bluuebunny/crossref_metadata_2025 huggingface dataset:
The energy requirements of sheep for maintenance and gain. I. Pen fed sheep
Authors: Coop I. E.
Published: March 2009

Four experiments have been conducted with sheep, housed and fed in pens, to determine the maintenance and live-weight gain requirements of sheep under such conditions.

1. Fifteen Corriedale sheep of initial live weight 115 lb. were fed at maintenance for 13 weeks. Daily DOM (digestible organic matter) requirement for maintenance was 0·92 ± 0·07 lb.

2. Twelve Romney ewes of mean live weight 106 lb. over the period were fed for 5 months, six on submaintenance and six on super-maintenance levels. Daily DOM requirement for maintenance was 0·99 ± 0·05 lb., and requirement for gain 2·29 ± 0·20 lb. DOM per lb. gain or loss.

3. Thirteen Romney ewes of mean live weight 110 lb. over the period were fed at sub- and supermaintenance levels for 8 weeks yielding the result: daily DOM intake for maintenance 1·04 ± 0·13 lb. and for gain 2·25 ± 0·24 lb. DOM per lb. gain.

4. Twenty-four Romney ewes of initial live weight 107 lb. were randomized into five groups and fed fresh grass, dried grass, sheep pellets, lucerne hay and rye-grass straw for 11 weeks at slightly below maintenance. There were no significant differences between groups and the mean estimate of maintenance was 1·00 ± 0·11 lb. DOM per day.

Converting these estimates to those of a 100 lb. sheep using the ¾ power of live weight, and then taking the mean gives the final estimate for maintenance of a 100 lb. sheep 0·92 lb. DOM, 0·96 TDN or 0·89 lb. SE.
The amino acid supplementation of diets rich in maize meal for weanling pigs
Authors: Evans R. E.
Published: March 2009

A comparison is made between a maize-rich diet containing 7% white-fish meal and a similar diet in which the protein supplement consisted of 6% ex. soya bean meal together with 0.3% L-lysine hydrochloride and 0.2% DL-methionine. The vegetable protein diet plus the amino acids proved in every way equal to the fish meal diet.

When the essential amino acids in the diet of weanling pigs are properly balanced as little as 10% digestible crude protein will support maximum growth.

The results obtained when 6% ex. dec. groundnut meal was used as a protein-rich supplement were not so favourable.
A comparison of the progeny of three breeds of fat lamb sires
Authors: Seebeck R. M.
Published: March 2009

Many trials have been carried out in Australia to assess comparative values of breeds of rams and owes for fat lamb production in various environments and for different markets. Although general trends have appeared, there is much conflicting evidence in the reports of these trials as to the order of superiority of breed for a particular environmentmarket situation, especially for that of the rams. Much of this conflicting evidence arises because no completely satisfactory method of assessment of superiority has been used. Many of the studies undertaken to compare different breeds of ram have used as their basic criterion the returns per ewe (for example, McConnell, 1910; Elliot, 1926; Colebatch & Scott, 1927; Coleman, 1927; Cook, 1934; Thompson, 1951; Coleman & McDonald, 1952). In this situation random fluctuations in lambing percentages and in percentages of lambs surviving to slaughter can affect the order of superiority of the breeds. In view of the comparatively small numbers of sheep often used in the breed comparison groups (and this is, of course, particularly true in the case of rams), these deviations can bo sorious. For example, McConnell (1910) found that Border Leicester x lambs had a higher return per ewe than Southdown x lambs, but in 1911, the same author found the reverse situation which appears to have been due to a reversal in order of lambing percentages.
An experiment measuring effects of N, P and K fertilizers on yield and N, P and K contents of grass
Authors: Widdowson F. V. , Penny A. , Williams R. J. B.
Published: March 2009

To obtain large yields of grass much N fertilizer is usually needed, and when such grass is cut and conserved large amounts of K soon are removed from the soil. Some soils contain so little ‘available’ K that yields are soon limited unless grass is given enough K fertilizer, but other soils supply more K and so need less K fertilizer. Soils differ so greatly in their ability to supply crops with K that it is difficult to generalize about the fertilizer K requirements of grass, especially as the use to which the grass is put greatly affects the soil K ‘balance sheet’. On average, grass in England grows well for not much more than 6 months each year. This implies that, when cattle are maintained on hay or silage for much of the remainder of the year, on average one-third of the grass product each year may have to be cut, removed from the field, and conserved. Much of the N, P and K contained in this grass is not returned to the soil.
Normal growth and development up to one year of age of Sudanese cattle with special reference to the influence of Sex and sire
Authors: Osman A. H. , Rizgalla Y.
Published: March 2009

Three years' data on a herd of Sudanese cattle were used to study the influence of sex and sire on their growth from birth to 1 year of age. The traits studied included body weights at birth, weaning and yearling ages, and body measurements at birth and weaning age. Analysis of variance indicated no significant sex by sire interactions. Male calves had significantly (P < 0.01) heavier birth, weaning and yearling weights and faster pre-weaning average daily gain than female calves. There were no statistically significant differences between sexes in post-weaning gain or body measurements. The sire effects were highly significant (P < 0.01) for birth and yearling weights and postweaning average daily gain, but not for weaning weight and pre-weaning average daily gain. Sire effects were also significant (P < 0.05) for height at withers and heart girth at birth and weaning age and for body length at weaning age. The heritability estimates of birth and yearling weights and post-weaning gain were relatively high, whereas the heritability estimates of weaning weight and pre-weaning gain were low.
Effect of moisture content and soil type on self diffusion of 86Rb in soils
Authors: Graham-Bryce I. J.
Published: March 2009

