bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-parametric lactation curves
Authors: Elston D. A. , Glasbey C. A. , Neilson D. R.
Published: September 2010

Lactation curves are fitted to data as a preliminary to estimating summary statistics. Two widely quoted curves are atbe-ct (Wood, 1967) and a(1 - e-bt) - ct (Cobby and Le Du, 1978), each of which has three parameters. Restriction to either of these curves imposes limitations on the fit to the data and can result in biased estimation of summary statistics. Alternatively, lactation curves can be generated by the use of a non-parametric method which requires only weak assumptions about the signs of derivatives of the curves. Because the non-parametric curves are more flexible, estimates of summary statistics are less likely to be biased than those based on parametric models. Use of the non-parametric curves is particularly advantageous around the time of peak yield, where the curves of Wood and Cobby and Le Du are known to fit data poorly.
Growth and carcass composition of Friesian, Limousin × Friesian and Blonde d'Aquitaine × Friesian steers
Authors: Keane M. G. , More O'Ferrall G. J. , Connolly J.
Published: September 2010

One hundred and twenty spring-born steers comprising 40 Friesians (FR), 40 Limousin × Friesians (LM), and 40 Blonde d'Aquitaine ' Friesians (BL), were reared together from shortly after birth to slaughter at a mean age of 771 days. They were at pasture in summer and were housed and offered grass silage plus concentrates in winter. All were implanted with anabolic agents. During the finishing winter, there was a 3 (breed types) ' 2 (3 or 6 kg concentrates per day) ' 2 (94 or 181 day finishing period) factorial arrangement of treatments.

Slaughter weights per day of age, carcass weights per day of age and carcass weights of FR, LM and BL were 846, 828 and 866 (s.e. 8·0) g, 464, 476 and 497 (s.e. 4·9) g and 358, 368 and 385 (s.e. 3·8) kg respectively. LM had lower carcass length, carcass depth, leg length and leg width values than FR or BL but when these measurements were expressed per kg carcass weight the values for LM and BL were similar. Both LM and BL had better carcass conformation than FR, and BL had a lower carcass fat score than either FR or LM between which there was no difference. FR, LM and BL had carcass lean, fat and higher-priced lean proportions of 634, 669 and 685 (s.e. 3·7), 185, 168 and 144 (s.e. 3·7) and 352, 361 and 361 (s.e. 1·4) g/kg respectively.

Increasing the concentrate level from 3 to 6 kg per day increased side weight by 9·6 kg (P < 0·001). This consisted of 0·6 kg bone, 3·3 kg lean and 5·7 kg fat. Extending the finishing period from 94 to 181 days increased side weight by 30·3 kg (P < 0·001). This consisted of 2·6 kg bone, 12·0 kg lean and 15·7 kg fat. Allometric regression coefficients for side lean, bone and fat weights on side weight were not significantly affected by breed type or concentrate level. The coefficients for lean, bone and fat were 0·80 (s.e. 0·04), 0·58 (s.e. 0·05) and 2·27 (s.e. 0·16) respectively. The coefficients for weights of lean in the hind-shin, fore-shin, fillet and brisket on side lean weight were 0·8 or lower. The corresponding coefficients for silverside, inside round, knuckle, rump and strip-loin were between 0·8 and 1·0 while the flank, shoulder, neck, chuck, plate, fore-rib and cube-roll had coefficients in the range 1·0 to 1·5.
The effect of beta-adrenergic agonists on carcass and meat quality in sheep
Authors: Warriss P. D. , Kestin S. C. , Brown S. N.
Published: September 2010

Twenty-four crossbred wethers (live weight 27·6 (s.e. 0·36) kg) were divided into three groups and given a concentrate diet. One group was a control, one was given cimaterol (10 mg/kg diet) and one was given clenbuterol (2 mg/kg diet). After 49 days on treatment the animals were fasted for 48 h and slaughtered at a live weight of about 36 kg. The effects of both beta-agonists were similar. Food conversion was proportionately 0·20 better in treated sheep which also produced heavier (18·3 v. 17·0 kg, P < 0·01) carcasses that were leaner. The cross-sectional area of the m. longissimus was increased proportionately by about 0·25 (P < 0·001) and the thickness of subcutaneous fat over the muscle reduced by 0·37 (P < 0·01). The loin joint from treated animals contained proportionately 0·30 more muscle (P < 0·001) and 016 (F > 0·01) less fat. Muscles from treated sheep had higher pHu values (P < 0·01) which resulted in reduced loss of exudate during storage (P < 0·01) and darker colour (P < 0·05). They also contained only about half as much intramuscular fat (13 v. 27 mg/g, P < 0·001) and less haem pigments (2·4 v. 3·9 mg/g, P < 0·001). The results indicate that beta-agonists substantially improve carcass quality but, under certain conditions of pre-slaughter handling, may reduce lean meat quality. The similarity of response to both beta-agonists suggests the observed effects on meat quality may be common to this class of drug.
The effect of pre-mating nutrition and exposure to the presence of rams on the onset of puberty in Awassi ewe lambs under semi-arid conditions
Authors: Kassem R. , Owen J. B. , Fadel I.
Published: September 2010

Two experiments are described investigating the possibility of advancing puberty in Awassi ewe lambs kept under semi-arid conditions in mid Syria using 197 single ewe lambs in 1982 and 165 in 1984. In both years, the animals were allocated to three groups each given different levels of supplementation with a barley/chopped straw mixture to achieve different levels of pre-mating growth (high, medium and low). In 1984, the three groups were further subdivided into four subgroups each given continuous exposure to teaser rams from different ages. These were 175, 200 and 230 days of age and a control group not given continuous access to the ram. The results for the two experiments showed that a higher proportion of ewe lambs on the high and medium treatments showed oestrus in their first season (H = 88%, M = 72%, L = 41%; P < 0·01). The high level of nutrition also advanced the mean date of first oestrus in the high group by 22 and the age at conception by 16·5 days as compared with the low level.

