bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of sowing date and harvesting date on the yield of sugar beet
Authors: Hull R. , Webb D. J.
Published: March 2009

A field experiment in each year 1963 to 1967 in Suffolk, England, tested the effect on yield of sugar beet of sowing dates ranging from 13 March to 11 May and harvest dates ranging from 20 September to 8 December. Sowings in March or early April gave similar yields of sugar but with later sowings yield decreased progressively faster. The relationship is represented by the equation

y = 106·3 (±2·24) + 0·212 (±0·184)x-0·009 (±0·003)x2,

y = yield as percentage of mean (60·1 cwt/acre of sugar), x = number of days after 12 March.

Delayed harvest increased sugar yield; the relationship is represented by the equation

y = 80·22 (±1·51) + 0·836 (±0·09)z-0·006 (±0·001)z2,

z = number of days after 19 September. This represents an increase of 0·247 cwt/acre/day of sugar in October and 0·083 cwt/acre/day in November, equivalent to about 2½ tons/acre of roots in October and 1 ton/acre in November.

The effect on sugar yield of different lengths of growing period, which ranged from 138 to 271 days, is represented by the equation

y = 38·7 (±26·6) + 1·045 (±0·267)a-0·0017 (±0·0007)a2,

a = number of days between sowing and harvest.

On average, sowing date had negligible effect on sugar percentage at harvest. In 3 years sugar percentage increased after the first harvest to a maximum and then decreased; in 2 years it decreased with consecutive harvests.
Body composition studies with the milk-fed lamb. I. Chemical composition and calorific content of the body and organs of newly-born lambs
Authors: Jagusch K. T. , Norton B. W. , Walker D. M.
Published: March 2009

The total body content of fat, protein, ash, moisture and energy of 43 male cross-bred lambs was determined after the lambs had suckled the ewe at pasture for between 2 and 5 days. Sixteen lambs were dissected into seven compartments, namely, carcass, skin, wool, blood, viscera (two groups) and vastus lateralis muscle, and the chemical composition of each was determined. The heats of combustion of the fat and fat-free tissues were also determined. The relationships between empty body weight and body and organ composition were described by logarithmic regression equations.
The Conditional Probability of Passing a Test for Uniformity
Authors: Hobson T. F. J. , Fyfe J. L.
Published: March 2009

The problem to be considered arose in connexion with applications for plant breeder's rights. An applicant has to submit material for scrutiny by the authority, one aspect considered being uniformity. The applicant may wish to conduct a preliminary test, of the same type as the authority's, to allow a calculation of the probability of passing the regulation test. In both tests only a sample is examined and the population frequency of off-types remains unknown. It is assumed here that the authority sets a critical frequency (e. g. 0–01) and specifies a size of sample (e.g. 300). The result is regarded as a failure if the observed frequency exceeds the critical frequency (e.g. if more than three off-types are observed in a total of 300). Given that this is the test procedure it is possible to calculate the conditional probability of passing the regulation test, knowing the result of a preliminary test.
The body composition of 3-month-old Rambouillet lambs of different live weights
Authors: Epstein H. , Herz A.
Published: March 2009

Summery

Carcass measurements were made on 24 Rambouillet lambs of different live weights but of the same age, and the lambs divided into 3 groups of 8 according to live weight. Group I, with the lowest mean live weight, had the lowest dressing percentage, relatively heaviest head and feet and lightest pelt, while group III, with the highest mean live weight, had the highest dressing percentage, the relatively lightest head and feet and the heaviest pelt of the three groups.

Group I contained the lowest percentage, and group II, of medium live weight, the highest percentage of muscle, while the relative weights of bone and fat tissue were similar. Group III contained the highest percentage of fat tissue and the lowest percentage of bone. The differences in the relative weights of the edible internal organs between the three groups were not significant.

Testis weight was relatively much greater in Group III than in the lighter animals. While dressing-out percentage increased with body weight, the increase was not equally distributed between fore and hindquarters. Hindquarters were relatively larger in group II than in group I; but the forequarters accounted for the greater part of the differences between groups II and III.
The structural carbohydrates and the in vitro digestibility of a ryegrass and a cocksfoot at two levels of nitrogenous fertilizer
Authors: Waite R.
Published: March 2009

‘Nitro-chalk” was applied to established swards of ryegrass S. 24 and cocksfoot S. 37 at the rate of 24 and 96 lb N/acre (27 and 107 kg N/ha) before growth commenced and after each cutting. The cuts were taken each time the grass reached a length of 10–11 in (8–9 in of cut herbage). The main effect was that the higher rate of fertilization allowed the grass to be harvested more frequently and this grass had lower pectin, cellulose and hemicellulose contents and a higher level of digestibility. A secondary effect was that the proportion of hemicellulose to cellulose was less in the more heavily fertilized grasses. The cocksfoot grasses at both levels of fertilizer were cut more frequently than the corresponding ryegrasses and were only slightly less digestible. There was some decline in the digestibility of the grasses from May to September which was associated with lengthening growth intervals and generally higher percentages of the structural constituents.
Production characteristics of the Jamaica Hope breed of dairy cattle
Authors: Wellington K. E. , Mahadevan P. , Roache K. L.
Published: March 2009