Self-diffusion coefficients (D) for Rb+ have been measured in a heteroionic Lower Greensand soil over a wide range of moisture contents at three different compactions. The moisture content is shown to have a considerable effect on the value of the self-diffusion coefficient, a rapid rise in the value of D taking place between 5 and 10% moisture content. It is shown that this effect is not simply due to the increased volume of water-filled pore space at higher moisture contents, and other possible factors which could influence the shape of the diffusion coefficient/moisture content curve are discussed. Diffusion coefficients for Rb+ in eight other soils at pF 2 are also reported, but no simple correlation with any of several soil properties measured could be found. A value of 1·0 × 10−7cm2/sec. would seem to be a reasonable generalization for the self-diffusion coefficient of Rb+ in moist calcium-dominated soils.
The effect of block size on the errors of modern cereal experiments
Authors: Patterson H. D. , Ross G. J. S.
Published: March 2009

The errors of 454 cereal experiments organized by the National Institute for Agricultural Botany between 1956 and 1960 are examined in relation to block size. All the experiments used long, narrow plots and were harvested by combine. The most important conclusion is that the gain in efficiency by using small blocks in cereal experiments is as great now as it was before combine-harvesting and long, narrow plots were introduced. An empirical rule is that the variance per plot is roughly proportional ton½, wherenis the number of plots per block.
Effects of seed crop husbandry, seed source, seed tuber weight and seed rate on the growth of ware potato crops
Authors: O'Brien P. J. , Allen E. J.
Published: March 2009

The results of 20 experiments which compared seed from July-planted crops with seed from earlier planted (April-May) crops either grown locally or from certified seed-producing areas are reported. The effects of dates of planting and harvesting of late-planted seed crops and seed storage temperature were examined in eight experiments. In five experiments, the effect of seed rate was studied on two weights of seed-tubers in the July-planted crops.

Tubers of several cultivars from the July-planted crops ended their dormancy close to the normal planting time of ware crops, 2–4 months later than tubers from spring-planted crops grown either locally or in areas certified for seed production. Tubers from seed crops planted in July produced fewer mainstems in ware crops than tubers from spring-planted crops, but effects on stem density were usually too small to have any significant effect on foliar ground cover and consequently on tuber yield. Date of planting the seed crops in July and date of harvest of the seed-tubers had no effect on sprout or ware crop growth in Record or Wilja. Ware tuber yields were similar for the different seed sources in 12 out of 15 experiments, suggesting little difference in the performance of tubers from seed crops planted early and late in the season.

At equivalent seed rates, small seed-tubers (12·5 ± 2·5 g) from July-planted seed crops usually produced more stems and tubers and greater ware yields than larger tubers (37·5 ± 2·5 g). For the smaller seed, the results suggested optimum seed rates for ware tuber yields of c. 0·88, 0·88 and 0·59 t/ha for Wilja, Record and Saturna, respectively. These are substantially lower than those currently used in the UK. For the larger seed, rates of c. 2·64, 2·64 and 1·76 t/ha were adequate for Wilja, Record and Saturna, respectively.
Phosphorus kinetics of cattle grazing tropical pastures and implications for the estimation of their phosphorus requirements
Authors: Coates D. B. , Ternouth J. H.
Published: March 2009

Twelve yearling Droughtmaster heifers were grazed on a tropical grass/legume pasture in north-east Australia for 1 year in four paddocks, each of 4 ha. One paddock was fertilized annually with 10 kg P/ha (treatment HPF). The other three paddocks had low soil P and low pasture P status. In one of the low soil P paddocks, P was added to the drinking water (treatment HPS) but no supplement was provided in the other two paddocks (treatments LP1 and LP2). In February, May and August 1989, the P kinetics of the heifers were monitored following oral administration of ruminal chromic oxide capsules and i/v injection of32P. At the same times, oesophageal-fistulated steers were grazed in the paddocks to obtain extrusa samples to estimate the P content and digestibility of selected forage.

The liveweight gain per heifer was higher in the HP treatments (196 kg) than in the LP treatments (152 kg). The intake, absorption and excretion of P were closely related but the faecal excretion of P relative to P intake was less in heifers with than without P supplement. The P intakes of the LP heifers were about half the quantities recommended in the nutrient feeding standards for the observed food intakes and weight gains. The coefficients of P absorption in the LP heifers in May and August were high (> 0·8) and did not decrease with age or liveweight. The coefficients of P absorption of heifers given supplementary P were as high as those for LP heifers, but those of heifers on the fertilized pasture were significantly lower in May and August. The endogenous faecal excretion of P was related to P intake but more closely to dry matter intake and plasma inorganic P together. The reasons for the difference between observed P intakes of LP heifers and recommended requirements are discussed in relation to the assessment of P requirements of grazing cattle. The results from this experiment suggest that recommended P requirements are higher than necessary to sustain the measured liveweight gains of cattle on grass/legume pastures in the tropics.
A study of factors affecting the efficiency of feed conversion in Red Danish heifers
Authors: Owen J. B. , Nielsen E.
Published: March 2009

Data from 692 daughters of 38 Red Danish bulls, tested as heifers in the Danish cattle progeny testing stations 1963–64, were analysed to provide information on the efficiency of feed utilization by dairy cows. The results showed that because of, the feeding system adopted, efficiency measured as FCM per food unit was automatically closely related to FCM yield.

