bluuebunny/crossref_metadata_2025 huggingface dataset:
Attempts at storage of sheep ova at low temperatures
Authors: Averill R. L. W. , Rowson L. E. A.
Published: March 2009

Eighty-three fertilized sheep ova were stored at 0–8° C. for 6–72 hr. in sterile sheep serum or Ringer's solution and subsequently transferred to suitable recipient ewes in order to determine their viability following storage.

In Exp. 1, nine out of twelve ova stored in sheep serum, but none out of five ova stored in Ringer's solution, continued development after subjection to storage at 5–8° C. for 6–9 hr. Seven out of fifteen, none of nineteen, and none of nine ova were found developing in recipients after subjection to 5–8° C. in serum for 24, 48 and 72 hr., respectively.

In Exp. 2, lambs were born to recipients of four out of six ova stored for 24 hr. at 4·5–7° C, and of two out of five ova stored for 72 hr. at these temperatures. None of the recipients of twelve ova stored for 24, 48 and 72 hr. (four ova of each duration) at 0·4° C. produced live lambs.

In Exp. 3, none of thirty-four ova developed after subjection to freezing to −79° C. in 12·5% glycerol in serum.
Experiments on the nutrition of the dairy heifer. II. Experimental methods in short-term experiments
Authors: Bailey G. L. , Broster W. H. , Burt A. W. A.
Published: March 2009

1. Data from twenty-four short-term trials on the nutrition of dairy heifers have been used in a study of the effects of management, method of estimation of live-weight gain, length of experimental period, covariance analysis and the use of monozygous twins upon experimental error.

2. The value of rigid adherence to a routine and allowing ample time for the animals to settle down before the trial have been demonstrated.

3. Error standard deviations were associated with length of experimental period, those for 42-day periods being about half those per 21-day periods, but were not appreciably correlated with initial live weight.

4. No advantage could be demonstrated for the use of monozygous twins, or covariance analysis with initial weight or rate of gain, indicating that genetic effects contributed little to the error in experiments lasting 3–6 weeks.

5. There was no significant difference between errors in live-weight gains calculated from the regression of live weight on time, from single initial and final weights, or from two initial and final live weights, indicating that deviations from linear regression are not solely in the nature of random day to day fluctuations in live weight.
The effect of selection for heifer milk yield on the production level of mature cows
Authors: Robertson Alan , Khishin S. S.
Published: March 2009

The effect of selection of dairy bulls on their daughters' 1st lactation yields has been investigated, using contemporary comparison information availreable for some 1273 bulls. It was shown that incomplete repeatability of individual records would introduce a negative bias into the regression of the increase in production of a bull's daughters with age on his contemporary comparison and this bias was calculated. The observed regressions on 1st lactation contemporary comparison were close to zero after correction for bias both for increase from 1st lactation yield to 2nd (— 0·08) and for the increase from 2nd lactation to 3rd (+ 0·09). Selection on 1st lactation yield should not, therefore, change the increase of yield with age, in agreement with results of other workers. The results are related to the problem of the heritability of the separate lactations.
The production of living sheep eggs
Authors: Averill R. L. W.
Published: March 2009

1. In the 1954–5 and 1955–6 breeding seasons, 117 ewes of the Border Leicester, Welsh Mountain and Suffolk breeds were used in order to investigate the effects of PMS treatments on (a) the length of the dioestrous cycle, (b) the number of ovulations per ewe, (c) the proportion of eggs which were cleaved, uncleaved or abnormal when recovered, and (d) the ability of fertilized superovulated eggs to develop normally.

2. In the 1954 and 1955 anoestrous periods, ninety-four 2-tooth and mature ewes of mixed breeds were used in order to investigate (a) the proportion of ewes which could be induced to ovulate and exhibit oestrus as a result of treatment with progesterone and PMS, (b) the proportion of the mated ewes which had cleaved, uncleaved or abnormal eggs, and (c) the ability of fertilized eggs shed during anoestrum to develop normally up to the 21st day of pregnancy.

3. Dioestrous cycles in untreated ewes were significantly shorter for Welsh Mountain than for Border Leicester ewes, and their length was not affected by the year in which they were measured. The first and second cycles of the breeding season tended to be shorter than the third cycle.

4. The length of the dioestrous cycle was shortened by treatment of both Border Leicester and Welsh Mountain ewes with PMS. The average extent of this reduction was 0·6 days, and the effect was significant.
The effect of protein level on the digestibility of the carbohydrates
Authors: Bolton W.
Published: March 2009

1. The effect of different levels of protein on the digestibility of the carbohydrate fraction of two compounded diets which differed widely in their contents of indigestible organic matter has been determined.

2. Digestibility of the available carbohydrate (the sugars, dextrins and starches expressed as starch) apparently increased with increase in the protein content of the diet.

