bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of the amount and the origin of calcium carbonates on the isotopically exchangeable phosphate in calcareous soils
Authors: Talibudeen O. , Arambarri P.
Published: March 2009

The kinetics of the isotopic exchange of phosphate ions in soils with and without phosphate added in the laboratory were examined in relation to the amount and origin of the CaCO3they contained. The isotopic exchange index, ‘Pr/Pe’, and the recovery of added phosphate were inversely proportional to carbonate content in soils containing carbonates of similar geological origin; soils from the Lower Lias showed the biggest change in Pr/Pewith carbonate content.

In soils from the Cretaceous Chalk, the first-order rate of isotopic exchange of the ‘slow’ phosphate fraction was constant. It increased to a larger but constant value in the soils incubated for 6 months after adding phosphate in the laboratory. This rate constant is therefore specific to the calcium phosphates in a group of soils derived from the same calcareous parent material and with similar phosphate manuring.
Nutritive value of mustard cake derived from seeds of different genetic make up for growing chicks
Authors: Cilly V. K. , Lodhi G. N. , Ichhponani J. S.
Published: March 2009

Cakes derived from Taramira (Eruca sativa), Raya (Brassica juncea), Toria (B. campestris var. toria) and yellow and brown sarson (B. campestris var. sarson) were evaluated for their contents of crude protein, true protein, essential amino acids, available carbohydrate and tannins. Feeding trials were also conducted to compare the suitability of these cakes with groundnut cake for broilers and White Leghorn chicks up to 4 weeks of age.

The crude protein content of Taramira cake was 33% whereas all the other cakes contained 37–38%. True protein accounted for 80–83% of crude protein in all the varieties and albumin and globulin constitutes the bulk of protein. The critical amino acid content of all the brassica seed proteins was found to be higher than that of other vegetable proteins although varietal differences were observed with respect to a few essential amino acids. The hulls accounted for 19% of whole Brassica seed and their removal raised the concentration of protein from 39 to 46% and reduced the crude fibre content from 15 to 6% in the defatted meal. Tannin content was higher in Taramira (1·74%) than in all other varieties (1·0–1·4%) and the major quantity of it was localized in the endosperm. The average metabolizable energy content of all the mustard cakes was 9·62 and 8·75 MJ/kg for meat-type and egg-type chicks, respectively. The nutritive value of Taramira cake was poorer than that of other Brassica cakes or groundnut cake for supporting growth rate of chicks of either breed.
The effects of the date of defoliation of the seed potato crop and the storage temperature of the seed on subsequent growth: 2. Field growth
Authors: Wurr D. C. E.
Published: March 2009

Six experiments carried out over 3 years investigated the effects of the date of defoliation of the seed potato crop and the storage temperature of the seed on the growth of the subsequent ware crop.

Defoliation of the seed crop in July tended to reduce foliage dry weight particularly at later harvests, and in two experiments in 1974 affected the tuber yield. In one of these experiments defoliation in July resulted in a lower yield than from defoliation in August, while in the other experiment it significantly reduced the bulking rate of the ware crop and gave a lower yield of King Edward at the final harvest. Storage of the seed tubers at low temperature (2–3 °C) tended to increase the amount of foliage produced but only in two out of six experiments was there any effect of storage temperature on yield; in both storage at low temperature gave the lowest yield.

There was a significant relationship between the effect of storage temperature on tuber yield and its effect on the time to emergence of 50% of the plants. It is suggested that in these experiments a combination of late planting and weather conditions before emergence reduced the effect of storage temperature on the time to 50% crop emergence and therefore reduced its effect on tuber yield.

In 1973 when there was a large effect of storage temperature on yield, there was a significant relationship between the tuber yield of the ware crop and the physiological age of the seed measured as accumulated day degrees above 0 °C from dormancy break to planting.
Indices of the carcass composition of Dorset Horn top-cross lambs. III. Relationships between chemical composition, specific gravity and weight of carcasses and joints
Authors: Pradhan S. L. , McManus W. R. , Goldstone C. L. , Hart R. F. , Khandekar V. N. , Arnold G. W.
Published: March 2009

The half-carcasses from twelve Dorset Horn x Border Leicester-Merino lambs (3-5 months old) were used to investigate the relationships between the weight of the carcass and its cuts and their chemical composition. The specific gravity of the whole carcass and of the cuts was also measured.

Half-carcass weight and chemical composition were highly correlated. Weight could be used to predict the chemical composition with a reasonable degree of accuracy. The loin, the leg, the leg plus loin and the residual were shown to be highly correlated with the chemical composition of the halfcarcass. The loin and leg plus loin are the most convenient to use.
Effects of varying static and changing moisture contents during incubation on ammonia and nitrate levels in soil
Authors: Ekpete D. M. , Cornfield A. H.
Published: March 2009

The effects of varying static and changing moisture contents on mineralization of nitrogen after incubation (28° C.) for 3, 6 and 12 weeks were studied.

Mineral-nitrogen, accounted for entirely by nitrate, increased with increasing static moisture content up to 40-50% water-holding capacity (W.H.C). With further increasing moisture up to waterlogging, both mineral-nitrogen and nitrate decreased, the latter to negative values, indicating disappearance of nitrate originally present in the soil. Ammonia accumulated only at moisture contents above 50 % W.H.C. and its extent of accumulation increased with moisture content.

