treatments had large effects on the percentages of N, P, K, Na, Ca and Mg in the herbage and on the amounts removed in the crop. Without applied N, but with adequate P and K, percentage of N varied according to the amount of clover in the sward. With applied N there was less variation and the average percentage of N was about 1·7 with 39 kg N and 2·0 with 78 kg N/ha/cut. Percentage of P ranged from 0·14 to 0·54 and percentage of K from 0·5 to 3·5. Apparent recoveries up to 74, 65 and 96 % were obtained from the N, P and K treatments, respectively.

For continuous production by cutting and removing the herbage, a mixed sward containing clovers appears to require, without applied N, about 120 kg K/ha/year. With applied N, an additional 0·3 to 0·5 kg K/kg N appears to be needed. The amount of P required will depend mainly on the concentration desired in the herbage and on the rate of N used. To produce herbage with 0·3 % P in the dry matter about 15 kg P/ha/year, plus approximately 0·1 kg P/kg N applied seems to be needed; for 0·4 %P the corresponding quantities are about 40 kg P/ha plus 0·3 kg P/kg N applied.
Studies on the agronomy, genetics and interrelationships of yield and its morphological components in a diallel set of families ofLolium perenneL.
Authors: Thomson A. J. , Wright A. J. , Rogers H. H.
Published: March 2009

Five selected clones ofLolium perennewere selfed and diallel crossed without reciprocals to produce 15 families. These families were grown in a replicated field trial for 2 years at four rates of applied nitrogen – 0, 225, 450 and 675 kg N/ha – per annum. The data recorded included dry-matter yield, number of fertile and sterile tillers per plant, mean dry weight per fertile and sterile tiller and total dry weights of fertile and sterile tillers. Conventional analyses of variance and diallel analyses were applied to the data as well as path analyses, used to examine the interrelationships between yield and the tiller characters.

The main effect ofyearswas significant only for mean dry weights per tiller and dry-matter yield. Increasing the rate of applied nitrogen increased the number of tillers and yields but decreased mean tiller dry weights. Differences betweenprogenieswere due to both general and specific combining ability for most characters. Relatively high narrow-sense heritabilities were obtained for the tiller characters although there were differences between the two years.

The progenies achieved their yield through different combinations of tiller characters, some having large numbers of fertile tillers with medium dry weights and others having numerous sterile tillers with high dry weights. Although there was inconsistency in the interrelationships between characters, number of tillers was always more important in determining yield than mean dry weight per tiller.

The results are discussed in relation to the predictive value of tiller characters on yields and the implications for breeding programmes.
Prospects for the development of F1hybrid varieties of perennial ryegrass (Lolium perenne) and other herbage grasses
Authors: Foster C. A.
Published: March 2009

Consideration is given to the prospects of producingF1hybrid varieties of perennial ryegrass,Lolium perenne, and other herbage grass species for commercial use. In the light of the results of interpopulational hydridization in this and other crop species and of the technical and economic disadvantages inherent in other methods ofF1hybrid seed production, it is concluded that the development of interpopulationalF1hybrid varieties, by the field interpollination of parent populations, is a desirable and worthwhile breeding objective.
Associations among certain morphological traits of diallel cross progenies in Bromus inermis Leyss
Authors: Mishra S. N. , Drolsom P. N.
Published: March 2009

A study of correlations among certain morphological traits of progenies from a 6 x 6 diallel cross was made. In general, genotypic correlations were similar in sign to the phenotypic correlations in all but two of the 21 cases, but there were differences in magnitude (nine differed by 0·40 and four of these by more than 0·70). Some estimates of the environmental correlations were large (1·57, 1·52, 0·78, 0·75, 0·73 and 0·54). Positive and significant correlations indicated that improvement in some characters related to forage and seed yield should be possible by selection among the diallel progenies.