Analysis based on pooled, within-bull, values showed that (a) both efficiency and FCM were negatively associated with body-weight gain during lactation, suggesting that feed allowances per unit FCM were low in relation to those for maintenance, (b) weight measured after calving was positively associated with efficiency and FCM yield whereas the association of these latter variables with weight at the end of the winter period was negative, and (c) the gain in weight during lactation was much lower in cows heavy at calving and higher in those heavy at the end of the winter.

The between-bull correlations, although less reliable than the within-bull values, clearly indicated that the selection for FCM yield would result in increased cow weight.

It is suggested that the selection of dairy cattle should not be based solely on milk yield but that suitable adjustments should be made so that selection for efficiency is safeguarded. Quantitative assessment of such adjustments would necessitate changing feeding procedures at central testing stations.
Interaction of nutrient supply and plant density in relation to maximal yield of the swede crop
Authors: Lang R. W. , Holmes J. C.
Published: March 2009

The effects of changing plant density and nutrient supply on the yield of swedes were measured in nine experiments over 3 years. With small populations, a large nutrient supply was required to reach the maximal yield of roots, but with large plant populations the same nutrient rate depressed yield. This interaction is illustrated by a response surface, and reasons for it are discussed. The interaction is of limited importance in practice because it was small over the range of population and nutrient supply commonly used. Even with small populations, the compensation achieved by applying more fertilizer was uneconomic. On crops with large populations, such as swedes for human consumption, however, the normal recommended rate of fertilizer should not be exceeded because of loss of yield as well as increased cost. More fertilizer and greater plant density were needed to give maximal total yield (roots + tops) than of roots alone. Effects of nutrient supply and plant population on plant establishment and dry-matter content of the swedes are discussed.
Comparison of dry and wet feeding of growing pigs
Authors: Braude R. , Rowell J. G.
Published: March 2009

A co-ordinated trial has been carried out at eighteen centres to compare the following amounts and methods of providing water to growing pigs: (1) water in the feed in the ratio of 2½: 1; (2) water in the feed in the ratio of 4:1; (3) dry feeding with water available separately ad lib.; (4) water in the feed in the ratio of 1½: 1 and also available separately ad lib.

Pigs on dry feeding had substantially worse growth rate and feed conversion; carcass lengths were slightly smaller and eye muscles slightly wider. Fat measurements were not significantly affected.
Investigations on the physiology of yield in winter wheat, by comparisons of varieties and by artificial variation in grain number per ear
Authors: Bingham J.
Published: March 2009

Elliott (1962) estimated that the average grain yield of wheat in the United Kingdom increased by 6·1 cwt per acre between 1947 and 1957. By considering results of yield trials carried out by the National Institute of Agricultural Botany he attributed 3·8 cwt of this increase to greater yielding ability of new varieties and the remainder to ‘other factors’, including the increased use of fertilizers, chemical weed control, better seed dressings and combine harvesters. The genetic improvement obtained by breeding new varieties is due partly to the incorporation of characters which are comparatively easily recognized, such as resistance to various diseases and lodging. However, even when these major limiting factors are absent from the environment the new varieties give higher yields, presumably due to physiological superiority. Many investigations, reviewed by Thome (1966), have sought to identify and establish the relative importance of the responsible physiological characters, but the information is still far from complete. This shortcoming is now the chief hindrance to more efficient choice of varieties for use as parents and selection of improved genotypes by the breeder. The objective of the three experiments reported here was to provide further information on the physiological basis of varietal differences in yield in wheat.
A study of the effects of two methods of grazing poultry on the persistence and palatability of seven herbage species
Authors: Cowlishaw S. J.
Published: March 2009

For three years the persistence of six grasses and one herb sown singly or in combination under poultry grazing was studied. Established swards were regularly mown and either not grazed (control) or grazed every other week or every other month. The results are compared with those from earlier trials and reasons for the differences are discussed. Red fescue, perennial rye-grass and smooth-stalked meadow grass increased in amount, red fescue being particularly unpopular with poultry. Meadow fescue and timothy were slightly, and cocksfoot and yarrow drastically, reduced under poultry grazing.

The preferences of poultry for certain herbage species and varieties are discussed but no reasons adduced owing to lack of data.

