bluuebunny/crossref_metadata_2025 huggingface dataset:
Multibreed designs. 1. Variation between breeds
Authors: Taylor C. S.
Published: September 2010

When testing facilities are limited and the number of breeds and/or crosses to be tested is potentially large, then multibreed designs which involve a large number of breeds with only a few animals per breed give the optimum allocation of animals within and between breeds for various objectives. Multibreed designs could therefore form a useful adjunct to existing breed testing and selection programmes. How far such designs should be introduced would depend, among other things, on the degree of confidence in existing information, on the success of existing testing schemes, and on the relevance of the selection criteria currently being used. In this, the first of a series of papers on multibreed designs, the general approach is outlined, and designs for measuring between-breed variation are considered.

To estimate the extent of between-breed variation, the best overall design is to have four unrelated animals per breed and as large a number of breeds as possible. Valuable experimental work on breed variation can therefore be done without vast facilities.
Phenotypic and genetic parameters of productivity in Galway ewes
Authors: O'Ferrall G. J. More
Published: September 2010

Records from a selection flock of Galway ewes collected over a 6-yr period (1966 to 1971) were used to obtain estimates of the phenotypic and genetic parameters of ewe productivity. The number of lambs born (NLB) and weaned (NLW), the weight of lamb weaned (WLW), ewe body weight (EBW) and greasy fleece weight (GFL) were used as measures of productivity, mean values being 1·25, 0·88, 25·6 kg, 52·8 kg and 2·8 kg, respectively. Each ewe's annual performance was adjusted to a 4-yr-old ewe equivalent and expressed as a deviation from the appropriate flock × year subgroup mean; these deviations were combined into a single index value for each ewe for NLB, NLW and WLW. Records for 975 individual ewes representing 84 sires which had three or more progeny were used in a half sib analysis of variance.

Estimates of heritability were 0·18, 0·24 and 0·25 for NLB, NLW and WLW based on index record and 0·07, 0·16 and 0·30 respectively for 2-yr-old ewes. Heritability estimates of EBW and GFL were 0·73 and 0·52 respectively. The genetic correlations between EBW and NLB2, NLW2, WLW2 and GFL were 0·85, 0·42, 0·62 and 0·53 respectively; those between EBW and index records were slightly negative. Phenotypic correlations were generally lower than the corresponding genetic ones.

Ewes born as multiples were more productive than singles. They were 1·8 kg lighter (P < 0·01) at 18 mo and weaned 2·5 kg more lamb (P < 0·05) at 2 yr of age. The repeatability of NLB ranged from 0 to 0·2.
Comparative retail value of beef carcasses from different groups of animals
Authors: Harries J. M. , Williams D. R. , Pomeroy R. W.
Published: September 2010

A technique for evaluating beef carcasses in terms of their retail value, has been applied to 132 half-carcasses from seven groups of cattle (Jersey, Hereford, Polled Hereford, Lincoln Red, Devon, South Devon and Charolais × Jersey) to test the general applicability of the method, in particular the regression equations for predicting retail value. Significant differences in retail value were found between the groups of animals, South Devon and Charolais × Jersey having a high retail value per kg side weight, and Jerseys a low one. There was a very high correlation between retail value per kg side weight and the proportion of muscle in the side. Relationships between retail value and proportion of fat in the side were also investigated. It is not possible to decide, from these data, whether the differences found in retail value are a true breed effect, or whether they are due solely to differences in composition.
A note on the use of a feed flavour to stimulate the feed intake of weaner pigs
Authors: Campbell R. G.
Published: September 2010

An experiment was conducted to study the post-weaning response of young pigs to a flavouring substance (Firanor No. 3) designed to be incorporated into the sow's milk if added to her diet during lactation. During the first 3 weeks after weaning the average feed intake and growth rate of all pigs were 0·755 kg/day and 0·385 kg/day respectively. The average feed intake and growth rate of pigs weaned from sows given a flavoured diet during lactation and subsequently offered a flavoured weaner diet were 0·818 kg/day and 0·450 kg/day respectively, each significantly greater than the corresponding results for pigs which had no previous experience of the flavouring or which had access to flavoured feed in only one period.
Use of an improved technique to analyse repeated measurements of live weight from an experiment involving sequential weaning treatments
Authors: Shanmugalingam V. S. , Gibb M. J. , Treacher T. T.
Published: September 2010

A new technique was used to analyse data from an experiment involving sequential measurements on the same experimental units. Results may be inconclusive if analysed in several univariate analyses of variance, one for each occasion, because the successive measurements contain the cumulative effect of treatments.

An experiment was carried out in which two pre-weaning herbage allowances and four ages of weaning were applied to 80 lambs and their live weights recorded twice-weekly until 25 weeks of age. The direct and residual treatment contrasts were evaluated over time using a response surface equation. The continuous variation of treatment effects over time was demonstrated simply by plotting the treatment contrasts and fitting the most appropriate equations to them. Treatment effects were tested by analyses of orthogonal regression coefficients over time, evaluated within each sex of each treatment group by multivariate analysis of variance.

Fitted equations of treatment contrasts were used to demonstrate the continuous variation of effects of pre-weaning herbage allowance on live weights of unweaned lambs, the residual effect of pre-weaning allowance on the weights of weaned lambs, and, separately, the effects of weaning and weaning age on live weights of the lambs.