Path analysis was used as a means of analysing phenotypic correlation coefficients among seven contemporary variables. The method was employed to analyse the system of all possible correlations among certain plant measurements. By this technique one may find the maximum effect, compatible with the data, which can be assigned to a general size factor (common to all variables) and determine the nature and degree of influence of residual, group, and special factors. In most of these the influence of the general size factor predominated (minor in the case of leaf width, pCX = –0·31; and florets per spikelet, pGX = –0·09). Only two of the 21 correlations required factors in addition to the general size (florets per spikelet and spikelets per panicle, excess correlation –0·46; and leaf width and culm diameter, excess correlation +0·53). Special factors acting on each part separately from the other were present in all cases. The study indicated that the genetic differences in this study were largely in general size and to a small extent in group and special factors.
Energy utilization in the laying hen in relation to ambient temperature
Authors: Davis R. H. , Hassan O. E. M. , Sykes A. H.
Published: March 2009

Energy balances have been determined, using the comparative slaughter procedure, over 3-week periods on groups of laying hens kept at ambient temperatures of 7·2, 15·6, 23·9, 29·4 and 35 °C.

Energy intake declined as the environment became warmer (kcal ME/kg¾/day = 203· 1·13°C); heat production, as measured by the difference between energy intake and energy retention, also declined with increasing ambient temperature (kcal/kg¾/day = 151 – 1·11°C). There was a linear relationship between heat production and ambient temperature with no thermoneutral zone or critical temperature.

The energy available for egg production remained almost constant at 50 kcal/kg¾/day equivalent to a rate of egg production of 82% at each ambient temperature.
The intensive production of herbage for crop-drying III. The effect of the continued application of nitrogenous fertilizers to grassland
Authors: Holmes W.
Published: March 2009

1. The experiment previously described (series 4, Holmes, 1949) on the effect of massive applications of nitrogenous fertilizers on the productivity of a ryegrass dominant pasture was continued for 3 years (1946, 1947, 1948). The manurial treatments ranged from none to the application of 312 lb. nitrogen per acre and this was applied with and without 135 lb. P2O5 and 168 lb. K2O per acre. Farmyard manure was applied to one block in 1948.

2. With the heaviest nitrogen treatment plus phosphate and potash the average yield for 3 years was 8000 lb. dry matter and 1640 lb. crude protein (similar to the yield in 1946) compared with a control yield of 4720 lb. dry matter and 590 lb. crude protein. The yields declined from year to year when phosphate and potash were not applied, the decline being greatest with the heaviest application of nitrogen.

3. The seasonal distribution of the yield of herbage was very considerably modified by the time when fertilizers were applied.

4. The botanical composition of the swards was related to the yield, 70% of the grasses in the highest yielding sward being perennial ryegrass and cocksfoot while the lowest yielding sward contained only 35% of these grasses.

5. The manurial treatments had no effect on the pH, loss on ignition or the content of readily soluble P2O5 in the soil, but in the first year there was some evidence of a general reduction of readily soluble K2O to a low level.
The intensive production of herbage for crop-drying IV. The effect of massive applications of nitrogen with and without phosphate and potash on the yield of grassland herbage
Authors: Holmes W.
Published: March 2009

1. A small-scale plot experiment was carried out from 1947 till 1949 to study the effect of massive dressings of nitrogen with and without phosphate and potash on the yield of a ryegrass-dominant sward. A 4 × 4 Graeco-Latin square was used.

The nitrogen treatments were: (1) no nitrogenous fertilizer, (2) 260 lb., (3) 520 lb., (4) 416 lb. nitrogen per acre per annum. These applications were divided into four or five equal dressings, the first being applied in March and the others after successive cuts.

In 1948 and 1949 the following mineral treatments were also applied: (A) no mineral fertilizer, (B) 180 lb. K2O per acre, (C) 120 lb. P2O5 per acre, and (D) treatments B and C combined. These treatments were applied in two parts, half in spring and half in midsummer.

2. Applications of phosphate did not affect the yields of herbage but yields were severely restricted in the absence of potash.

3. Where potash was applied there was no significant change in the annual yield of herbage from 1947 to 1949 for any one of the treatments. The nitrogen treatments increased the yields from 4300 lb. dry matter and 600 lb. crude protein per acre with treatment 1 to 9000 lb. dry matter and 1900 lb. crude protein with treatment 3. The yield response of dry matter to nitrogen applications was curvilinear, but that for crude protein was rectilinear.

4. Increasing the application of nitrogen per cut from 52 to 104 lb. per acre raised the protein content in the dry matter of the herbage from 15·20 to 18·25%.

5. The plots receiving the nitrogen treatments gave earlier production and also produced a greater proportion of the total yield in July-September than the untreated control plots.

6. Where potash was present the average net efficiency of recovery of nitrogen for 3 years was 47, 39 and 37% for treatments 2, 3 and 4 respectively.

