bluuebunny/crossref_metadata_2025 huggingface dataset:
An evaluation of naturally occurring fixed ammonium in soils
Authors: Freney J. R.
Published: March 2009

1.Fixed ammonium could be completely recovered from clay minerals by leaching small amounts of clay with large volumes of salt solutions (containing the cations but not K+, Rb+, or Cs+), but no clay fixed ammonium could be found in soils when analysed by this technique.

2. It is suggested that ammonium fixation is largely a laboratory phenomenon caused by the use of extractants containing potassium ions which trap exchangeable ammonium, or the use of reagents which decompose organic nitrogen compounds.
Seed Ripening in grasses
Authors: Stoddart J. L.
Published: March 2009

1. Floret samples of S321 perennial rye-grass (Lolium perenne L.), S215 meadow fescue (Festuca pratensis L.) and S352 timothy (Phleum pratense L.) were taken at 3-day intervals from inflorescence emergence to seed harvest. These were analysed for total chlorophyll content, chlorophyll a: chlorophyll b ratio and total anthocyanin content.

2. All varieties showed qualitatively similar patterns of total chlorophyll content. At emergence chlorophyll first increased on exposure to light and then fell as anther formation progressed. After fertilization a rapid increase in floret chlorophyll content coincided with early seed formation due to pigmentation of the expanding seed epidermis. Polymerization of carbohydrates to form endosperm starch resulting in increasing dry-matter content caused a concomitant fall in total chlorophyll when assessed on this basis. The final stages of seed maturation were accompanied by a further gradual decline to a very low level.
Combining ability of winter bean (Vicia faba L.) inbreds
Authors: Bond D. A.
Published: March 2009

Analyses of yields for 12 sets of test-crosses of inbred lines of winter beans are given.
Bone-muscle relationships in lamb and mutton carcasses
Authors: Russel A. J. F. , Barton R. A.
Published: March 2009

Carcass weight, bone weight, bone length, and bone weight per unit length were examined as possible indices of the weight of muscular tissue in lamb and mutton carcasses.
Results of an experiment at Woburn testing farmyard manure and N, P and K fertilizers on five arable crops and on a long ley:II. N, P and K removed by the crops
Authors: Widdowson F. V. , Penny A. , Williams R. J. B.
Published: March 2009

1. From 1960 to 1964 an experiment at Woburn, Bedfordshire, measured yields and the amounts of N, P and K removed by five arable crops (barley, grass-clover ley, potatoes, oats and sugar beet) and by a long ley; each was manured with all combinations of N, P and K fertilizers and with farmyard manure (D) and with both fertilizers and farmyard manure (DN1PK and DN2PK).
Extremity skin temperature in British and Zebu cross cattle
Authors: Johnson K. G. , Webster M. E. D.
Published: March 2009

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.

2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.

Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.
The effect of constant long daily photoperiod upon the onset of puberty in ewes
Authors: Smith I. D.
Published: March 2009

The effect upon the onset of reproductive activity of exposure of ewe lambs of three British breeds (Border Leicester, Southdown, Suffolk) to constant long daylight hours (16 h light/8 h dark) was studied.

Oestrus, ovulation and conception were depressed but not inhibited; however, only the incidence of conception was significantly less than in the control group. Athough the treatment retarded the onset of oestrous activity, the age at first oestrus was still within the normal age range for puberty.
Productivity and intensive sheep stocking over a five-year period
Authors: Spedding C. R. W. , Betts J. E. , Large R. V. , Wilson I. A. N. , Penning P. D.
Published: March 2009

During the last ten years or so, the management of sheep for intensive lamb production has been studied on a considerable scale, and a variety of grazing systems have been investigated (Dickson, 1959; Cooper, 1959; Spedding & Large, 1959; Boaz, 1959). It is still too soon to specify precisely the place that any of these systems should occupy in sheep-production processes, in relation to breed, lambing percentage, weight of lamb at slaughter, stocking rate, botanical composition of the pasture, size of ewe and level of her milk yield. Quite apart from these biological considerations, the full economic implications are by no means clear. What has emerged most clearly, however, is that much higher stocking rates can be tolerated than had generally been regarded as safe and that, at these stocking rates, productivity can be extremely high.
The use of fats in pig feeding:II. The digestibility of various fats and fatty acids
Authors: Bayley H. S. , Lewis D.
Published: March 2009

The apparent and corrected digestibilities of beef tallow, H.E.F. and soyabean oil have been determined in the newly weaned pig. Determinations of the individual fatty acids in the food and faecal lipids allowed the digestibility of each acid to be calculated separately. The purest available forms of oleic, stearic and palmitic acids and their corresponding triglycerides were also used in the determination of digestibility. Although the digestibility of each fatty acid is to some extent a characteristic of the acid, the extent of absorption can also be modified by the other acids in the diet. The results.of these experiments give no clear indication of a difference between feeding fatty acids in the free form or as the triglycerides. The digestible energy values of the fats have been calculated as the product of gross energy value and corrected digestibility.
The effect of season and of supplimentary feeding on the the rumen contents of African cattle grazing subtropical herbage:I Distribution of nitrogen and dry matter
Authors: Elliott R. C. , Reed W. D. C. , Cmelik S. H. W. , Topps J. H.
Published: March 2009