In the second experiment, no interaction between feeding level and presence of ram was observed and although there were no significant effects on occurrence of oestrus, continuous exposure to vasectomized rams from 175 days reduced mean age at first oestrus by 16 and age at conception by 19 days as compared with the unexposed controls.

It is concluded that these practices have important implications for the efficient use of semi-arid range land by Awassi sheep on a semi-intensive system.
Effect of diet and of remating interval on milk production and milk composition of the doe rabbit
Authors: Fraga M. J. , Lorente M. , Carabaño R. M. , de Blas J. C.
Published: September 2010

The influence of four diets and two remating intervals (1 or 9 days after parturition) on several milk and production traits was studied in 73 lactations of 46 Californian C? × New Zealand $ does. Three diets were formulated to provide increasing levels of fibre concentration (180, 202 and 238 g acid-detergent fibre per kg dry matter (DM)); a fourth diet contained added pork lard (35 g/kg) at the lowest level of fibre. The energy: protein ratio was maintained between 72 and 84 kj digestible energy (DE) per g digestible protein.

The DE intake increased significantly when fat was included in the diet but was not affected by dietary fibre concentration. An increase in the DE content of the diet tended to decrease food conversion ratio at a mean rate of 0·16 kg/kg per MJ/kg DE. Fat addition also improved milk yield, litter weight at 21 days and survival index, mainly when litter size was higher than nine pups born alive. Neither live-weight gain nor prolificacy of does were affected by any of the variables studied.

The type of diet did not affect milk DM, crude protein, fat and energy concentrations, the mean values being 287·8, 116·1, 134·2 g/kg and 27·73 MJ/kg, respectively. The proportions of short- and medium-chain fatty acids in milk fat were not affected by type of diet. The effect of fat addition on milk fat composition was limited to the long-chain fatty acids, mainly C18: 0 and C18: 1. These changes in addition to differences in milk intake could also affect the survival index of pups.

Does remated 1 day after parturition showed a lower total milk yield than those remated 8 days later, the decrease being more apparent at the end of lactation. Remating interval did not affect the other variables studied.
Effects of protein concentration in the diet on milk yield, change in body composition and the efficiency of utilization of body tissue for milk production in ewes
Authors: Cowan R. T. , Robinson J. J. , McHattie I. , Pennie K.
Published: September 2010

Twenty-five mature Finnish Landrace × Dorset Horn ewes, each suckling two lambs, were used to measure the effects of dietary concentration of crude protein on food intake, milk yield and changes in body composition during the first 6 weeks of lactation. Diets were complete mixes of milled hay and concentrates, and the amounts of barley and fish meal were altered to give crude protein concentrations of 116 and 143g/kg dry matter. Ten ewes were slaughtered at 5 to 7 days of lactation and the remaining ewes were slaughtered at 40 to 43 days of lactation.

The higher concentration of crude protein in the diet did not alter food intake or digestion. Milk yield was not altered in the first 3 weeks of lactation but was increased in weeks 4 and 5 (P<0·05). Production of milk protein was increased by a higher protein concentration in the diet (P<0·01) and this effect was evident from the 2nd week of lactation. Weight of chemically determined fat in the body decreased from 179 to 13-0kg from 6 to 42 days of lactation (P<0·001) for ewes on diets of both concentrations of crude protein.

It was concluded that the higher level of protein intake during early lactation increased yields of milk and milk protein. The data suggest that the energy lost from the body was used more efficiently by ewes given the diet of high, rather than low, protein content.
Response of Slovak Spotted cattle to stresses evoked by physical stimuli and the administration of pharmaceutical agents
Authors: Jedliĉka J. , Mojto J. , Vanĉiŝin J. , Kmetová E. , Páleník S.
Published: September 2010

Nine bulls of the Spotted Slovak breed were exposed to different stressful stimuli. The stimuli used were noise, electric shock and the administration of insulin, adrenocorticotrophic hormone and the sedative xylazine (Rompun). The levels of glucocorticoids, free fatty acids and glucose were determined in blood samples obtained through a permanent, indwelling, jugular cannula. It was found that insulin, adrenocorticotrophic hormone and electric shock evoked significant increases in the concentration of glucocorticoids in the blood. Noise did not affect the blood level of glucocorticoids. The stimuli did not induce any change in the blood levels of free fatty acids. Blood glucose levels were increased following insulin, adrenocorticotrophic hormone, electric shock and xylazine but not following noise. Insulin, as expected, decreased the concentration of glucose in the blood.
A note on the relationship between litter size at birth and litter weight at weaning in domesticated and feral mice
Authors: Congleton W. R.
Published: September 2010