This study is the first comprehensive estimation of breed parameters for the Jamaica Hope breed of dairy cattle. It has shown that the breed has considerable potential for milk production undser good husbendry in a tropical environment. Improvements in reproductive performance may be achieved, without prejudice to production performance, by using milk yield per day of calving interval (which has a moderatoly high repestability) as a criterion for selection.
Voluntary intake of food by mature sheep following restricted feeding
Authors: Keenan D. M. , McManus W. R. , Freer M.
Published: March 2009

Nine Merino wethers were used in a cross-over experiment to compare the voluntary intake of three diets after a 4-week period in which the intake of the same diets was restricted, either to a level which maintained the live weight and energy status of the sheep, or to one which resulted in losses of 18% and 26% in their live weight and total energy content respectively. The diets were prepared from lucerne hay; chaffed (L), ground and pelleted (P) and pelleted after mixing with ground wheat (W).

The voluntary intake of food increased only slowly during the 4 weeks after restrictions were removed; the total intake of digestible organic matter from diets W, L and P was in the ratio 100:122:146. Differences between diets L and P, but not W, were associated with their rates of disappearance from the rumen. Sheep which had been severely restricted ate less food during the first fortnight and no more during the second fortnight than those which had previously maintained their energy status. The difference in the first fortnight was less for diet P than for diet L. The process of adaptation by the sheep to unrestricted feeding was associated with an increase in the net rate of disappearance of volatile fatty acids from the rumen.

Sheep offered food ad lib. after a period of submaintenance feeding gained more weight than sheep which had previously been fed to maintain weight and this increase was greater with diet P than with diet L. However, the differences in live-weight change consisted largely of water in the gut and did not result from a relative increase in the voluntary intake of food or in the efficiency of energy utilization.
Potassium uptake by potatoes
Authors: Addiscott T. M. , Mitchell J. D. D.
Published: March 2009

Potatoes (var. Pentland Dell) were grown in pots containing soils from the Bothamsted ley–arable experiments. When about half the initially available K was used, the tops were harvested and the potential limiting K uptake, inferred from K uptakes, was – 4150 cals/equiv. The plants grew on until they exhausted the available K and died, having set tubers. The potential then limiting K uptake, inferred from total K uptakes, was – 4900 cals/equiv., similar to the mean potential in the exhausted soils, – 4710 ± 61 cals/equiv. The significance of these measurements is discussed.

Total K uptake was closely related to the amount of K that had to be removed from each soil to lower the potential to – 4900 cals/equiv. and the relationship suggested that the potatoes did not use any K from initially non-available reserves.

Dry-matter yields of tubers and of tops + roots, and the ratio of the two, were well related to quantity and potential of K in the soil; tuber yield was also well related to K in tops. The K potential needed for maximum yield of tubers exceeded – 2430 cals/equiv.
A direct calorimeter for the continuous recording of heat loss from groups of growing pigs over long periods
Authors: Mount L. E. , Holmes C. W. , Start I. B. , Legg A. J.
Published: March 2009

1. A large direct calorimeter in the form of a pig: pen, with sleeping and dunging areas, is described. Groups of pigs can live in it for the whole fattening period, while sensible and evaporative heat lossesare measured continuously.
Control of the annual rhythm of breeding in ewes: effect of an equatorial daylength with reversed thermal seasons
Authors: Wodzicka-Tomaszewska M. , Hutchinson J. C. D. , Bennett J. W.
Published: March 2009

1. Three groups of seven Southdown and seven medium wool Peppin Merino ewes were subjected, respectively, to seasons of daylength corresponding to a latitude of 60° S., reversed seasonal lighting (60° N.) and an equatorial daylength with reversed thermal seasons, for 2½ years. During the next 20 months group 1 continued as before. Group 2 had a 32-week photoperiodic year and group 3 had a 32-week thermal year with equatorial daylength.
The evaluation of cattle foods and diets in terms of the ruminal concentration of volatile fatty acids I. The effects of level of intake, frequency of feeding, the ratio of hay to concentrates in the diet, and of supplementary feeds
Authors: Bath I. H. , Rook J. A. F.
Published: March 2009

1. A study was made of the effects of feeding regimen and the composition of the diet on the ruminal production ofV.f.a.'S in cattle.

2. The day-to-day variations in the pattern of rumen fermentation in cows given a diet of hay and concentrates indicated that within-cow differences in the molar proportions of the acids from diet to diet are of significance if they exceed about 3% (of the mean value) for acetic acid, about 10% for propionic and butyric acids, and about 25% for valeric acid. The results emphasized also the important differences to be found between cows given the same diet.

3. A change in the frequency of feeding from once to four times daily at a constant daily drymatter intake had little effect on the daily mean values for pH, concentration of totalV.f.a.'S, or the molar percentages of the individual acids, but almost invariably decreased the range of values observed between feeding.

4. With diets of hay and of hay and concentrates an increase in daily dry-matter intake was associated with a fall in pH and an increase in the concentration of totalV.f.a.'S; with the diet of hay and concentrates there was a considerable decrease in the molar percentage of acetic acid and a corresponding increase inN-butyric, but there was little change in the molar percentages of the acids with the diet of hay.
Partial inhibition of nitrate production by products of the mineralization of soil organic matter
Authors: Lewis D. G.
Published: March 2009

1. Soil samples were incubated at 60% W.h.c. at 20° C. and leached after 8 and 20 weeks. On subsequent incubation, the rate of nitrate production in the leached samples was greater than that in unleached control soils. The increase in nitrate production seems to be due to an increased rate of ammonification.

