bluuebunny/crossref_metadata_2025_split huggingface dataset:
The long-term accumulation and depletion of copper in the liver of different breeds of sheep fed diets of differing copper content
Authors: Woolliams J. A. , Suttle N. F. , Wiener G. , Field A. C. , Woolliams C. 
Published: March 2009

SUMMARYChanges in Cu concentration in the livers of adult Scottish Blackface (B), Welsh Mountain (W) and B × W ewes fed diets containing 4, 9, 17 and 29 mg Cu/kg D.M. were measured over a 28-week period. Measurement continued during two further periods of 18 weeks when first all sheep were fed the diet containing 4 mg Cu/kg D.M. and finally, when 4 mg Mo/kg D.M. was added to this diet.During the first period the increase on all diets was least in B ewes and, apart from the 4 mg Cu/kg D.M. diet, greatest in W ewes; this difference increased as the Cu in the diet increased. The rate of increase for all ewes diminished towards the end of the period. All breed types retained proportionately less Cu in their livers as the Cu in the diet increased; at one extreme B ewes fed 17 or 29 mg Cu/kg D.M. retained equal amounts.When during the second period all sheep were fed the 4 mg Cu/kg D.M. diet the Cu concentration in their livers decreased, the rate of decrease being greatest for ewes whose mean concentration in the liver was highest, but at similar concentrations the decrease was greater in B than W ewes. During the final period the decrease was faster and was again associated with the mean Cu concentration, but the decrease was not significantly affected by breed.Throughout the trial, W ewes had the highest concentration of Cu in their plasma, whilst B ewes and ewes fed the 4 mg Cu/kg D.M. diet throughout had the lowest concentrations both in plasma and in their kidneys at slaughter.The results show that breeds differ in their ability to retain Cu from the diet in their livers. The magnitude of these differences depends on the intake of Cu and Mo from the diet and is affected by the concentration of Cu in the liver. Breed differences in the absorption and endogenous loss of Cu are suggested.
The comparative effects of defoliation, treading and excreta on a Lolium perenne-Trifolium repens pasture grazed by sheep
Authors: Curll M. L. , Wilkins R. J. 
Published: March 2009

SUMMARYThe effects of treading and the return of excreta on a Lolium perenne-Trifolium repens sward defoliated by sheep set-stccked at high and low stocking rates were examined. Sward performance was measured inside ‘graze-through’ cages which allowed defoliation without treading and excreta return, and outside where sheep grazed either fitted with harness to prevent the return of excreta or unharnessed to allow the normal return of excreta. Live-weight gain was measured from excreta return and non-return swards. The treatments imposed had large effects on herbage growth and botanical composition.At a stocking rate of 25 yearling wethers/ha, sheep excreted about 1·1 kg N/ha/day, which increased soil N and led to an increase in herbage growth of about 26 %. The return of excreta increased ryegrass tiller density and this was partly responsible for a 26% reduction in the proportion of clover in the sward; the weight of clover was 13% loss where excreta were returned, and on this treatment stolon length at the end of the experiment was similar to that at the beginning. Doubling the stocking rate increased the N returned via excreta to about 1·3 kg N/ha/day, and this increased herbage growth by 53% but suppressed the proportion of clover by 21%, though not the weight of clover. Clover stolon length decreased during the experiment at this stocking rate, both with and without the return of excreta. Sheep live-weight change benefited from the stimulus to herbage growth where excreta were returned at the high stocking rate, but not at the low stocking rate.Treading by 25 sheep/ha increased soil compaction but had no significant (P > 0·05) overall effect on herbage growth and botanical composition. However, treading by double the number of grazing animals significantly reduced herbage growth by 10%, plant root weight by 47% and the proportion of clover in the sward by 11%.Differences in sward performance between stocking rates were due more to the difference in defoliation intensity between these stocking rates than to either treading or the return of excreta.
Fatty acid composition of depot fats from gnotobiotic lambs
Authors: Leat W. M. F. , Kemp P. , Lysons R. J. , Alexander T. J. L. 
Published: March 2009