The relationship between litter size at birth and litter weight at weaning is curvilinear, with an intermediate litter size resulting in the heaviest litter weight at weaning. Relative to feral mice, the mean and variation for litter size at birth was larger for domesticated mice which had been selected for fertility and crossbred. Consequently, some of the litters from the crossbred domesticated mice were larger than the litter size at birth which optimized litter weight at weaning, primarily due to increased pre-weaning mortality. If litter weight at weaning is to be optimized by indirect selection for litter size at birth, the variation around an intermediate optimum litter size at birth could be most effectively reduced by negative assortative mating.
The effect of different levels of management on the assessment of differences between varieties of chickens. 1. Eight-week body weight
Authors: Bowman J. C. , Powell J. C.
Published: September 2010

1. Analyses of records of eight-week body weight in broiler chickens have been carried out to estimate the effect of management level (measured by mean body weight of all varieties on each farm) on the components of variance due to differences between and within varieties, and to find out if there is any evidence of genotype-environment interaction.

2. It was found that as management improved, the between-variety genetic variance remained constant or possibly increased whilst the withinvariety (genetic and environmental) variance decreased markedly. The cause of these regressions is not known.

3. In four cases out of six there were significant genotype-environment interactions. In two cases, the genetic correlation between the performance of varieties on different locations was significantly different from 1·0.

4. It is suggested that on the basis of these findings it would be necessary to select between varieties on records taken from chickens maintained under conditions similar to those in which they will eventually be used. However, fewer chickens would be required to measure, with a predetermined level of accuracy, mean differences on well managed farms than on poorly managed ones.
Estimation of protein, chemical fat and energy content in pigs
Authors: Osińska Zofia
Published: September 2010

Complete chemical analyses of all body components of 20 Large White pigs were carried out. At the average live-weight of 90·3 kg. (empty body weight 86·5 kg.) the total protein content was found to be 12·7 kg. and that of the chemical fat 25·4 kg. The edible parts of the carcass (i.e. lean and separable fat) contained only 58·5% (range 55·2–61·3) of the total protein but as much as 85% of the total chemical fat. Simple and multiple correlations were computed between various carcass characters and protein, chemical fat and energy content. The results indicate that it may be possible to obtain fairly accurate estimates of the chemical composition and energy content of the edible parts of the carcass, of the whole carcass, and of the empty body by methods based on various systems of assessing the carcass quality.
The Fleece of Wiltshire × Wensleydale Sheep
Authors: Ryder M. L.
Published: September 2010

The coat of 16 Wiltshire × Wensleydale lambs was investigated and all were woolly, with no halo hairs on the back. The bulk of the coat consisted of curly-tip fibres, and most lambs had Valley (8) or Plain (6) fibre-type arrays, only two having Ravine arrays.

There was little difference in diameter between the primary and secondary fibres in the skin, and some evidence of ‘checking’ in the central primaries. The secondary/primary follicle ratio of 4·26 compared with a mid-parent value of 4·5. There was less latticed medullation in the crossbreds than in the Wiltshire.

The adult fleeces were visually similar to those of the Wensleydale and were intermediate in weight and staple length between the parent breeds. These findings could have practical application in the improvement of ‘hair’ sheep, in that a first cross with the Wensleydale would have a fleece of medium wool lacking hair or kemp.
The profile area of beef carcasses and its relationship to carcass composition
Authors: Fisher A. V.
Published: September 2010

The relationship was examined between the composition of carcasses from 30 castrated Hereford male cattle and their profile areas obtained from photographic negatives. The accuracy of this method n i determining fatness was compared with that of other methods including visual assessment.

Photographs were taken of a dorsal view of the intact carcass and lateral and medial views of the left side after splitting the carcass. A planimeter was used to measure the areas which were obtained from photographic negatives. Carcass lengths were recorded from the medial views. A panel of six judges assessed the sides for fatness on a seven-point scale with the aid of photographic standards.

Areas and carcass lengths, adjusted to dimensional parity, were used as independent variables in multiple regression analyses, with the weights of the dissected tissues as dependent variables. Explanation of variation in muscle weight was poor, but dorsal area and length were (very nearly) as good as visual score and side weight in predicting total fat weight.
Evolution of various adipose deposits in growing rabbits and sheep
Authors: Vezinhet A. , Prud'hon M.
Published: September 2010

The importance of the different adipose deposits with respect to the total dissectible fatty tissue in growing rabbits and lambs was studied. Development of the subcutaneous fat in the lamb is late and occurs after birth. In contrast, the internal types of fat, such as the perirenal and pelvic fat, represent at birth an important percentage of the total fat. They tend to lose part of their relative importance between 0 and 250 days after birth. In the rabbit the situation concerning the development of subcutaneous and perirenal fat is inverted. For both species the intermuscular fat remains almost constant in relative importance during the whole growth period.

After the period required for the establishment of the different fat deposits, we could observe in lambs, and to a smaller degree in rabbits, a relative growth which tends to become isometric with regard to the total fat deposits.
Differences in feed intake and the performance of Finn × Dorset ewes during late pregnancy
Authors: Shevah Y. , Black W. J. M. , Land R. B.
Published: September 2010

In two experiments carried out in the autumn of 1971 and 1972 (treatment prefixes 1 and 2 respectively), 84 Finn x Dorset ewes found by X-ray to carry from 1 to 4 foetuses were individually fed during the last 6 weeks of gestation either: 1A,ad libitum; 1H and 2H, 33 kcal M/kg ewe live weight+365 kcal per ME/kg foetus (anticipated birth weight); 1M, 80%; and 2L, 50% of the total energy fed to treatments 1H and 2H. The amounts given remained constant during the experimental period. The method of feeding according to foetal number within treatments, attempted to standardize the nutritional state within treatments.