2. Adding 100 p.p.m. of nitrate nitrogen to the soil before incubating had no effect on mineralization.

3. Adding a leachate of incubated soil to new soil samples reduced the rate of mineralization on incubation. This reduction is not due to nitrate or any other anion, since deionized leachate was equally effective.
Effects of conventional daily magnesium supplementation, breed of ewe and continued potassium fertilizer applications on plasma magnesium and calcium levels of ewes
Authors: Ritchie N. S. , Hemingway R. G.
Published: March 2009

1. Muriate of potash applied at rates of 0, 1 and 2 cwt./acre to herbage which had also received similar treatments in the previous year did not influence plasma magnesium or calcium values in lactating ewes.

2. 24 Cheviot ewes had slightly lower plasma calcium and magnesium levels than 24 Half-bred ewes of the same age both before and after lambing.

3. 6·6 g. of magnesium oxide given as a daily drench did not increase plasma magnesium values as measured by blood samples taken 24 hr. after drenching. Values were however increased by 0·5 mg. Mg/100 ml. four hours after drenching.

4. No clinical cases of hypomagnesaemic tetany occurred, even although the mean plasma magnesium level of all the ewes in the experiment was only about 1·0 mg./lOO ml.

5. Plasma magnesium values of ewes before lambing were significantly (P < 0·001) correlated with post-lambing levels. Values for the ewes during 1962 were equally significantly correlated with levels for the same sheep at comparable dates in 1961.
The nutritive value of Panicum maximum (Guinea grass) II. Digestibility by cattle and water buffaloes, related to season and herbage growth stage
Authors: Johnson W. L. , Ordoveza A. L. , Hardison W. A. , Castillo L. S.
Published: March 2009

Fifteen digestibility trials were conducted in the wet, early dry, and late dry seasons in the Philippines. Panicum maximum (guinea grass) was fed at growth stages of 1–4 months to Bos taurus (Holstein), Bos indicus (Red Sindhi), and Bos bubalis (water buffalo) bulls.

Significant differences were shown between digestibility coefficients from water buffaloes and those from Holstein cattle, the former having a 5–7 % advantage in most cases. Ratios of volatile fatty acids in rumen fluid from the two species were not different. Separate tables of digestible protein, TDN and digestible energy values for guinea grass were computed for cattle and water buffaloes.
Leaf strength studies of pasture grasses: I. Apparatus, techniques and some factors affecting leaf strength
Authors: Evans P. S.
Published: March 2009

Leaf tensile-strength measurements have been made at Grasslands Division, D.S.I.R., over several years on a number of pasture grasses (Evans, 1964; Wilson, 1965). These measurements were prompted by the work of Beaumont, Stitt & Snell (1933) and Kneebone (1961), who attempted to relate leaf tensile strength to animal production value, and Edmond (1960, 1964), who considered that the toughness of pasture species may be a factor determining their tolerance to animal treading. The following is a description of the apparatus developed for this work and of the techniques employed.
The effects of nitrogen and irrigation on timothy (Phleum pratense) grown for production of seed: II. Reproductive growth and yield of seed
Authors: Lambert D. A.
Published: March 2009

1. Plants of S.48 timothy were established on a 1 ft square (30 cm × 30 cm) pattern for production of seed. Plots at three levels of applied nitrogen, 0 (N0), 87 (Nl) and 261 (N2) lb N/acre (0, 97·5 and 292·5 kg/N ha) per annum were either irrigated to field capacity from 1 week before initiation of spikelets until 2 weeks before harvest, or not irrigated, during each of three years.

2. Application of nitrogen caused earlier initiation and emergence of inflorescences each year, and earlier general anthesis in the first and third years. Irrigation generally had no effect on the date of initiation, but it prolonged the period of reproductive development and delayed the date of harvest by 2–5 days.

3. The number of ears per plant was increased by the N1 treatment above the number produced by plants in the N0 treatment. In the N2 treatment the number of ears per plant was between the number in the N0 and N1 treatments in non-irrigated plots; in irrigated plots, plants in the N2 treatment sometimes had a lower number of ears than plants in the N0 treatment. The length of ears increased with the rate of application of nitrogen.
Studies on the sowing date of cotton in the Sudan Gezira: III. The effect of sowing date on yield and quality under different fertilizer and spraying treatments
Authors: Jackson J. E. , Faulkner R. C. , Schultz L. Razoux
Published: March 2009

Field experiments from 1959–60 to 1963–4 showed that when blackarm resistant strains of Egyptian type cotton were sown around the beginning of August and adequately protected from fleabeetle, the resultant crop was of higher yield and considerably better average quality than that from the normal mid-to-late August sowings. Effective length, maturity ratio, standard fibre weight, bundle strength and lea-count × strength product were all improved. Sowing in early July, tested in one season only, gave rather better quality but lower yield than sowing in early August. Sowing in late August or in September depressed both yield and quality. The importance of direct climatic effects and of blackarm, fleabeetle, bollworm, other insect pests and wilt in controlling the choice of, and response to, sowing date is briefly discussed.