1. Africander and Mashona steers, fitted with rumen cannulae, were used to study levels of various nitrogenous fractions and of dry matter in the rumen of cattle grazing on natural subtropical herbage throughout the year. Some steers received various concentrate foods in addition to veldt grazing during winter. During the summer rainy season, four steers, two of each breed, were under trial, while in the winter drought period two extra steers of each breed were added to the experiment. The eight steers were divided into four groups for the winter, one group received a protein-rich concentrate, another group received a carbohydraterich concentrate, a third group was given a mixture of the two concentrates, while the fourth group received no additional food.
The effect of season and of supplementary feeding on the rumen contents of African cattle grazing subtropical herbage:II. pH values and concentration and proportions of volatile fatty acids
Authors: Topps J. H. , Reed W. D. C. , Elliott R. C.
Published: March 2009

1. Africander and Mashona steers, fitted with rumen cannulae, were used to study pH values and concentrations of volatile fatty acids in the rumen of cattle grazing on natural subtropical pasture through the year. Some steers received concentrated, foods in winter. During the summer, rainy season, two Africander and two Mashona steers were studied while in winter a further four steers, two of each breed, were added to the trial. The eight steers in winter were divided into four similar groups, one group received a carbohydrate-rich concentrate, another group received a protein-rich concentrate, a third group was given both concentrates, while the fourth group received no additional food.
A comparison of grazing systems for dairy herd replacements
Authors: Leaver J. D.
Published: March 2009

An experimental and a conventional grazing system for 7- and 19-month-old dairy replacements were compared during 136 days of the grazing season. In the experimental system A, 24 calves were rotationally grazed around paddocks followed by 24 pregnant heifers which ate the herbage residue left by the calves. The conventional system B consisted of 24 calves and 24 pregnant heifers maintained at the same overall stocking rate as in system A, but the calves and heifers grazed in completely separate rotations. Half the calves on each system were drenched with an anthelmintic at weekly intervals from mid-July onwards to estimate within systems the effect of gastrointestinal worms on live-weight gain.
Body composition studies with the milk-fed lamb. II. The effect of the age of the lamb and the protein content of the diet on the chemical composition of the body and its organs
Authors: Jagusch K. T. , Norton B. W. , Walker D. M.
Published: March 2009

Eighteen male cross-bred lambs (aged 2–5 days) in two equal groups were given artificial milk diets of either low- or high-protein content; subgroups of three lambs were slaughtered after 2, 4 and 6 weeks on experiment. The composition of the change in empty body weight (E.B.W.), and the chemical composition of the change in weight of the separate compartments and organs, were determined by the comparative slaughter method.

Lambs given the high-protein diet made significant gains in weight and in all chemical components in all periods. The composition of their E.B.W. was closely related to E.B.W. regardless of age. Lambs given the low-protein diet made only small gains in weight in 6 weeks, of which 76% was fat. The chemical composition of their E.B.W. was closely related to E.B.W. within each age group. The net gain of protein of these lambs in 6 weeks represented only 1% of the total weight gain, and over 50% of the protein gain was in wool. The skin and blood lost protein during the first 2 weeks, and failed to recover this loss during the remaining 4 weeks. Other organs lost protein initially but recovered this loss between 2 and 6 weeks.

It was concluded that the initial loss of protein represented the labile protein reserves of the lamb, and the subsequent recovery was an adaptation to the low-protein diet. Furthermore, the results with both diets indicated that the skin and blood were the most inefficient of the organs in the body in utilizing the available N during a period of protein deficiency, or during a period of abundance in the dietary supply of N.
A comparison of the effects of anhydrous ammonia and a solid ammonium nitrate fertilizer on herbage production from a pure perennial ryegrass sward
Authors: Reid D. , Castle M. E.
Published: March 2009

In a 2-year experiment anhydrous ammonia (82% N) and an ammonium nitrate fertilizer (34·5% N) were applied at three annual rates—100, 200 and 300 lb N/acre (112, 224 and 336 kg/ha)—on an S.24 perennial ryegrass sward. At each rate the two fertilizers were applied either as a single dressing in the spring or as five equal split dressings over the season. Total yields of herbage dry matter and of crude protein were determined by cutting the herbage at approximately the same stage of growth five times each year. On the basis of total yield and seasonal distribution of yield anhydrous ammonia was best applied as a single dressing in the spring, whereas ammonium nitrate was best applied as five equal split dressings over the season. However, in both years anhydrous ammonia applied as a single dressing gave smaller yields and a poorer seasonal distribution of production than did ammonium nitrate applied as five equal split dressings. The factors contributing to the lower yield level with anhydrous ammonia applications are discussed. It is concluded that anhydrous ammonia has no marked advantages over ammonium nitrate as a nitrogen fertilizer for intensively managed grassland.
Increasing litter size in three breeds of sheep by superovulation
Authors: Newton J. E. , Betts J. E. , Large R. V.
Published: March 2009