All ewes (except those on 2L which remained constant) gained 6 to 8 kg live weight during the last 6 weeks of gestation and lost 8 to 10 kg at parturition. The birth weight of lambs was not affected by the range of energy (2·3 to 4·4 Meal ME/ewe per day) consumed during the last 6 weeks of gestation.

Plasma concentrations of free fatty acids (FFA), glucose and ketone bodies were determined weekly. The mean FFA levels were significantly higher in the low energy treatment groups than the high ones.

The present data indicated that if there is little change in body weight i n the early stages of pregnancy a 65 kg ewe bearing twin lambs, will require about 4 Meal ME/day during the last 50 days of gestation t o prevent a rise in plasma FFA concentration or loss of weight over the gestation period.
A note on the effect of twin births on production in the subsequent lactation
Authors: Wood P. D. P.
Published: September 2010

A study of the British Friesian Cattle Society's herdbook for 1961 showed that twin births were registered from 323 cows which had borne single calves the year before, and which had 2009 contemporaries of the same age calving single births in the same two seasons and in the same herds.

Least squares means of milk yield and fat percentage calculated from the truncated 305-day lactation showed that the twin mothers exceeded their contemporaries by 118±47 kg milk in lactations 2 days shorter. After correction for herd and year effects there was no difference between the twin birth lactation yield and the preceding single birth yield.

There was a reduction in fat percentage of 0±06% associated with the twin birth lactation.

The proportion of a sample of 194 twin mothers failing to calve again was 24±3% against 19±1% of the mothers of single calves, but no reasons for culling had been recorded.
A note on the prediction of silage intake by cattle
Authors: Richards I. R. , Wolton K. M.
Published: September 2010

In a series of feeding trials, measurements were made of silage drymatter (DM) content and pH, animal live weight and intake of DM other than silage. Silage intake has been related to these measurements by multiple regression. Subsequently, within the recorded ranges of the variables used, good predictions have been made of silage intake by large groups of cattle.
Observations on the effect of levamisole treatment on the production of dairy cows in England
Authors: Fox M. T. , Jacobs D. E.
Published: September 2010

A field study involving 1087 cows and 191 heifers on nine carefully selected English dairy farms was conducted to evaluate the effect of nematocidal treatment on subsequent milk production. As many of the cattle as possible were allocated to pairs according to specific criteria and dosed with either levamisole and oxyclozanide, or oxyclozanide alone, soon after calving. The remaining unpaired animals were assigned alternately to the two treatment groups according to calving date. The milk production and health status of all the cattle in the study were closely monitored.

Analysis of pooled milk production data over a 2-year period failed to show a statistically significant response to nematocidal treatment. When individual herd data were analysed, a significant response to treatment was recorded on one farm. It was noted that the apparent value of the response varied according to method of analysis.

Factors considered likely to account for differences in response between farms and also between trials are considered.
Estimates of genetic parameters for milk and fat yield for the first three lactations in British Friesian cows
Authors: Meyer Karin
Published: September 2010

A multivariate restricted maximum-likelihood procedure was used to estimate variance and covariance components between and within sires. This method, which considered all lactations simultaneously, accounted for the bias in later lactation records due to selection on dairy performance. Analysis was carried out for a mixed model with herd-year-seasons as fixed and sires as random effects, and fitting lactation length, calving age and month within season of calving as covariables. The data included 26 176 first, 19 978 second and 14 868 third lactation records for 679 test sires, and were analysed in 13 subsets. Additional records for proven sires, treated as fixed effects, were included to improve the data structure.

Estimates for all components were higher in later than in earlier data sets, probably, to a large extent, because of a scale effect. Pooled estimates of heritabilities for lactations 1 to 3 were 0·28, 0·19 and 0·24 for milk yield, and 0·27, 0·21 and 0·25 for fat yield. Genetic correlations of 0·91, 0·91 and 0·95 for milk yield, and 0·91, 0·91 and 0·99 for fat yield, were found between lactations 1 and 2, 1 and 3, and 2 and 3, respectively. Results suggest that dairy performance in all lactations is almost identical genetically.
Plasma metabolite and hormone concentrations in Friesian cows of differing genetic merit measured at two feeding levels
Authors: Flux D. S. , Mackenzie D. D. S. , Wilson G. F.
Published: September 2010

Physiological differences between cows in hormone and metabolite concentrations were sought that may account for genetic differences in milk production.