When soils with moisture contents of 10-50% W.H.C. during an initial 6-week period were changed to waterlogging for a second 6-week period, mineralnitrogen and nitrate accumulation decreased with increasing initial moisture in comparison with soils left at initial moisture contents for the second period.
Seasonal changes in the amounts of phosphorus and potassium dissolved from soils by dilute calcium chloride solutions
Authors: Blakemore M.
Published: March 2009

Variations during 12 months in the concentrations of soil P and K soluble in 0-01M CaCl2 solution were measured on several sites with contrasted histories at both Rothamsted and Woburn. Concentrations were always less in fresh than in airdried soils.

P concentrations in the heavy soils at Rothamsted were remarkably constant, seasonal variation only occurring where FYM or phosphate fertilizers had been applied during the year. At Woburn P concentrations were also constant in the poorer soils, but varied during the year in rich soils.

On Barnfield at Rothamsted the plots receiving FYM each year contained more soluble P than those treated with superphosphate. Where both FYM and superphosphate were applied, P concentrations were greater than the sum of values on plots receiving FYM and superphosphate separately because a given amount of P remained more soluble when FYM was regularly applied. P also remained more soluble on plots given ammonium sulphate.
The evaluation of grasses in micro plots
Authors: Rogers H. H. , Lazenby A.
Published: March 2009

1. Two experiments were conducted in a lowtemperature cabinet. In the first experiment three grass varieties (two North African fescues and S 22 Italian rye-grass) were subjected to two cutting treatments (herbage cut from 8 in. to 2 in. and from 4 in. to 1 in.). Dry-matter production, dry-matter content and tiller number were recorded from plots of 9, 16 or 25 plants. The second experiment, a uniformity trial, was planted with a uniform population of a North African fescue. The optimum plot size and shape within the cabinet, and the optimum arrangement of blocks, was determined using a Titan autocode programme.

2. Treatment and variety differences could be detected using very small plots. For the material and apparatus used, an 18-plant plot was the optimum size.
Absorption of methionine by foetal and neonatal lamb colon
Authors: Smith M. W. , James P. S.
Published: March 2009

Proximal colons taken from foetal and newly born lambs have been shown to actively transport methionine from lumen to blood when incubated under in vitroconditions. The lumen to blood flux of methionine, measured across foetal and early post-natal colons was approximately 25 and 15 times greater than the blood to lumen flux, each flux being determined in the presence of 1 mM methionine.

The ability of the colon to transport methionine decreased with age, there being no net transport across the colon of a 26-day-old lamb. The post-natal disappearance of this transport function appeared to be roughly exponential with a half-time of approximately 2 days.

The short-circuit currents and open-circuit voltages, measured across proximal colons of lambs of different ages, remained stable throughout incubation. The transtissue electrical resistance of colons taken from 9- and 16-day-old lambs was approximately double that recorded across colons taken from younger animals.

These results are discussed both in relation to what is already known concerning amino acid transport in the neonatal pig colon and in relation to what their possible physiological significance might be to normal post-natal development in lambs.
Effects of length of sprouting period on growth and yield of contrasting early potato varieties
Authors: Allen E. J. , Bean J. N. , Griffith R. L. , O'Brien P. J.
Published: March 2009

Three experiments carried out in 3 years (1973–5) which examined the effects of length of sprouting period and temperature of sprouting on growth and yield of three early potato varieties are described. In Home Guard in 1973 at the earliest harvests, tuber yields increased with increase in length and temperature of sprouting period. At later harvests tuber yields decreased with increase in sprouting period especially at the higher temperature (13 rather than 8 °C) and increasing the temperature of sprouting reduced tuber yield. In 1974 length of sprouting period had few effects on yield at any harvest and increasing the temperature increased yields only at the first harvest. In Vanessa cold storage at 3 °C prior to entry to sprouting temperatures induced an earlier onset of sprout growth than continuous exposure to temperatures conducive to sprout growth. Long sprouting periods produced less sprout growth and at the earliest harvest lower tuber yields than all except the shortest period. Judged from the onset of sprout growth increases in length and temperature of sprouting generally increased tuber yields especially at early harvests. In Pentland Javelin sprout growth was very slow and tuber yields at early harvests decreased at both sprouting temperatures if sprouting began after mid-November. At later harvests effects of both factors were small.

The implications of differences in the effects of sprouting periods according to variety and, in Home Guard, season, are discussed in relation to the provision of the most desirable sprouting environment and to variety testing. The similarity in the effects of lengthening the sprouting period and of increasing the temperature of sprouting suggest that temperature is the major causal factor in sprout growth and its effect on field growth. Sprouting periods may therefore be measured most accurately by accumulated day degrees > 0 °C and a close relationship between such a scale and tuber yields is demonstrated. The relevance of such scales for advice to growers is discussed.

