bluuebunny/crossref_metadata_2025 huggingface dataset:
The morphology of bovine sweat glands and the effect of heat on the sweat glands of the Ayrshire calf
Authors: Findlay J. D. , Jenkinson D. McEwan
Published: March 2009

1. The normal sweat glands of twenty-eight calves, nineteen live adult cattle and eighteen slaughtered cattle from temperate breeds were examined. In every animal the lumen of the sweat glands contained a fluid-like material.

2. It appeared on examination and rough measurement that the size of the sweat glands taken from animals after slaughter was smaller than that of the glands taken from live animals even when the same sampling technique was used for both.

3. The sweat glands of sixteen calves were examined before and at intervals after the animals had been subjected to a hot environment. The glands were always seen full of a fluid-like material.

4. It is concluded that if the calf sweat gland is stimulated by heat stress it must function either (a) by simple diffusion through the sweat gland wall and hence to the skin surface, or (b) by a secretory process not involving degeneration of the glandular epithelium. It is probable that at least part of the contents of the lumen of the sweat glands is derived from the epithelium by a process of active secretion.
Observations on the grazing behaviour of lactating dairy cattle in a sub-tropical environment
Authors: Holder J. M.
Published: March 2009

1. Three trials are reported in which the grazing behaviour of separate groups of cows, one receiving supplementary food, either as conserved roughage, concentrate or fodder crop, was observed over 24 hr. periods. A fourth trial, assessing the effect of summer temperatures on unshaded milking cows, is briefly described.

2. In trials 1 and 2 the stall feeding of either conserved roughage or concentrate reduced grazing as compared with unsupplemented cows by approximately 10%.

3. Allowing access to a fresh ‘strip’ of a fodder crop at a set time each day, whilst not altering total grazing time, very markedly altered periodicity of grazing. Cows delayed grazing up to 3 hr. whilst awaiting a fresh ‘strip’.

4. Environmental temperatures up to 87° F. did not alter total grazing time as compared with grazing time when temperature reached a maximum of only 70° F.

5. The value of supplementary feeding of dairy cattle at pasture, at least where the intake of pasture is sufficient for maintenance and a low level of production, appears to be open to question.
The uptake of radioactive strontium by crops under field conditions in the United Kingdom
Authors: Milbourn G. M.
Published: March 2009

1. Field experiments are described in which the absorption of radioactive strontium by rye-grass and lucerne has been investigated during 1958 on five soil types which represent a range in exchangeable soil calcium content. 89Sr was applied as a spray to both arable land and to established pasture.

2. Absorption was reduced by a factor of up to 4 in rye-grass (shallow rooted) following ploughing to 11 in. compared with leaving the contamination on the soil surface. These results are compared with those obtained in an earlier series of experiments in 1957.

3. The ratio of 89Sr to calcium was highest in crops grown on soil low in calcium (2 m-equiv. Ca per 100 g. extracted with N-ammonium acetate).

4. The addition of lime reduced absorption of 89Sr from the soil only when the exchangeable soil calcium content was relatively low. Some effect was observed in soils containing 7–8 m-equiv. Ca/100 g., a considerably larger one in a soil containing 2 m-equiv.

5. Only small differences occurred in the ratio of 89Sr to calcium between lucerne and rye-grass. This comparison was not made beyond the first 6 months of growth.

6. Experiments carried out with established pastures on four soil types indicate that 89Sr is more readily absorbed from the ‘plant-base’ than after incorporation with soil. Ploughing and reseeding may reduce the ratio of 89Sr to calcium in herbage by a factor of up to 4. This effect may be greater on mature swards.

7. The liming of contaminated swards reduces the ratio of 89Sr to calcium in herbage by a factor of 2 to 3 regardless of the calcium content of the soil, and liming followed by ploughing and reseeding by a factor of 3 to 7.
A chemical study of soft fat in cross-bred pigs
Authors: Lea C. H. , Swoboda P. A. T. , Gatherum D. P.
Published: March 2009

Iodine values, melting (slip) points and fatty acid analyses for back (‘bung’) and perinephric (kidney) fats from 114 pure and cross-bred pigs are reported.

In most cases the effects of breed were small, but half-Hampshire crosses showed a high proportion of pigs producing abnormally soft and highly unsaturated fats, though others were normal.

Although a general correlation existed between iodine value and melting-point the relationship broke down in some cases, and the ratio of monoene to saturated fatty acids of carbon chain length 16 and 18 is suggested as a better chemical index of softness due to causes other than dietary lipid.
Soil phosphate values in relation to phosphate supply to plants from some Nigerian soils
Authors: Bache B. W. , Rogers N. E.
Published: March 2009

Phosphate uptake and dry-matter yield from unfertilized pots and relative yield (ratio of unfertilized to fertilized yield) of Rhodes grass were used as plant indices of P supply from twenty-four soil samples from long-term manurial trials in Nigeria. Although measurements of the soil P quantity factor were generally the more important, intensity measurements also made a highly significant independent contribution to the P supply. Inorganic P (a quantity measure) combined with the log of P concentration in a saturation water extract (an intensity measure) gave a multiple correlation coefficient of R = 0·954*** with relative yield, accounting for 91% of its variation. The best single measure was resin-extractable P, which gave r =0·930*** for correlation with relative yield. Organic P did not appear to contribute to plant growth.
The response of seven barley varieties to inoculation in the field with different isolates of Cercosporella herpotrichoides Fron
Authors: Davies J. M. L. , Jones D. Gabeth
Published: March 2009