Ewes of three breeds, Devon Longwool, Kerry Hill and Welsh Mountain were injected with different levels of Pregnant Mare Serum Gonadotrophin (PMSG) for 3 consecutive years. Within the levels of PMSG examined (0–1500 i.u.) the highest mean litter size was obtained at 1000 i.u. for the Devon Longwool (2·10) and the Welsh Mountain (2·33), and at 1500 i.u. for the Kerry Hill (2·41). This represented a response of 0·66, 1·28 and 0·56 extra lambs born for the Devon Longwool, Welsh Mountain and Kerry Hill breeds, as untreated ewes of these breeds produced 1·44, 1·05 and 1·85 lambs/litter. The lambing percentage attained was, however, lower than the response in litter size indicated, due to the incidence of barren ewes and of lamb mortality.

Though the Devon ewes were heavier than the Kerry's, twin lambs out of the latter were bigger than twins from the Devon's. The relationships of body weight and of natural fertility to optimum dosage of PMSG are considered. There is discussion of the maximum litter size and minimum birth weight compatible with the production of viable lambs.
The interaction between nitrogen and water in The growth of Grass Swards: I. Methods and dry matter results
Authors: D'Aoust M. J. , Tayler R. S.
Published: March 2009

An experiment examined the interaction between nitrogen and irrigation on a sward of Lolium multiflorum (Italian ryegrass). Between rates of 100 and 200 units of nitrogen per acre, the response to nitrogen over the whole season was not increased by irrigation. Positive and negative interactions occurring in different periods cancelled each other out. Between rates of 200 and 400 units of nitrogen per acre, irrigation substantially increased the response to nitrogen, negative interactions being small relative to positive interactions. The results suggest that the moisture status of the upper few inches of the soil is an important factor in determining response to applied nitrogen. Response to nitrogen was increased when irrigation improved the moisture status of this zone.
Seasonal oestrogenic activity of various legumes
Authors: Newton J. E. , Betts J. E.
Published: March 2009

Oestrogenic activity was recorded by teat length extension in wether lambs grazing red clover S. 123 in September and October 1965 and between 21 April and the end of October 1966. The number of lambs born alive to ewes grazing red clover (S. 123) for the 2 weeks prior to mating and for 4 weeks after mating was reduced. Oestrogenic activity was also recorded in wether lambs on lucerne var. Eynsford and on white clover S. 100 from mid-June to mid-October 1966.

Oestrogenic activity was confirmed in red clover, but not in lucerne, by mouse bioassay. Slight oestrogenic activity was shown in one white clover sample only.
Nutritional stress and pre-implantation embryonic mortality in Merino sheep
Authors: Edey T. N.
Published: March 2009

1. Embryonic mortality and reproductive performance were studied in 150 mature Merino ewes, groups of which were restricted to approximately 15% of their maintenance requirement from days 0to7 (group 1), 6to13 (group 3) and 13to20 (group 4) respectively. Groups 2and5 were controls. Ovulation point counts, returns to service, pregnancy test by laparotomy at day 40 and lambing performance were used to assess and apportion the embryonic loss.
Mineral balance studies on lactating ewes with particular reference to the metabolism of magnesium
Authors: L'Estrange J. L. , Axford R. F. E.
Published: March 2009

1. Balance experiments, in which urine was collected by a catheter inserted into the bladder, were carried out on four lactating ewes on two diets of fresh spring herbage and on one of hay plus cake, and the metabolism of magnesium, calcium, phosphorus, potassium and sodium were studied.
Mother–offspring relationships in Awassi sheep:II. Milk yields and weight gains of lambs in a mutton flock
Authors: Folman Y. , Eyal E. , Volcani R.
Published: March 2009

The majority of Awassi flocks in Israel and throughout the Middle East are kept under primitive extensive conditions. Their main product is the lamb, and milk as a by-product is gained occasionally after weaning. A few estimates of the milk yields of these sheep may be found in the literature (Hirsh, 1931; Finci, 1957; Becker, 1958), however, none are based on actual measurements.
Liquid manure as a grassland fertilizer:V. The response to mixtures of liquid manure (urine) and dung
Authors: Castle M. E. , Drysdale A. D.
Published: March 2009

1. A small-scale plot experiment was conducted at the Hannah Institute for the 3-year period 1963–65, to study the comparative effect of applications of various mixtures of dung and urine (slurry treatments) on the yield and quality of an established S23 ryegrass and S100 white clover sward.
Sodium and potassium relationships in sugar beet
Authors: Draycott A. P. , Marsh J. A. P. , Tinker P. B. H.
Published: March 2009

Three field experiments with sugar beet grown on a light calcareous soil tested a wide range of amounts of sodium and potassium fertilizer with either magnesium or nitrogen. Both sodium and potassium increased sugar yield and there was a large negative interaction between them. Magnesium also increased sugar yield, but the larger dressing of nitrogen decreased it. Sodium, potassium and nitrogen fertilizers also affected the concentration of impurities in the root juice at harvest.

Plant samples were also analysed in August when the crop usually contains most sodium. Sodium fertilizer greatly increased the sodium and decreased the potassium concentration in the dry matter of the tops but the composition of the roots changed little. Potassium dressings slightly increased potassium in the tops but did not affect the root composition.