7. Where potash was present the content of vigorous grasses in the sward (perennial ryegrass and timothy) was increased in relation to the quantity of nitrogen applied, from approximately 40% in treatment 1 to 75% in treatment 3. The content of vigorous grasses in the sward was reduced in the absence of potash.

8. The results and their practical implications are discussed.
Placement of fertilizers for sugar beet
Authors: Cooke G. W.
Published: March 2009

Ten experiments on sugar beet in 1949 tested a phosphate-potash fertilizer applied in different ways. There was no damage to germination or plant establishment by fertilizer placed in bands 2 in. to the side and 2 in. below the level of the seed.

There were no significant differences between the yields of sugar given by placed and broadcast fertilizer. Similar yields were given by broadcast applications applied early and worked deeply into the seed-bed and by dressings on the seed-bed which were worked in shallowly. Split dressings where half the fertilizer was broadcast and half was drilled beside the seed were not markedly superior to placing or broadcasting all the fertilizer. In most of the experiments placing gave more vigorous growth than broadcasting the fertilizer during late spring and early summer; at harvest this superiority had vanished.

The results of these experiments confirm those carried out in 1947 and 1948. There is no advantage from placing the full dressing of fertilizer beside the seed in districts where the crop is normally grown, except that labour is saved in applying the fertilizer.
The self-selection of diet by pregnant ewes
Authors: Gordon J. G. , Tribe D. E.
Published: March 2009

1. Eight Cheviot ewes, bearing twins, housed in individual pens, and given the choice of a protein concentrate, a carbohydrate concentrate, hay, minerals and water, failed to select a ration that allowed them to bear and rear strong healthy lambs.

2. Three ewes maintained under these conditions developed a condition resembling pregnancy toxaemia.

3. The amount of food eaten by each ewe decreased during the last few weeks of pregnancy, This is probably the reason for the disappointing performance of the ewes at lambing.

4. The possible influence on the behaviour of the ewes of the constant presence of food is discussed.
Stocking intensity and pastoral production: II. Herbage intake of Merino sheep grazed at different stocking rates
Authors: Langlands J. P. , Bennett I. L.
Published: March 2009

Estimates were made at monthly intervals between January and December 1965 of the intake and nutritive value of the diet of unmated Merino ewes grazed continuously at stocking rates ranging from 2·5 to 37·1 sheep/ha. Oesophageally fistulated sheep were used to estimate intake and nutritive value.

Drought conditions existed during the experiment. Digestibility declined linearly with increasing stocking rate. The intercepts of the relationship between digestibility and stocking rate differed between months, being at a maximum in spring. Nitrogen content was also greatest in spring but did not change consistently with increasing stocking rate. Organic-matter intake declined linearly with stocking rate and increased asymptotically with total herbage available, the asymptotic relationship being the more precise. Neither relationship differed significantly between months. Organicmatter intake/ha increased continuously with increasing stocking rate and the maximum intake was predicted to occur at a stocking rate greater than that at which the sheep survived.
The chemical composition of British agricultural liming materials
Authors: Chater Margaret , Williams R. J. B.
Published: March 2009

Ninety-four British liming materials were examined. The contents of Ca, Mg, K, P, S, Sr, B, Fe, Mn, Zn, Cu, Co, Mo, Ni, Cd and Na in the acid-soluble fraction, and Mn, Cu, Co, Mo, Ni, Sr, Ti, Cr, Ga, Pb, Sn, V, Y, Zr and Ba in the acid-insoluble fraction were determined by chemical and spectrographic analysis. Water soluble nitrate was also determined.

Only manganese, providing on average 3 kg Mn/ha for a 10 t/ha dressing, was found in agriculturally significant quantities in the acid-soluble fraction of the limestones or shell-sands analysed. Magnesium, present only in significant amounts in the dolomitic limestones, provided on average 27 kg Mg/ha from a 10 t/ha dressing.