Seven commercial barley varieties were inoculated with mycelial suspensions of different isolates of Gescosporella herpotrichoides. There were significant varietal differences in eyespot susceptibility. There were significant differences between isolates which originated from both wheat and barley. The yield of the varieties was reduced between 30 and 50% depending upon the isolate used. Significant interactions between isolates and varieties were found for the incidence of disease, its effect on tiller number and upon total yield.
Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude III. The response of mature and young rams to a thermal burden induced by exercise
Authors: Symington R. B.
Published: March 2009

Mature and young Merino, Persian and Native rams were compelled to run 1 mile in 10–12 min. The response to the thermal burden induced by this exercise was measured in terms of body and skin temperatures, rate of respiration and length and temperature of the scrotum.

1. Marked increases were recorded in every body response immediately after the exercise. Body, skin and scrotal temperatures returned to normal within 2 hr. but respiratory rate remained elevated for a further 4 hr.

2. There were breed differences in the initial and subsequent measurement of every response. At 7.0 a.m. when there was no thermal stress body temperatures and rates of respiration were: Merino 102·9° F.; 3·-6 cyc./min. Persian 101·4° F.; 23·8 cyc./min. Native 102·1° F.; 28·9 cyc./min. Merino rams had the greatest ability to combat rising ambient temperature, Native rams the least. Persian rams recuperated quickest after exercise, Native rams slowest. The different responses of wool and hair breeds were apparently due to their coats. Merino fleece stabilized body temperature, did not aggravate the effects of exercise unduly and did not greatly hamper elimination of heat from the body after exercise.

3. In all breeds respiratory evaporation was the principal thermolytic process. Rate of respiration was a sensitive indicator of thermal stress but it could not be used as an index of heat tolerance because the associated changes in respiratory volume were not known.

4. Age was seldom of significant importance to determine response to thermal burden. In general young rams were affected less adversely by exercise and more adversely by rising ambient temperature than were mature rams. These differential effects were probably due to leggy conformation, low live weight and physical fitness in young rams on one hand, and incomplete development of the thermoregulatory system on the other.

5. Increase in scrotal pendulance was related inversely to ability to maintain normal body temperature.

6. In view of the influence of age and body conformation on the response to exercise it was questioned whether comparable heat tolerance indices could be obtained by this method.
Nitrogen studies in a coffee soil I. Seasonal trends of natural soil nitrate and ammonia in relation to crop growth, soil moisture and rainfall
Authors: Robinson J. B. D.
Published: March 2009

1. The general seasonal trends of top-soil nitrate and ammonia-N, and growth of the coffee tree are described for conditions of both soil and climate which are representative of a large proportion of the coffee-producing area in Kenya.

2. When rainfall is heavy and persistent at the beginning of a rains period soil nitrate-N levels decrease rapidly, partly because of leaching losses and partly through uptake by the crop. Under conditions of rainfall and cropping similar to those described for the first half of 1954, the flush of nitrate-N in the early part of the rains will not be detected under field conditions. When the onset of the rainfall season is more gentle and substantial water movement through the upper part of the soil profile does not take place, for example, Short Rains, 1954, nitrate-N values do not decrease rapidly and there is indirect evidence of the stimulatory effect of this type of rainfall on nitrate-N formation in a remoistened field soil.

3. Rapid and substantial build-up of nitrate-N is shown to take place during intervening dry weather between the rainfall periods. This is particularly marked in the top 6 in. of the soil profile and is attributed to nitrate-N formation in the absence of leaching losses; to a decreased rate of uptake by the coffee tree in the absence of vigorous growth and to the physical movement of nitrate-N upwards into the top-soil.

It may be inferred from the results that alternate periods of rain and sunshine, rather than continuous heavy rain, will favour high soil nitrate-N levels and a more satisfactory nitrogen nutrition of the coffee tree.

4. During periods of very low soil moisture ammonia-N builds up in the dry top-soil.

5. The sharp peak and rapid decline in the rate of coffee growth during the Long Rains period coincides with very low soil nitrate-N values although climatologically conditions for continued growth are still excellent. This suggests that low available soil nitrate -N may be at least partially responsible for this early and rapid decline in the growth rate.