3. Alteration in the cereal portion of the diet involves an adjustment in the amount of protein supplement if the nutritive ratio is to remain unaltered.
The influence of irrigation frequency on growth and yield of groundnuts (Arachis hypogaeaL.) under arid conditions
Authors: Ishag H. M.
Published: March 2009

A study was carried out for 2 years in the arid zone of the northern region of the Sudan to investigate the effects of watering intervals on flowering, growth, yield and yield components of three groundnut cultivars. The variation in air temperature prevailing above the canopy through frequent and extended watering intervals affected the periodicity of flowering. MH 383 gave the highest pod yield and it was drought tolerant compared with Ashford and Turkish cultivars. Pod losses were smaller with longer watering intervals. Number of pods per plant was the yield component most affected by watering. Leaf area index increased with frequent watering and reached a value of 5·8. Net assimilation rate decreased at first, but later increased with the pegging of gynophores.
Genotype-environment interactions in fodder kale (Brassica oleracea L.)
Authors: Bradshaw J. E. , Chapman I. M. , Young A.
Published: March 2009

Two potential new kale cultivars were compared with five control cultivars in 12 trials involving five sites in the north of England and the south of Scotland, 2 years, and a range of sowing and harvest dates.

The differences between cultivars were small for dry-matter and digestible organic-matter yield. Genotype-environment interactions were relatively large by comparison and hence only tentative estimates could be made of relative yield performance in a wider range of environments. However, the set of trials was satisfactory for determining the heights, dry-matter contents and digestible organic-matter contents of the cultivars despite the presence of statistically significant genotype-environment interactions.

Joint regression analyses revealed that the two cultivars with the lowest mean freshweight yields were also the least responsive to environmental change and that environments resulting in low digestible organic-matter contents were best for discriminating between cultivars.
The digestion of untreated and formaldehyde-treated soya-bean meals and estimation of their rumen degradabilities by different methods
Authors: Rooke J. A. , Norton B. W. , Armstrong D. G.
Published: March 2009

The effect of treating soya-bean meal with formaldehyde was studied in cattle by supplementing a hay–barley diet with two levels of either untreated or formaldehydetreated soya-bean meal. The formaldehyde treatment had no significant effect upon apparent N digestibility in the whole tract; it increased the amounts of non-ammonia N and amino acid N entering the small intestine but this increase was not statistically significant. However, increasing the proportion of either soya-bean meal in the diet increased the flow of non-ammonia N to the small intestine and apparent N digestibility in the whole tract. The formaldehyde treatment reduced the apparent degradability of the soya-bean meal N, determinedin vivofrom 0·74 for the untreated meal to 0·38 for the formaldehyde-treated meal. Thein saccotechnique produced values for the apparent degradability of the two soya-bean meals which ranked them in a similar manner as did thein vivotechnique but gave lower values for degradability than thein vivotechnique.
Interactions between rate, spray interval and number of applications of the synthetic pyrethroid Decis in cow pea (Vigna unguiculata) pest control
Authors: Dina S. O.
Published: March 2009

The relationship between rate, spray interval and number of applications of Decis for pest control in cow pea was investigated. In 1978 and 1979, neither the rates nor the interaction effects were significant in grain yield when 12·5 and 25·0g a.i./ha of Decis were applied three times weekly or twice at intervals of 10 or 14 days.

Further trials in 1980 showed that for the contro l of thrips (M. sjostedti), rate, interval and number of applications were significant for samples at 49 days after planting and beyond, suggesting that the residual life of Decis is about 10 days. Three applications were significantly better than two for lowering the population of C. tomentosicollis and the number × interval interaction was also significant. The number, rate and interval were significant without interaction effects for shrivelled pods caused by all hemipteran pests. In all the trials in 1980 and 1981, damage by the pod borer M. testulalis was low. Rate and number × interval interaction were generally significant but no differences were observed in grain yield. However, in 1980 the higher rate and three applications gave better quality crop, resulting from less hemipteran damage.

An analysis of cost–benefit of the trial showed that 12·5 g a.i./ha gave higher returns than 25 g, as did two applications than three, but the trend in the spray interval was less consistent.
A multivariate study of pig carcass growth and composition: 1. production and Grading Characteristics
Authors: Evans D. G. , Kempster A. J.
Published: March 2009

Pigs from different companies (source populations) in years 3–5 of the Meat and Livestock Commission's Commercial Pig Evaluation were characterized in terms of eight production characteristics and grading measurements using canonical variates analysis in a multivariate general linear model. For pigs fed to a restricted scale, the first canonical variate was strongly associated with fat thickness measurements and the efficiency with which feed was converted into live-weight gain (FCR); the second canonical variate was associated with killing-out percentage. For pigs fedad libitum, a discriminant variate formed from the sum of the first two canonical variates was strongly associated with P2and loin fat thickness measurements and FCR, and a discriminant variate formed from the difference of the first two canonical variates was strongly associated with killing out, length and shoulder fat thickness. The first three canonical variates accounted for 88 and 90% of the variation between source populations for restricted andad-libitumfed pigs respectively. A graphical display of the source populations indicated that there were six to eight groupings depending on feeding regimen.