The acid-insoluble fraction of the limestones contained, on average, a twentieth of the concentration of Mn in the acid-soluble fraction. The concentration of K was much larger and depended on the amounts and nature of the insoluble fraction. The acidinsoluble fraction contained no significant amounts of other plant nutrients. The relative concentrations of Mn and K in both fractions emphasize that results based on the total amounts of elements in limestones could overestimate their potential value as sources of plant nutrients.
Potatoes for canning – design of growing systems
Authors: Thompson R. , Gray D. , Pascal J. A.
Published: March 2009

Effects of set size, density of planting, harvest date and spatial arrangement on yield and size grading of potatoes were examined using the cultivar Maris Peer. The results indicate that highest economic returns would be obtained by growing crops at between 70 and 110 eyes/m2, using small sets for late season production and large ones only for very early production, with as near a square pattern of planting as possible.

Based on these findings four growing systems were tested on a field scale, a 1·5 m raised bed with four rows, a 0·6 m ridge, a 0·9 m ridge containing two rows 0·3 m apart, and a 0·75 m ridge. Highest yields and returns were obtained from the two-row, 0·9 m, ridge system, which also had certain cultural advantages.
The effect of sulphur deficiency on the uptake and incorporation of nitrogen in ryegrass
Authors: Millard P. , Sharp G. S. , Scott N. M.
Published: March 2009

Sulphur deficiency reduced the yield and sulphur content of ryegrass at the fourth cut, while increasing the nitrogen content and N:S ratio. The distribution of the forms of nitrogen was also altered, with a decrease in the proportion of nitrogen recovered as amino acids and an increase in the concentration of asparagine. Amino acid analysis showed that the concentrations of the sulphur-containing amino acids cyst(e)ine and methionine were depressed by sulphur deficiency as well as those of arginine, histidine, lysine, glycine, leucine, serine and threonine. Sulphur deficiency, therefore, decreases the quality of crude protein found in grass, as well as reducing the yield.
The effect of paclobutrazol on plant height and seed yield of oil-seed rape (Brassica napus L.)
Authors: Scarisbrick D. H. , Addo-Quaye A. A. , Daniels R. W. , Mahamud S.
Published: March 2009

The effect of paclobutrazol (applied at several concentrations and timings) on stem length and the seed yield of oil-seed rape was explored in three field trials during 1981–4. Spring applications were most effective in reducing plant height, but they had an adverse influence on the yield components. Autumn applications increased seed yield in one season, but were less effective in the final trial when soil conditions were much drier at establishment. Data indicated that autumn treatments may increase the productivity of the uppermost racemes. Future studies must investigate the persistency of paclobutrazol in the soil, and its possible influence on subsequent arable cropping.
Regulation of water loss under moisture stress in sunflower genotypes: stomatal sensitivity in relation to stomatal frequency, diffusive resistances and transpiration rate, at different canopy positions
Authors: Prasad T. G. , Sashidhar V. R. , Chari Malathi , Rao S. Rama , Devendra R. , Kumar M. Udaya
Published: March 2009

Transpiration rate, diffusive resistances, canopy conductances and water potentials were determined at three canopy positions in non·stressed and stressed plants of sunflower hybrid BSH·1 and five other cultivars of sunflower under field conditions. The leaf area (LA) and stomatal frequency (f) was determined at the three canopy positions in field·grown plants and the total number of stomata per plant was calculated as the product of LA and f. These variables were then related to the dry·matter accumulation and seed yield in these cultivars. Cultivars with either a high leaf area or high number of stomata per plant were more productive under non-stress conditions. Under stress conditions, cultivars differed in the extent of change in conductance (g) and transpiration rate at different canopy positions. In the hybrid BSH·1, g was low at all levels in the canopy associated with a higher (less negative) water potential and this hybrid had lower transpiration rates at all canopy levels under stress although the number of stomata per plant was high. Stomatal sensitivity associated with a higher threshold water potential for stomatal closure is discussed as a possible explanation for the higher dry·matter accumulation and productivity of hybrid sunflower BSH·1 under moisture stress conditions.
The effect on the rumen composition of feeding sheep diets supplying different starches. I. The variation in rumen composition of sheep fed lucerne or wheat as the sole diet
Authors: Chou K. C. , Walker D. M.
Published: March 2009

1. Three fistulated and four unfistulated crossbred sheep were each fed once daily with diets of lucerne or wheat.

2. A pre-feeding sample of the rumen liquid was examined for its content of protozoa, of various chemical components and for its enzymic activity on glucose and on soluble starch. Several samples were taken from each sheep at intervals over periods of up to 8 weeks, during which time the sheep were maintained solely on the single diet.

3. Considerable variation occurred, both between sheep and between samples from the same sheep, in the concentrations of ciliate protozoa and of lactic acid, especially on the wheat diet.