Thanks are due to the Sudan Gezira Board for kindly supplying the results of the large-scale sowing date trials and for the grading of experimental cotton, to the Shirley Institute of Manchester for the fibre and spinning tests and to the Chief, Agricultural Research Division, Ministry of Agriculture, Sudan, for permission to publish this paper.
Voluntary intake of low-protien diets by ruminants: I. Intake of food by cattle
Authors: Elliott R. C
Published: March 2009

1. A study was made of the voluntary intake hay, of low nutritive value, by heifers of two breeds of African cattle when given four different amounts concentrate foods (9, 18, 27 and 36 g/kg W0.73/day) each providing three levels of protein (1·3, 2·6 and 3·9 g DCP kg W0.73/day). The trial was designed two incomplete Latin squares, one for each breed, with thirteen treatments, thirteen heifers and four replicates.

2. Voluntary intakes of low-protein hay by Africander and Mashona heifers were similar and these increased as levels of supplementary protein were raised and intakes of hay were reduced amounts of concentrate provided to them became more liberal. Inter-relationships of food intake and dietary composition were, however, very complex.

3. Increased allowances of dietary protein and concentrate generally corresponded with higher intakes of total food and digestible energy. But this was not true at the lower levels of protein input where there was evidence that food and digestible nutritient intakes were depressed when liberal amounts of concentrate were fed to the cattle.
The use of coarsely chopped barley straw in high concentrate diets for beef cattle
Authors: Forbes T. J. , Irwin J. H. D. , Raven A. M.
Published: March 2009

An experiment was carried out in which the performance of cattle given diets containing 20 and 40% of coarsely chopped straw (1–3 in lengths) was compared with that of similar cattle given an all-concentrate diet. Each diet was offered ad libitum and twelve Hereford cross steers and twelve Friesian steers were used in the experiment. The live-weight gains and food conversion ratios were significantly better for the Hereford cross animals but there was no significant difference in over-all dry matter intakes. When the combined response of both breed types was considered there was a significantly linear decrease in live-weight gain with increasing straw intake, to the extent of 0.95 kg per week for each 10% increase in straw intake up to 40% in the diet. Similarly there was a significant increase in the conversion ratios of dry matter (P < 0·01) and organic matter (P < 0·01) with increasing straw intake. The effect on the dry matter conversion ratio was an increase of 1·67 units for each 10% increase in straw intake.

Two digestibility trials were carried out, one with coarsely chopped straw and one with coarsely milled straw, the levels of straw in the diets being the same. There was a slight decline in the digestibility of most constituents associated with milling but reductions were not very pronounced. A treatment was included in the second trial in which milled straw was included at 20% of the diet without maintaining the over-all crude protein content of the diet. The apparent digestibility of the organic matter was 5 percentage units lower with this treatment than with that containing the same level of straw in which the level of protein had been maintained.
The effect of sowing and harvesting dates, plant population and fertilizers on seed yield and quality of direct-drilled sugar-beet seed crops
Authors: Scott R. K.
Published: March 2009

Sixteen field experiments made between 1963 and 1967 on direct-drilled sugar-beet seed crops compared the effects of cultural practices on the yield and quality of seed. Sowing in July gave earlier flowering and ripening than sowing in August and usually increased yields, cluster size and percentage germination. Downy mildew was sometimes more prevalent in late sowings.

Seed yields increased as the crop changed colour from green to yellow and percentage
germination increased greatly as more clusters contained ‘mealy’ rather than ‘milky’ perisperm. Because of natural shedding and bird damage, seed yields then decreased and losses of 0·6 cwt/acre/day were recorded for early ripening treatments. Cluster size and percentage germination continued to increase while yield was decreasing. Crops ripened a month earlier in 1967, the ‘earliest’ year, than in 1965, the latest year.

Crops grown in rows 10 in apart lodged less than those sown 20 in apart, ripened earlier and produced, on average, 3 cwt/acre more seed, which was slightly smaller. In one experiment rows 5 in apart gave similar yields but smaller clusters than rows 10 in apart. Row width had little effect on percentage germination. Increasing the distance between plants in the row gave smaller yields with wider spaced rows, but with narrow rows plants 6 in and 12 in apart yielded more than those 2 in apart. Yields from a plant population of 52,200 plants/acre were 4 cwt/acre greater when plants were 12 in apart in narrow (10 in) rows rather than 6 in apart in wide (20 in) rows. Spacing further apart in narrow rows increased seed size. In wide rows many plants 12 in apart lodged, made secondary growth and produced small, late maturing clusters, of which few germinated.

Response to fertilizer nitrogen applied in spring was less, and less was needed for maximum yield on the thin Cotswold soils than on the silty clay loam in Lincolnshire, where it doubled yield in 1966. Phosphate and potash applied in spring had little effect on
yield. Usually fertilizers had no effect on cluster size or germination percentages, but
1·6 cwt/acre N given to a late-ripening crop in 1965 decreased seed size and germination.