In principal component analyses of residual variation, the first principal component on both feeding regimens was strongly associated with fat thickness measurements. The first three principal components accounted for 91 and 90% respectively of the variation for restricted andad-libitumfed pigs.
White-seeded beans (Phaseolus vulgaris) resistant to halo blight (Pseudomonas phaseolicola), to bean common mosaic virus, and to anthracnose (Colletotrichum lindemuthianum)
Authors: Conway Janet , Hardwick R. C. , Innes N. L. , Taylor J. D. , Walkey D. G. A.
Published: March 2009

Halo blight resistance was transferred in a backcrossing programme from PI 150414 to a Michigan-type bean. The resistant selections obtained gave yields that were up to 10% higher than that of cv. Seafarer and had seed of good quality that was suitable for baking in tomato sauce. These selections were also resistant to the common strains of bean common mosaic virus (BCMV) and to the lambda race of anthracnose.

In addition, selections with white seed of similar size to Seafarer were obtained from crosses between Seafarer and cold-tolerant lines with large, coloured seeds. In trials over 4 years these selections gave 20% higher yields than Seafarer and were less sensitive to environmental changes. Like Seafarer, they were homozygous for theIgene for resistance to BCMV but were susceptible to halo blight and anthracnose. Although not as suitable for canning in tomato sauce as other material in the National Vegetable Research Station programme, they offer useful parental material for further cycles of breeding.
The effect ofRhizobiuminoculation on white clover in improved hill soils in the United Kingdom
Authors: Newbould P. , Holding A. J. , Davies G. J. , Rangeley Anne , Copeman G. J. F. , Davies A. , Frame J. , Haystead A. , Herriott J. B. D. , Holmes J. C. , Lowe J. F. , Parker J. W. G. , Waterson H. A. , Wildig J. , Wray J. P. , Younie D.
Published: March 2009

The benefits to establishment and growth of white clover cvs Aberystwyth S.184 and Grasslands Huia of inoculation with three strains ofRhizobium trifolii, using the peat or liquid inoculum techniques, were investigated during 1975–8 on improved hill soils ranging from brown earth through dry and wet peaty podzol to deep peat.

Inoculation induced positive response in either number of seedlings, plant cover or dry-matter production in 18 out of 139 comparisons, had no effect in 118 and produced a negative response in three. Most of the positive responses to inoculation were at sites with wet peaty podzol or deep peat soils but of the five sites where increase in clover D.M. production was found in the first harvest year one was a brown earth. The positive agronomic responses occurred only when the proportion of plants with nodules was high and where a substantial proportion ( > 50%) of the latter contained introducedRhizobiumstrains at least in the year of sowing. The three negative responses were in numbers of seedlings on one brown earth and two dry peaty podzol soils and with the Huia cultivar only. Despite lack of statistical significance at individual sites the dominant overall trend was for inoculation to enhance seedling establishment and the early growtli of white clover in all soil types.

On one brown earth and one dry peaty podzol soil there was some evidence that spraying theRhizobiumon to emerging white clover seedlings was more beneficial, atleast in microbiological terms, than the customary peat inoculum procedure.

The incorporation of even a small amount of nitrogen (30 kg/ha) into the seed bed at the time of sowing adversely affected germination, establishment and growth of white clover in some soils. Sometimes the effects of this nitrogen persisted into the first harvest year.
The apparent digestibility of crude protein by the ruminant: III. The application of the general equation to rations containing urea
Authors: French M. H.
Published: March 2009

The digestibility of the crude-protein equivalent (N × 6·25) of rations containing urea conforms with the general equation, y = 70 log x − 15, correlating the dry-matter crude-protein content (x) with its coefficient of digestibility (y), irrespective of whether the urea nitrogen is absorbed as ammonium salts or converted to microbial protein prior to digestion.
Reproduction in farmed red deer:3. Hind growth and mortality
Authors: Blaxter K. L. , Boyne A. W. , Hamilton W. J.
Published: March 2009

The growth and mortality of red deer hinds from 3 months of age were analysed using data from a farmed stock. Calf mortality from 3 to 15 months of age was 11 % and was highest in the 2 months immediately after weaning. Mortality in the 8 years subsequent to the hinds reaching 15 months was low and based on 924 yearly records of survival was 1·8% per annum.

The rate of growth of the calves during their first winter was markedly affected by the amount of feed given and slightly (though highly significantly) greater for the larger calves. In the subsequent summer there was no effect of weaning weight on gain. This varied considerably from year to year.

The subsequent growth of the hinds showed that an equilibrium weight of about 82 kg was achieved, and that body weight at the beginning of the year, age, and whether or not the hind produced a calf, all affected the increase in body weight during a particular year.

The results are combined to estimate the effects of culling the hind stock at different ages on the number of surplus female calves and the effects on lifetime reproductive performance of the body weight of hinds when 15 months of age. The latter can be predicted from weaning weight and winter feed intake provided gain from 10 to 15 months at pasture can be estimated. The partial effects of giving additional concentrated feed in the first winter were estimated and found to be appreciable.