4. Analyses for nitrogen, pH, dissolved C02, volatile fatty acids and for the molar proportions of acetic and propionic acid showed differences due to diet.
The effect on the rumen composition of feeding sheep diets supplying different starches. II. The partition of nitrogen, pH, volatile fatty acids, protozoal numbers, enzymic activity and certain other chemical constituents
Authors: Chou K. C. , Walker D. M.
Published: March 2009

1. Three fistulated cross-bred sheep were fed diets which consisted solely of lucerne, cereals or potatoes. Potatoes were fed both in the raw and in the cooked form.

2. A pre-feeding sample of the rumen liquid was examined for its content of protozoa and various chemical components and for its enzymic activity on glucose and on soluble starch.
The effects of leys and their management on the yield of succeeding wheat crops on heavy land
Authors: Hanley F. , Ridgman W. J. , Jarvis R. H.
Published: March 2009

1. One long-term experiment comparing the effects of leys and arable cropping on the yield of arable crops and three experiments on the effect of management of lucerne/grass leys on the following arable crops, all conducted on heavy clay land, are described and the results discussed.

2. In the first two years after breaking a ley yields of wheat were higher than on plots which had had all-arable cropping and it is suggested that this effect could be due to a combination of disease and weed control and the nitrogen status of the soil.
The effect of potassium carbonate solution on the drying of lucerne: 1. Laboratory studies
Authors: Tullberg J. N. , Angus D. E.
Published: March 2009

The drying rate of fully exposed individual lucerne plants was substantially increased following brief immersion in 0·18 M potassium carbonate solution. The increase was maintained over a range of drying conditions, and at low moisture contents, but the use of more concentrated potassium carbonate solutions yielded no further increase. Changes in leaf:stem ratio had a smaller effect on the drying rate of potassium carbonate treated lucerne than on untreated lucerne.

Tests with diffusive resistance and viscous flow porometers support the hypothesis that potassium carbonate solution changes the water transmitting properties of the cuticular waxes.
Effects of sex and gonadectomy on the growth and development of Southdown × Romney cross lambs. Part I. Effects on live–weight growth and components of live weight
Authors: Everitt G. C. , Jury K. E.
Published: March 2009

The influence of sex and gonadectomy on liveweight growth and its components was examined in a comparative slaughter experiment using Southdown – Romney cross lambs run under New Zealand pastoral feeding conditions.

Twenty ram lambs were castrated and 20 ewe lambs spayed at docking, at approximately 4 weeks of age. Ten ram and 10 ewe lambs were killed at this age and 5 lambs from each of the four ‘sexes’ (entire and gonadectomized, male and female) were killed 4, 8,12 and 24 weeks after docking.

Live-weight gain was higher for males than females and higher for entire than gonadectomized lambs, with some evidence of a greater depression in growth associated with castration than spaying. Effects on carcass weight followed those on live weight; weights for entire rams, wethers, entire and spayed ewes were 16.92, 14.72, 14.02 and 12.46 kg. respectively at approximately 7 months of age.
The distribution of herbage at different heights in ‘grazed’ and ‘dung patch’ areas of a sward under two methods of grazing management
Authors: Tayler J. C. , Rudman J. E.
Published: March 2009

A study of the horizontal and vertical distribution of herbage in grass-dominant swards was made to assess the relative importance of different sources of wastage during grazing. A sward grazed by cattle under two contrasting managements was divided, for the purpose of herbage sampling, into two categories: ‘grazed’ herbage, on ground with no obvious dung contamination, and ‘dung patches’, which were of ungrazed or lightly grazed herbage resulting from the effects of faeces dropped at previous grazings. In each category, samples were cut at two successive heights to provide an estimate of the quantity of herbage in the upper region of the sward (over 2½ in. from ground level) and in the lower region (½-2½ in. from ground level).

After grazing, some 35% of the original crop remained in ‘grazed’ areas, and some 20% in ‘dung patches’. In terms of vertical distribution, most of the residue (40% of the original crop) was in the lower region, from ½ to 2½ in. above ground level.