6. In the light of observed trends in nitrate-N and coffee growth the timing of fertilizer nitrogen application to mature coffee has been altered. During the Long Rains split applications are recommended with the particular object of maintaining a supply of readily available nitrate-N in the soil. An additional and supplementary fertilizer nitrogen application is also suggested in the Short Rains period.
The indirect estimation of the digestibility of pasture herbage II. Regressions of digestibility on faecal nitrogen concentration; their determination in continuous digestibility trials and the effect of various factors on their accuracy
Authors: Greenhalgh J. F. D. , Corbett J. L. , McDonald I.
Published: March 2009

1. A mixed sward was divided into two areas receiving high (H) or low (L) levels of fertilizer nitrogen, and on two occasions, in spring and summer, herbage cut from each area was given to three steers in a continuous digestibility trial lasting 45 days. Digestibility and faecal nitrogen concentration were measured for each animal for each 24 hr. period, and equations relating these variables were calculated for each trial from the unit 24 hr. observations and from averages over three animals and over successive 2-, 3-, 5- and 9-day periods.

2. In the two spring trials herbage digestibility remained constant for the first 12 days and then declined by about 0·4 units per day. In the summer trials digestibility declined throughout by 0—25 units per day. The nitrogen content of the herbage was consistently 25% higher for treatment H, and declined steadily throughout each trial.

3. Both season of cutting and fertilizer treatment had a significant effect on the faecal index regressions obtained. Equations calculated from average values for three animals and 3 days predicted digestibility coefficients from 3% faecal nitrogen as follows: equation (1) spring H, 76·5; (2) spring L, 77·5; (3)summer H, 71·8; (4) summer L, 72·8.

4. The joint residual standard deviation for equations (1) to (4) had the low value of ± 0·90 units of digestibility, indicating that ‘single-sward’ regressions are considerably more accurate than those embracing a great variety of herbages. Even greater accuracy was obtained when digestibility and faecal nitrogen concentrations were measured for periods longer than 3 days; in general, residual variance varied inversely with period length. Using values for individual animals in the regressions increased the residual variance slightly, but because differences between animals in the digestibility-faecal nitrogen relationship were small and generally nonsignificant, the increase was by a factor of the order of 1·6, not 3.

5. Standard errors of prediction were calculated, although there is evidence to suggest that these underestimate the error of digestibility coefficients predicted for free-grazing animals. It is concluded that faecal index regressions are accurate enough for measuring digestibility per se in grazing experiments. In the measurement of herbage consumption, however, the experimental error is likely to be high, partly because indigestibility is the factor required to be predicted, but mainly because of large differences in appetite among similarly treated animals.
The effects of fertilizers on herbage production Part I. The effect of nitrogen, phosphate and potash on yield
Authors: Reith J. W. S. , Inkson R. H. E. , Stewart A. B. , Holmes W. , Maclusky D. S. , Reid D. , Heddle R. G. , Clouston D. , Copeman G. J. F.
Published: March 2009

The paper reports the results for six factorial experiments carried out over a period of 3 years, and designed to measure the effects of nitrogen, phosphate and potash on the yield of dry matter and to determine the effect of nitrogen on the phosphate and potash requirements of grass being cut five times per annum for conservation.

Heavy dressings of nitrogen reduced the percentage of dry matter in the fresh herbage, but produced a very large increase in the yield of dry matter. There were quite large variations in the response to this plant food, but 348 lb. N per acre per annum practically doubled the yield and generally the response curves were substantially linear.

The response to nitrogen depended on an adequate supply of potash and at five of the centres there were very large interactions between these two nutrients. The need for potash was greatest at the highest nitrogen rate and was much greater in the second and third than in the first year of the experiments.

At the highest nitrogen rate some of the responses to potash were very large. The yields of dry matter showed no large or consistent differences between applying 336 lb. K2O in one dressing during the winter months or applying this amount in five equal dressings, one for each cut. The results demonstrated the ability of the soils to supply potash and showed that the regular cutting and removal of herbage, especially if heavy dressings of nitrogen were applied, exhausted the potash reserves in the soil.

Phosphate had practically no effect on the yield of dry matter either in the presence or absence of nitrogen.

With adequate potash the production of dry matter per lb. of fertilizer nitrogen was practically independent of rate and the overall mean results are between 14·0 and 15·7 lb. In the absence of fertilizer potash there was a very large effect of rate: 15·0 lb. dry matter per acre was produced per lb. N with the 87 lb. N per annum treatment, 13·7 lb. with 174 lb. N and 10·0 lb. with the 348 lb. N treatment.

Approximately 70–75% of the annual production was obtained before the end of July. Thus 1 lb. of fertilizer nitrogen produced considerably more dry matter per acre during May, June and July than later in the season.
A quantitative study of the inheritance of resistance to bacterial blight in Upland cotton
Authors: Innes N. L. , Brown S. J.
Published: March 2009

Populations derived from a diallel set of crosses involving five inbred Upland varieties were tested for bacterial blight resistance at Wad Medani in the Sudan and at Namulonge in Uganda. Four of the varieties carried a knownBgene for resistance; noBgene was present in the fifth, which was used as a susceptible parent. The importance of genotype/environment interaction was emphasized and it was found that theBgenes did not maintain the same dominance relationships at the two sites.

The Reba gene,B9L, segregated as a gene or ‘effective factor’ of large effect but Mendelian segregation was not discernible in hybrid populations not involving Reba. Most of the genetic variance was accounted for by additivity and dominance. Although statistical analysis failed to reveal epistasis there was a strong interaction in theB2×B6cross.