Tuber growth rates for Vanessa and to a lesser extent Home Guard in 1974 were extremely high, in excess of 10 t/ha/week for Vanessa. These high rates were associated with high levels of radiation received by coastal sites in May and June and are discussed in relation to the canopy structure of the varieties.
The infestation of crops of oil-seed rape (Brassica napus L.) by insect pests
Authors: Free J. B. , Williams Ingrid H.
Published: March 2009

During 3 years a total of ten crops of winter rape and two crops of spring rape were sampled for insect pests and pest damage once or twice a week from the green bud stage to just before harvest. The most common pests were Meligethes aeneusFab., and Ceutorhynchus assimilisPayk.; the former was usually the more numerous, especially on spring rape crops. Ceutorhynchus quadridensPanz. and Dasyneura brassicaeWinn. were less abundant. C. assimilisand M. aeneus immigrated to winter rape crops when temperatures exceeded 15 °C. Maximum infestation of M. aeneus occurred either at the green bud stage, or when flowering began or at full flower depending on temperature; maximum infestation of G. assimilis occurred during flowering, which varied in time from mid to late May. In response to changing temperatures successive waves of immigration sometimes occurred. Immigration to spring rape occurred at green bud stage.

The two methods used for sampling pests, sweep nets and water traps, gave different results. Water trap collections primarily reflected pest flight, and were not necessarily related to the pest population on the crop.

Ovary maturation of M. aeneus occurred between their emergence from hibernation and migration to winter rape. They began laying 3 weeks after their arrival on winter rape but immediately they arrived on spring rape. The proportion of male to female M. aeneus present on crops was variable. C. assimilis fed for 3–4 weeks after their arrival on winter rape before their ovaries developed and they mated.

On both winter and spring rape the number of M. aeneus declined during flowering and that of C. assimilis declined while pods were maturing. Their decline on winter rape was associated with their emigration to new host plants. New generation M. aeneus emerged before winter and spring rape were harvested, and new generation C. assimilis emerged before spring rape but not winter rape was harvested.

The implications of these findings are discussed in relation to pest control.
Effect of timing of ram introduction on fertility in progestagen-PMSG treated anoestrous ewes
Authors: Boland M. P. , Gordon I.
Published: March 2009

In exploiting to the full the possible advantages of a synchronized oestrus in ewes, the mating management of the ram requires special attention. Previous recommendations (Gordon, 1963) on ram management stated that progestagen-PMSG synchronized ewes should be run with rams at a ram to ewe ratio of 1:10 in the days following treatment. Preliminary work from this laboratory has shown that delaying the introduction of rams until 48 h following sponge withdrawal could improve conception rates significantly (Joyce, 1972). The purpose of the present experiment was to investigate further the effect of time of ram introduction on ewe fertility following oestrous synchronization.
The effect of increased air movement on the heat production and emission of steers
Authors: Blaxter K. L. , Wainman F. W.
Published: March 2009

1. Four steers were used in thirty-five experiments each lasting 4–5 days in which the effects of variation in air velocity from 0·4 to 1·6 m.p.h. at environmental temperatures of 0°, 10° and 20°C. on heat production were studied using a respiration chamber. Measurements were made on animals with winter coats and in the same animals after shearing.

2. Standing time was increased by exposure to cold and slightly reduced by exposure to wind. The wind was so small that it had no effect on the measured coat depth. Piloerection increased winter coat depth by 30%. Heat production was increased by 17–20 kcal./hr. on standing.
Variation in growth and efficiency in twin calves
Authors: Taylor C. S. , Young G. B.
Published: March 2009

Individual variation in the triple relationship of food intake, live weight and gain was examined in 40 twin calves. Appetite largely determined food intake.

Regression analyses of fortnightly gain on protein and starch equivalent and mean weight are presented. Gain per lb. of P.E. or S.E. showed real but irregular changes from fortnight to fortnight. The food differential between heavier and lighter animals decreased during adaptation to new surroundings and diets.
Activity and energy expenditure in laying hens
Authors: Van Kampen M.
Published: March 2009

The energy cost of nesting activity and oviposition of hens in different environments has been determined.

The oxygen consumption of hens on a wire floor reached a peak during the last 15 min before oviposition. However, the oxygen uptake of hens accustomed to a litter floor had fallen to a minimum at this time.

The energy cost of expelling the egg is minimal. There is a good correlation between the locomotor activity and the heat production.

The variations in heat production and body temperature on different types of floors are explicable by the differences in nesting activity.
Free amino -nitrogen used as a monitor for the uptake and movement of amino acids in sheep
Authors: Chalmers Margaret I. , Grant I. , Annand Maureen G. , White F.
Published: March 2009

Free amino -N estimations were used to monitor the movement of amino acids in the vascular system of sheep. The net uptake of free amino-N by portal drained viscera was measured in whole blood and compared with the net gain in the plasma flow.

In normally fed sheep eating dried grass, lucerne or silage the net gain of free amino -N in the plasma of portal blood contributed less than 80% to the total uptake in whole blood. When the protein component of the diet was added into the abomasum (casein supplement to a low nitrogen basal ration) the plasma contribution to the net gain in portal blood averaged 95%.