Two groups of New Zealand Friesian cows, differing in genetic merit for fat production (high breeding index (HBI) and low breeding index (LBI)) by approximately 23 breeding index units (20 kg fat on the United Kingdom improved contemporary comparison scale), were each divided into two further groups, one of which was given freshly cut pasture to appetite and in the other intake was restricted to 70% of appetite. Eighteen blood samples were collected over a 24-h period from each of 16 cows fitted with indwelling jugular catheters. Samples were analysed for growth hormone, insulin, free fatty acids and β-hydroxybutyrate. Mean concentration of insulin was significantly higher in the HBI underfed group than in any other group (P< 0·01). Glucose concentration was significantly lower in the LBI group (P< 0·05), whose intake was restricted. The concentration of (3-hydroxybutyrate was significantly higher in the cows whose intake was restricted (P< 0·01) and the concentration fell markedly after feeding. Growth hormone concentrations were higher in the cows on restricted intake (P< 0·05) and in HBI cows but the differences were not statistically significant.

It was concluded that different patterns of blood metabolites and hormones are associated with cows that differ in genetic merit. Aspects of insulin and glucose metabolism, particularly at low planes of feeding, appear to offer most promise as indicators of high milk-solids production.
The estimation of killing out in cattle from knowledge of breed, and visual appraisal of external fat cover and conformation
Authors: Bailey P. J. , Cook G. L. , Kempster A. J. , Sains A. G.
Published: September 2010

Data for a total of 3715 cattle from four sources were used to examine the relative importance of live weight at slaughter, and visual assessments of carcass conformation and subcutaneous fat cover, as predictors of killing out. The sources were the Meat and Livestock Commission's beef breed evaluation programme (1689 steers of different breeds and crosses), the beef demonstration unit at the National Agricultural Centre, Stoneleigh (814 commercial dairy-bred cattle), an East Anglian abattoir (405 commercial cattle) and the Milk Marketing Board's Warren Farm (807 dairy-bred steers by different sire breeds). An assessment of live body conformation was also examined as a predictor in the Warren Farm data.

Carcass conformation provided a more precise prediction of killing out than did either live weight or subcutaneous fat score. Regression coefficients in the different groups ranged from 5·4 to 12·0 g/kg for each increase in conformation class (six-point scale). The live conformation assessment was a less precise predictor (within sire breed residual s.d. = 17·7 g/kg) than the carcass assessment (15·6 g/kg).
Methods of analysing the effect of season of birth on weaning weight in a zebu × temperate beef herd in Kenya
Authors: Carles A. B. , Riley Janet
Published: September 2010

A study was made of weaning weights in a beef herd, using a rotational crossbreeding system including the Boran breed (zebu) and two temperate beef breeds (Devon and Limousin), and a seasonal calving period spanning the onset of the rains.

Significant sources of variation in calf weaning weights were crossbred type, age at weaning, sex, dam's age, season of birth, year and a year × crossbred type interaction (all P < 0·001).

The adjusted mean weaning weight was 203 kg. Weaners sired by a temperate bull were generally 1·08 times the weight of those sired by a zebu bull. Steers were 1·06 times the weight of heifers. Marked increases in weaning weights occurred as dams increased in age from 3 to 6 years and slight increases continued up to 9 years of age. Weaners born to 9-year-old cows were 1·09 times the weight of those from first calvers.

Alternative methods for investigating the effect of season of birth were examined and the final choice was a covariate for time from birth to the onset of the rains. Calves born in the earliest part of the calving period were approximately 1·14 times the weight of those born just after the onset of the rains.
The heritabilities and genetic correlations among eight blood constituents, and their relationship to aspects of performance and genetic polymorphisms, in the sheep
Authors: Woolliams J. A. , Wiener G. , Field A. C.
Published: September 2010

Blood samples were taken from Scottish Blackface ewes of five lines (selected for long and short cannon bones, for hairy and fine fleeces, and an unselected control line) at ages ranging from 9 to 69 months. The samples were analysed for the concentrations of copper, glucose, calcium, magnesium, phosphorus, total protein, albumin and globulin in plasma.

The components of variance and covariance between sires and within sires were estimated and heritabilities were calculated for the eight blood constituents and live weight. The heritabilities ranged from 0·20 (s.e. 0·08) for the concentration of copper to 0·43 (s.e. 0·10) for total protein. Only one of the 34 genetic correlations was significantly different from zero, this being between the concentrations of calcium and phosphorus.

Ewes that had had a single lamb 9 months earlier had lower concentrations of copper, calcium, albumin (P < 0·001) and glucose (P < 0·01) than ewes that had not lambed. Concentrations of glucose (P < 0·05) and total protein (P < 0·001) were also decreased according to the number of lambs born to the ewe 3 months later.

Ewes with low red cell potassium concentrations had higher concentration of glucose in plasma than ewes with high red cell potassium concentrations (P < 0·05). Haemoglobin type affected the concentrations of copper (P < 0·01) and total protein (P < 0·05), with ewes of type B having higher and lower concentrations respectively. The constituents measured were not significantly affected by transferrin type.
The effect of daylength on the growth of lambs. 5. Skeletal long photoperiod
Authors: Brinklow B. R. , Jones R. , Forbes J. M.
Published: September 2010

Four experiments were carried out, with a total of 98 Suffolk-cross lambs fed at a restricted level, to study the effects of skeletal long photoperiod (7 h light: 10 h dark: 1 h light: 6 h dark) compared with short photoperiod (8 h light: 16 h dark) on growth and blood levels of hormones. The experiments started when the lambs were from 2 to 10 months of age and continued for 9 to 14 weeks.

In the first experiment, the weight gains of both females and castrated males were significantly increased by skeletal long photoperiod. Plasma prolactin was increased and cortisol decreased by skeletal long photoperiod.