At Namulonge, where it was possible to test for leaf and boll resistance, the proportion of dominant and recessive alleles was the same for both phases of the disease.
The relationship between productivity and some components of canopy structure in ryegrass (Lolium spp.)
Authors: Rhodes Ian
Published: March 2009

Productivity and percentage conversion of light energy were measured in (a)clonallypropagated swards of populations of genotypes selected from the variety S. 321 forcontrasting combinations of leaf rigidity and tiller angle, and (b) families from assortativecrosses between genotypes of this variety of differing canopy structure. A further experiment was carried out to examine the canopy structure and pattern of light interception of populations, families and genotypes of contrasting productivity.

Under infrequent cutting (28–34 days) the tiller population selected for erect tillers and rigid leaves was more productive than those selected for prostrate tillers and rigid leaves, and prostrate tillers and lax leaves. Under frequent cutting (14–17 days), however, the populations with prostrate tillers were most productive.

Considerable differences existed in the productivity of the S. 321 families, and their relative performance differed under the two cutting frequencies. Under infrequent cutting the highest yielding family was 17% more productive than the base population, whilst under frequent cutting the yield of the most productive family was 19% greater than that of the base population.

The heritability of sward yield was 0·64 under infrequent cutting and 0·86 under frequent cutting.

The most productive genotypes, populations and families under infrequent cutting had the highest leaf-area index (LAI) at complete light interception and the lowest extinction coefficients for visible radiation (Kvis). By contrast, under frequent cutting the most productive types had high extinction coefficients and large LAI in the basal layers of the canopy.

The physiological basis of differences in productivity is discussed in relation to canopy characters whioh may be used as selection criteria for increasing the efficiency of light utilization in herbage grasses.
The influence of feathering and environmental temperature on the heat production and efficiency of utilization of metabolizable energy by the mature cockerel
Authors: O'Neill S. J. B. , Balnave D. , Jackson N.
Published: March 2009

The effect of temperature on the heat production, of temperature-acclimatized feathered and defeathered cockerels was examined at 15, 22, 25, 29, 34 and 38 °C. The maintenance ME requirements and the net availability of ME (NAME) were determined for each temperature.

The fasting heat production of defeathered cockerels measured at 22, 29, 34 and 38 °C, decreased continually with increasing temperature. The feathered cockerels also showed a general decrease in fasting heat production with increasing temperature between 15 and 34 °C, but there were relative increases in fasting heat production between 22 and 29 °C.

The ME requirement for maintenance and the NAME were determined from measurements of heat production at different levels of ME intake. In general, the maintenance ME requirement decreased with increasing temperature for both feathered and defeathered cockerels. The NAME for the defeathered birds varied between 75 and 77% at 29, 34 and 38 °C. There was evidence for the feathered birds of an increasing NAME with increasing temperature, one feathered bird having a NAME of 56% at 15°C, increasing to 81% at 34 °C.

The importance of feathering and environmental temperature on the heat production and the possible effect of feather cover and activity on the NAME are discussed.
A physiological analysis of the growth of oilseed rape
Authors: Allen E. J. , Morgan D. G. , Ridgman W. J.
Published: March 2009

For seed crops other than cereals there have been comparatively few comprehensive field studies which have analysed the physiological basis of the effects of genotype and agronomic treatments on growth, development and yield. Milbourn & Hardwick (1968), working on vining peas (Pisum sativum L.), have recently shown that pod growth rate and the yield of seeds are not simple functions of leaf area index and that sourc es of materials other than the leaves are important in affecting the yields of pods and seeds. Furthermore, Flinn & Pato (1970) have shown that the pods themselves can contribute to assimilation in the field pea (Pisum arvense L.). Field experiments carried out at Cambridge in 1968 and 1969 have produced evidence on the relative importance of leaves and other photosynthetic tissues in determining the yields of pods and seeds in another seed crop, namely oilseed rape. The experiment in 1969 is described and discussed below.
Studies on the adaptability of three breeds of sheep to a tropical environment modified by altitude VII. Sexual activity in relation to age of ram
Authors: Symington R. B.
Published: March 2009

The effect of age on attainment of puberty and on seminal characteristics in yearling and mature rams was studied in German Merino, Persian Blackhead and indigenous Native rams living on Rhodesian highveld.

1. Puberty occurred at age and live weight proportional to mature live weight. Well-grown Native lambs ejaculated first at 169 days of age and 46 lb. live weight; Merino lambs when 250 days old and 79 lb. live weight and Persians were intermediate. Onset of sexual maturity was related more closely to live weight than to age, since runts ejaculated first at live weights close to those of well-grown lambs.
Studies of the effects of soil aggregate size on the emergence and growth of beet (Beta vulgaris L.) I. Seedling emergence
Authors: Hammerton J. L.
Published: March 2009

A fine soil separate gave the highest and most rapid seedling emergence. This was considered to be due to its better moisture supply characteristics and the lower mechanical impedance compared with coarser seed-beds. There was no evidence that natural seed clusters are any less responsive to soil aggregate size than processed beet seed clusters.