SUMMARYThe fatty acid composition of the depot fats of lambs reared for 4–5 months under gnotobiotio conditions have been determined and an estimate made of the endogenous synthesis of stearic acid.In an uninoculated gnotobiotic lamb no hydrogenation of dietary lipids occurred in the rumen and this was reflected in the virtual absence oftransacids in depot lipids. In this animal the stearic acid content of perirenal depot fat accounted for 16% of the total fatty acids which was similar to the value found in newborn lambs (17%). Inoculation of the rumen of two gnotobiotic lambs with seven species of bacteria resulted in the establishment of partial hydrogenation processes in the rumen. Varioustransisomers of octadecenoic acids were produced in these lambs from the dietary fatty acids but no stearic acid was formed.These findings are compared with the fatty acid composition of depot fats of other herbivorous and omnivorous animals.
Thein vitrodigested cell wall and fermentation characteristics of grasses as affected by temperature and humidity during their growth
Authors: Moir K. W. , Wilson J. R. , Blight G. W. 
Published: March 2009

SUMMARYTotal cell wall,in vitrodigested cell wall and fermentation-gas production were determined in the separated tops and stubble of five tropical and two temperate grass species grown under controlled temperatures and humidities. As the day/night temperatures increased from 18/10 to 25/17 °C the total cell wall andin vitrodigested cell wall increased. With a further increase to 32/24 °C the total cell wall increased, but not thein vitrodigested cell wall.In vitrodigested cell-wall values were also calculated from a previously derived relationship betweenin vitrodigested cell wall and total cell wall. The differences between observed and calculated values increased (negatively) with increasing growth temperature suggesting that thein vitrodigested cell wall was depressed with increasing growth temperatures, but the extent of this depression was small.In vitrogas production from the fermentation of plant tops or stubble in buffered rumen fluid for 24 h was significantly affected by growth temperature and humidity, apparently because of changes in chemical composition induced by the treatments. The volume of gas produced between 24 and 48 h fermentation times was appreciably lower from stubble than from plant tops and this was thought to be due to a higher resistance of part of the cell wall of stubble to digestion by rumen bacteria. Gas production in this period was slightly lower in the tops of grasses grown at the lower temperatures, but this could have been an indirect effect from an associated decrease in the total cell wall.
Studies on the nutritive value of some common Egyptian feedingstuffs. I. Nitrogen retention and ruminal ammonia curves
Authors: El-Shazly K. 
Published: March 2009

1. Ten successive trials with two Rahmany adult ewes were carried out with the aim of comparing the nutritive values of the nitrogenous constituents of some concentrates used in Egypt as supplements in summer rations (decorticated cottonseed cake, linseed-oil meal and beans (Vicia faba)) and of animal proteins (meat meal, fish meal and casein) and of barseem (Trifolium alexandrinum). Wheat straw was employed as the main roughage in the ration. Nitrogen intake for all supplements was 10·16 g./day.2. Apparent digestion coefficients for crude protein were estimated. Casein had the highest digestibility coefficient while meat meal was the least digestible.3. Nitrogen retention and ruminal ammonia curves are given for each period. Only three proteins, namely, barseem, cottonseed cake and linseed meal gave positive nitrogen balance at the critical level of nitrogen intake used throughout the trials. Fish meal improved nitrogen retention significantly. Meat meal and beans did not improve nitrogen retention. The addition of 70 g. starch to beans improved nitrogen retention significantly.
A large-scale test of the effects of food restriction on the performance of fattening pigs
Authors: Braude R. , Townsend M. Jill , Harrington G. , Rowell J. G. 
Published: March 2009