Exchangeable sodium in the top soil of plots given sodium fertilizer decreased rapidly early in the season, but increased again from August, probably because sodium was taken up rapidly early in the summer and returned later in dead leaves. Soil potassium decreased throughout the season on plots where potassium was applied, but did not change on plots without potassium fertilizer; this is explained by fixation and release from non-exchangeable forms.

On this soil there was no reason to regard sodium in its effect on yield, other than as a replacement for potassium, but its behaviour in the soil and effect on the composition of the plant was quite different.
Protein and lysine levels in practical rations
Authors: Braude R. , Lerman P.
Published: March 2009

A co-ordinated trial has been carried out at twenty-one centres to obtain information on the following problems: does the addition of synthetic lysine to a ‘standard’ ration, widely recommended and used in this country, beneficially influence the performance of growing pigs, and is the effect influenced by whether the source of supplementary protein is white fish meal or soya bean meal ?

In comparison with a ration providing levels of crude protein and lysine recommended in the A.R.C. ‘Nutrient Requirements of Pigs’, the ‘standard’ ration which contained less crude protein and total lysine, produced slightly lower performance, but about the same profit. The performance on the ‘standard’ ration could be improved by the addition of synthetic lysine, but such supplementation would not be profitable unless the cost of synthetic lysine was less than 21s./kg.

The response to added synthetic lysine was similar on rations in which the source of supplementary protein was either white fish meal or soya bean meal.
Storage of fertilized cattle ova in vitro
Authors: Sreenan J. , Scanlon P. , Gordon I.
Published: March 2009

We have obtained evidence of normal development of cattle ova following storage at 10 °C. Of thirty-two treated ova transferred to the oviducts of pseudo-pregnant rabbits, twenty-three were recovered and ten of these had undergone further cleavage.
Observations on the casting of ewes
Authors: George J. M.
Published: March 2009

1. Observations were made on the casting, or accidental immobilization in dorsal recumbency, of Dorset Horn ewes under grazing conditions for a 12-month period.
Seed size as a varietal difference in broad beans (Vicia Faba L.)
Authors: El Saeed E. A. K.
Published: March 2009

1. Emergence and dry-matter production of largeand small seeds of two varieties of broad beans (Beladi and Rebaya 34) were studied.
Field experiments comparing ammonium sulphate, ammonium nitrate, calcium nitrate and urea combine-drilled with spring barley
Authors: Devine J. R. , Holmes M. R. J.
Published: March 2009

1. Twenty-one experiments were carried out in various parts of England and Scotland in 1959–61 comparing two or more of the nitrogen sources ammonium sulphate, ammonium nitrate, calcium nitrate and urea, combine-drilled in compound fertilizers for spring barley.

2. Ammonium sulphate and ammonium nitrate combine-drilled at rates from 35 to 105 lb./acre of nitrogen checked early growth slightly in some of the experiments, with no important difference between the two sources, which also gave similar grain yields.

3. Calcium nitrate and urea combine-drilled at 45 lb./acre of nitrogen had no large effect on early growth, while at 70 and 90 lb./acre both fertilizers seriously delayed brairding and reduced the plant population in many of the experiments, especially in eastern England. They gave lower yields than ammonium sulphate and ammonium nitrate in many of the experiments in which early growth was affected, and gave lower mean yields at all rates of application.

4. In eleven of the experiments, broadcast applications of two or more of the four nitrogen fertilizers were compared. All sources gave similar mean yields.

5. There was a slightly smaller yield from combine drilling than from broadcasting ammonium sulphate and ammonium nitrate, and a markedly smaller yield from calcium nitrate and urea.
Results of fertiliser experiments on carrots in 1941 and 1942
Authors: Garner H. V.
Published: March 2009

Field experiments of modern design that included carrots were first made at Woburn in 1934, to compare the value of nitrogen in dried poultry manure with ammonium sulphate. The experiments were repeated at several centres and continued until 1939. Most other crops responded well to nitrogen but in only one of the five experiments containing carrots did ammonium sulphate at 3 cwt/acre increase the root yield, and in two it significantly depressed yield. Ammonium sulphate tended to lessen plant numbers, but it increased the yield of tops (Rothamsted Experimental Station, 1934)
The artificial rearing of lambs on cold reconstituted whole milk and on milk substitute
Authors: Large R. V. , Penning P. D.
Published: March 2009

1. Two experiments with 52 lambs are described investigating the use of reconstituted cold milk for rearing lambs and comparing full cream dried milk with a milk substitute.

2. The use of cold milk resulted in high growth rates and few health problems.

3. Satisfactory food conversion efficiencies were obtained by feeding of cold reconstituted whole milk and cold milk substitute.