One week's and 4 weeks' grazing made no difference to the persistence and palatability of the grasses tested, but these were always in a short leafy condition when grazed.
Genotype-environment interactions in a herd of bacon pigs
Authors: Hale R. W. , Coey W. E.
Published: March 2009

It seems safe to say that all official performance testing and progeny testing schemes for bacon pigs, up to the present, have been based on an implicit assumption that the pigs found to be superior under the management methods at the testing station would also be superior under other systems of management on commercial farms. If consideration is limited to reasonably good standards of management there is probably little danger in this assumption, though there is little direct evidence as yet to support it. The danger of mistakes in the selection of superior genotypes would be more likely to arise if there were systematic differences between the methods of management at the testing stations and on commercial farms. Actually such a difference does occur as regards methods of feeding. At testing stations, the pigs are generally fed more or less to appetite, being given as much as they will readily clear up in two feeds per day in England (N.P.B.A., 1957) and Northern Ireland (Heaney, 1962) and in three feeds per day in Denmark (Clausen & Thomsen, 1957). In the Republic of Ireland (Department of Agriculture, 1960) three feeds per day are given on a scale which must involve little, if any, restriction in the later stages of fattening. Such practices have the object of discovering the strains which become too fat before they reach bacon weights. Many farmers, on the other hand, adopt some form of restriction during the later stages of fattening, with the object of finishing the pigs at the right stage of fatness, and thus of improving the grading of the carcases at the factory.
Studies of the skeleton of the sheep VIII. Studies of the effects of protein and energy intake on productivity and skeletal mineralization in the pregnant and lactating ewe
Authors: Duckworth J. , Benzie D. , Cresswell E. , Hill R. , Boyne A. W.
Published: March 2009

1. Effects on productivity and skeletal mineralization of high as opposed to moderate levels of protein and, or, energy intake by the ewe during pregnancy and lactation in the presence of adequate calcium, phosphorus and vitamin D have been studied.

2. Two experiments were undertaken. One experiment used 4½-year-old Cheviot ewes and the other used 3½- and 4½-year-old Scottish Blackface ewes. Weight records, blood samples and in vivo and flesh-free radiographs were obtained, and bone ash determinations were carried out.

3. The results showed that contrary to indications from earlier experiments in this series superiority in ewe weight, lamb growth, and mineralization of the ewe skeleton did not necessarily result from raising the protein and, or, energy values of the feed above the ‘moderate’ level.

4. Discrepancies between the in vivo and flesh - free radiological assessments were noted for consideration.
Statistical appendix
Authors: Campbell R. C.
Published: March 2009

Bleasdale & Nelder (1960) refer to several models which have been used in studying the relationship of yield and density in crop plants and indicate that they regard as most satisfactory the equation:

where ω = yield/plant, ρ = number of plants/unit area and A and B are constants. The estimation of the constants for any given case is a very unattractive arithmetic exercise requiring a fairly large number of observations and a tedious iterative calculation; Nelder (1961) has discussed the least squares fit with the equation in the form

which may readily be derived from (1) by the substitutions

The data in the present case do not justify attempting this process but some progress can be made by the substitutions

by means of which it is easy to derive from (1) that
Bacteria of the ovine rumen I. The composition of the population on a diet of poor teff hay
Authors: Gilchrist F. M. C. , Kistner A.
Published: March 2009

1. The composition of the bacterial population in the rumen of adult merino wethers conditioned to a diet of poor teff hay was studied during three consecutive periods of 60, 109 and 42 days when the ration was 1200,600 and 300 g. per day, respectively.

2. In all three periods there was no significant difference between the three sheep with regard to either the viable counts of the functional groups of bacteria fermenting cellulose, starch, glucose, xylose and lactate or the percentage proportions of the different morphological types occurring in each group.

3. The reduction of food intake had little or no influence on either the numbers or the morphological types of bacteria in each functional group.

4. The animals lost weight at approximately the same rate throughout the three periods of the experiment which was ended when they were in a state of prostration.

5. These results suggest that, providing the diet is changed only in respect of quantity, important functional groups of rumen bacteria can survive at levels of food intake which are insufficient for the survival of the animal.
A note on the amino acid composition of the protein in heather shoots
Authors: Moran T. , Pace J.
Published: March 2009

The composition and feeding value of the common heather has been extensively studied by Thomaset al.(1934, 1935, 1953, 1955, 1956). He has shown that as the heather ages the protein content declines. Thus, samples from 2-year-old growths had a crude protein content (on a dry-matter basis) of 11·9% while that of growths 8 years old was 6·5–6·9%. Little or no information, however, appears to be available on thequalityof heather protein, as judged by its amino acid composition.
Technique for evaluating the potential for growth of shoot and root buds of white clover (Trifolium repens)
Authors: Newton P. C. D. , Hay M. J. M.
Published: March 2009

An assay was developed for assessing the potential for growth of shoot and root buds of white clover. This paper describes the technique and the experimental results on which it was based. The assay involved the incubation of nodes under standard conditions and the monitoring of bud activity at the nodes. Shoot buds were of primary interest but the assay was also used to investigate the activity of root primordia. Correlative influences were reduced by separating individual nodes and by removal of their subtending leaves and petioles. The optimal environmental conditions for incubation were: a constant temperature of 20 °C, a 24 h photoperiod of low irradiance (4 W/m2) and a high relative humidity (≥ 90%). The technique proved suitable for the monthly screening of 1000–2000 nodes sampled from field populations of white clover.
Nutritive value of the olive leaf: effects of cultivar, season of harvesting and system of drying
Authors: Cabrera-Gomez A. , Garrido A. , Guerrero J. E. , Ortiz V.
Published: March 2009