Ramularia leaf spot, which defoliated crops in the Cotswolds, was worst on early sown and closely spaced plants, and was unaffected by fertilizer.
Experiments on the nutrition of the dairy heifer: VII. Observations on the effect of the energy intake on the utilization of protein in growth and in lactation
Authors: Broster W. H. , Tuck Valerie J. , Smith T. , Johnson V. W.
Published: March 2009

Eight feeding trials on cattle showed that the response in live-weight gain was curvilinear when protein or energy level was varied independently in rations based on poor quality roughages to which cereals and groundnut were variously added to give a range of protein and energy intakes. Live-weight gain was increased by 0·12 lb/day for each 0·1 lb additional digestible crude protein/day at levels of intake below 0·7 lb/day and by 0·03 lb/day at higher levels. It was increased by 0·4 lb/day for each additional 0·1 lb starch equivalent daily/100 lb live weight at total intakes below 0·9 lb daily/ 100 lb and by 0·2 lb/day at higher levels. Over the range 0·5–2·0 lb digestible crude protein daily and 0·7–1·2 lb starch equivalent daily/100 lb live weight the effects of these nutrients were additive.

A Latin square nitrogen balance trial demonstrated that a portion of the nitrogen from a protein supplement was retained in the body despite the excretion of the greater part of it in the urine and a further part in the faeces. Nitrogen retention was increased by a supplement of readily available energy through a decrease in urinary nitrogen loss. Nitrogen balance was not increased by a supplement of a fibrous energy source because this induced an increase in faecal nitrogen loss.

In a further feeding trial milk yield was found to be affected in a similar manner to growth. At a yield of 30 lb/day the response per lb starch equivalent added to the diet was 0·5 lb milk including 0·05 lb solids not fat and to an increase of 0·1 lb digestible crude protein daily it was 0·25 lb milk including 0·025 lb solids not fat.
The apparent behaviour of maize and sorghum stomata during and after drought
Authors: Glover J.
Published: March 2009

Maize stomata are shown to be markedly affected by severe drought lasting about a week or more, in that they do not recover their apparent pattern of normal behaviour after the water supply to the plant is restored, although the leaves regain their turgidity and seem normal. On the other hand, sorghum stomata recover well from severe drought lasting 14 days and their recovery follows fairly closely behind the restoration of turgidity to the leaves. It is suggested that this difference in ability of stomata to recover from severe drought in some measure accounts for the superiority of sorghum as a grain crop in dry regions.

Severe drought in maize is shown to be less damaging to the young plant than to the old, because the stomata of the unopened leaves behave normally when unfolded after the drought is broken.
Effect of previous cropping and manuring on the nitrogen fertilizer needed by sugar beet
Authors: Draycott A. P. , Last P. J.
Published: March 2009

Six field experiments made between 1960 and 1968 determined the effect of previo cropping and manuring on the nitrogen requirement of sugar beet. Three were at Silsoe in Bedfordshire on soils developed over Lower Greensand and Gault Clay and three were at Broom's Barn (Suffolk) on Calcareous Drift soils over chalk. Each experiment lasted 2 years, a preparatory crop followed by sugar beet.

Spring barley and potatoes were treatment crops in all the experiments and winter wheat, a ryegrass ley and barley undersown with trefoil were included in the Suffolk experiments. Nil, 0·6 or 1·2 cwt N/acre was tested on the sugar beet in the first three experiments and 0, 0·5, 1·0 or 1·5 cwt N/acre in later ones.

All the experiments showed that previous cropping influenced the nitrogen requirement of the sugar beet. There was a linear relationship (r = – 0·86) between the amount of fertilizer nitrogen given minus that removed by the preparatory crop, and the quantity of nitrogen fertilizer needed by the sugar beet for maximum sugar yield. Sugar beet grown after barley or potatoes (each given 0·5 cwt N/acre) needed on average 1·0 cwt N/acre at both Broom's Barn and Silsoe for maximum sugar yield. Sugar beet after winter wheat or a ryegrass ley also needed 1·0 cwt N/acre at Broom's Barn. When the previous potato crop was given 1·5 cwt N/acre, 0·5 cwt/acre sufficed for maximum yield of sugar at both centres; also after ploughed-in trefoil, sugar beet needed only 0·5 cwt N/acre.
The effects of rates and time of application of nitrogenous fertilizer on barley in south-east Scotland
Authors: Holmes J. C. , Gill W. D. , Rodger J. A. B.
Published: March 2009

1. Two series of simple nitrogen manuring trials, one on level of sulphate of ammonia applied to the seedbed at twenty-two centres and the other on the time of top dressing with ‘Nitro-Chalk’ at nineteen centres, were conducted on commercial farms in south-east Scotland during 1954 to 1957.

2. The optimum level of sulphate of ammonia varied with season and farm type. The optimum dressing was at least 0·9 cwt. N/acre in the dry season of 1955, and in the other years was estimated to be 0·9 cwt. N/acre on arable farms and about 0·-25–0·4 cwt. on ley rotation farms when the barley did not follow sheeped turnips. In the latter event no fertilizer was best.

3. The nitrogen content of the grain increased little until after the 1 cwt. sulphate of ammonia level, although the optimum yield was not obtained in many experiments without some rise in the grain nitrogen content.
The influence of huddling and body size on the metabolic rate of the young pig
Authors: Mount L. E.
Published: March 2009

1. The oxygen consumption of young pigs from 1 to 37 days of age has been measured in a closed circuit respiratory metabolism chamber, over the environmental temperature range 4–37° C.