4. During the first 3 weeks of rearing, the growth rates and food conversion efficiencies on the milk substitute were similar to those obtained on the full cream milk.
Long-term effects of fertilizers on herbage production: I. Yields and botanical composition
Authors: Heddle R. G.
Published: March 2009

In a factorial experiment on a mixed grass/clover sward, continued over 13 years, D.M. yields were strongly affected by N and K, which showed a marked interaction. P had very little effect on yield. There was evidence of a depressing effect on yield of continued application of KC1 at low rates of N input: this is thought to be due to excess Cl. It may be associated with the effect of Cl on clover growth, since it did not occur in predominantly grassy swards heavily dressed with N, in spite of high Cl content in the herbage.

The botanical composition of the herbage was strongly affected by the fertilizer treatments.
Long-term effects of fertilizers on herbage production: II. Chemical composition
Authors: Heddle R. G. , Crooks P.
Published: March 2009

The effects of Nitro-chalk, superphosphate and potassium fertilizers on the chemical composition of grassland herbage and the removal of major plant nutrients have been traced over 14 years.

Without fertilizer N, but with adequate K, clover supplied a yearly average of up to 87 lb Nsol;acre. With an annual application of 348 lb N and adequate K, 237 lb of N was recovered annually.

Without applied P, herbage P concentration fell with time especially under heavy N treatment. When P was applied, herbage P concentration did not fall, irrespective of N treatment: K depressed P concentration irrespective of P application. Maximum removal of P occurred with annual applications of 348 lb N, 43 lb P and 280 lb K: at these rates gain and loss of P approximately balanced.

Herbage K concentration was greatly increased by K fertilizer. It was reduced by N when no K was applied but applying K counteracted this effect. Removal of K slightly exceeded the 280 lb of K applied when 348 lb N was also applied.
The influence of nutritional level in early pregnancy of the ewe
Authors: Coop I. E. , Clark V. R.
Published: March 2009

A series of three large-scale field trials, involving 3500 ewes over a 3-year-period, was conducted to study the effect of restricted nutrition of breeding ewes in early pregnancy. Control or non-restricted ewes were fed at approximately maintenance level and restricted ewes at approximately half-maintenance. The majority of ewes fell into two categories—those 2–3 weeks pregnant at the time restriction was commenced and those 5–7 weeks pregnant. Restriction was applied for from 5 to 8 weeks, live-weight differences of approximately 10 1b were achieved.

Differences in performance in individual trials were invariably very small, and nonsignificant. The main effect of restricted nutrition over all trials was to decrease twinning by 0·5% and decrease the number of barren ewes by 0·8%. These differences are considered to be negligible. Only one statistically significant effect was observed within one of the trials—this was a depression in twinning in ewes 18–24 days pregnant at the time of applying the treatment, but this effect could not be confirmed in the other two trials. However, the fleece grown was affected by treatment—the fleece weight being depressed by approximately ½ lb, and grade reduced slightly.

It is concluded that restricted nutrition at the level and time applied has no effect on reproductive performances of ewes and therefore the practice of restriction in early pregnancy to conserve feed for late pregnancy is a sound policy.
Transgressive segregation for frost resistance in hexaploid oats (Avena spp.)
Authors: Jenkins G.
Published: March 2009

Results are presented from freezing tests on five varieties of winter oats from diverse origins, on their crosses in the F1and F2generations and on selected F3lines from six of the crosses.

Analysis of the F1results indicated that frost resistance was mainly determined by recessive genes, additive in their effect, but in the F2experiment there was evidence of non-allelic gene interaction. Significant general combining ability (GCA) effects were obtained in both the F1and F2experiments but specific combining ability (SCA) effects were significant only in the F2crosses. The variety Novosadsky II displayed consistently high general combining ability.

Tests on F3lines derived from selected F2plants revealed considerable transgression for frost resistance in all six crosses studied. The results are discussed in relation to breeding for improved frost resistance in oats.
Length of tongue in a honey bee in relation to the pollination of red clover
Authors: Hawkins R. P.
Published: March 2009

Red clover florets are generally longer than a honey bee's tongue. Original data are submitted showing that honey bees can reach to a depth of 7 mm into the corolla tube of a red clover floret. The importance of this figure is discussed in relation to breeding bees with longer tongues and the breeding of red clover with shorter corolla tubes. Breeding a variety of red clover with more nectar so that honey bees can reach it is considered to be the best solution and would produce an increase in yield of both seed and honey.
The effect of time of sowing on flowering and fertile tiller production in S. 48 timothy
Authors: Langer R. H. M. , Ryle G. J. A.
Published: March 2009

1. In a field experiment all plants of S. 48 timothy produced ears after being sown on or before 24 April; more than 90% of the plants still flowered if sown up to 19 May but fertility declined after later sowings, until only vegetative growth resulted in plants sown on or after 30 June.

2. In a pot experiment, during which the performance of individual tillers was recorded, all tillers arising after 23 July were found to remain vegetative. Ear-bearing capacity declined towards this date but was still high in tillers appearing as late as 2 July in plants sown in the middle of May.

3. Tillers on the main stem were more fertile and produced heavier ears than other tillers of the same age and order of succession on the plant.