The results suggest that the cells as well as the plasma are involved in the transport of amino acids in blood and that in ruminants all amino acids have to be measured in blood for a quantitative calculation of the absorption from portal drained viscera.
Growth and flowering of cotton (Gossypium hirsutumL.) as affected by daylength and temperature
Authors: Bhatt J. G.
Published: March 2009

Over 14 h of daylight and high day temperature singly or in combination delayed flowering of the upland cotton J 34, whereas the photosensitive variety MCU 5 did not flower under long days alone or long days plus high temperature. These treatments promoted vegetative growth and made the plants tall and bushy. Though the treatments were discontinued 75 days after germination the subsequent reproductive growth was adversely affected with significant reduction in boll weight.

The upland genotypes when grown at latitudes 29° N, 21° N and 11° N flowered progressively earlier and at lower nodes at more southerly latitudes because of reduction in daylength and temperatures. It is concluded that the upland cottons of northern India differ from classical types because daylength together with temperature appeared to determine flowering.
Comparison of direct drilling, reduced cultivation and ploughing on the growth of cereals
Authors: Elliott J. G. , Ellis F. B. , Pollard F.
Published: March 2009

An experiment on spring barley (cvs Impala and Julia) on sandy loam soil near Oxford was made from 1969 to 1973 to compare mouldboard ploughing, deep and shallow tined cultivation followed by conventional seed-bed preparation, and direct-drilling.

In 1969 fewer barley plants on the direct-drilled plots than on cultivated plots gave fewer fertile ears/m2 and significantly less grain. In 1970, 1972 and 1973 yields did not differ between treatments. In 1971 there were more ears/m2 and more grain was obtained from direct-drilled than from ploughed plots. Mean grain yields over 5 years did not differ significantly between cultivation treatments. Ploughing and deep tine cultivation resulted in better shoot growth early in the season, more straw and more dicotyledonous weeds than direct-drilling. In comparable tillage operations on the same farm considerably less energy was needed for direct-drilling than for mouldboard ploughing and conventional seed-bed preparation.
Compensatory growth in immature sheep: III. Feed utilization by sheep subjected to feed deprivation followed by realimentation
Authors: Drew K. R. , Reid J. T.
Published: March 2009

Experimental conditions and design were described in Part I. When compared with continuous growth, there was a 46% increase in rate of gain following refeeding, but no increase in intake per kg0·734 (MBS) per day. Part of the reason for this was the rapid accumulation of body water after realimentation. If the total cost of feed, including that of the weight-loss phase, is used to calculate the feed required per unit of gain, however, the sheep realimented at 26 kg to reach an empty body weight (EBW) of 45 kg had a requirement 27% higher than ad libitum continuously fed sheep taken to the same final EBW.

The only treatment effect on digestibility or metabolizability of the diet that was not accounted for by level of intake was a depression immediately after underfeeding commenced. The metabolizable energy (ME) value later decreased markedly as a result of the relatively high proportion of gross energy lost in the urine (14·4%).

There were no significant differences between normal growth and refeeding in maintenance requirement or efficiency of energy retention above maintenance. The combined figures were 107 ± 14 kcal ME/kg MBS/day and 52 ± 7% respectively.
Defoliation studies in hybrid maize: I. Grain yield, quality and leaf chemical composition
Authors: Singh R. P. , Nair K. P. P.
Published: March 2009

In order to examine whether high yield of maize could still be maintained at high plant densities by creating an ‘erectophile canopy’ through artificial defoliation of laminae, an experiment at Pantnagar, India, was made on the effect of density, stage and degree of defoliation in two divergent seasons, Kharif (rainy) and spring, of the year 1972. The defoliation treatments were either partial (clipping off the apical half of individual leaves) or complete (full leaf removal) and were imposed at three stages of plant growth, namely when 10 or 16 leaves were fully open or 12 days after silking. These treatments were applied at two plant densities, 60000 and 90000 plants/ha.

Grain yield of maize increased significantly with the increase in population density in the spring season. The trend was diametrically opposite in the Kharif season. Defoliation at the 10th fully open leaf stage produced more grains than defoliating 12 days after silking, which in turn produced more than defoliating at the 16th fully open leaf stage, when plants were in full bloom. Increase in the degree of defoliation at the latter two stages of plant growth reduced grain yield, the effect being more at the 16th leaf stage. However, 50% defoliation at the 10th leaf stage increased grain yield in the Kharif season.

The percentage protein content of grain declined with the increase in population density whereas increase in degree of defoliation increased the grain protein content. Higher protein content of grain was recorded in the spring than in the Kharif season. The leaf protein decreased as the plants neared maturity, especially at the higher degree of defoliation treatments.

Sucrose and reducing sugars declined significantly with the increase in degree of defoliation. The reduction in sucrose was large enough to account for the reduction in total sugar percentage. Similar trends were observed in the sugar-to-protein ratio.
Teat shape associated with teat cup crawl and production in Friesian cows
Authors: Rathore A. K.
Published: March 2009

A total of 580 Friesian cows from four dairy farms selected at random were grouped by teat shape. The incidence of teat cup crawl was recorded at the time of afternoon milking.

Teat cup crawl was significantly higher (27·4%) in the cows with cylindrical shape teats than in cows with funnel shape teats (8·1%).