1. A co-ordinated trial has been carried out at twenty-six centres to study the effects of feeding different quantities of food to fattening pigs. The treatments studied were ad lib. feeding throughout, ad lib. feeding to 120 lb. live weight after which the amount of food given was restricted to 6·5 lb./pig/day and two scales of feeding according to live weight, one moderate and one severe (Table 1).2. Food conversion was best for the pigs on the most restricted feeding scale, being 8% better than that for the pigs fed ad lib.3. The slower growing pigs were less fat, slightly longer and their depths of eye muscle were greater.4. The ad lib. fed pigs had higher killing-out percentages and higher weights into cure.5. The bacon sides from pigs fed on restricted diets yielded a higher proportion of gammon and fore-end and had thicker streaks.6. Restriction of feeds led to softer fats.7. An economic appraisal has been made which shows that, on the basis of certain assumptions, the medium feeding scale would have led to a smaller profit per year than the ad lib. or the ad lib. restricted treatments under the price structure and system of grading prevailing during the period of the experiment.
Some water and dry-matter relationships in the food and droppings of laying hens
Authors: Tyler C. 
Published: March 2009

1. An experiment with one non-laying and four laying hens was carried out. Food and water consumption was measured hourly from 06.00 to 22.00 hr. and in the same period the exact time of each excretion was noted. Determinations of water and dry matter were made on each separate excretion.2. Each bird showed a typical pattern of behaviour in relation to the time of day when it ate food and drank water. For any one bird, variations of this pattern from day to day were small.3. For each bird there was a highly significant relationship between water intake and temperature on the one hand, and water excretion via droppings and eggs on the other. Water intake, however, had a far greater influence than had temperature on water output.4. Calculations showed that, despite errors caused by not knowing the amount of metabolic water produced, the excretion from the lungs varied greatly from bird to bird on constant intakes of water and also in the same bird at different intakes.
A study of the amount of some invertebrates that are eaten by wild birds in the Egyptian western desert
Authors: Hegazi E. M. 
Published: March 2009

SUMMARYA study was conducted at two different sites in the Egyptian western desert to investigate the activity of carnivorous birds on some invertebrates. At the first site (sand-dunes in the Gharbaniat area, 52 km west of Alexandria), the most interesting bird found was the great grey shrike Lanius excubitor which seizes its prey and impales it upon spines of Lycium europaeum or on barbed-wire fencing. Studies carried out from January to July 1977 indicated that this bird prefers to feed on certain tenebrionid or scarabaeid beetles as well as some orthopterous insects and small lizards of the area. At the other site (inland depression near Omaycd, 80 km west of Alexandria, and 12 km from the sea) a snail-eating bird, (bifaciated lark) Alaemon alaudipes, was found to be the commonest bird where the non-saline soil of the site is suitable for the desert snail, Eremina desertorum, to breed, so much so that the snails constitute one of the prominent features of the site.The latter bird is more active in the winter than in the summer. From February to the end of June 1979, the estimated snail flesh weight eaten by A. alaudipes birds was about 6·50 kg taken from an area of 2·4 ha. The birds seize a snail, fly upwards to a distance of 6–23 m, select a hard stone, then drop the snail. The snail eventually breaks, and the flesh exposed is readily eaten by the bird. In January 1980, a survey was conducted to investigate the species of birds found in the area that extends between Alexandria and el Alamein. Twenty-six resident, as well as migratory, bird species were observed. The number of species and individual birds in cultivated areas, and sites near the sea shore, were found to be greater than those in natural ecosystems at a distance from the sea.
Variability of the blood composition of dairy cows in relation to time of day
Authors: Mansion R. , Rowlands G. J. , Little W. , Collis K. A. 
Published: March 2009