Total production as live-weight gain was not significantly different, but the yield of conserved herbage was greater in treatment R (five rotations) than in treatment RR (nineteen rotations). Frequent grazing reduced herbage production, and this effect was not offset by any less intense defoliation of the frequently grazed sward. The average quantity of herbage residue was no higher in treatment RR than in treatment R, although the time of occupation per plot by the cattle in RR was only a quarter of that of the cattle in treatment R.
Heat tolerance in dehydrated steers
Authors: Bianca W.
Published: March 2009

Six steers kept in an environment of 15°C. were deprived of water for four consecutive days. This treatment, by depressing appetite, caused a reduction in voluntary hay intake to one-quarter of its normal level and a decrease in body weight by 10%.

In spite of this reduction in feed intake, which must have been accompanied by a fall in metabolic heat production, the animals were less able to tolerate heat than when they were normally watered: during 4 hr. exposures to temperatures of 40.0°C. dry bulb and 32.5°C. wet bulb the waterdepleted animals showed higher values of rectal and skin temperature. This was associated with a slower initial rise and lower final values of respiratory rate (130 versus 155 respirations/min.).
The effect of year, suckling, dry season and type of dam (ewe or gimmer) on milk production in East African Blackheaded sheep as measured by lamb growth
Authors: Sacker G. D. , Trail J. C. M.
Published: March 2009

1. The mean daily live weight gains of lambs were used to estimate the milk production of ewes and gimmers during the first 8 weeks of lactation. Records of 1178 lambings of East African Blackheaded sheep between the years 1952 and 1962 were available.

2. Gimmers had significantly lower production than second and subsequent lamb ewes. Ewes rearing twins had a significantly higher yield than ewes rearing singles. There appeared to be no difference in yield between ewes producing twins but rearing singles, and ewes rearing natural singles.

3. A long dry season with resultant lowered plane of nutrition significantly reduced the live-weight gain of lambs.
A yield-tenderometer relationship in shelled peas for adjusting yields to a given maturity
Authors: Berry G.
Published: March 2009

A model relating the yield of shelled peas to maturity, as measured by the tenderomoter, has been given. The model has been fitted satisfactorily to data from pea experiments carried out over a period of 4 years and covering a range of plant densities and irrigation treatments. Comparison with other published work suggested that the model may be generally applicable to wrinkled-seeded varieties. A formula is given for interpolation of pea yields to a given maturity, although it was shown that linear interpolation is generally adequate.
Rothamsted irrigation 1964–76
Authors: French B. K. , Legg B. J.
Published: March 2009

A series of irrigation experiments was done at Rothamsted where the soil is a flinty silty clay loam over flinty clay. The results are compared with those obtained by Penman (1962, 1970, 1971) at Woburn where the soil is a loamy sand over sand. The limiting deficits, Di, above which irrigation increased yields, were about 2·5 times greater at Rothamsted than at Woburn; this ratio approximates to the ratio of the water-holding capacities of the soils (– 0·1 to – 15 bar) to a depth of 1 m. The limiting deficits at Rothamsted were 80 mm for spring-sown field beans, 84 mm for main-crop potatoes, 100 mm for spring barley and 140 mm for spring and winter wheat. The responses to irrigation were not determined accurately as there were few years with a large response for any crop. However, the evidence is that the maximum response that could be expected for potatoes was 0·19 t/ha/mm water, and for grain dry matter of beans 0·006 t/ha/mm. The figure for potatoes agrees with that obtained by Penman at Woburn; the response of beans was much smaller at Rothamsted, partly because of severe attacks of broad bean stain virus.
Body composition in lactating sheep and its indirect measurement in the live animal using tritiated water
Authors: Foot J. Z. , Skedd E. , McFarlane D. N.
Published: March 2009

In two experiments with female Scottish Blackface or Border Leicester x Scottish Blackface sheep nine or ten animals were slaughtered in mid lactation and the remainder either in November at the time of the subsequent mating (Expt 1) or at weaning (Expt 2).

The sheep were infused periodically, including just before slaughter, with 100 μCi tritiated water (TOH) in order to measure total body water by dilution and to estimate body fat using the inverse relationship between the proportions of fat and water in the body. The accuracy of the methods was assessed when the sheep were slaughtered. In the ton lactating Scottish Blackface sheep of Expt 1 fat made up 11.5% of the total body weight with an S.D. of 8·38% whereas the 11 sheep slaughtered at mating were twice as fat (23·2, S.D. 4·01 %). The 25 Border Leicester × Blackface sheep were all thin, whether they were slaughtered in mid lactation (4·4, S.D. 2·56%) or at weaning (3·4, S.D. 2·81%).