Milk yield was significantly higher in the cows with funnel shape teats than in cows with cylindrical shape teats. There was significant reduction in milk yield due to teat cup crawl in both groups of cows, the reduction in milk yield being higher in the cows with cylindrical shape teats.
Effect of diets low in calcium and phosphorus on the development of growing lambs
Authors: Field A. C. , Suttle N. F. , Nisbet D. I.
Published: March 2009

Five groups of four 8-week-old Blackface lambs were used to compare the effects of dietary deficiencies of calcium and/or phosphorus: four were given for 16 weeks a semi-purified diet low in Ca (0·07 %) and P (0·13 %), either unsupplemented (LCaLP) or supplemented with 0·3 % Ca (NCaLP), 0·3 % P (LCaNP) or both (NCaNP), and the remaining group was slaughtered initially.

The only clinical abnormality observed was twisting of the forelegs in group LCaLP. Food intake was depressed by 26 % in LCaNP group, by 41·5 % in NCaLP group but was largely unaffected in group LCaLP. Apparent D.M. digestibility was lower for group NCaLP (57·7 %) than for other groups (61·2 %). Differences in live weight and body fat reflected the differences in food intake between treatments but the weights of fat-free body components were lowest in the groups given low P diets.

The LCaNP diet decreased plasma Ca and increased plasma P but the NCaLP diet had the opposite effects. The LCaLP diet had no effect on plasma Ca and decreased plasma P less than the NCaLP diot.

The three mineral deficient diets caused equally marked decreases in Ca and P retention but did not induce negative balances; they also impaired the quality of bone in the tibia and lumbar vertebra, by reducing both the amount of bone matrix and the degree to which it was mineralized, and produced histological lesions of rickets and osteoporosis. Diets low in P caused a marked fall in Mg content of the skeleton.

Urolithiasis was common in lambs given diets adequate in P.
The question of grain content and forage quality in maize: comparisons between isogenic fertile and sterile plants
Authors: Bunting E. S.
Published: March 2009

Results are presented from four experiments in which comparisons were made between isogenic sterile and fertile plants of maize to study the effects of grain content on yield and quality of shoot dry matter. In two experiments comparisons were made over a range of densities, extending from 5 to 25 plants/m2 in 1972 and 5 to 20 plants/m2 in 1973. The other two experiments, grown in 1974 at a density of 10 plants/m2, were sampled 30, 60 and 90 days after flowering.

In 1972 and 1973 yield of shoot dry material was about 10% higher in fertile plants at the lowest density, 5 plants/m2, but grain formation had a negligible effect at higher densities. In 1974, at 10 plants/m2, the yield advantage for fertile plants was 6–7%. These results are in line with other European data, but show a much smaller effect of grain formation on shoot dry matter yield than is normally recorded in USA trials. The discrepancies probably reflect differences in environmental conditions.

Absence of grain had little effect on contents of nitrogen, ash and in vitro digestible dry matter, and increased content of pepsin soluble material and hot water soluble carbohydrates. Percentage content of dry matter in the shoot was higher in fertile plants in 1973, and during the later stages of crop development in 1974.

The results suggest that the importance attached to high grain content as an essential requirement for yield and quality in forage maize is exaggerated, and that the restriction of maize breeding and testing programmes to assessments of grain production, in the belief that the best grain varieties will also be best for forage, can no longer be justified in northern European countries.
Fatty acid composition of adipose tissue of Jersey cattle during growth and development
Authors: Leat W. M. F.
Published: March 2009

The effect of age on the fatty acid composition of depot fat of Jersey cattle has been investigated. Serial samples of subcutaneous fat were obtained by biopsy of the same animals from 3 months to 2 years of age. Samples of depot fat were also obtained from various anatomical locations of animals slaughtered between birth and 11 years of age.

In subcutaneous fat at biopsy the percentage stearic acid remained constant to 1 year of age and then declined from 20% to 5% during the period 1–2 years post partum.

In perinephric fat the stearic acid content increased from 10–15% at birth to 40% at 1 year of age, and then declined during the period 1–2 years post partum.

Changes in the percentage stearic acid above the 10% level were accompanied by inverse change in octadecenoic (C18:1) acid, and below 10% mainly by change in hexadecenoic (C16:l) acid.

There was a gradient of unsaturation between subcutaneous and internal body fats, and also within the subcutaneous fat itself.

Evidence is presented to suggest that the decrease in the unsaturation of depot fat during the period 1–2 years post partum is associated with the deposition of more unsaturated fatty acids during the fattening phase of development.
The duration of the breeding season in Suffolk × Galway ewe lambs
Authors: Keane M. G.
Published: March 2009

The duration of the breeding season was studied in 33 Suffolk × Galway ewe lambs which had a mean live weight of 45·9 ± 1·4 kg. The mean dates of onset and cessation of oestrous activity were 8 November ± 1·4 days and 12 January ± 2·6 days, respectively. The mean number of heat periods exhibited was 4·37 0·3 and the duration of the breeding season was 81 ± 5·7 days. Only 18·2 % of animals had ≥ 6 heat periods while 45·5 % of animals had ≤ 3 heat periods. The incidence of silent heats was 9·2 %.
The development of plant components and their effects on the composition of fresh and ensiled forage maize: 3. The effect of grain content on milk production
Authors: Phipps R. H. , Weller R. F. , Fulford Rosemary J.
Published: March 2009

Maize (Anjou 210), a density-sensitive genotype, was established at 5 and 15 plants/m2 and produced crops containing 50 and 26% grain respectively. Prior to ensiling, the high and low grain crops contained 6·9 and 20·4% water-soluble carbohydrates in the dry matter respectively and were reduced to 0·4 and 1·6% of the dry matter in the silage. The high grain silage contained a lower concentration of acid-detergent fibre, cellulose, lignin, cell-wall constituents and organic acids than the low grain silage. These differences were not reflected in the in vitro digestible organic matter in the dry matter values which were similar in both silages.