2. The values obtained for single pigs alone in the chamber have been compared with the results of measurements on groups of pigs 3–6 days of age taken together.

3. It has been found that as environmental temperature falls below 30° C. and the grouped pigs huddle together, oxygen consumption per kg. for the group becomes smaller than values for single pigs of the same individual weight, and corresponds more with results from the larger single pig.

4. Rectal temperature is maintained in pigs of the group at a lower energy cost than that required for the single pig, the saving in energy expenditure becoming proportionately greater as ambient temperature falls.

5. These results are discussed in relation to body size and skin temperature.
Sweating in cattle VI. Density of sweat glands and its relationship with cutaneous evaporation
Authors: Taneja G. C.
Published: March 2009

Two calves (Zebu × Australian Illawara Shorthorn and Shorthorn) of about 7–8 months of age were exposed to controlled atmospheric conditions. Cutaneous evaporation from the shoulder and belly areas of these calves was measured by the capsule method. Density of the sweat glands in the shoulder and belly areas of these calves was measured, using a biopsy punch. Density was estimated by counting the hair follicles.

(1) The Zebu cross sweats more than the Shorthorn, at least from the shoulder area, and this is related to its higher sweat gland density as compared with that of the Shorthorn.

(2) In the Zebu cross cutaneous evaporation from the shoulder area is greater than that of the belly and this is associated with the differences in the number of sweat glands.

(3) In the Shorthorn cutaneous evaporation is the same from both shoulder and belly areas and the number of sweat glands in these regions is also the same.
Effects of time and rate of nitrogen application on tillering, ‘sharp eyespot’ (Rhizoctonia solani) and yield in winter wheat
Authors: Bremner P. M.
Published: March 2009

Various rates of nitrogen fertilizer were applied in early and late spring to two densities of winter wheat to examine their effects on grain yield and its components. A severe attack of ‘sharp eyespot’ (Rhizoctonia solani) allowed an assessment of the effects of the treatments on the incidence of this disease.

The disease level was much higher where nitrogen was applied early and increased with increase in nitrogen up to 120 units applied; it was slightly higher at the higher density. Grain yield was slightly greater where nitrogen was applied late; early application gave more, but smaller, ears. Main shoots produced at least 70% of the grain in the high-density plots but less than 50% at the low density. Tillers appearing after early March contributed little to grain yield at the higher density but substantially at the lower one. Tillers produced after early April died without heading. In general, the chances of survival of a tiller diminished with delay in the time of its appearance, but some early tillers died while later ones survived and produced ears. The chances of survival of later tillers were greater at low density and high rates of nitrogen.
Dietary effects on beef composition: III. Weight, composition and potassium–40 content of fat-free muscles
Authors: Judge M. D. , Firth N. L. , Johnson H. R. , Kessler W. V. , Harrington R. B. , Garrigus R. R.
Published: March 2009

The effects of several dietary regimens on the fat-free mass and the dry-matter, ash and potassium-40 content of selected bovine muscles were estimated. Muscle data from 104 half-sib Angus steers were secured at several stages of growth and after several feeding regimens. The results indicated that a hay diet, by comparison to a higher energy silage diet in the early feeding period (216–340 kg live weight), suppressed the fat-free weight, reduced the dry-matter content and increased the ash content of several muscles. These effects of early diet were reversed, however, when the animals were subsequently fed higher-energy rations and slaughtered at heavier weights (409 and 454 kg live weight). Data on potassium-40 gamma emissions by composite muscle samples confirmed the existence of age- or weight-associated decreases and suggested possible dietary influences on potassium levels in bovine muscles. The trends in these data indicated that low dietary energy (hay feeding) in the early feeding period delayed the decline in muscle potassium that normally accompanies maturation.
Biochemical appraisal of a milk diluent for semen
Authors: Friis Jakobsen K. , Mann T.
Published: March 2009

1. A study was made of the effects of a milk diluent on bull, ram and boar spermatozoa. Respiration and fructolysis of spermatozoa were used as the two main criteria of sperm activity. The milk diluent was a standardized and commercially available milk product, consisting of sterilized and homogenized milk, supplemented with milk fat.

2. The rate of oxygen uptake measured manometrically in the presence of air was increased by the addition of the milk diluent throughout the entire incubation period. Fructose utilization was assessed by the rate of lactic-acid production. The rate of the anaerobic lactic-acid formation was higher in the presence of the milk diluent during the later stages of incubation.

3. The effect of the milk diluent on sperm respiration was most striking in experiments with the sperm-rich portion of boar ejaculate obtained by fractionated collection. A somewhat less marked effect was observed with bull semen, and in ram semen the effect was comparatively weak.
A comparison of meal and pelleted forms of creep feed for suckling pigs
Authors: Braude R. , Jill Townsend M. , Rowell J. G.
Published: March 2009

Three creep rations were fed in the form of meal, pellets and ground pellets. The compositions of the first two rations were similar to those of the rations used in general farming practice; the compositions of the pellets and ground pellets were identical. The experiment was carried out for 8 weeks from birth at thirteen centres and involved a total of 152 litters. No difference between meal and ground pellets was found in either food consumption or weight gain. Pigs on pellets consumed 18% more than pigs on meal, but this did not result in a significant improvement in weight gain. Treatment × centre interactions were not significant.
Reproductive rates and milk yield of Kenana cattle in Sudan
Authors: Alim K. A.
Published: March 2009

An analysis has been made of the reproductive rates and milk yield of Kenana cattle in a closed dairy herd in Sudan.