Experiment 2 included females and castrated males; prolactin was stimulated by skeletal long photoperiod and there was a significant positive correlation between live-weight gain and prolactin.

The weight gains and carcass characteristics of the female lambs used in the third experiment were not affected by photoperiod. Live-weight gain was negatively related to plasma cortisol.

In experiment 4, there were 12 intact males and 12 castrated males. The intact animals grew significantly faster; skeletal long photoperiod caused a depression in testosterone levels in plasma even though it tended to increase live-weight gain.

When the data from all four experiments were pooled, it was found that skeletal long photoperiod gave a significant increase in live-weight gain in animals whose pineal gland was intact (40 per photoperiod; 138 v. 113 g/day); there was no effect on gut fill at slaughter and the increase in carcass weight (0·5 kg) was not significant.
The effect of age on halothane susceptibility in pigs
Authors: Carden A. E. , Webb A. J.
Published: September 2010

The effect of age on incidence of susceptibility to halothane anaesthesia in pigs was studied on animals that were repeatedly exposed to the anaesthetic. In three trials, 232 Piétrain/Hampshire and 201 Landrace pigs were given three 3-min halothane tests, at 19, 35 and 54 days of age. In a fourth trial 253 Landrace pigs received four 5-min tests, at 21, 35, 49 and 63 days. All pigs were offspring of positive × positive matings. Maximum-likelihood estimates of the probability of positive reactions were 0·47, 0·73 and 0·88 at the three ages in Pietrain/Hampshire; 0·20, 0·63 and 0·60 in the first Landrance trial; and 0·64, 0·86, 0·84 and 0·90 in the second Landrace trial. Thus, in all trials, the incidence of halothane positive reactions increased with age. In both breeds and at all ages, the incidence was lower in males than in females.
A note on energy requirements for maintenance of lean and fat Angus, Hereford and Simmental cows
Authors: Ferrell C. L. , Jenkins T. G.
Published: September 2010

Mature Angus (A), Hereford (H) and Simmental (S) cows (16 each) that had been randomly assigned and fed a maize silage-based diet at different levels of intake during lactation were selected.

Lean and fat A, H and S cows were fed the maize silage-based diet individually to provide metabolizable energy (ME) intakes of 542, 506; 476, 437; and 624, 597 kj/kg0.75 per day respectively for 84 days. Daily weight gains of lean cows were greater than those of fat cows (0·40 v. 0·11 kg/day) even though daily ME intakes were less (55·2 v. 62·4 MJ/day). Theoretical estimates of ME requirements for maintenance were less for lean than for fat cows, and maintenance of A and H cows tended to be less than those of S cows.

These results suggest that cow maintenance requirements increased in association with fatness that resulted from the previously imposed nutritional regimes and tended to differ among cow breeds.
Heat loss from groups of growing pigs under various conditions of environmental temperature and air movement
Authors: Holmes C. W. , Mount L. E.
Published: September 2010

Continuous measurements of heat loss throughout the 24 hours have been made on groups of pigs living in a large direct calorimeter equipped as a pig pen. Five experiments, each lasting 24 days, were carried out on groups of six pigs each weighing about 20 kg, and these were repeated when body weight was 60 kg on groups of three pigs, chosen from the original six in each case. Each group was exposed initially to an environmental temperature of 20°C for 10 days, followed by either 9°C (two groups at each weight), 30°C (two groups at each weight), or a continuation of 20°C (one group at each weight). In another experiment lasting 66 days a group of four pigs was exposed to 12 and 20°C at two levels of air movement.

Heat loss from the groups showed a marked 24-hr cycle, with a maximum n i the afternoon and a minimum in the early morning. The mean amplitude of the cycle at 20°C was 20% of the mean value; this proportion increased at 9 and 12°C.

Heat loss was approximately proportional to (body weight)1·0 over the weight range 17·34 kg, and to (body weight)0·8 over the weight range 35·54 kg, when food intake increased in proportion to (body weight)1·0. Over the weight range 55·67 kg, when food intake was constant at 1·83 kg/day per pig, heat loss was proportional to (body weight)0·4. In both 20 and 60-kg pigs, heat losses showed little difference between 20 and 30°C, but were increased at 9°C.

Evaporative loss from the pen, as a proportion of total heat loss, was approximately 21% at 9°C, 29% at 20°C, and 61% at 30°C. Voluntary water intake exhibited a marked 24-hr cycle similar in timing to the heat loss cycle.

There was no lasting effect on heat loss associated with raising the mean air movement rate in the pen from 10 to 26 cm/sec.
The effect of source and level of dietary protein on the performance of in-lamb ewes
Authors: Forbes T. J. , Robinson J. J.
Published: September 2010

The aim of the investigation was to evaluate the specific effect, if any, of grass protein on the birth weight of lambs born to ewes wintered indoors. Grass meal was used as a substitute for fresh grass, and soya bean meal—representing a more conventional source of protein for winter diets—was compared with it. Both sources of protein were included at two levels, providing a high (90 g or 0·2 lb/day) and a low (45 g or 0·1 lb/day) intake of digestible crude protein.

The digestibility of dry matter was significantly higher for the diets containing soya bean meal (67·7%) than for those containing grass meal (58·2%). Dry-matter digestibility was not affected by level of protein intake. The digestibility of crude protein was significantly affected by protein source and level of intake.