Consolidation slightly hastened emergence, though the mechanism of this is not clear. Sowing at ¾ in. was superior to deeper sowing (1½ in.), both in speed of emergence and in ultimate emergence. This was partly an effect of decreased mechanical impedance, and partly due to the shorter period over which the seedlings were susceptible to pathogens. Heavy dressings of soluble fertilizers were found to delay emergence, though without effect on the ultimate emergence.
Studies on the Northern Rhodesia Hyparrhenia veld III. The effect on the growth and grazing-behaviour of indigenous cattle of restricting their daily grazing time by night kraaling
Authors: Smith C. A.
Published: March 2009

1. The effects of restricting the daily grazing hours of indigenous cattle have been studied on grazing behaviour and cattle weights. The cattle grazed on natural veld.

2. Three cattle-management treatments, i.e. free range, moderate kraaling (11 hr. grazing day) and severe kraaling (7 hr. grazing day), were compared during seasonal periods of low cattle-weight gains, large cattle-weight gains and large cattle-weight losses.
Milk production from pasture
Authors: Glover J. , Dougall H. W.
Published: March 2009

It is shown that the available energy, T.d.n. or S.e., contained in the dry matter of Kenya pastures at all stages of growth is remarkably constant. Thus in the early stages of growth of such pastures when the available D.c.p. is present in amounts suitable for very high milk yields the available energy limits their attainment. During later growth, as the amount of C.p. in the pasture becomes increasingly diluted by carbohydrate there is a progressive decrease in amount of available D.c.p. and it in turn becomes inadequate to sustain the original limited level of productivity.
Protein, lysine and feed intake level effects on pig growth: I. Main effects
Authors: Blair R. , Dent J.B. , English P.R. , Raeburn J.R.
Published: March 2009

A total of 512 pigs were given from 50 lb live weight one of 16 diets, i.e. with 4 lysine levels at each of 12, 14, 16 and 18% protein, at one of 4 levels of intake. They were killed at 100, 150, 200 or 250 lb live weight.

Live-weight gain was not improved significantly by increasing the protein level above 16, 14, 12and 12%, respectively, for the 50–100, 100–150, 150–200and200–2501bstages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the protein to 18%. Gain in lean meat and in the efficiency of conversion of feed to lean meat were improved by increasing the above protein levels slightly.

Live-weight gain was not improved significantly by increasing the lysine level above 1·04, 0·74, 0·70 and 0·59%, respectively, for the 50–100, 100–150, 150–200 and 200–250 lb stages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the lysine level to 1·22%. Raising the lysine level at each level of protein had no significant effect on the rate and efficiency of lean meat gain.

Live-weight gain was significantly improved by increasing the level of feed intake almost to ad libitum levels for the 50–100, 100–150 and 150–200 lb stages. There was a suggestion of a similar effect in the 200–250 lb pigs although it was not statistically significant. Conversion of feed to live-weight gain was improved in the 50–100 lb pigs only by increasing the level of feed intake: in the older pigs increasing the level of feed intake caused a worsening in feed conversion ratio. Increasing the level of feed intake gave a significant improvement in rate of lean meat gain but a significant worsening in the efficiency of conversion of feed to lean meat during all stages up to 200 lb.

Interaction effects of these factors and sex, on growth performance, are described.
The tillering pattern in barley varieties: II. The effect of temperature, light intensity and daylength on the frequency of occurrence of the coleoptile node and second tillers in barley
Authors: Cannell R. Q.
Published: March 2009

Controlled-environment experiments showed that development of the coleoptile node tiller (T1) was suppressed much more than that of the tiller appearing in the axil of the first true leaf (T2) by high temperature (24/15 °C; 19/10 °C; 10/6 °C), by reduced photoperiod (16 h; 12·5 h) or by low light intensity (1100 ft-c; 1000 ft-c), but minimally in the newest variety, Deba Abed. Unlike previous field experiments, the T1 tiller appeared on more Spratt Archer than Maris Badger plants. Maris Badger plants produced more T1 tillers in a high-low temperature regime (19/10 °C; 10/6 °C) than in continuous low temperature (10/6 °C). In a field experiment T1 tiller number (and yield), but not the number of other major shoots, were severely reduced by late sowing of Spratt Archer, progressively reduced in Maris Badger, but minimally in Deba Abed. This seemed to be associated with higher temperatures at later sowings.
Calorimetric studies on the effect of dietary energy source and environmental temperature on the metabolic efficiency of energy utilization by mature Light Sussex cockerels
Authors: Shannon D. W. F. , Brown W. O.
Published: March 2009

Experiments to determine the net availabilities of the metabolizable energy (NAME) of a cereal-based diet and a maize-oil diet for maintenance and lipogenesis and the effect of environmental temperature on the NAME of the cereal-based diet are described. Four 1- to 2-year-old Light Sussex cockerels were used.

The relationship between ME intake and energy retention was linear for each diet. The NAME'S of the cereal-based diet given at 22° and 28 °C (70.6 ± 1.83 % and 73.6 ± 3.54%, respectively) were significantly (P < 0.05) lower than the NAME of the maize-oil diet (84.1 ± 1.85%). It is concluded that the beneficial effect of maize oil on the efficiency of energy utilization is due to a reduced heat increment rather than a reduction in the basal component of the heat production. The higher efficiency from the maize-oil diet led to an increase in the energy retained as fat.