4. Many plants sown late in the field produced ears which formed vegetative proliferations after the end of the summer.

5. The results are discussed in relation to the response of timothy to the changing environment, notably the length of day. It is suggested that timothy does not react to favourable photoperiods immediately upon germination and that failure to flower in plants sown after the middle of May does not necessarily imply any inadequacy of the environment to cause floral initiation, since it was possible for tillers appearing up to 2 July to produce ears, with few exceptions. Factors inherent in the organization of the plant are considered to be responsible for a decline of ear-boaring capacity from tiller to tiller, which occurred irrespective of changing environmental conditions.
Factors influencing the composition and nutritive value of herbage from fescue and Molinia areas
Authors: Davies R. O. , Jones D. I. H. , Milton W. E. J.
Published: March 2009

It has been established that the mineral deficiencies can be rectified on both the fescue dominant and Molinia dominant swards of mid-Wales without recourse to ploughing and reseeding (Milton & Davies, 1947). The processes adopted consisted either of liming the native swards in the absence of fertilizers or else fertilizing the sward either in the presence or absence of lime. The grazing animal played an important part in the changes that took place. Some of the treatments resulted in the partial or complete extinction of the native hill herbage and its replacement by grasses and clovers of high productivity and mineral content.
Studies on the cutting management of grass-clover swards. I. The effect of varying the closeness of cutting on the yields from an established grass-clover sward
Authors: Reid D.
Published: March 2009

1. A 3-year experiment is described in which perennial rye-grass/white clover swards were cut to within either 1 in. of 2–2½ in. of ground level when the herbage had reached either the ‘grazing’ or the ‘silage’ stage of growth. Superimposed on the cutting treatments were several fertilizer treatments which involved application of varying amounts of nitrogen at different dates over the season.

2. Throughout the experiment cutting to within 1 in. of ground level gave greater dry-matter and crude-protein yields of mixed herbage and of clover than cutting to within 2–2½ in. of ground level, the increase in dry-matter yield ranging from 39 to 49%.

3. The response of clover to these ‘height of cutting’ treatments developed more slowly than the response of the sward as a whole, and was modified in the later stages by the particular fertilizer nitrogen treatment applied.

4. It is suggested that the greater herbage yields obtained from close- than from lax-cut swards resulted from the differential effects of the two cutting treatments on stem and leaf formation in the grasses, but the need for further investigation is stressed.

5. Discrepancies between the effects of the ‘height of cutting’ treatments in this experiment and those reported by other workers are indicated, and it is shown that these discrepancies probably result from the varying cutting frequencies adopted.

6. Cutting the sward at varying stages of growth and increasing the rate of fertilizer nitrogen application had very similar effects on mixed herbage and clover yields in this experiment to those reported previously by other workers.

7. Where the total amount of fertilizer nitrogen applied over the season was small (4 cwt. ‘Nitro-Chalk’/acre) delaying the first dressing until after the first or second cut reduced the dry-matter and crude-protein yields of mixed herbage, and had little effect on those of clover. A similar delay where greater total amounts of fertilizer nitrogen were used (8–12 cwt. ‘Nitro-Chalk’/acre) reduced the dry-matter yields of mixed herbage, and slightly increased the dry-matter and crude-protein yields of clover. Under these heavy nitrogen treatments the crude-protein yields of mixed herbage decreased only where the delay involved a reduction in the total amount of fertilizer nitrogen applied over the season.

8. Although delaying the first dressing of the season reduced mixed herbage yields at all fertilizer nitrogen levels, it resulted in a more uniform distribution of production over the season. The practical significance of this is discussed.
Metabolism of nitrogen during long-term incubation of soil treated with fresh and rotted organic materials
Authors: Cornfield A. H.
Published: March 2009

The metabolism of nitrogen during incubation, at 28° C. for 184 days, of a soil treated with 1% by weight of five different bulky organic manures and 0·5% calcium carbonate was studied.

1. Ammonia and nitrite could not be detected at any sampling date with any treatment, hence nitrate levels in treated soils compared with that in the control soil indicated the extent of mineralization or fixation of nitrogen.

2. A good straw compost (carbon/nitrogen ratio, C/N, 20·6) was the only material which showed mineralization of nitrogen over practically the whole of the incubation period.

3. Rotted farmyard manure (C/N 15–6) caused a small, whilst fresh grass (C/N 22·6), caused a fair amount of nitrogen fixation in the early stages, but there was a small overall mineralization of nitrogen by the final sampling.

4. A poor straw compost (C/N 42·5) and straw (C/N 147·0) both caused considerable fixation of nitrogen in the early stages. With continuing incubation the bulk of the nitrogen fixed by the poor compost, but only a small portion of that fixed by the straw, was released.
The comparative fertility of bovine semen of four ages diluted with skim-milk and skim-milk + glycerol
Authors: O'Connor L. K. , Smith G. F.
Published: March 2009

A split-sample experiment involving 14,319 first inseminations was carried out at sixteen artificial insemination centres to compare the fertility of semen diluted with skim-milk and skim-milk containing 10% glycerol when used on the first, second, third and fourth days after the day of collections.