Lamb birth weights were not significantly affected by source or level of dietary protein. There was a tendency for birth weights to be higher on the diet containing grass meal at low protein intakes. Ewe weight gains during the last eight weeks of gestation were significantly affected by level of dietary protein, and net body weight change was significantly affected by both source and level of protein. Gestation treatments had no effect on the performance of ewes or lambs during the first three weeks of lactation.

The retention of nitrogen during the 18th–20th weeks of gestation was affected by both source and level of dietary protein. Mean nitrogen retention was higher with diets containing soya bean meal (5·8 g per day) than with diets containing grass meal (3·6 g per day). There was no correlation between nitrogen retention and lamb birth weight.
The influence of castration on the growth of male pigs in relation to high levels of dietary protein
Authors: Prescott J. H. D. , Lamming G. E.
Published: September 2010

1. A factorial split-plot experiment was conducted to investigate the growth of entire and castrate male pigs on conventional diets and diets containing higher levels of protein. Thirty-two Large White pigs were fed ad libitum from 50 lb to slaughter at 260 lb live weight. The carcasses were dissected.

2. The live-weight gain of entire males was the same as that of castrates on the conventional diet, but they grew non-significantly faster than castrates on the higher protein diet.

3. The entire males had a lower dressing percentage and less fat in the carcass than the castrates, but more lean, bone and rind, and a similar lean: bone ratio. The leanness of the entire males was increased on the higher level of dietary protein whereas the leanness of the castrates was unaffected except in the leg. The interactions were not significant.

4. The carcasses of the entire males were proportionately heavier in the head and shoulders and lighter in the middle than those of the castrates.

5. The majority of the entire males had flesh with a slightly tainted flavour.
Influence of manure gases on the onset of puberty of replacement gilts
Authors: Malayer J. R. , Brandt K. E. , Green M. L. , Kelly D. T. , Sutton A. L. , Diekman M. A.
Published: September 2010

To determine whether gases generated during the breakdown of accumulated manure in an environmentally regulated building affects the onset of puberty in gilts, 42 crossbred gilts, born from 1 o t 15 September 1985, were reared indoors from 10 to 30 weeks of age on concrete slats over a pit that was drained and refilled with clean water biweekly (clean group). Forty-two gilts were reared over a pit where manure was allowed to accumulate (control group). These two groups had similar feeding, water, floor space, lighting and room temperature. A third group of 42 crossbred gilts was reared from 10 to 30 weeks of age in an open-front building with a concrete apron (outdoor group). Concentration of aerial ammonia in the control environment was three- to five-fold higher than in either the clean or the outdoor environment (P < 0·001). Average daily gain and food conversion efficiency were similar for the two indoor treatment groups, but the outdoor group gained less weight than either indoor group (P < 0·05). At 26 weeks of age all gilts were exposed to mature boars daily for 2 weeks, then every 2nd day for an additional 2 weeks. A greater proportion of gilts in the clean environment attained puberty 7 days (P < 0·05) and 10 days (P < 0·07) after first exposure to boars. These data suggest that odorous gases, such as ammonia, in the air of environmentally regulated buildings may diminish the stimulatory influence of boars on the onset of puberty in gilts.
A note on the effects of previous photoperiod exposure and gradual transitions of light intensity at dawn and dusk on growth in Holstein heifers
Authors: Zinn S. A. , Chapin L. T. , Tucker H. A.
Published: September 2010

Long-day photoperiods of 16 h light (L) and 8 h dark (D) stimulate a proportional increase in live-weight (LW) gain of peripubertal Holstein heifers of 0·08 to 0·17 compared with heifers exposed to short days of less than 12 h L per day (Peters, Chapin, Leining and Tucker, 1978; Peters, Chapin, Emery and Tucker, 1980; Petitclerc, Chapin, Emery and Tucker, 1983; Zinn, Chapin and Tucker, 1986). One factor that could account for some of this variation in the magnitude of the growth response to long days is that the previous photoperiod exposure may influence the response to a subsequent different photoperiod (Moore-Ede, Sulzman and Fuller, 1982). For example, exposure to 13L: 11D induced pulsatile activity of serum luteinizing hormone (LH) in ewes previously exposed to 16L: 8D, but reduced serum LH to undetectable levels in sheep previously exposed to 8L: 16D (Robinson and Karsch, 1987). Thus, sheep exposed to identical photoperiods exhibited different responses depending on previous photoperiod exposure.
Dynamic and static selection policies when generations overlap
Authors: Hopkins I. R.
Published: September 2010

Where genetic differences between age groups change during a selection programme, proportional contributions of each age group to replacements should also change in order to maximize genetic responses to selection. Sums of discounted returns were estimated for such a ‘dynamic’ selection policy and these were compared with those from ‘static’ selection policies in which genetic contributions of different age groups remained unchanged. Four selection methods, two sets of genetic differences between age groups at the outset, three age structures and two discount rates were used.