The standard error of estimate of body water from TOH space in Expt 2 was 1·2 kg c.v. 2·8%) and lower in Expt 1.

The precision with which an animal could be weighed was very important in determining the accuracy with which body fat could be predicted from live weight and TOH space. In both experiments the standard error of estimate for body fat in lactating sheep was between 600 and 700 g, compared with 1·3–2·7 kg when body fat was predicted from live weight alone. These estimates were sufficiently accurate to be of value in following changes in body composition in live animals as their nutritional and physiological state alters and for comparing animals in groups where the average fatness is greater and the range wider than in the sheep used in Expt 2.
The distribution of insect pests on crops of oil-seed rape (Brassica napus L.) and the damage they cause
Authors: Free J. B. , Williams Ingrid H.
Published: March 2009

During 3 years the distribution of pests on ten crops of winter rape and two of spring rape, and the damage they caused, has been determined.

During immigration the adults of all pests infested crop edges more than crop centres, particularly on large crops, irrespective of the presence of wind breaks. The proportion of M. aeneus and G. assimilis at the crop edge gradually diminished as they moved further into the crop, and their larvae and pods with C. assimilis emergence holes were more evenly distributed over the crops than the adults. Damage by M. aeneus was not the only cause of podless stalks. The larvae of D. brassicae were largely confined to the edges of crops; split pods were largely but not solely confined to the edges.

In winter rape crops correlations were found between the percentage of podless stalks per plant and the number of M. aeneus present, and the percentage of pods infested with C. assimilis larvae and the adult C. assimilis population. In two fields infested with D. brassicae the diminution in the proportion of split pods from crop edge to crop centre was positively correlated with diminution in the number of adult D. brassicae.
Thermoneutral zone of chickens as determined by measuring heat production, respiration rate, and electromyographic and electroencephalographic activity in light and dark environments and changing ambient temperatures
Authors: Kampen M. Van , Mitchell B. W. , Siegel H. S.
Published: March 2009

Electromyographic (EMG) activity, electroencephalographic (EEG) activity, heat production (H), respiration rate (RR), and body temperature (TB) of unacclimatized chickens were measured during periods of light and darkness at ambient temperatures (Ta) between 7·7 and 37·7 °C. The difference between pectoral muscle and abdomen temperature was less than 0·1 °C over the entire temperature range. Body temperature increased (P ≤ O·l) when Tawas above 27·5 °C and was higher in the light than in the dark (P ≤ 0·05). Respiration rate decreased significantly with increasing Ta. The decrease, however, was not as great during the dark (P ≤ 0·05) as during the light period (P s£ 001). Heat production decreased (P ≤ 0·01) with increasingTaup toTa= 22·3 °C. There was no significant difference between heat production during the light period and that during the dark period. EMG amplitude declined (P ≤ 0·01) with increasingTaup to 27·5 °C in the light and 22·3 °C in the dark and was higher (P ≤ 0·05) in the light than in the dark. Mean frequency of EMG activity was independent of light andTa. The percentage of low-frequency EEG activity in the dark did not change significantly over the entireTarange, but in the light it decreased asTaincreased above 25·7 °C (P ≤ 0·05). The percentage of high-frequency EEG activity appeared as a mirror image of low-frequency activity. Overall results indicated a thermoneutral zone between 32·2 and 37·7 °C in the light and between 27·5 and 37·7 °C in the dark.
Loss of starch and fibre of whole grain in nylon bags suspended in the rumen of steers
Authors: Toland P. C.
Published: March 2009

Several investigations (Shaw & Norton, 1906; Darnell & Copeland, 1936; Kimberley, 1976) have reported no appreciable loss of nutrients of unbroken grain voided by cattle. Although the chemical composition of voided whole grain may be similar to the grain as fed, losses in grain dry matter ranging from 10 to 26% for cereal grains passing through the alimentary tract of steers have been measured (Toland, 1976, 1978a, 6). In one of these studies (Toland, 19786) the disappearance of grain dry matter of whole oats and wheat in nylon bags suspended in the rumen for 48 h was approximately 20 and 35 % respectively. Further analyses of this dry matter remaining in the nylon bags for 48 and 96 h of incubation would indicate which components of the grain were being broken down in rumen fermentation. This report provides information on the differential loss of the fibre and starch components of the grain dry matter from incubation in nylon bags for the two varieties each of oats and wheat and for an additional cereal grain, triticale.
Animal production studies in Jamaica. IV. The costs of developing and maintaining pangola grass pastures
Authors: Nestel B. L.
Published: March 2009