Comparisons of the results are made with mortality rates and body weights estimated by others for wild populations.
Effects of feed restriction during the laying period on the performance of two strains of mature caged commercial layers in the humid tropics
Authors: Benyi K. , Akinokun O. , Lebbie S. H. B.
Published: March 2009

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

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

Strain × treatment interaction had significant effects on egg production and feed efficiency.
The role of protein supplements in nutrition of young grazing cattle and their subsequent productivity
Authors: Hennessy D. W. , Williamson P. J. , Lowe R. F. , Baigent D. R.
Published: March 2009

The effects of supplements of protein meal or sorghum grain given to young cattle for 140 days during their first winter and spring post-weaning, were recorded over 560 days for cattle grazing on low quality pastures in subtropical Australia. The supplements were offered to steers in four treatment groups, replicated three times, at the following rates per head to late spring: (a) mineral mix (M) + cotton-seed hulls, 90g/day (control), (b) M + protein meal, 600 g/day (protein daily), (c) as for (b) but at 2·1 kg/3·5 days (protein twice-weekly), or (d) M + sorghum grain, 560 g/day (sorghum). For the next 130 days, to late summer, only supplement (c) was continued while the remaining three groups were not supplemented. None of the supplements was offered for the final 290 days of the experiment when the steers grazed an improved pasture.

At the end of the first spring, the live weight of the steers supplemented daily and twice-weekly with protein was respectively 229 and 216 kg. These were significantly (p < 0·01) heavier than the sorghum-supplemented (174 kg) or control steers (160 kg). At the end of the first summer, the steers given supplements of protein meal twiceweekly, or daily, remained significantly heavier (265, 250 kg respectively) than sorghum-supplemented or control steers (209, 198 kg). By the second summer, the steers previously given protein supplements were still heavier than the steers from the control group (357v. 317 kg, respectively).

In steers which were offered the protein supplement during winter and spring, samples of blood taken at the end of spring had lower (P< 0·01) plasma ratios of glycine to branched-chain amino acids (valine, leucine and isoleucine) and a lower ratio of methionine: valine, than in the steers which were not offered the supplement. These ratios were significantly (P< 0·05) correlated with live-weight change over the preceding 140 days. On this basis it was considered that the improved growth of the steers offered the protein supplements was associated with an increased availability of specific essential amino acids, which may have initiated in the steers an increased appetite for pasture D.M.
The effects of feeding protected and unprotected casein on the milk production of cows grazing ryegrass
Authors: Minson D. J.
Published: March 2009

Milk production of cows grazing Rhodes grass without the addition of grain supplements can be increased by feeding casein protected from deamination in the rumen with formaldehyde (Stobbs, Minson & McLeod 1977; Flores, Stobbs & Minson, 1979). No increase in milk production was achieved when unprotected casein was fed, indicating that production on a tropical grass was limited by the quantity of amino acids absorbed from the small intestines (Stobbs et al. 1977). Formaldehydetreated casein (formal-casein) increased by 5% the milk production of cows grazing ryegrass in New Zealand when an energy supplement was also fed but had no effect oh milk yield when only ryegrass was fed (Wilson, 1970). In a review of this subject Clark (1975) reported that pen studies showed post-ruminal supplementation with casein increased milk production from 1 to 4 kg/day. The result with ryegrass in the absence of an energy supplement is therefore unexpected and warrants further study.
A revised model for the estimation of protein degradability in the rumen
Authors: McDonald I.
Published: March 2009

Estimates of the degradability of protein in the rumen are essential for the application of new systems which have been suggested for the evaluation of the protein requirements of ruminants (Agricultural Research Council, 1980). The effective percentage degradability (P) of protein supplements in the rumen is dependent not only on the course of degradation of the protein particles in the rumen, but also on the time distribution of their stay in the rumen, and will decrease if there is an increase in the rate of passage of the particles. It was shown by Ørskov & McDonald (1979) that if the percentage protein disappearance (p) from samples incubated for time t is described by the equation and if k is the fractional rate of passage from the rumen, then the effective degradability can be calculated as . The calculation depends on the equation for p remaining valid from t =0 (time of ingestion) until a time when all the particles have passed beyond the rumen. It has been found that for some protein supplements, linseed meal for example, the equation for p does not hold true for low values of t. The present note proposes a modification to the formula for effective degradability so that it may remain valid under these circumstances.
Availability of magnesium in soils
Authors: Alston A. M.
Published: March 2009

Twenty-five soils, including some subsoils, with widely differing properties were cropped with perennial ryegrass in the glasshouse, and measures of Mg availability in the soils were related to the Mg concentration in the plants.

No single measure satisfactorily characterized Mg availability. The ion activity ratio, √aMg/√aca+Mg when the soil neither gained nor lost Mg on equilibration with 0–02 N-CaC12, was more highly correlated (r = 0·;75***) with Mg concentration in the ryegrass than was the best of the capacity measures tested (CaCl2-extractable Mg, r = 0·68***), particularly if the potential buffering capacity (PBCMg) of the soils was also taken into account, in which case r = 0·83***.