SUMMARYA blood sample was taken at each hourly interval between 07.00 and 16.00 h on five consecutive days from each of two groups of five lactating and two groups of five nonlactating cows. The sampling was organized so that each cow was sampled twice daily and once at each time of day. Samples were analysed for blood glucose and haemoglobin, serum urea, inorganic phosphate, Ca, Mg, Na, K, total protein, albumin, Fe and Cu and plasma β-hydroxybutyrate. The sources of variation in the concentration of each constituent were determined.Definite patterns of changes in concentrations with time of day were observed for β-hydroxybutyrate, urea, Ca, Na, Mg and Cu. In lactating cows there was a 2½-fold increase in the concentration of β-hydroxybutyrate from the lowest at 07.00 to the highest at 11.00 h. Variation in the concentrations of the other constituents with time of day was a relatively small proportion of the total variance.It was concluded that diurnal variation in blood composition was unlikely to be a major source of error in interpretation for the usual constituents of a metabolic profile test. However, if β-hydroxybutyrate were to be included great care would be required in selecting a time for sampling.
Relationships between the responses of spring wheat genotypes to temperature and photoperiodic treatments and their performance in the field
Authors: Ford Margaret A. , Austin R. B. , Angus W. J. , Sage G. C. M. 
Published: March 2009

SUMMARYThirty-eight spring wheat genotypes of north temperate or low latitude origin, all reasonably well adapted to the English environment, were grown in controlled environments providing the four combinations of 10 and 14 h photoperiods and temperatures of 8 and 16 °C for 6 weeks. They were then transferred to a glasshouse to assess their responses to these treatments. In separate experiments the responses of the genotypes to vernalization for 2 and 4 weeks at 2 and 8 °C were compared with unvernalized controls. The genotypes were also compared in field experiments from early, intermediate or late sowing over 3 years.Both high temperatures and long days hastened ear emergence. At the higher temperature more leaves and spikelets were produced on the main stem while in long days the plants had fewer leaves and spikelets.Most genotypes of north temperate and low latitude origin were responsive to photoperiod but not to the vernalization treatments. As a group, the low latitude ones were as responsive as the north temperate group. Five genotypes of north temperate origin were responsive to vernalization but not to photoperiod and were designated as ‘winter’ ones. Pitic 62 and Hork, from low latitudes, were responsive to vernalization and Hork was unique in also being responsive to photoperiod. The main difference between the north temperate and low latitude genotypes was in time to ear emergence and it is suggested that these differences were due to the effects of earliness genes as distinct from those determining photoperiodic response.Taking all genotypes individually there were no correlations between yield or its sensitivity to sowing date and any of the attributes measured in controlled environments. However, considering class means, the winter genotypes were the latest to reach ear emergence in the field, and their yields, while greatest from the earliest sowings, were proportionally more depressed by late sowing than the others of the north temperate origin. Thus, it may be unwise for plant breeders to incorporate a vernalization response in spring wheat varieties unless genes for ‘earliness’ are also included. The low latitude class gave only slightly lower yields than the north temperate class.It is concluded that genes other than those controlling responses to photoperiod, temperature and vernalization were more important determinants of the differences in yield among this set of genotypes.
The effect of feed intake on nutrient and hormone levels in jugular and portal blood in goats
Authors: de Jong A. 
Published: March 2009