The average age at first calving was 38·4 months and calvings were most frequent between September and December.

The average length of productive herd life of cows was 5·42 lactations.

The average interval between successive calvings was 395 days, and this was influenced by years and age.

The mean generation interval was 6·72 years.

The average milk yield in 224 days was 338 gal. with a standard deviation of 152 gal.

There was a close relationship between milk yield and lactation length; r = 0·866 ± 0·013.

Milk yield increased by age until the fourth lactation when it was about 137% of the first lactation. The rate of increase in yield between first and second lactation was highest and amounted to 22%.

Year of record had a pronounced effect on milk yield.

Month of calving had a slight effect on milk yield.

The repeatability estimates of single records milk yield, calving intervals, lactation periods and dry periods were 0·432 ± 0·046, 0·058 ± 0·059, 0·192 ± 0·058 and 0·069 ± 0·065, respectively.

The increase in repeatability estimates between earlier and later successive milk yield records was accompanied by a decrease in the coefficients of variation of these records.

The heritability of a single record milk yield was 0·239 ± 0·245.

The rate of annual genetic superiority in milk yield of dams of cows and dams of bulls was found to be 0·74% of the herd average.
Relationship between levels of iodine and cyanogenetic glucoside in pasture and the productive performance of sheep
Authors: Flux D. S. , Butler G. W. , Rae A. L. , Brougham R. W.
Published: March 2009

This paper describes an experiment designed to test the goitrogenic effect of white clover (Trifolium repensL) in ewe lambs grown and taken through a complete reproductive cycle. The sheep were setstocked on four pastures made up of perennial ryegrass and short-rotation rye-grass, both alone and together with cyanogenetic white clover. Since these species differ in iodine content when grown on the same soil, there were probably differences in dietary iodine intake of the sheep in the four groups. Half the animals in each group were injected intramuscularly with an iodinated poppy-seed oil to serve as an iodine depot.

At slaughter, 19 months from the commencement of the experiment, thyroid weights indicated a goitrogenic action in the non-injected ewes grazing short-rotation rye-grass and white clover and to a lesser extent in the non-injected ewes grazing perennial rye-grass and white clover. There was evidence of a slight goitrogenic action in noninjected ewes grazing perennial rye-grass. The thyroids of non-injected ewes had similar iodine contents, lying within the range of 0·23–0·29% of the dry weight.

In injected ewes, the total iodine content of the serum was three to four times higher than with non-injected ewes and the iodine content of the thyroids was three times greater. All injected ewes had thyroids of normal weight.

No effects of iodine supplementation on growth, reproduction or wool production were found.

Lambs born to the ewes in the fifteenth month of the experiment were slaughtered when 3–5 months old, the age varying with pasture treatment. Thyroid weights indicated a goitrogenic effect from the clover-containing pastures.
Alteration of porcine skeletal muscle myoglobin by the environment
Authors: Thomasf N. W. , Judge M. D.
Published: March 2009

Animals reared in constant ambient temperatures had significantly more skeletal muscle myoglobin than those reared in alternating temperature environments when the humidity was moderate or high. These differences did not exist when humidity levels were low. Comparisons ofthe effect of humidity level in constant ambient temperatures revealed high myoglobin in pigs subjected to moderate as compared to low humidity at 27°C, but humidity effects were nonexistent when the ambient temperature was 21 or 32° C. It is postulated that animals reared in alternating temperatures experienced intermittent and persistent development of tissue hypoxia and, asa consequence, had reduced aerobic metabolic pathways in muscle as compared to animals rearedinconstant ambient temperatures.
Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude I. The annual fluctuation in body temperature and body temperature increase between 6.30 a.m. and 12.30 p.m.
Authors: Symington R. B.
Published: March 2009

Early morning and midday body temperatures of rams and ewes of three breeds of sheep were measured once weekly for a period of 10 months in Northern Rhodesia and 12 months in Southern Rhodesia.

1. In all breeds seasonal fluctuations in body temperature were due to concurrent fluctuations in ambient air temperature.

2. Mean annual body temperatures were: Merino 102·2° F.; Persian 101·7° F. and Native 101·7° F. Wool and hair breeds differed considerably in their early morning temperatures and in their body temperature increases from 6.30 a.m. to 12.30 p.m. Mean annual values for these measurements were Merino 101·73 and 1·92° F.; Persian 100·81 and 1·83° F.; Native 100·73 and 1–92° F. At all times Merinos showed markedly greater uniformity of body temperature than either hair breed. There was no evidence to show that the thermoregulatory mechanisms of these animals had been stressed unduly.

3. Sex had no consistent effect on body temperature or on rise in body temperature.

In general, lactating ewes showed a significantly higher initial body temperature than either empty or pregnant ewes, but the respective heat tolerances as measured by body temperature increase did not differ appreciably. Body temperature differed little in empty and pregnant ewes.

4. Although the youngest group of ewes in each breed showed the highest early morning temperature, there was no evidence that heat tolerance was less in young than in old animals.