Exchangeable Mg (r = 0·67***) was a poorer index of Mg availability than percentage Mg saturation (r = 0·73***) or exchangeable Mg expressed as a percentage of the total exchangeable bases (K, Na, Ca and Mg) in the soil (r = 0·81***). This latter quantity was better than the activity ratio as a predictor of Mg availability (r = 0·81*** compared with r = 0·75***).

A significant proportion of the variation in Mg concentration in the ryegrass could be attributed to the K content of the soils, and closer correlations were obtained when K was included in the composite activity ratio, √aMg/(√aca+Mg + B. aK) (r = 0·88***) or when a term for exchangeable K was included in regression analysis with √aMg/√aca+Mg and PBCMg (r = 0·93***).

The concentration of Mg in equilibrium soil solutions was generally a less satisfactory indicator of Mg availability than were the activity ratios. Soils derived from basaltic parent material had much higher contents of readily exchangeable Mg than the remainder: parent materials other than basalt had little influence on the availability of Mg in the soils. Exchangeable Mg and per cent Mg saturation were higher in gleyed soils than in freely drained soils derived from similar parent material.
A relationship between thyroid activity, acetate infusion and food intake in rams
Authors: Borhami B. E. A. , El-Shazly K.
Published: March 2009

Six mature rams were used in a 6 × 6 latin square experiment. They were put on a high concentrate ad lib. diet. Voluntary food intake was measured on the rams which received the following treatments: control, thiouracil, sodium acetate, thyroxine, sodium acetate plus thiouracil and sodium acetate plus thyroxine. Acetate was infused intraruminally at the level of 6·2 g/kg W0·75 per day for 4 successive days. Thyroxine was injected subcutaneously at the level of 0·3, 0·6, 0·9 and 0·9 mg/kg W0·75/day successively. Thiouracil was given orally as the propionyl derivative at a level of 0·03, 0·06, 0·06 and 0·06 g/kg W0·75/day successively.

Respiration rate, pulse rate and rectal temperature were measured before and 1 h after dosing. A period of at least 25 days was allowed between the trials. All the results were calculated as feed intake (g dry matter)/kg W0·75.

Injection of thyroxine, sodium acetate and both together inhibited food intake significantly. Thiouracil showed no significant effect on feed intake but it relieved part of the depression caused by acetate. Pulse rate showed significant differences between treatments but rectal temperature and respiration rate did not change significantly. The results are discussed in the text.
Estimates of the frequency of fertilization in field beans (Vicia faba L.)
Authors: Rowland G. G. , Bond D. A. , Parker Mary L.
Published: March 2009

Fertilization of four field bean cultivars was examined in irrigated and non-irrigated plots. The overall fertilization of the ovules examined was 33%; in irrigated plots it was 25% and in non-irrigated plots, 41%. Only 48% of fully formed flowers had at least one fertilized ovule. Fertilized ovules occurred most frequently at the first ovule position in the ovary (nearest the stigma), and this frequency declined at successive ovule positions. There was in general a higher fertilization percentage at the upper flowering nodes while fertilization percentage dropped from the first flower position in a raceme to the last. At all the flowering nodes and raceme-flower positions, the cultivars Erfordia and Outlook generally had a higher fertilization frequency than Maris Bead or TI. The significance of these results is discussed.
The contribution of clay and organic matter to the cation exchange capacity of the soil
Authors: Hallsworth E. G. , Wilkinson G. K.
Published: March 2009

Partial regression analyses have been used to calculate mean values for the cation exchange capacities of the clay and organic matter from five groups of soils.

It has been found that figures obtained for exchange capacities of the clays were in accord with what was known of their mineralogical composition. The corresponding figures for humus differed widely, the differences approaching significance, and were related to the mean pH of the soil group concerned.

The data on which this paper is based were obtained when the authors were at the Agricultural Chemistry laboratories of the University of Sydney, to the Research Grants Committee of which they are greatly indebted for generous financial assistance. They are particularly indebted to Dr G. Wilkinson, C.S.I.R.O., Division of Statistics, Adelaide, for helpful discussions, to Miss H. V. Rayner and Miss J. Walker for certain of the analyses.
Effects of planting date on growth and yield of pigeon pea (Cajanus cajan(L.) Millsp.)
Authors: Hammerton J. L.
Published: March 2009

Two dwarf pigeon pea cultivars, each at two spacings, were planted at 4-weekly intervals over a year. Differences in height and number of branches between cultivars and spacings were generally small but planting date had much greater effects. Heights at reaping were > 2 m in plantings made in March or April, but decreased with later planting toca. 1 m in November–February plantings. Time from planting to reaping varied fromca. 120 days in September-February plantings to > 225 days in March or April plantings. Four of the 13 plantings showed loss of mainstem dominance. Defoliation by rust disease showed no seasonal pattern, nor any association with yield. March plantings showed a ‘preliminary’ flowering in which only some wide-spaced and perimeter plants flowered in late July. Yields varied from 0–5 to 10 t/ha as green pods, but one cultivar at a spacing of 0·45 × 0·45 m (49385/ha) gave a mean yield ofca.5 ±0·57 t/ha. Late-May planting appeared the most efficient, giving a large number of pods per day, per flowering branch and per metre of height, but plants exceeded 2 m in height and took 200 days from planting to reaping. December or January planting gave smaller plants, takingca. 125 days from planting to reaping. Day-length was a dominant factor influencing growth and yield, but part of this may have been a response to radiation rather than to photoperiod.
Comparison of the production rate of bacteria in the rumen of buffalo calves estimated by using labelledStreptococcus bovisand mixed ruminal bacterial cells
Authors: Verma D. N. , Singh U. B. , Srivastava S. K. , Srivastava R. V. N.
Published: March 2009