Two groups of autumn-calving Freisian cows were offered either the high or low grain silage ad libitum as the sole forage plus an 18% crude protein concentrate during a 14-week experimental period. The cows which received the high grain silage produced significantly more milk of a significantly lower milk fat content than the cows which received the low grain silage.

The increased milk production coupled with the smaller loss of water-soluble carbohydrates during ensiling show that a high grain content in forage maize is a desirable attribute. It is suggested that density tolerance should be one of the selection criteria used by plant breeders to allow crops to be established at high plant densities from which near maximum dry-matter yields could be obtained, while still containing a high proportion of grain.
Effects of feeding ryegrass of varying maturity on the metabolism and composition of lipids in the rumen of sheep
Authors: Gerson T. , John A. , King A. S. D.
Published: March 2009

Two experiments were carried out to test the effects of ryegrass maturity on rumen lipid metabolism. In the first experiment the effect of stage of maturity of perennial ryegrass on lipid metabolism in the rumen was studied with grazing sheep fitted with rumen cannulae. The pasture was either immature (13·8% crude protein), mature (8·1% crude protein) or senescent (5·5% crude protein).

The ratesin vitroof triacyl glycerol lipolysis and linoleic acid (18: 2w6) hydrogenation were found to decrease with increasing age of the ryegrass.

In the second experiment the sheep were dosed with emulsified linseed oil (30 g) via rumen cannulae while grazing immature or senescent ryegrass and the rumen digesta and blood plasma sampled at 0, 4 and 8 h after dosing.

The proportions of linseed oil retained in the rumen were greater and blood plasma linoleic (18:2w6) and linolenic (18:3w3) acid concentrations higher when senescent ryegrass was fed.

It was concluded that the rates of rumen lipolysis and hydrogenation decreased with the age of pasture and that after dosing with linseed oil the polyunsaturated fatty acid concentrations in blood plasma increased.
The effect of interval between harvests and nitrogen application on the concentration of nitrate-nitrogen in the total herbage, green leaf and ‘stem’ of grasses
Authors: Wilman D. , Wright P. T.
Published: March 2009

The effect of six intervals between harvests and three levels of N application on the concentration of nitrate-N and total N in total herbage, green leaf and ‘stem’ was studied in two varieties of perennial ryegrass during 30-week periods in each of the first two harvest years of a field experiment. The effect of two intervals between harvests on the concentration of nitrate-N in Italian ryegrass total herbage was studied in the same experiment. The effect of two intervals between harvests and three levels of N application on the concentrations of nitrate-N and total N in total herbage was studied in five grasses during a 32-week period in a second field experiment.

Increasing the interval between harvests tended to increase the concentration of nitrate-N in herbage; however, this seemed due mainly to the average date of harvest being later in the year with the longer intervals. The concentration of nitrate-N in herbage increased from June to September. Italian and hybrid ryegrass and tall fescue were much higher than perennial ryegrass in nitrate-N concentration at the highest level of applied N (525 kgN/ha per year). Apart from the species and time of year effects, the nitrate-N concentration seemed to be determined mainly by the amount of N applied divided by the number of days between the date of application and the date of sampling. The ‘stem’ of perennial ryegrasa tended to be slightly higher in nitrate-N concentration than green leaf. The proportion of nitrate-N in total N was increased by increasing the interval between harvests and by applying N and was nearly twice as high in ‘stem’ as in green leaf. Both the nitrate-N and the total N concentration of herbage, particularly the latter, seemed to be inversely related to solar radiation receipt.
The relationship of soil mineral NO3-N with stem NO3-N concentration, and of fertilizer-N with the amount of nitrogen taken up by winter wheat, in experiments testing nitrogen fertilizer in combination with aphicide and fungicides, from 1980 to 1982
Authors: Darby R. J. , Widdowson F. V. , Bird E. , Hewitt M. V.
Published: March 2009

Experiments on winter wheat were made from 1980 to 1982 to test fungicide and aphicide sprays in factorial combination with four amounts of nitrogen fertilizer, applied in either one or two dressings in spring. The wheat was grown on three farms with contrasting calcareous clay soils from three soil series; each year it followed a 2-year break on one farm, a cereal rotation on the second and continuous wheat on the third. Soils were sampled to a depth of 0·9 m at seedling emergence in autumn, and again in February and April, to determine the NO3-N and NH4-N in each 0·3 m horizon. Crops were sampled for growth analysis at monthly intervals from March onwards and analysed for nitrogen content. Measurements of stem sap NO3-N concentration were also made at 2-weekly intervals from February or March to late June.