The addition of glycerol to the heat-treated skimmilk diluent significantly reduced the decline in fertility with increasing age. However, there were indications that glycerolization also reduced initial fertility.
The influence of heavily fertilized grass on mineral metabolism of dairy cows
Authors: Mudd A. J.
Published: March 2009

Groups of lactating dairy cows were fed on grass which had received various amounts of nitrogen and potash fertilizers. In the early part of the season not only was the herbage concentration of calcium and phosphorus lower in grass which had received potash fertilizer but in addition the ‘availability’ of the calcium to cows was depressed. Grass which had received large amounts of nitrogen fertilizer had a comparatively low dry-matter content in the autumn. Cows fed such grass were in negative balance for calcium at this time. As expected high dietary potassium gave rise to high excretion of potassium in the urine which in turn was correlated with high excretion of magnesium. These various factors are likely to affect the incidence of metabolic disease.
The uptake of initially available soil potassium by ryegrass
Authors: Addiscott T. M.
Published: March 2009

The potassium potential which limits uptake of K by ryegrass, ‘the uptake potential’, was derived from the uptakes of K and from the quantity/potential relationships of a number of soils by a method which avoids exhausting the soil by cropping. This potential was – 5600 cal/equiv in Rothamsted soils, but the method was unsuitable for Woburn soils. In Rothamsted soils uptake of K was more closely related to quantity than to potential of K, but in Woburn soils it was equally well related to both. From 28 days until 82 days, when the initially available K had been used in most soils, diffusion in the soil seemed to control rate of uptake of K. On longer cropping, much initially nonavailable K was released, the grass still grew and the mean K potential had fallen to only –5189 cal/equiv in Rothamsted and –5336 cal/equiv, in Woburn soils.
Comparisons of liquid and solid fertilizers and anhydrous ammonia for sugar beet
Authors: Draycott A. P. , Holliday R.
Published: March 2009

Six field experiments (1963–8) in eastern England compared solid fertilizer with liquid fertilizer or anhydrous ammonia for sugar beet. Two glasshouse experiments investigated the interaction between depth of placement of fertilizer and soil moisture.

Yields of sugar were the same from broadcast solid and sprayed liquid in all the experiments, but nitrogen uptake by the crop was less from liquid than from solid. Three experiments tested placement of liquid 4 in to the side and either 2 or 6 in below the seed. Plants with deep-placed fertilizer consistently out-yielded those with shallowplaced fertilizer, but yields were never significantly different from broadcast solid fertilizer. Dry-matter yields of sugar beet grown in containers indoors showed that the crop responded to deep placement when the surface soil was watered infrequently.

With anhydrous ammonia injected during seed-bed preparation, sugar yield and nitrogen uptake were the same as with solid fertilizer in the seed bed, and were greater than with anhydrous ammonia injected in the ploughed land during early spring. A side-band injection of anhydrous ammonia before singling gave a crop containing as much nitrogen at harvest as, but less sugar than, nitrogen applied in the seed bed.
Distribution of iron, manganese and phosphorus in the paddy soil profile
Authors: Islam M. A. , Choudhury A. A.
Published: March 2009

Soils collected from paddy fields were kept in a waterlogged condition in glass cylinders with and without drainage. After about 2 months of waterlogging soil samples were collected from each cm. depths of the cylinders, both from the bright and dark sides of the cylinders. The soil samples were analysed for iron, manganese and phosphorus. At the beginning these elements were uniformly distributed throughout the entire soil depth, but as a result of waterlogging a distribution pattern developed. More of these elements concentrated on the surface and illuminated sides of the cylinders. It is assumed that such a phenomenon also occurs in the paddy field. These elements by concentrating on the soil surface limit the feeding zones to the top 3–5 cm. of the soil.
β-Globulin polymorphism and economic factors in dairy cattle
Authors: Ashton G. C.
Published: March 2009

1. The serum β-globulin phenotype of 141 bulls located at Cattle Breeding Centres in England and Wales was determined by starch-gel electrophoresis.

2. The distribution of the contemporary comparison values of these bulls with respect to β-globulin type was investigated. The great majority of the bulls were βAA, βAD, or βDDwith very few βAEand βDEand no βEEtypes.

3. The contemporary comparison values for 130 bulls of the three types βAA, βADand βDDeach fell into a normal distribution. The mean and its standard error and the standard deviation of the mean and its standard error were calculated for each of the three curves. The mean contemporary comparison value for the βAAbulls was + 12·2 ± 5·4 gal., for the βADbulls + 26·8 ± 5·4 gal., and for the βDD bulls + 38·2 ± 5·5 gal. The βAAand βDDmeans were significantly different (P< 0·01).

4. The pooled contemporary comparison values of the βAA, βADand βDDbulls did not give a normal distribution curve, neither did the contemporary comparison values for a sample of 1028 bulls quoted by the Milk Marketing Board. However, when the contemporary comparison values of the βAA, βADand βDDgroups were superimposed around the same mean, the ensuing distribution was normal.

5. It is concluded that the β-globulin locus is concerned in the genetic control of milk yield. The estimated mean genetic value of βDover βAis approximately + 50 gal. This is about one-sixth of the total genetic variation in milk yield in the major milk breeds.