5. Black-coated Native ewes had higher initial body temperatures and a smaller body temperature increase during the summer months in Southern Rhodesia than brown or broken-coloured Native ewes. These effects were due to differences in coat density rather than to differences in coat colour or skin pigmentation.

6. In all breeds the magnitude of the diurnal and annual variation in body temperature was different in Northern and Southern Rhodesia. Differences were largely of climatic origin but low plane of nutrition in Southern Rhodesia possibly reduced critical body temperature and impaired thermoregulatory ability.
Proportionality of organ development in osteodystrophic dwarf beef cattle
Authors: Hafez E. S. E. , Rupnow E. H.
Published: March 2009

Sixteen osteodystrophic dwarf cattle and ten controls of comparable age were slaughtered. The components of the body and eviscerated carcass were weighed and measured. At birth the dwarfs were thick and blocky. At the time of slaughter a bulging forehead was common but not always extreme and not always present. The symptoms of dwarfism became increasingly pronounced with age, due to retarded growth. The dwarfs had shorter thoracic cavity, abdominal cavity, body, loin, hind leg, arm bone and forearm bone than the controls. No explanation can be given for the difference. However, the dwarfs were hydrocephalic and had significantly lighter adrenal and pituitary glands than the control animals. The dwarf animals had more blood, heavier feet, less abdominal fat, smaller loin ‘eye muscle’ area at the 12th rib and a less deep loin ‘eye muscle’. The dwarf females had a lighter rumen (with and without contents) and large intestines (without content) as a percentage of live weight than the controls and dwarf males. There was no difference in palatability of the meat or percentage of wholesale cuts from the dwarf and control animals except for percentage of plate. The following three ratios were disproportionate in the dwarfs as compared with the controls:
The effect of microdoses of ionizing radiation on poultry ontogenesis
Authors: Kushner H. F. , Dobrynina A. Ya. , Kostin I. G. , Zubareva L. A. , Samoletov A. I. , Salganik M. G.
Published: March 2009

An insignificant short-term increase in the natural dose of ionizing radiation during the embryogenesis period is beneficial not only for the embryonic development of the chicks, but also for their postembryonic growth and development as well as the egg production of the pullets.

Irradiation of incubated eggs with microdoses of radioactive radiations is another possibility for the utilization of atomic energy bringing about an improvement in the economically useful properties of poultry.
The effect of changing plant density on floral initiation and development of barley (cv. Sultan)
Authors: Leakey R. R. B.
Published: March 2009

Barley plants were grown at low, high, increasing and decreasing densities in an attempt to manipulate the environment. The effects on tiller production and development were measured.

Increasing density with time had less effect than decreasing it. Tiller number was the most plastic character, tiller production being earlier in those plants which emerged into low density, being delayed or inhibited in other treatments. The number of spikelets/ear and the length of the inflorescence were found to be less stable characters than the stage of ear development. Percentage spikelet survival showed a downward trend, with increasing density stress.
An assessment of the energy requirements of the pregnant ewe using plasma free fatty acid concentrations
Authors: Robinson J. J. , Fraser C. , Bennett C.
Published: March 2009

An experiment was conducted in which 57 North Country Cheviot ewes, bearing variable foetal loads, were offered different amounts of feed intake during the latter half of gestation. Plasma free fatty acid (FFA) concentrations were estimated at 10-day intervals during the last 55 days of gestation. From the relationship between FFA concentration, energy intake, lamb birth weight and ewe body weight, estimates of the energy requirements of the pregnant ewe were predicted.

The additional metabolizable energy (ME) intake above maternal maintenance required to prevent elevation of plasma FFA concentrations above a predetermined basal level 5 days pre-partum was calculated as 335 kcal/kg lamb birth weight.

The results obtained from the use of plasma FFA concentrations in assessing the energy requirements of the pregnant ewe are discussed in relation to those obtained by other methods.
Studies on the Northern Rhodesia Hyparrhenia veld Part II. Seasonal milk production using natural veld
Authors: Smith C. A.
Published: March 2009

A description is given of a double change-over, grazing trial designed to test the value of Hyparrhenia veld grazing for milk production during the rains.

Three feeds were offered to lactating cows, and the effects of qualitative differences between the feeds were measured on milk yields. The treatments were:
Environmental temperature and the energy metabolism and heat emission of steers
Authors: Blaxter K. L. , Wainman F. W.
Published: March 2009

1. The energy metabolism and heat emission of two steers was determined at the maintenance level of nutrition in an environment of – 5, 5, 15, 25 and 35° C. and at a submaintenance level of nutrition in environments of – 5 and 19° C.

2. Shivering was observed at temperatures of – 5 and + 5° C. in both animals. Respiratory distress occurred at 35° C. being more severe in one animal than in the other. The animals stood for longer periods at the extreme temperatures.

3. The digestibility of food increased slightly as environmental temperature increased. Losses of energy as methane and in urine did not change in response to environmental temperature.
The effect of time of application of phosphate and potash on sugar beet
Authors: Adams S. N.
Published: March 2009

1. Twenty-nine experiments on sugar beet in 1957–59 compared ploughing-down of phosphate and potash in the previous autumn with spring application before the seed-bed preparations.

2. On average, spring application gave a higher yield of sugar and tops than ploughing-down, both in the wet summers of 1957 and 1958 and in the dry summer of 1959.