Measurements of soil mineral N were used to calculate the fertilizer nitrogen dressings used in the experiments. The concentration of NO3-N in the stem sap was related to NO3-N in soil; concentiations remained high until most of the soil NO3-N had been removed by the crop. The time at which stem sap NO3-N concentration declined therefore acted as an index of soil N supply, and the data showed that fertilizer-N was needed when the NO3-N concentration fell below a 200 μg/ml threshold. Yields benefited from N applied in February or March only when stem sap NO3-N concentration fell below the threshold at this time.

Apparent fertilizer nitrogen efficiency exceeded 70 % where yields were very large, but ranged between 53 and 64% where yields were smaller because either soil physical problems or disease restraints were present.

A severe attack by take-all (Gaeumannomyces cerealis) caused premature senescence at one centre in 1980; this apparently prevented previously assimilated nitrogen from moving into the grain.
The effect of cereal concentrate supplementation on the digestibility of herbage-based diets for lactating dairy cows
Authors: Arriaga-Jordan C. M. , Holmes W.
Published: March 2009

Two experiments were conducted, one with seven and the other with eight lactating cows, to measure the effect of supplementation with a cereal concentrate on the digestibility of fresh herbage and to provide equations relating digestibility of herbage to faecal indicators. Cattle were housed with free access to fresh herbage from individual Calan–Broadbent gates for recording feed intake, and faecal output was estimated by the use of chromic oxide. In both experiments a cereal supplement depressed herbage organic matter digestibility by 8 g/kg for each kg of fresh concentrate provided within the range 1–6 kg. The depression was associated with reduced digestibility of cellulose. Herbage digestibility was significantly related to faecal nitrogen and faecal cellulose. Herbage intake was depressed by concentrate supplementation and the response in milk yield to supplementation was small.
The effects upon rumen microbial protein synthesis of giving sheep diets of rolled barley and hay supplemented with increasing quantities of soya-bean meal
Authors: Rooke J. A. , Overend M. A. , Armstrong D. G.
Published: March 2009

A ruminant animal is largely dependent upon microbial protein synthesized within the reticulorumen for amino acids to meet its requirements for maintenance and production. The major precursor for rumen microbial protein synthesis is ammonia arising both from degradation of feed proteins within the rumen and from nitrogen recycled to the rumen. The concentration of rumen ammonia-N required to sustain maximal rates of microbial protein synthesis in vivo has been variably reported to range from 22 to 235 mg ammonia-N/1 rumen fluid (Miller, 1982). Most experiments which have investigated the concentrations of rumen ammonia-N required for maximal rates of microbial protein synthesis have used the addition of urea to the diet as the means of increasing rumen ammonia-N concentrations. However, little attention has been paid to the effects upon rumen ammonia-N concentrations and upon the efficiency of rumen microbial protein synthesis of supplying increasing amounts of a readily degradable protein in the diet, although Beardsley et al.(1977) found that as increasing amounts of soya-bean meal were fed to sheep, net losses of N across the forestomachs of the sheep were increased. In this paper, two experiments are described in which increasing amounts of soya-bean meal were fed to sheep receiving a basal ration of rolled barley and hay; the digestion of organic matter (OM) and of amino acid N (AAN) within the rumen, the net quantities of microbial AAN entering the small intestine and the efficiency of rumen microbial AAN synthesis were measured.
The Saxmundham rotation experiments: rotation I
Authors: Trist P. J. O. , Boyd D. A.
Published: March 2009

At Saxmundham Experimental Station in East Suffolk a four-course rotation experiment testing fertilizer treatments has continued with only minor modifications since the 1899/1900 crop year, the crops being wheat, roots (mainly mangolds), barley and either beans, peas or clover. Factorial combinations of nitrogen (N), phosphorus (P) and potassium (K), with two additional treatments testing farm-yard manure and bonemeal, are applied annually to the same plots regardless of crop.

All crops, particularly mangolds and sugar beet, yielded badly without P. N was as important as P for cereals, but had little effect on mangolds and sugar beet unless P was also applied; its effects on the legume yields were slight. On this heavy soil K had little effect on the yield of any crops except the legumes.
The effect of the early application of nitrogenous fertilizer and of the time of cutting in spring on the yield of rye-grass/white clover swards
Authors: Cowling D. W.
Published: March 2009

1. In four different years, swards of perennial rye-grass/white clover were treated with nitrogenous fertilizer (0, 30 or 60 lb. N per acre) in mid-February to produce an early growth of grass. The effect of the time of the first cut, taken in March or April, on the annual yield was studied.

2. The total annual yield was reduced when an increasing quantity of grass was removed at the first cut because this interfered with the development of inflorescences and reduced yield at the second cut.

3. Fertilizer treatment increased early growth and advanced by 2-14 days the date in spring at which the yield was adequate for grazing; this improvement improvement was small compared with the extent to which this date was affected by differences in the weather from year to year.