The mean fasting heat production at 28 °C was 15 % lower than at 22 °C (43.2 ± 1.45 and 51.2 ± 1.09 kcal/kg/day, respectively). The NAME of the cereal-based diet was not significantly different when the birds were kept at 22° or 28 °C. The lower metabolic rate at 28 °C was reflected in a lower maintenance requirement and in an increase in the deposition of body fat.
In vitro maturation and attempted fertilization of cattle follicular oocytes
Authors: Sreenan J.
Published: March 2009

Maturation studies were carried out on 241 cattle oocytes. Media used were bovine follicular fluid and growth medium. Both media supported a resumption of meiosis in ca. 80 % of cases, but growth medium proved superior in terms of final maturation.

Fertilization attempts were carried out on 564 oocytes following culture (27–32 h) in growth medium. In vitro fertilization attempts (107 oocytes) and in vivo fertilization attempts (82 oocytes) in the rabbit yielded negative results. Following in vivo fertilization attempts in the ewe, ova containing pronuclei as well as apparently normal cleaved ova were recovered.
Sweating rate and the electrolyte content of skin secretions of Bos taurus and Bos indicus cross-bred cows
Authors: Johnson K. G.
Published: March 2009

Sweating rate and the electrolyte content of secretions from the skin of cattle have been measured on five Bos taurus and five B. indicus cross-bred cows by absorbing secretions into filter papers under polythene disks applied to shaved skin areas on the shoulder, sacral and lumbar regions for 5 min. The increase in weight of the filter paper was taken as a measure of sweating rate and the distilled water eluate from the filter paper was analysed for sodium and potassium. Animals were exposed for 4 h to air temperatures of 20–45 °C at 30% r.h., and for 5–7 h to air temperatures of 40 and 45 °C at 40% r.h. Estimated sweating rates were low by comparison with previously reported values, probably due to rising levels of humidity under the polythene disks during exposure to the skin. B. indicus cross-bred cows had higher sweating rates than B. taurus cows at high air temperatures but the difference between the groups was not significant statistically. Sweating rates were generally highest on the shoulder and lowest on the lumbar region.

The amounts of sodium and potassium recovered from filter papers were small and very variable at low air temperatures but increased significantly with air temperature (P < 0·01). No significant differences in the amounts of electrolyte recovered from filter papers were recorded between the species groups or between different sites of collection. The secretions from cattle skin at high ambient temperatures contained at least four to five times as much potassium as sodium. Total sodium and potassium loss through the skin of these experimental animals at the highest ambient temperatures was estimated to be no more than 1–3 % of the sodium and potassium intake in the feed. Absorbing sweat on to filter paper as a method of measuring sweating rate and sweat composition is rather less satisfactory for use with cattle than with man.
Evapotranspiration from barley grown at different plant densities
Authors: Kirby E. J. M.
Published: March 2009

Evapotranspiration from spring barley plots grown at a range of densities was estimated using the neutron probe technique. Early in the season rainfall led to percolation and kept the soil at field capacity, but from the beginning of June significant differences were found in the cumulative evapotranspiration. As the crop canopy was complete by this time in all densities, it seems probable that evapotranspiration at this time was dependent on rooting density. Although the total water use at the end of the season was similar at all densities, the more rapid use earlier in the season at higher densities may have led to a reduction in growth at the grain filling stage.
The influence of live weight and body condition on the subsequent milk production of Blackface ewes following a period of undernourishment in early lactation
Authors: Peart J. N.
Published: March 2009

In each of two years, 36 Blackface ewes were brought to a high state of body condition at mating and in early gostation. At approximately 16 weeks prepartum the ewes were divided into two similar groups and fed to maintain the live weight and body condition of one group (fat), and to decrease that of the other group (lean). At 8 weeks prepartum mean differences of 14kg live weight and two scores of body condition had been created between the groups. During the last 6 weeks of pregnancy food was rationed to all ewes per unit of live weight to provide the theoretical requirements of Blackface ewes in late pregnancy. Both groups of ewes made similar live-weight gains in late pregnancy and blood plasma F.F.A. values confirmed that the ewes had been similarly nourished regardless of live weight or body condition. During early lactation food was restricted to fat and lean groups of ewes for either a 2- or 4- week period followed by ad lib. feeding for the remainder of lactation. A lamb-suckling technique was used to measure milk production during a 10-week lactation. During the first and second weeks of lactation the mean milk production of groups of both fat and lean ewes was approximately 2·1 and 1·3 kg/day for twin- and single-suckled ewes respectively. Ad lib. feeding following restricted feeding during the first 2 weeks of lactation resulted in increased milk production of fat and of lean ewes to mean maximum values of approximately 2·7 and 1·7 kg/day for twin- and single-suckled ewes respectively. In contrast, groups of ewes which had restricted feeding for the first 4 weeks of lactation showed almost no increase in milk production when fed ad lib. During the extended period of restricted feeding the milk production of twin-suckled ewes which were fat at parturition was significantly greater than that of twin-suckled lean ewes but there was no difference with singlesuckled ewes. All groups of ewes lost similar amounts of live weight and body condition during their respective periods of restricted feeding. In the respective 6-week periods following ad lib. feeding the live-weight gain of the lean ewes was significantly greater than that of the fat ewes (339 v. 222 and 356 v. 250 g/day for twin- and single-suckled ewes respectively), but they did not attain parity of live weight by the end of lactation. When fed ad lib. the mean intake of all groups of ewes attained similar maximum values of approximately 2·2 kg D.O.M./day. The results indicate that the stage of lactation is an overriding factor governing the response to increased nutrition and that body condition of ewes at parturition acts as a buffer between nutrient intake and nutrient requirements for lactation. It is suggested that when body reserves of ewes are severely depleted, factors other than nutrient intake may become limiting to milk production.
The effect of nitrogen fertilizers on the ensiling characteristics of perennial ryegrass and cocksfoot
Authors: Jones D. I. H.
Published: March 2009