The cost of developing and maintaining pangola grass pastures has been examined under a range of conditions. The direct cost of improving pastures to the stage where they were established as 5–10 acre, fenced, watered units of pangola grass was about £30 per acre. Under favourable conditions this cost could be reduced to £20, but with difficult land or poor techniques the cost could rise to £40 or more per acre. In addition to the direct cost of establishment there was an indirect cost due to land being out of use or stock numbers having to be reduced. This indirect cost appeared to be highest on lands where planting costs were least. It was suggested that there might be an inverse relationship between direct and indirect costs which tended to narrow the total range of establishment costs.
Evaluation of the number of spermatozoa in bull semen. A comparison between electronic counting, light scattering and absorptiometry
Authors: Iversen Simon
Published: March 2009

The number of spermatozoa in bull semen was determined by electronic counting, light scattering and absorptiometry. Electronic counting was found to be accurate, fast and reliable and seems to be the method of choice.

Determination of the light scattering was found to be the more sensitive of the indirect methods, but absorptiometry also yields consistent and reliable results. The accuracy obtained by absorptiometry was found to be independent of the sensitivity of the instrument.
The relationships between tuber size and tuber concentrations of nitrogen, phosphorus and potassium
Authors: Allen E. J. , Wurr D. C. E.
Published: March 2009

In each of two experiments two potato varieties were grown at a range of plant densities in order to provide mature tubers of different sizes for the study of the relationshipsbetween tuber size and tuber concentration of nitrogen (N), phosphorus (P) and potassium (K). As tuber size increased, the concentrations of tuber nutrients (g/100 g dry matter) declined to a minimum value and then tended to increase with a further increase in tuber size. This suggests that when tuber samples are taken for the determination of tuber nutrient concentration on a dry-weight basis the sampling procedure should ensure that results do not vary because of differences in the tuber size distribution.
Intake and utilization of food by growing lambs with parasitic damage to the small intestine caused by daily dosing with Trichostrongylus colubriformis larvae
Authors: Sykes A. R. , Coop R. L.
Published: March 2009

Four groups of eight lambs, 4 months of age and reared parasite-free from birth, were used to investigate the effect of the intestinal parasite Trichostrongylus colubriformis on the intake and efficiency of utilization of food, using balance trial and comparative slaughter techniques. One group (CI) was killed initially as control. Two further groups (ALC and ALI) were offered ad libitum a complete ruminant diet. The ALI group was dosed orally each day for 14 weeks with 2500 infective larvae. Sheep in a further group (PF) were individually paired to members of the ALI group, and given the same amount of food as their pair. Balances of nitrogen, Ca and P and the digestibility of dry matter and energy were determined for the ALI and PF groups during weeks 6–7 and 12–13 and after 98 days of infection the sheep were killed. The bodies of these and the CI and ALC sheep were analysed for water, fat, nitrogen, Ca and P contents.

Parasitism reduced food intake over the whole experiment by 9%, but had no effect on the digestibility of energy or nitrogen. At the first trial the N balances of the ALI group were inferior to those of the PF group due to increased urinary N excretion, but there was no difference at the second trial. Ca and P balances of the ALI group tended to be inferior to those of the PF group at both trials. The weight gain of the ALI sheep was only 50 % of that of the PF sheep with the same digestible energy and protein intakes. The protein content of the gain in empty body weight of the ALI sheep was 80 g/kg compared with 112 and 124g/kg in the ALC and PF groups, respectively. Possible causes of the poor protein anabolism are discussed.

The gross efficiency of utilization of metabolizable energy for growth was calculated to be 13·3 % in the ALI sheep, compared with 26·2 and 24·2 % respectively, in the ALC and PF groups. It was not possible to determine whether this was due to change in maintenance requirement or in efficiency of fattening.

The Ca and P content of the skeletons of the ALC and PF sheep increased by 55 % during the 98-day period, while no net change occurred in the ALI sheep. It was concluded that this was caused by an induced mineral deficiency resulting from parasitic damage in the small intestine.