The rate of production of bacteria in the rumen of buffalo calves kept on two rations was measured using14C labelledStreptococcus bovisand35S whole ruminal bacterial cells. The animals received daily either 15–20 kg green maize or 25–30 kg green cow pea in 12 equal amounts at 2-h intervals. The bacterial cells from the rumen of animals maintained on the same diet were tagged with35S byin vitroincubation in the presence of35S-sodium sulphate. SimilarlyStreptococcus bovisof rumen origin was grown in the presence of U-14C dl-leucine. The cells were injected into the rumen in a single dose. The dilution of the specific radioactivity of bacterial cells in the rumen with time was taken for calculation of the turnover time and rate of production of bacteria.

The average production rates of bacteria were 88·3 ± 3·88 and 92·3 ± 1·82 g/kg digestible organic matter and 101·8 ± 1·55 and 103·3 ± 1·49 g/kg digestible organic matter in animals fed green maize and cow pea, when estimated by using mixed rumen whole bacterial cells andStreptococcus bovisrespectively. There was no significant difference in the rate of bacteria production when estimated by either method.
A theoretical examination of Burns' (1975) equation for predicting the leaching of nitrate fertilizer applied to a soil surface
Authors: Towner G. D.
Published: March 2009

The modelling of the redistribution of soluble salts in soils, in which it is assumed that the amount of water transferred from layer to layer is related to the excess over field capacity of the water content of a layer, is critically examined.

The equation obtained from the dispersion equation by neglecting the diffusive term is solved for the leaching of surface-applied nitrates. It is shown that, by comparing the finite-difference form of this equation to the algebraic formulation of Burns' (1975) model, the two approaches are essentially the same, but that Burns makes approximations that are too inaccurate. In particular, it is incorrect to relate the transfer of water to the excess over the field capacity of the water content of the layer. Burns' model, when applied correctly, requiresmany calculations to be performed, which is costly of computer time. However, it is unnecessary in this problem as the analytic solution is simple and quick to apply.
Effect of leaf and flower removal on seed yield of lentil [Lens esculenta(L.)]
Authors: Pandey R. K.
Published: March 2009

Field studies were carried out to determine the sources of photosynthate for developing pods and to assess the effect of defoliation and flower removal at different stages on the performance of lentil. The leaves of flowering nodes were the primary source of assimilate to pods. Removal of 25–75% of leaves reduced seed yield by varying degrees depending on crop growth stage. The plants compensated for the loss of foliage to some extent, possibly through increased efficiency of the remaining leaves. One complete or 50% defoliation reduced seed yield to different extents at the vegetative, flowering, early pod formation and late pod formation stages, the greatest effect being seen at flowering and early pod formation. Plants compensated considerably by production of new leaves when defoliated at the vegetative phase. Increased moisture supply greatly enhanced the compensation ability of the lentil plants.

Removal of all flowers up to 1–2 weeks after an thesis under unirrigated conditions and up to 3 weeks after anthesis in irrigated conditions did not adversely affect the seed yield. Flower removal beyond this period resulted in a significant reduction in seed yield. Little seed yield was obtained when flower removal was continued for either 6 or 8 weeks under unirrigated conditions. The plants compensated for the loss of earlier-formed flowers by setting pods from later-formed flowers. Compensation was greatly enhanced when the crop was irrigated during the reproductive phase. There was relatively little or no effect of the deflowering treatments on the number of seeds per pod or weight per seed. The flowering period of the deflowered plants was extended and their senescence was delayed. When 25% of the flowers were removed at different intervals during the reproductive phase, seed yield was not adversely affected. An increased intensity of flower removal decreased yield but the decrease was not proportional to the degree of flower removal. The plants apparently compensated by setting new pods.
The digestibility of Rhodes grass (Chloris gayana) in relation to season and proportion of the diet of sheep
Authors: Tagari H. , Ben-Ghedalia D.
Published: March 2009

Digestibility trials were carried out to study the digestibility of Rhodes grass fed alone and in mixed concentrate diets. Twelve Awassi rams were used to examine the seasonal effect on the digestibility of Rhodes grass harvested at 21-day intervals.

A consistent increase in the content of crude protein up to the 6th harvest was observed, being accompanied by an increase in crude protein digestibility and voluntary feed intake.