The effect of three levels of N fertilizer on the ensiling characteristics of S. 24 perennial ryegrass and S. 37 cocksfoot have been examined during first growth in two growing seasons. The effects of sucrose supplementation, inoculation with Lactobacillus plantarum and wilting were also examined in certain cuts. All silages were made in the laboratory using a small scale vacuum silage technique.

The perennial ryegrass herbage was higher in water soluble carbohydrates than the cocksfoot, N fertilizers decreased soluble carbohydrates and dry-matter content in both species. Buffering capacity was not consistently different between grasses or between N levels.

Herbage was cut at two stages of maturity in the first year. In the first cut (8 days before ear emergence), perennial ryegrass silages were well preserved irrespective of the amount of N applied to the grass. Cocksfoot silages were well preserved only when the lowest level of N fertilizer had been applied (50 kg/ha). Supplementation of cocksfoot with sucrose prior to ensiling markedly improved silage quality, but inoculation had no effect. In the second cut (26 days after ear emergence) the grasses were higher in drymatter content and showed a lower buffering capacity, but neither ryegrass nor cocksfoot silages were well preserved unless supplemented with sucrose prior to ensiling.

In the second year of the experiment only one cut was taken (9 days after ear emergence). As in the previous year, silages made from herbage at a late stage of growth were poorly preserved. Wilting prior to ensiling resulted in well-preserved silages.

It is concluded that the need for additives and wilting to ensure satisfactory preservation varies in relation to the variety of grass used and its stage of growth.
Studies of compensatory growth in sheep
Authors: McManus W. R. , Reid J. T. , Donaldson L. E.
Published: March 2009

A number of observations have been made on 5- to 6-month old wether Hampshire heep undergoing uninterrupted growth (36·2% gain in shrunk wool-free live weight over 58 days), undernutrition (a 21·7% fall in body weight over 27 days) and then followed by compensatory growth (a gain of 62·2% in live weight over 52 days).

Sheep being underfed had increased, and compensating sheep had decreased, apparent digestibility coefficients of feed dry matter compared to control sheep. Sheep undergoing compensatory growth drank more water, ingested more food per unit body weight, laid down less body fat, more protein and retained more water in their bodies than did control sheep. Tritiated water allowed estimation of total body water with an accuracy comparable to other reports in the literature.

Changes in the weight and in RNA-P and DNA-P content of anterior pituitary, thyroid and adrenal glands were measured. Sheep thyroid glands were examined histologically to assess relative TSH outputs and no significant differences detected.

Rat bio-assay of cavernous sinus plasma for somatotrophin and ACTH activity was made on these sheep. Somatotrophin was detected, but experimental groups did not statistically significantly differ in relative potency (TJ.S.P. units/ml fresh plasma). Compensating sheep had. significantly lower plasma somatotrophin potency per unit empty body-weight values than did the underfed sheep.

No ACTH activity was detected in the sheep plasma of the several groups.

During severe undernutrition the anterior pituitary gland decreased in size, but not in cell numbers, and still elaborated somatotrophin. Decrease in body size tends to increase the ratio of circulating somatotrophin per unit body size and thus may facilitate, in a permissive manner, the enhanced growth rate of animals undergoing compensatory growth.

Restitution and gain of body size by compensatory growth is accompanied by hypertrophy of the anterior pituitary gland. This gland, after compensatory growth, showed evidence of enhanced synthesizing capacity.
The effects of diet supplements and gamma irradiation on dissimilation of low-quality roughages by ruminants: II. Effects of gamma irradiation and urea supplementation on dissimilation in the rumen
Authors: McManus W. R. , Manta L. , McFarlane J. D. , Gray A. C.
Published: March 2009

Results of two in vivo sheep experiments in which gamma-irradiated material in teryleno bags was fermented in the rumen are reported.

Exp. I concerned the testing of rice straw, nassella (Nassella trichotoma) and cotton lint, each subjected to six dose levels of gamma irradiation (0, 5, 10, 25, 100 and 200 Mrad) when wet and when in the dry state. The tests were made in sheep fed either a lucerne hay or a rice-straw base diet.