The results showed that the superiority of the dynamic policy was greatest where genetic differences at the outset differed most markedly from their steady-state values, where discount rates are high and where there are large numbers of age groups and the selection method allows culling in all age groups. Under most conditions initial genetic differences are probably the most important factor. The proportional advantage in sums of discounted returns is variable and generally small within the framework of this study ranging from zero to roughly 8% unless breeding objectives before and during the programme were negatively correlated. In the latter case the proportional superiority of the dynamic policy was much greater.
Growth, food intake and cold exposure in mice. 1. Cold exposure of adolescent mice
Authors: Bateman N. , Slee J.
Published: September 2010

1. Adolescent mice were exposed from 33 to 84 days of age to a warm (30°C) or to one of four cold (15°C, 10°C, 5°C or 1°C) environments. Before and after exposure the mice were kept at a normal mouseroom temperature of 23°C. Controls remained at this temperature throughout. Voluntary food intake, live weight and growth efficiency were individually monitored before, during and after exposure, i.e. from 19 to 112 days of age.

2. Food intake during exposure was linearly related to temperature, ranging from 4 g/day at 30°C to 14 g/day at 1 °C. Intakes differed only slightly between males and females. Food intake at 10°C was 70% above controls. Oxygen consumption in adults at 10°C was 74% above controls.

3. Male growth was unaffected by temperature. Superiority over females (56% at 30°C) diminished at lower temperatures (12% at 1 °C) because females grew 41% faster at 1 °C than at 30°C. Females whose growth was depressed at 30°C, showed compensatory growth on returning to 23°C.

4. Growth efficiency was strongly, but not entirely linearly, related to temperature, and increased approximately three-fold between 1°C and 30°C. Efficiency was maximal at 30°C in males and at 23 °C in females. Males grew 76% more efficiently than females at 30°C and only 12% more efficiently at 1°C.

5. Increased food intake in the cold satisfied energy requirements and allowed females to grow faster.

6. Individual differences in appetite persisted throughout life, but rankings in growth and efficiency changed with age. Food intake was strongly correlated with growth rate in weanlings, but growth rate was always the main determinant of growth efficiency.

7. The variance of adolescent growth rate was unaffected by the treatments.
Circularly polarized modes in magnetized spin plasmas
Authors: MISRA A. P. , BRODIN G. , MARKLUND M. , SHUKLA P. K.
Published: September 2010

The influence of the intrinsic spin of electrons on the propagation of circularly polarized waves in a magnetized plasma is considered. New eigenmodes are identified, one of which propagates below the electron cyclotron frequency, one above the spin-precession frequency, and another close to the spin-precession frequency. The latter corresponds to the spin modes in ferromagnets under certain conditions. In the non-relativistic motion of electrons, the spin effects become noticeable even when the external magnetic field B0 is below the quantum critical magnetic field strength, i.e. B0 < BQ = 4.4138 × 109T and the electron density satisfies n0 ≫ nc ≃ 1032m−3. The importance of electron spin (paramagnetic) resonance (ESR) for plasma diagnostics is discussed.
Five-year outcome of cognitive behavioral therapy and exposure with response prevention for bulimia nervosa
Authors: McIntosh V. V. W. , Carter F. A. , Bulik C. M. , Frampton C. M. A. , Joyce P. R.
Published: September 2010

Background

Few data exist examining the longer-term outcome of bulimia nervosa (BN) following treatment with cognitive behavioral therapy (CBT) and exposure with response prevention (ERP).

Method

One hundred and thirty-five women with purging BN received eight sessions of individual CBT and were then randomly assigned to either relaxation training (RELAX) or one of two ERP treatments, pre-binge (B-ERP) or pre-purge cues (P-ERP). Participants were assessed yearly following treatment and follow-up data were recorded.

Results

Eighty-one per cent of the total sample attended long-term follow-up. At 5 years, abstinence rates from binging were significantly higher for the two exposure treatments (43% and 54%) than for relaxation (27%), with no difference between the two forms of exposure. Over 5 years, the frequency of purging was lower for the exposure treatments than for relaxation training. Rates of recovery varied according to definition of recovery. Recovery continued to increase to 5 years. At 5 years, 83% no longer met DSM-III-R criteria for BN, 65% received no eating disorder diagnosis, but only 36% had been abstinent from bulimic behaviors for the past year.

Conclusions

This study provides possible evidence of a conditioned inoculation from exposure treatment compared with relaxation training in long-term abstinence from binge eating at 5 years, and the frequency of purging over 5 years, but not for other features of BN. Differences among the groups were not found prior to 5 years. CBT is effective for BN, yet a substantial group remains unwell in the long term. Definition of recovery impacts markedly on recovery rates.
The interest group analogy: international non-governmental advocacy organisations in international politics
Authors: BLOODGOOD ELIZABETH A.
Published: September 2010

What can models of interest group behaviour from American politics tell us about the existence, activities, and influence of international non-governmental advocacy organisations (advocacy INGOs) in International Relations? In this article I detail an analogy between traditional American interest groups and advocacy INGOs in order to suggest a new approach to theorising INGOs. American politics theories of interest groups provide insights to questions which International Relations has been unable to answer satisfactorily, including where INGOs are likely to be found; how INGOs will grow in the future; the organisational structure of INGOs; the impact of competing groups on the quality and content of foreign policy and international agreements; and the roles of INGOs in different stages of the policy process. Viewing INGOs as interest groups provides a curative to the tendency to view them as self-sacrificing knights in shining armour. Competing INGOs representing narrow interests can nevertheless contribute to the common good in the form of effective, efficient policy.