In the second experiment Rhodes grass and concentrate mixed diets were examined. Sixteen Awassi rams were allocated to four diets which included 16, 32, 52 and 100% Rhodes grass. Dry-matter digestibility was found significantly different between the all-grass diet and the rest. The digestibility of crude fibre in the whole diet decreased significantly with the increase in concentrate content. The digestibility of crude fibre of Rhodes origin was calculated. It appears that the detrimental effect of concentrate on the digestibility of crude fibre of Rhodes grass origin is limited. This finding is supported by the high C2/C3 ratios in rumen liquor which were maintained up to 68% concentrate in the diet.

This study indicates that Rhodes grass may serve as a highly efficient roughage component in dairy rations.
The growth and carcass composition of strains of mice selected for large and small body size
Authors: Fowler Ruth E.
Published: March 2009

The growth and carcass composition of two strains of mice (N- andC-strain), which had both been selected for large and small body size by Falconer, have been studied.

Differences in body weight between mice of theN-strain and their controls were apparent at birth and were fully maintained up to 30 weeks of age. The patterns of growth were similar in all three lines, although the large line grew at a faster rate than the small line, the controls being intermediate. Differences in absolute and relative rates of growth between the three lines reach a maximum from 21 to 35 days of age and declined thereafter.

Growth in the large line of theN-strain from 14 to 40 days of age was largely due to an increase in body protein and water; after this age, increase in weight was caused mainly by fat deposition. In the small line of this strain, protein, water and fat were deposited at a more constant rate during the whole growing period. Differences in rates of growth may account for the differences in the percentage composition found between mice of the large and small lines of theN-strain at the same age.
Studies on the nutritive value of some common Egyptian feedingstuffs. II. Effect of concentrates rich in proteins on cellulose and dry-matter digestion
Authors: Akkada A. R. Abou , El-Shazly K.
Published: March 2009

1. In a series of digestibility trials using two Rahmany ewes (see previous publication, el-Shazly, 1958), protein supplements in the form of concentrates, pure proteins or green roughage, supplying 10.16 g. N per day, did not affect significantly the digestibility of cellulose in wheat straw.

2. Decorticated cottonseed cake given at three different levels, i.e. 10.16, 20.32 and 30.48 g. N, did not produce a significant change in wheat-straw cellulose digestibility.

3. The digestibility of dry matter was significantly improved by all supplements used except fish meal and decorticated cottonseed cake at a level of 10.16 g. N per day.

4. Total volatile fatty acids were estimated just before feeding and at different intervals after feeding.

5. The implication of these results for microbial activity are discussed.
Nitrogen, sulphur and carbon uptake from some nitrogenous fertilizers using 15N, 35S and 13C as tracers
Authors: Low A. J. , Piper F. J.
Published: March 2009

1. Pot culture experiments are described comparing the recovery of nitrogen, and sulphur by the difference and ‘labelled atom’ methods and the recovery of carbon by the latter method. Italian ryegrass was used as the test crop with ammonium sulphate, calcium nitrate and urea as the fertilizers.

2. The recovery of fertilizer nitrogen was less using the ‘labelled atom’ technique than the conventional difference method.

3. The recovery of sulphur from ammonium sulphate ‘labelled’ with 35S was measured. It was considerably less than the nitrogen, but not inconsiderable especially as a basal dressing of ‘unlabelled’ K2SO4 was applied.

4. Using urea ‘labelled’ with 13C there was no evidence that any of the carbon was in the ryegrass four weeks after application.
The analysis of yield-density relationships in binary mixtures using inverse polynomials
Authors: Wright A. J.
Published: March 2009

The reciprocal relationship commonly used in the analysis of plant yield-density relationships in monoculture is extended to allow a similar treatment of binary mixtures, using the model:

w–1a = Aa × Baapa × Babpb

where wa is the plant weight of component a in mixture with component b, and pa and pb are the plant densities of a and b respectively. The model gives a good fit to fresh weights taken from a glasshouse experiment involving monocultures and mixtures of red clover (T. pratense L.) and Italian ryegrass (L. multiflorum L.) in different proportions, all grown at a range of plant densities. The interpretive and predictive uses of the model are discussed.
Availability of magnesium to ryegrass from soils during intensive cropping in the glasshouse
Authors: Sinclair A. H.
Published: March 2009

Ten Scottish soils were cropped in a glasshouse with three sowings of perennial ryegrass (Lolium perenne, cv. Dutch Barenza) without added magnesium. After 25 cuts (185 weeks) growth was poor in some soils, but soil Mg was not limiting growth in others.

Uptake of Mg and the Mg concentration in the ryegrass correlated well over the entire cropping period with the equilibrium Mg-concentration ratio Mg/(Ca, Mg) = CR0, determined from the Mg quantity/intensity isotherms measured before cropping in 0·01 m chloride solutions. A CR0value of 0·16 was required in the early stages of cropping to give 0·2 % Mg in grass dry matter.