4. The response in total annual yield to N averaged 17.2 and 14.9 lb. of dry matter per lb. N respectively for the 30 and 60 lb. N per acre applications. The highest responses were measured when little or no grass was removed at the first cut. Where a larger crop was removed at the first cut the response to N was reduced; exceptionally it was negative.
A method of testing the resistance of potato cultivars to tuber damage caused by squeezing
Authors: De Maine M. J.
Published: March 2009

Tubers from nine cultivars grown in four plantings over 3 years at two sites in Scotland were tested for resistance to cracking by squeezing between two flat surfaces. The force was applied by a lever to which a steel plate was fixed, pressing the tuber against a wooden base. The weight on the lever was recorded when wet hair-line cracks appeared on the tuber surface.

There were significant differences between cultivars from the same planting. The rank positions of some cultivars were relatively stable but others differed widely between plantings. The grouping of cultivars into the upper, middle or lower parts of the range for squeezing resistance was similar to that for resistance to external damage based on Potato Marketing Board farm surveys. The test could be used to help breeders identify genotypes highly susceptible to external mechanical damage. If combined with tests of resistance to other types of mechanical abuse common in the bulk handling of tubers a more accurate estimate of damage resistance on the farm should be possible.
Studies on the leaching of urea in sodic soils
Authors: Singh Balwinder , Bajwa M. S.
Published: March 2009

Laboratory experiments were conducted in PVC columns to study the leaching and transformation of applied urea in sodic soils (Gharachon loam-Aquic Natrustalf and Domeli silty clay loam-Aquic Camborthid) reclaimed by gypsum application and kept submerged for 7 or 14 days after fertilizer application. The effect of different depths of irrigation water (5, 7·5, 10, 20 and 30 cm) on urea leaching was studied in a sandy loam sodic soil. In another experiment, the effect of time interval (0 or 4 days) between urea application and initiation of submergence with distilled water (for 7 or 14 days) was investigated involving two recently reclaimed sodic soils (Gharachon loam and Domeli silty clay loam). The results showed that the extent of urea leaching mainly depended upon soil texture. In Domeli silty clay loam, urea penetrated to 20 cm depth with peaks in concentration at 12·5 cm at both 7 and 14 days of submergence. In Gharachon loam urea-N moved to 25 cm depth after 7 days and to 35 cm after 14 days. In the sandy loam sodic soil peaks of urea-N concentration were observed at 12·5, 22·5 and 27·5 cm depths after infiltration of 5, 7·5 and 10 cm depth of water, respectively. Leaching with 20 and 30 cm depths of water moved urea deeper (below 50 and 70 cm, respectively). In recently reclaimed soils, leaching initiated immediately after fertilizer application displaced urea to slightly deeper layers compared with leaching initiated 4 days after urea application. Leaching may not be an important loss mechanism of urea-N in loam or silty clay loam sodic soils. However, in light-textured sandy loam sodic soils leaching beyond the root zone can be expected to create fertilizer management problems.
A device for measuring and sampling urine output from free-grazing steers
Authors: Betteridge K. , Andrewes W. G. K.
Published: March 2009

A non-surgical device which collects a pre-determined proportion of the urine voided by free grazing male cattle is described. The behaviour of animals trained to wear the collection equipment was similar to that of their contemporaries without the equipment. The performance and maintenance of the device are discussed.
Comparative aspects of copper metabolism in silage-fed sheep and deer (Cervus elaphus)
Authors: Freudenberger D. O. , Familton A. S. , Sykes A. R.
Published: March 2009

Ten yearling red deer stags (Cervus elaphus) and ten yearling Coopworth wether sheep were housed in individual pens and offered ryegrass-white clover silage, containing 9–10 mg Cu, 1·4–1·7 mg Mo and 2·4 g S/kg D.M., in amounts close to maintenance energy requirement. For six animals of each species the diet was enhanced with 4·8 mg Mo and 3 g S/kg D.M. Liver biopsy samples were obtained during weeks 1, 6 and 12. The animals were then re-randomized and five of each species offered the basal diet and the remainder the basal diet supplemented with 4 mg Cu/kg D.M. Liver biopsy samples were obtained after a further 4½ weeks. Plasma samples for estimation of total and trichloroacetic acid-soluble Cu were taken weekly.

The mean liver Cu concentration in sheep was 11-fold greater than in deer. Both diets induced liver Cu depletion, though there was a trend for a greater rate of depletion on the Mo- and S-enhanced silage. The rate of depletion (mg Cu/kg liver D.M./day) was 7-fold greater in sheep than in deer, although it was not possible to determine whether this reflected a species-, as opposed to a Cu status-induced effect. In both species highly significant linear relationships were observed between initial liver Cu concentration and rate of liver Cu depletion. This was interpreted to indicate that endogenous loss was directly proportional to liver Cu content in both species. Individual estimates for the minimum rate of endogenous loss of Cu (μg/kg W/day) ranged from 0·2 to 2·71, mean 1·43, and from 2·83 to 14·75, mean 8·35 in deer and sheep, respectively.

During repletion the rate of increase of liver Cu in supplemented groups tended to be greater in sheep than in deer and calculated minimum values for availability of Cu were 0·061 and 0·037, respectively.

Liver Cu concentrations of less than 20 mg/kg D.M. were maintained in deer for several weeks without apparent symptoms of deficiency.