Leaves of olive trees (Olea europaea L.) of eight cultivars, Manzanilla, Picual, Hojiblanca, Edremit, Conservolia, Picholine-Marroqui, Chemlali and Frantoio, were collected in different seasons and years in Córdoba, Spain. Their chemical composition and in vitro organic matter digestibility values were determined. Differences in composition and nutritive value between cultivars, years and seasons were studied in Manzanilla, Picual and Hojiblanca, the three most important local cultivars. There were significant differences both between cultivars and seasons (P < 0·05) and a non-significant difference between years.

The effect of various drying procedures (fresh, oven-dried, air-dried indoors or air-dried outdoors) on chemical composition, in vitro digestibility and in vivo digestibility in sheep was also examined. The in vivo organic matter digestibility of fresh leaves was significantly higher than that of dried leaves. No difference was found between leaves air-dried indoors and oven-dried leaves. However, leaves air-dried outdoors were significantly less digestible. Quick drying in an oven reduced the digestibility of crude protein and acid detergent fibres compared to air drying indoors. There was a significant decrease in digestibility of 11% when leaves were dried separated from the branches as compared to leaves dried on the branches.
Effect of condensed tannins upon body growth, wool growth and rumen metabolism in sheep grazing sulla (Hedysarum coronarium) and perennial pasture
Authors: Terrill T. H. , Douglas G. B. , Foote A. G. , Purchas R. W. , Wilson G. F. , Barry T. N.
Published: March 2009

Areas of sulla (Hedysarum coronarium) and pasture (Lolium perenne/Trifolium repens/Holcus lanatus) were grazed by young sheep (29·5–34·8 kg initial liveweight) in four experiments, and effects upon body growth, wool growth and rumen metabolism were measured.

Sulla contained 40–50 g condensed tannins (CT)/kg DM, whilst the pasture contained small amounts of CT (2–6 g/kg DM). After chewing during eating, a lower proportion of total CT was readily extractable and greater proportions were protein-bound and fibre-bound. Nutritional effects attributable to CT were assessed by oral administration of polyethylene glycol (PEG), which binds and inactivates CT, to half the animals grazing each forage. Rates of body growth were consistently higher for lambs grazing sulla than those grazing pasture, with the CT concentration in sulla being neither stimulatory or inhibitory to body growth or voluntary feed intake (VFI). The action of CT reduced carcass fatness in sheep fed both diets, in the one experiment where this was measured. CT present in both sulla and pasture decreased rumen ammonia concentration and decreased molar proportions of iso-butyrate and iso and n-valerate. During spring and early summer, when wool growth rates were highest, CT present in both pasture and sulla increased wool growth rate; when wool growth rates were low during winter, CT had no effect upon the wool growth of sheep grazing either forage. Numbers of protozoa and molar proportions of n-butyrate in rumen fluid were increased by CT in sheep grazing sulla but not pasture.

It was concluded that the higher rates of body growth and VFI in lambs grazing sulla was most likely to be due to its very high ratio of readily fermentable: structural carbohydrate.
Not all sheep prefer clover: diet selection revisited
Authors: Newman J. A. , Parsons A. J. , Harvey A.
Published: March 2009

Several previous studies have shown that the proportion of clover in sheep diets was greater than the proportion of clover in the mixed species swards being grazed. Various hypotheses have been put forward to explain this observation. One widely held hypothesis is that sheep prefer (actively select) clover to grass. This hypothesis was tested by offering 12 sheep, six that had been recently grazing perennial ryegrass and six that had recently been grazing white clover, the choice between foraging on grass or clover provided as turves. It was found that, rather than prefer clover, the sheep preferred the opposite species to the one they had previously grazed. From these observations, alternative hypotheses are proposed to explain the disparity in composition of the diet relative to the swards observed in previous studies, and the evidence for a constant preference for clover and its basis in grazing behaviour is reconsidered.
Effect of centre of production, maturity and storage treatment of seed tubers on the growth of early potatoes: II. Field growth
Authors: Goodwin P. B. , Brown A. , Lennard J. H. , Milthorpe F. L.
Published: March 2009

Studies were carried out on the effect of source, time of lifting and post-harvest treatment of apparently virus-free Arran Pilot seed potatoes on subsequent crop growth. The experiments were carried out in 1961–2 and 1962–3 at Efford, Sutton Bonington and Edinburgh. Seed tubers from the more southern region, which were older and showed greater sprout development at planting, gave plants with a higher stem number at soil level, a higher tuber number and a greater percentage of the tuber yield as seed grade than northern-produced seed. High bulking rates were associated with early emergence, high tuber numbers and late apparent time of tuber initiation. In 1962 southern seed produced plants which initiated tubers early and had low bulking rates and low final yields. In 1963 seed source had little effect on the time of tuber initiation of resulting plants, and southern-produced seed gave plants with high bulking rates and high final yields. Early lifted and greened tubers gave rise to plants with the same pattern of response as seed produced at the southern centre. It is suggested that this variation in response between years was due to the climatic conditions at the time of tuber initiation in the field crop.