Seven soils released 12–37 mg non-exchangeable Mg/kg, between one-fifth and one-third of the total Mg uptake. These reserves probably came from vermiculite minerals, but the release was too slow to maintain Mg concentrations of 0·2 % in the ryegrass.
Aspects of the water relations of spring wheat (Triticum aestivum L.) in response to induced drought
Authors: Jones H. G.
Published: March 2009

This paper describes a field study of the variation in leaf water potential (ѱL), leaf conductance (gL) and other aspects of crop water relations in a set of ten spring wheats. The two main soil moisture regimes used were irrigation and drought; the latter being imposed by placing rainwater gutters between the crop rows to intercept a proportion of any rainfall. The development of plant stresses, the changes in leaf conductances during the growing season and the relationship between these variables and soil moisture depletion are described. Mean daytime leaf water potentials declined during much of the season even in well irrigated plots. There was also evidence that stomata tended to be most open during the period just prior to anthesis. Data on variation of ѱL and gL within the crop are also presented and indicate that most evaporation occurs from the flag leaf in the spring wheat canopy.

Although genotypic variation was found for the mean values of ѱL and gL, interactions between variety and water regime were generally non-significant. Although yields were not well correlated with most aspects of crop water relations measured, partly because of the dominance of other factors such as maturity and disease susceptibility, a strong negative correlation was observed between yield and gL for the period 7–14 days before anthesis.

Stomatal frequencies were not related to leaf conductances and there was no evidence that the stomatal behaviour adapted to previous drought stress. The growth responses observed, however, could be regarded as adaptations for reducing evaporation. The results are discussed in relation to the breeding of drought tolerant varieties of wheat.
Field comparison of West African planting and harvesting practices in yam (Dioscorea rotundata): pre-sprouting, dry season planting, and double-harvesting
Authors: Onwueme I. C.
Published: March 2009

Experiments were made to compare the practices of planting yam at the onset of the dry season (November) or at the beginning of the rains (February). Setts were also planted in February after pre-sprouting either outdoors from November/December, or indoors without water from November. Comparisons were also made between plots that were harvested first in mid-season and again at the end of the season (doubleharvesting), and plots that were harvested only at the end of the season (singleharvesting).

Setts that were pre-sprouted outdoors had low percentage emergence, produced weak plants, and yielded poorly whether double-harvested or single-harvested. Setts prepared and planted in the field in November emerged over a very long time, and attained half-maximum emergence only 10–19 days earlier than setts prepared and planted in February. Whether in double-harvesting or in single-harvesting, tuber yield/sett for the November planting was significantly greater than for pre-sprouted plantings, but not greater than for the direct February planting. The first harvest of the November planting had more mature tubers and a higher percentage of marketable tubers than the others. In all treatments, single-harvesting resulted in slightly greater yield than double-harvesting, but the differences were not significant. Each second-harvest tuber from double-harvesting was more amorphous in shape, more woody, and had more eyes (buds) on it than the single-harvest tuber. It is concluded that for efficiency of land utilization, February planting is preferable to November planting, and that singleharvesting is likely to be more economical than double-harvesting.
Some effects of conservation of grass upon magnesium metabolism in sheep
Authors: Powley G. , Johnson C. L.
Published: March 2009

Metabolism trials were conducted with sheep to study the effects of conservation of herbage as silage, frozen or artificially dried grass upon the magnesium and calcium availabilities in the conserved products.

When the diet was changed, approximately isomagnesaemically, from hay and barley to each of the conserved products, there was a highly significant (P < 0·001) decrease in the plasma magnesium concentration. However, the plasma magnesium concentrations of the ewes eating the artificially dried grass were significantly lower (P < 0·05) than the corresponding values when they ate the frozen grass or silage. No changes were seen in the plasma calcium concentrations.

The apparent availability of magnesium in the silage was significantly higher (P < 0·05) than that in the frozen and artificially dried grasses. Also, the apparent availability of magnesium and calcium was lower in the dried grass than in the other two products, whilst the retention of both magnesium and calcium was significantly lower (P < 0–05) when the dried grass was eaten as compared with the frozen grass and silage. The percentage urinary loss of magnesium was greatest on the silage and least on the dried-grass diet.

It was concluded that artificially drying grass caused a reduction in magnesium availability.
Fibre medullation in Blackface lambs and hoggs
Authors: Pilkington J. M. , Purser A. F.
Published: March 2009

A method has been described of assessing the average degree of medullation in fleece samples. This method combines information about the various fibre types and the proportion of each present in the sample, by assigning 100 fibres to classes with scores 1–5 according to the degree of medullation. A weighted mean score was determined, ten times this mean being defined as the ‘medullation index’. The index has been used for 2 years on samples taken from 2-month-old lambs and 14-month-old hoggs of the Blackface breed. Drawings of fibre types showed that the internal and external diameters and their ratio all increase with the score.

The mean medullation index for the 2-month-old lambs in the 2 years was 25·6 and 24·8. The effects of sex and type of birth of lamb and age of dam were assessed by fitting constants, but their contribution to the total variance was very small. The regression of medullation on age of lamb when sampled was −0·11 units per day in both years, and was highly significant. Possible explanations for this decline of medullation are discussed.

The mean medullation index for 14-month-old hoggs was 16·1 in both years. Estimate of correlation between lamb and hogg for the 2 years were + 0·45 and + 0·33. It is probable that variation in medullation within the fleece and in fibre shedding account for these low values.