SUMMARYAdult goats provided with permanent jugular and portal vein catheters were used to study the effect of feeding hay and concentrates on blood composition in order to determine which blood constituents might act as signals in the control of feed intake. Animals were fed limited amounts of feed, or were allowed to eat unlimited amounts for restricted periods, once or twice daily. Blood samples were collected at hourly intervals up to 9 h after feeding and often more frequently in the initial hour, and were analysed for volatile fatty acids (VFA), lactate, glucose, insulin and glucagon.Feed consumption resulted in rapid and large increments of jugular blood acetate, propionate,n-butyrate and 3-methylbutyrate concentrations whereas isobutyrate and 2-methylbutyrate increased only slightly. Jugular propionate,n–butyrate and 3–methyl–butyrate increased within 10 min and acetate within 20 min after feed was offered, both when hay and when concentrates were eaten. Fasting decreased circulating VFA to very low values. As a rule changes of portal VFA paralleled those in the general circulation although both the concentrations and the changes were much greater. Plasma lactate increased within 30 min on a concentrate diet but not at all on a hay diet.Blood glucose declined in the initial hour after feeding and subsequently increased, resulting in a more or less elevated plateau. In some but not all experiments glucose declined before feed consumption, probably owing to ‘anticipation’. Circulating plasma insulin and glucagon appeared to increase slightly, if at all, after feeding. Increased feed intake was reflected in higher base line glucose and insulin concentrations in the jugular vein but the jugular glucose and insulin response to feed consumption was unaffected. Jugular glucagon was not influenced by the amount of feed. Jugular insulin and glucagon sometimes showed a brief peak during eating. Portal glucose, insulin and glucagon gave essentially the same pattern as seen in the jugular vein.In conclusion, it appears that, of the substances studied, acetate, propionate, nbutyrate and 3-methylbutyrate are most suited for the function of feedback signals in the physiological control of feed intake in goats under the conditions of the present experiment. It seems less probable that glucose, insulin and glucagon can play such a role.
Estimation and inheritance of stability parameters of grain yield in maize
Authors: Dhillon B. S. , Singh Joginder 
Published: March 2009

SUMMARYOne hundred and ninety hybrids involving 20 broad-based yellow maize populations were evaluated together with their parents for stability in expression of their grain yield potential by means of linear regression on to an environmental index. Both linear and non-linear components were observed to be significant; the linear component, in general, being the more important. Two high yielding parents, namely variety A 3D and composite Jawahar, had general adaptability, while synthetic A 22 was suited to poor environment and variety SO 4D to good environment. Seventeen hybrids had above average yield and the majority of these exhibited general adaptability.Combining ability analysis revealed that GCA (general combining ability) was more important than SCA (specific combining ability) in the expression of mean yield. Inheritance of linear regression was controlled predominantly by GCA whereas both GCA and SCA were equally important in the expression of non-linear fluctuations. Variety Cuba was the most desirable parent, as it transmitted to its progeny high grain yield potential and low linear response. The other good combiners for grain yield were variety SC 4D and Prolific composite but these transmitted above average linear response.Lack of association between grain yield and linear regression of both parents and GCA effects indicated their independent mode of inheritance. It suggested, therefore, that high yield can be combined with general adaptability or responsiveness to either good or poor environment.
Studies of the permanent incisor eruption, and body development, of the Large East African Zebu (Boran): 2. Relations of incisor eruption with body growth, body development, and carcass composition
Authors: Carles A. B. , Lampkin K. Meidie 
Published: March 2009

SUMMARYA comparison was made of the growth curves for early and late eruptors (steers whose eruption age of the first incisor pair was less than the mean, and greater than the mean respectively). From birth to 195 weeks early eruptors were consistently heavier than late eruptors (P < 0·01) by approximately 4% of the overall mean body weight. Growth was linear from birth up to 126 weeks of age, and the variability increased markedly from about 60 weeks of age.The average daily gain from birth to 195 weeks was 341 g. Linear growth-rates for consecutive stages within this period were generally faster for early eruptors, with the differences ranging between 4 and 6% of the mean for periods exceeding 60 weeks. Comparison of these differences showed that linear growth-rates were only significantly different for growth periods of approximately 120 weeks and longer. When the specific growth-rates were compared no differences were significant.The differences between the growth rates of fast and slow eruptors (steers whose eruption period was less than the mean, and greater than the mean respectively) were not significant, both for linear and specific growth rates.Early eruptors had larger heads (head length x head width) relative to body weight (P < 0·05), indicating eruption at an earlier stage of body development. Also early eruptors had longer narrower heads, suggesting slower maturation rates.Partial correlations between eruption age and head length varied from 0·37 to 0·74 (P < 0·01) showing a close relation with stage of head development. Partial correlations with other measures of skeletal development showed that they were of negligible importance relative to head development.Relations between eruption age of the first incisor pair and six measures of carcass composition were negligible, as none of the partial regression coefficients was significant.