6. The distribution of butterfat percentages with respect to β-globulin phenotype in four Ayrshire and one Friesian herds was investigated. No difference between the mean first lactation butterfat percentage of the βAA, βAD, and βDDcows in each herd was found. There was an indication (not significant) that the mean butterfat percentage of the βAEand βDEcows in three of the four Ayrshire herds studied was higher than the mean of the other groups.
The value of calcium nitrate and urea for sugar beet, and the effect of late nitrogenous top dressings
Authors: Adams S. N.
Published: March 2009

1. Twenty-eight experiments on sugar beet in 1956–8 compared ammonium sulphate, calcium nitrate and urea applied to the seedbed before sowing. The three fertilizers were compared at rates which supplied nil, 0·6 and 1·2 cwt. N/acre. Treatments in which 0·6 cwt. N/acre was held back until the end of June were also included.

2. Average responses in sugar yield were low, 0·6 cwt. N/acre provided virtually all the nitrogen required for maximum sugar production. The heavier nitrogen dressing, on the other hand, substantially increased the yield of tops.

3. Calcium nitrate and urea were as effective as ammonium sulphate at raising sugar yield. There was no damage to germination with any fertilizer, and when urea containing 4·5% biuret was used for topdressing in 1956, no damage was seen. Calcium nitrate and, to a lesser extent, urea produced more tops than ammonium sulphate.

4. Putting all the nitrogen into the seedbed was as effective as a split dressing in raising sugar yield. Leaching of nitrogen in a wet summer is therefore not important to sugar beet. Late nitrogen, on the other hand, never harmed sugar production if some had been given to the seedbed.
Measurements of the ‘motility’ of bull sperm cells under various conditions
Authors: Rikmenspoel R.
Published: March 2009

In this paper the results are described of experiments on bull sperm cells with the photo-electric device for measuring the ‘motility’, as developed by Rikmenspoel, van Herpen & van Dam (1956).

It was found that the velocity distribution of sperm samples differs only slightly from a Gaussian one. The form of the distribution curve, which is a bit skew, is rather constant between ejaculates. This means that generally the ‘motility’ of a sperm sample can be characterized by the mean velocity of the sperms, the standard deviation of the velocity distribution and the number of cells moving normally. The mean ratio of velocity and frequency of rotation (the ‘speed’ of the screwing movement of the head of the sperm cell) was found to be a less important motility characteristic for most experiments.

The scattering of the above-mentioned properties in various ejaculates were measured, while the sperm samples were all kept in the same conditions. It was found that the mean velocity has a rather constant value.

A linear relationship between the mean velocity of the sperms of a sample and the viscosity of the diluent is found. This holds also for the dependence of the ‘speed’ of the head movement and the viscosity.

The mean velocity of sperm cells was found to increase approximately in a straight-line relationship with the temperature in the range 33–41° C. There were indications that the mean velocity may reach a maximum in the region of 42–45° C.

If sperm samples are stored at 4° C, the mean velocity and the number of cells moving normally is found to decrease exponentially. The decrease of the number of cells moving normally is three to four times faster than that of the mean velocity. Some evidence was obtained that the characteristic time for the decrease of the number of cells moving normally is bull-specific.
Experiments on rumen retention time, fermentation rate and dry-matter digestibility in zebu and european-type cattle on a grass hay ration
Authors: Phillips G. D. , Hungate R. E. , MacGregor A. , Hungate D. P.
Published: March 2009

1. Experiments are described in which retention time of digesta in the reticulo-rumen, fermentation rates of rumen contents, and dry-matter digestibilities were studied simultaneously in four grade European and three zebu steers.

2. Fermentation rates and rumen retentions were significantly negatively correlated.

3. Correlations between digestibility and the other two factors were not significant at a high level.

4. The multiple regressions calculated for retention time and fermentation rate were significant at the 5% level and that for digestibility approached this level.

5. While only fermentation rates show significant differences for the two types of cattle, the results suggest that grades and zebus differ also in the rate of passage of digesta through the rumen.

6. The loss in weight of substrate per unit of fermentation products was measured inin vitroexperiments.

7. Using certain assumptions, estimates are made of the extent to which the measured fermentation rates could account for the loss in weight of dry matter during digestion, and are compared with the loss actually found.
Ammonia toxicity in the ruminant
Authors: Lewis D.
Published: March 2009

1. The normal level of blood ammonia in the sheep seems to be somewhat higher than in nonruminants.

2. The toxicity of ammonium acetate, ammonium chloride or urea placed in the rumen follows different metabolic pathways. In the case of the chloride there is an uncomplicated metabolic acidosis which is not, however, adequate to account for the toxic symptoms. When the acetate is administered there is also a respiratory alkalosis and in the presence of urea the changes in the acid-base status, though interesting, do not account for the toxicity.

3. The toxicity is almost certainly due finally to a direct effect of the circulating ammonium ion level though in the case of urea, there is an earlier effect that may be of a pharmacological type and is less severe.

4. The organisms within the rumen rapidly reach a maximum level of adaptation (7 days) to handle large quantities of ammonia by a synthetic pathway.

5. The intravenous administration of L-arginine did not markedly ameliorate the ammonia toxicity.