Seed of a required state at planting can usually be obtained by growth at the centre of ware production provided disease can be controlled and the time between harvesting of seed and planting is longer than about 3 months.
Effect of light on spring breeding of mutton merino ewes
Authors: Goot H.
Published: March 2009

Mutton Merino ewes, all of which had lambed in the preceding in-season, were divided into two groups some 30 days after lambing.

The ‘light’ group was subjected, over 84 days, to a simulated decrease in daylength, achieved by first adding artificial light to the daylight and then stepping down the light at weekly intervals, from approximately 17 h, on 22 January, to natural daylength (13 ¾ h), on 20 April 1967. The control group was exposed to the normally increasing daylength.

Starting on 1 March, the ewes in both groups were ‘teased’ and hand-service commenced on 20 April.

The breeding activity (oestrus, ewes lambing, lambs born and twin births) as well as the length of gestation and birth weight appeared to be unaffected by the light.

It would appear that the ‘short-day’ photoperiodic theory is not applicable to all breeds of sheep, and it is suggested that in sheep with a long sexual season genetic heterozygosity may be responsible for regulating the breeding season by allowing other environmental stimuli, besides light, to trigger-off sexual activity.
The assessment of herbage legume varieties: I. Lucerne
Authors: Davies W. Ellis , Reusch J. D. H.
Published: March 2009

The performance of four varieties of lucerne, du Puits, Provence, Grimm and S 205, as spaced plants, in broadcast plots and in drills, with and without a companion grass was compared by yield of dry matter, percentage and yield of crude protein, leanness, weediness and reaction to leaf spot (Pseudopeziza medicaginis).
Studies on the Northern Rhodesia Hyparrhenia veld V. The yield of veld compared with giant Rhodes grass (Chloris gayana)
Authors: Smith C. A.
Published: March 2009

A plot trial compared the herbage yields of Hyparrhenia veld and giant Rhodes grass (Ghloris gayana cultivar) cut at grazing and hay stages of growth at four levels of N fertilizer. Veld outyielded Rhodes grass in all treatments.

The milk yields from Hyparrhenia veld and a giant Rhodes grass pasture were similar when grazed at low and high stocking rates with and without N fertilizer.
The utilization of the energy of different rations by sheep and cattle for maintenance and for fattening
Authors: Blaxter K. L. , Wainman F. W.
Published: March 2009

1. Six diets in which the percentage of hay varied from 0 to 100% and the percentage of flaked maize varied conversely from 100 to 0% were each given to three sheep and three steers in a series of 72 calorimetric experiments. In addition the fasting metabolism of each animal was determined on two occasions.

2. The loss of energy in the faeces increased linearly with the percentage of flaked maize in the diet, but the loss of N in the faeces did not, the loss being proportionately smaller for diets containing more than 60 % maize.
Magnesium metabolism in the dairy cow IV. The availability of the magnesium in various feedingstuffs
Authors: Rook J. A. F. , Campling R. C.
Published: March 2009

1. The ‘availability’ of the magnesium of diets consisting solely of roughage or succulent feeds, including herbages cut at different seasons and at different stages of growth, and of diets of hay supplemented with various concentrate feeds, was assessed in metabolism trials conducted with two non-pregnant, non-lactating Shorthorn cows.

2. The highest daily intakes of magnesium (1720 g./day) were provided by a diet of red clover: grasses and hays generally gave a considerably lower intake of magnesium (8–10 g./day), and most of the other diets provided intermediate amounts. However, with timothy hay and barley straw, intakes of 5 and 2 g./day, respectively, were recorded. Supplements to a diet of hay of dairy cubes or of oilcakes rich in protein gave a massive increase in magnesium intake but a supplement of flaked maize provided little additional magnesium.

3. The ‘availability’ of the magnesium of the diets was generally low, within the range of 5–30%. With diets of single feeds no clear distinction between the various roughages and succulents in the ‘availability’ of their magnesium was established, though within the group of herbages the lowest values tended to occur with grasses cut at an early stage of growth and the highest values at the mature stage. A supplement of flaked maize increased the ‘availability’ of dietary magnesium and one of protein-rich oil cakes decreased the ‘availability’ of dietary magnesium.

4. The results are discussed in relation to the development of hypomagnesaemia in cattle grazing spring pasture.
Effects of nitrogen fertilizers on total nitrogen, soluble nitrogen and soluble carbohydrate contents of grass
Authors: Nowakowski T. Z.
Published: March 2009

Italian rye-grass given ammonium sulphate or sodium nitrate at 56 or 112 lb. N/acre was analysed for total nitrogen, soluble nitrogen (non-protein-nitrogen) and soluble carbohydrates.