Dry -matter disappearance of all test materials was influenced by irradiation treatment: levels of 10 and in some instances 25 Mrad depressed, and other levels substantially enhanced, intraruminal degradation rate tested over 72 h. Materials irradiated in the dry state were better dissimilated than those irradiated in the wet state.

On severe shaking for 14 h in water, solubility values as high as 35 % were obtained for irradiated test materials receiving the highest dose of irradiation but such values were never of the same magnitude as total dry-matter losses in the rumen. When irradiated material was immersed in gently flowing water for 12 h solubility values of 1 % were found for material dosed at 100 or 200 Mrad and of nil for other dose levels. At no level of irradiation was solubility depressed. It was concluded that enhanced losses of irradiated dry matter in the ruminal environment arose substantially from fermentation.

Intraruminal dissimilation of irradiated test material from terylene bags was always greater on lucerne hay base diets than on rice straw base diets.

Exp. II investigated the influence of urea supplementation, at levels of 1 % and 2 % of diet, on the dissimilation of irradiated test samples of cotton lint and rice straw for sheep fed a rice-straw base diet.

Similar effects of irradiation on cotton lint and rice straw to those found in Exp. I were observed. Overall, urea supplementation depressed dissimilation rate of rice straw and severely depressed degradation of cotton lint irrespective of irradiation dose up to an irradiation dose level of 100 Mrad. It is concluded that urea supplementation per se depressed the activity of cellulolytic organisms.

It is considered that feeding trials with low-quality roughages irradiated at levels at or greater than 25 Mrad are warranted.
High Level Cereal Diets for the Growing/Finishing Pig: VI. An Evaluation of Flaked Maize, Wheat and Barley When Included at High Levels in the Diet of the Weaned Pig Grown to Cutter Weight (160 lb)
Authors: Lawrence T. L. J.
Published: March 2009

In a randomized block 3x2 factorial experiment 72 Large White type and Large White x Landrace pigs were restrictedly fed to 160 lb (72–5 kg) live weight on diets (as wet mashes) containing high levels of maize, wheat or barley in either ground meal or ground flaked forms. A further five groups of six litter-mate Large White type hog pigs per group were used in digestibility and nitrogen balance studies. The diets of meal were formulated to be iso-nitrogenous and to contain similar levels of lysine and for each cereal similar levels of protein and vitamin/mineral supplements were included in the flaked diets. There were no significant cereal x processing interactions for any of the parameters studied. Overall, flaking improved digestibility and this was reflected in a higher (P >0-05) digestible energy content of the flaked diets (3402 kcal/kg air dry weight) compared with the meal diets (3334 kcal/kg air dry weight). The digestible energy contents of the maize, wheat and barley diets were significantly different (P < 0-001) at 3477, 3431 and 3195 kcal/kg air-dry diet respectively. Nitrogen retention, growth rate and efficiency of food conversion were all significantly poorer for the flaked, compared with the meal based diets. The nitrogen retained from the wheat-based diets was significantly lower than that retained from the maize- and barley-based diets. Growth rates of pigs given the wheat- and barley-based diets were similar but taken together were significantly (P < 0-05) better than those obtained from pigs given the maize-based diet. Efficiency of food conversion followed a similar pattern but the differences were not statistically significant.
The effect of the intensities of potassium and sodium in soil on the growth of sugar beet
Authors: Rowell D. L. , Erel Kamil
Published: March 2009

In a pot experiment, the growth of sugar beet on one soil with three levels of exchangeable Na ceased when the intensity of K measured as the activity ratio aK/√[a(Ca + Mg)] in the equilibrium soil solution had fallen to 6 × 10–4 (mole per litre)½;, the intensity of Na, aNa/√[a(CaH-Mg)], to between 1·7 and 4 × 10–3 (mole per litre)½;and exchangeable Mg to 0·14 m-equiv per 100 g soil. It was concluded that both the Na and the K intensities were exhaustion values but that K supply was preventing further growth. The additions of Na did not affect either yield or the uptake of K, Mg and Ca, but more Na was taken up from soils with higher Na levels.
The influence of nutrition during winter on growth rate and sulphur content of wool of pregnant Scottish Blackface and Romney ewes
Authors: Doney J. M. , Evans C. C.
Published: March 2009

Pregnant ewes of the Scottish Blackface and Romney breeds were group fed to achieve different patterns of live-weight change between mating and parturition. One group had a net maternal live-weight increase of about 8%, the second a net loss of about 5% and the third a loss of about 16%. Wool growth and sulphur content of the wool were measured at intervals. During the period 6–8 weeks prepartum wool growth rate in the Blackface breed was low and there were no significant differences amongst treatments. Differences in sulphur content were highly significant (ranging between 3·97 and 3·46% for fine and coarse fractions respectively in the well-nourished sheep down to 3·68 and 3·20% in the undernourished group). In the Romney breed the situation was reversed. In the prepartum period there were no significant differences amongst groups in sulphur content (mean value 3·68%), but differences in wool growth rate were highly significant (0·021, 0·012 and 0·009 g/100 cm2/day).