Ten days after applying fertilizer the differences in total-N between the grass receiving 56 and grass receiving 112 lb. N/acre were very small. Total-N in grass decreased with growth, but the effect of the rate of nitrogen on total-N increased. At first the grass given sodium nitrate contained more soluble nitrogen than grass given ammonium sulphate, the difference being greater at 56 lb. N/acre; soluble nitrogen decreased with increasing growth. Ten days after applying fertilizer, the nitrate-N content of grass was very high (ranging from 0·1 to 0·9% in the D.M.) and it gradually decreased. At both levels of nitrogen application, grass given sodium nitrate contained much more nitrate-N than grass given ammonium sulphate. Forty days after applying nitrogen the nitrate-N contents of grass which received 56 and 112 1b. N/acre as ammonium sulphate were 0·039 and 0·222% of the dry matter, respectively; the grass supplied with sodium nitrate gave values of 0·082 and 0·438%.

Total soluble carbohydrates in the grass were small early in growth and gradually increased. Nitrogen dressings had little effect on the content of soluble sugars (glucose + fructose + sucrose) but greatly decreased the fructosan. The pattern of changes in the total soluble carbohydrate content followed that in fructosan content. Early in growth, the total soluble carbohydrate/crude protein ratio was very small in grass from all treatments except the ‘control’. This ratio increased with growth and at the last sampling was 2·13 in grass receiving no nitrogen, and in grass supplied with 56 and 112 lb. N/acre as ammonium sulphate it was 1·44 and 0·72 respectively; the corresponding figures for grass receiving sodium nitrate were 1·13 and 0·66. The total soluble carbohydrate carbon/soluble nitrogen ratio in grass with no nitrogen was 18 at the first sampling and it increased gradually, reaching 70 at the last sampling. This ratio was considerably less with all nitrogen treatments than with ‘control’. The values obtained with 112 lb. N/acre were less than those obtained with 561b./acre, irrespective of the form of nitrogen used.

The relationship between the soluble carbohydrate carbon content and the soluble nitrogen in grass is illustrated graphically and discussed.
Lameness in buffalo in N.E. Malaya
Authors: Hill R. , Rajagopal N. M.
Published: March 2009

The skeletons of most of a group of lame buffalo from an area around Pasir Puteh and of some of a group of similarly lame animals from an area S.W. of Pasir Mas were poorer than those of a control group from around Kota Bharu. Analyses of blood and liver indicated that the defective mineralization of the skeleton was caused by a shortage of phosphorus rather than of calcium or copper.

Evidence for a relationship between lameness and the quality of the skeleton was not strong and further study including a feeding experiment is needed to establish the validity of this.
Wool length and radiant heating effects in sheep
Authors: Parer J. T.
Published: March 2009

1. When Merinos of varying wool lengths were exposed at constant air temperature of 36° C. (c. 97° F.) to infra-red radiation of energy equivalent to that which they might receive from the sun, the following responses were noted:

(a) A very highly significant (P < 0·001) inverse relationship between respiration rate and wool length.

(b) A non-significant inverse relationship between rectal temperature and wool length.

(c) A very highly significant (P < 0·001) quadratic relationship between back wool-tip temperature and wool length.

(d) A very highly significant (P < 0·001) inverse relationship between back-skin temperature and wool length.

Thus, the length of wool determines to a large extent the degree of protection given to the sheep against radiant heat.

2. The rate of conduction of heat per unit area through the back wool in different sheep was hyperbolically related to wool length. Below 1 cm. woollength heat was taken up very rapidly; beyond 4 cm., increasing wool length afforded negligible additional protection.
Utilization of urea by sheep
Authors: Schwartz H. M. , Schoeman C. A. , Färber M. S.
Published: March 2009

1.The breakdown of urea, soluble starch and glucose was followed in the rumen of fistulated sheep and in artificial rumens containing rumen ingesta or strained rumen fluid.

2. Carbohydrate remained in the rumen two to three times as long when starch was dosed in vivo as when glucose was given.

3. The relative rates of breakdown of urea and carbohydrate by strained rumen fluid in vitro differed markedly from those in vivo. This was due to the fact that straining removed large numbers of starch- and glucose-utilizing micro-organisms which were attached to the larger food particles, while the concentration of the urea-splitting organisms which were freely suspended in the strained liquor was apparently the same as that obtained in the strained material. Strained rumen fluid should therefore not be used for studies of the utilization of urea in vitro.
A study of the ‘dissolved faeces fraction’ method for the indirect estimation of herbage intake
Authors: Langlands J. P. , Corbett J. L.
Published: March 2009

1. Samples of faeces obtained from eleven continuous digestibility trials in which sheep, steers or cows were given fresh herbages grown in different seasons in 2 years were analysed for the ‘dissolved faeces fraction’ (D.I-.F.).

2. Dry-matter intake by sheep was linearly related to the weight of D.F.F. excreted and the equation predicted intakes that were 20 %higher at the mean intake than those estimated from a similar type of relationship obtained by Owen (1961). A logarithmic relationship was derived when the observations for all species were combined.
Sodium and potassium balances and growth on high and low sodium diets
Authors: Horrocks D.
Published: March 2009

1. Ten-day balances of sodium and potassium were recorded for Shorthorn and Zebu steers fed
poor quality chaffed hay with and without sodium supplements.

2. Sodium supplementation had no appreciable effect on growth, all animals being close to a
maintenance regime.
Sodium and potassium balances and growth on high and low sodium diets
Authors: Horrocks D.
Published: March 2009

1. Sodium and potassium balances and the growth rate of steers have been recorded for animalsreceiving a protein supplement on a high and low salt regime.

2. Zebu steers receiving less than an average of 0-2 g. sodium per day were able to grow at 82 % of the rate of Zebu steers receiving salt supplement. Shorthorn steers under the same conditions grew at 72 % of the rate of Shorthorns receiving the supplement.
Methods of predicting kilograms of retail cuts in the beef carcass
Authors: Tuma H. J. , Dinkel C. A. , Minyard J. A. , Breidenstein B. C.
Published: March 2009

Various carcass measurements were obtained from 216 Hereford steers and evaluated in an attempt to find traits or combinations of traits which accurately estimate carcass composition. Carcass weight and trimmed retail cuts from the round proved to be the best single estimators of kilograms of retail cuts. Prediction equations were developed using carcass weight, trimmed retail cuts from the round, longissimus dorsi area, measures of fat thickness at the 12th rib, untrimmed round weight and weight of kidney, heart and pelvic fat in various combinations. Eighty-four to 94 % of the total variation in actual kilograms of retail cuts could be accounted for by using these equations.
The value of urea nitrate and urea phosphate as nitrogen fertilizers for grass and barley
Authors: Gasser J. K. R. , Penny A.
Published: March 2009

Urea nitrate, urea phosphate, and a mixture of urea phosphate and urea were tested as nitrogen fertilizers to find whether the presence of the anion decreases the damage urea causes to germinating seeds and seedlings and increases the efficiency of urea by preventing loss of ammonia.

Urea nitrate was compared with ammonium sulphate for grass grown in pots in the glasshouse and with ammonium nitrate for permanent grassland in the field. In the glasshouse, a large dressing of urea nitrate damaged the early growth of grass in sandy-loam soil. On average of sandy-loam and clay-loam soils with a small dressing of fertilizers, grass recovered similar amounts of N from urea nitrate and ammonium sulphate; with the large dressing it recovered less from urea nitrate.

In the field, 100 and 200 lb N/acre were applied to permanent grassland which was cut twice. The herbage was ‘scorched’ by the urea nitrate because its solution is very acid. Urea nitrate at 200 lb N/acre produced less dry matter containing less nitrogen than did ammonium nitrate.

Urea nitrate, urea phosphate and urea phosphateurea mixture were compared with ammonium nitrate for barley and grass grown in clay-loam and sandyloam soils. Tests were made of 33, 67 and 100 lb N/acre for barley and 100, 200 and 300 lb N/acre for ryegrass; the fertilizers were applied immediately before sowing. On the light Woburn soil early growth of barley was least good with urea nitrate, which also damaged the early growth of grass.
The grazing habits of African-owned, East African zebu cattle in Zambia (Northern Rhodesia)
Authors: Smith C. A.
Published: March 2009

The grazing behaviour of village cattle in the Eastern Province of Zambia (Northern Rhodesia) was studied.

Usually, the cattle graze in the bush during the rains and on the dambos in the dry season. Where most of the upland was cultivated, the cattle were forced to graze in the dambos during the rains contrary to correct land use. The arable land and crop residues are grazed after the harvest in middry season.
The partition of certain mineral nutrients in the colostomised laying pullet and the determination of faecal endogenous calcium and phosphorus excretion by an isotopic dilution method
Authors: Brown W. O. , McCracken K. J.
Published: March 2009

1. An experiment is described in which the partition of calcium phosphorus, sodium, potassium and manganese in the excreta of the colostomized laying hen fed a diet adequate in these minerals is examined.
Finishing cattle on sorghum grain and sorghum silage. Effect of hormone implantation and urea
Authors: Morris J. G. , O'Bryan M. S.
Published: March 2009

1. The suitability of three ratios of sorghum grain to sorghum silage (40:60, 60:40, and 80:20) with and without a supplement of 60 g. urea per head per day for the finishing of cattle in yards was examined.
Relationships between set characters and yield in maincrop potatoes
Authors: Bleasdale J. K. A.
Published: March 2009

1. Data are presented indicating that both the total yield of potatoes and the proportions of the yield in size grades were a function (independent of set size) of the number of main stems per unit area for the maincrop varieties Majestic and King Edward.
Protein, lysine and feed intake level effects on pig growth. III. Regression analysis and economic aspects
Authors: Dent J. B. , Blair R. , English P. R. , Raeburn J. R.
Published: March 2009

Data from the experiment described in the first paper of this series were subjected to regression analysis. Lean meat and live-weight gain response to both lysine and crude protein intake was almost linear in period 1 but in later periods little response was evident. Response of live-weight gain to increased energy was continuous though diminishing in the later periods. In periods 1 and 2 lean gains showed positive though diminishing response to energy.

In a multivariate regression analysis it was clear especially for younger pigs that the response to dietary lysine for both live-weight and lean meat gains is influenced by the dietary level of crude protein and the energy intake. Separate multivariate analysis for each sex indicated that females are more efficient converters of lysine and energy into live weight and lean meat. Also an interaction between sex and dietary lysine level was suggested.

A methodology for an economic analysis taking the joint objectives of total cost of production, speed of grain and quality of gain is established as a basis for design of high profit system of production.