All the live-weight data recorded in the experiment were used in the analyses. The assumptions made for the application of the method were satisfied and the results were much more informative than those of several univariate analyses of variance.
The effects of lactation, pregnancy and calendar month on milk records
Authors: Bar-Anan R. , Genizi A.
Published: September 2010

The effects of the lactation, pregnancy and calendar month on monthly milk records of 1st and 3rd lactation Israeli-Friesian dairy cows were studied. The analyses involved 717 966 monthly records in 76 788 lactations of cows diagnosed as pregnant in herds providing 20 or above lactations per herd per year and lactation number. The records were grouped into 18 lactation classes according to yield post partum: high, medium and low cows within high, medium and low herds, separately for 1st and 3rd lactations.

The objects of the investigation were to estimate factors for relating persistency to peak yield, and to examine how interactions between peak yield and persistency should be taken account of in post partum breeding policies.

The major factor affecting yield was the number of months post partum; heifers dropped in yield by 0·173 from the 1st to the 10th month of lactation and cows by 0·46. The herd level affected the shape of the lactation curve. In high-yielding herds peak yields were achieved later than in low-yielding herds, but the rates of yield decline from the 2nd to the 10th month were similar in high- and low-yielding herds. Within herds, there were large differences in the rate of decline between cows with high and low peak yields. The monthly decline within herds from the 2nd to the 10th lactation month for animals of high and low peak yield were –0·0347 and –0·0217 for heifers and –0-0633 and –0·0520 for cows.

Effects of pregnancy on milk yields were observed from the 1st month post conception, but the effects were small. The effects of 7 months of pregnancy on test-day yields were 3 to 4 kg milk, independent of the yield level of the cow. It was suggested that the effect of herd level could be disregarded but that account should be taken oflactation number and the yield level of the cow within her herd. Heifers and cows in high-yielding herds may be mated later than cows in low-yielding herds. Since pregnancy had a similar effect on high- and low-producing cows, and within herds the higher yielding cows were less persistent in yields than the remainder, it might be a reasonable management policy to breed most of the cows in a herd of a particular lactation at approximately the same time post partum.
A comparison of ‘on-farm’ and station testing in pigs
Authors: Roberts D. J. , Curran M. K.
Published: September 2010

Data were extracted from Meat and Livestock Commission records from 44 herds with 392 progeny-tested sires in both farm and station environments. The farm data contained 4182 and 17 251 male and female progeny respectively, and the station data 2982 and 1490 male and female progeny respectively. Both sets of data were adjusted separately for the effects of month of test within sex. The farm data were also corrected to a constant end-of-test-weight corresponding to that at the station. Comparisons were made between both different and the same sexes in the two environments. Phenotypic correlations between a simple index measure in both environments ranged from +0·20 (farm females:station males) to +0·30 (farm females:station females). Genetic correlations between similar traits ranged from –018 (weight/age, farm males:station females) to +081 (simple index, farm males:station females). The correlations between female farm progeny and station male progeny were generally lower than for any other comparisons.
Methionine requirements of weanling European pigs given cassava flour/soya bean meal diets
Authors: Balogun O. O. , Fetuga B. L. A.
Published: September 2010

Forty-eight Large White × Landrace weanling pigs weighing initially 9·69 (s.e. 013) kg were used to evaluate the dietary methionine requirements of weanling European pigs reared under a humid, lowland, tropical environment. Response criteria used were growth rate, efficiency of food conversion, carcass quality, and the weights of some organs and individual muscles. The pigs (three male castrates and three females per treatment) were given a cassava flour-soya bean meal diet containing 202 g crude protein per kg dry matter and supplemented with increments of multiples of 0·8 g DL-methionine per kg diet. Total dietary methionine levels ranged from 2·3 to 7·9 g per kg diet dry matter. All diets contained 14·75 MJ digestible energy per kg dry matter. The experiment lasted 42 days, at the end of which the pigs were slaughtered at an average live weight of 17 kg.

Growth rate and feed efficiency were significantly improved when the basal diet was supplemented with DL-methionine (P< 0·001). No significant treatment differences in organ weight were found. Methionine requirement was significantly influenced by sex and age of the pigs, with castrates having lower requirements than females. Pooled estimated methionine requirements for optimum growth rate and efficiency of food conversion were 4·0 and 4·3 g/kg diet dry matter respectively. Maximum proportion of lean was recorded on the diet containing 3·1 g total methionine per kg dry matter.
The value of shape as a predictor of carcass composition in pigs from different breeding companies
Authors: Kempster A. J. , Evans D. G.
Published: September 2010

Carcass data for a total of 1385 pigs from years 3 to 6 of the Meat and Livestock Commission's Commercial Pig Evaluation were used to examine the value of different shape assessments as predictors of carcass composition, when used in addition to carcass weight and fat thickness over the m. longissimus at the head of the last rib (P2). The sample comprised pigs from 13 breeding companies and a purebred Large White control.

The standard deviation of carcass lean proportion at equal weight and P2 was 24·5 g/kg. The addition of carcass length or visual conformation assessments (five-point scales) provided a small improvement in precision (minimum residual standard deviation = 24·2 g/kg). This improvement was associated with a reduction in the variation of lean to bone ratio.

The addition of an effect for breeding company to weight and P2 improved the precision substantially (residual standard deviation = 23·1 g/kg). The improvement was due mainly to the identification of differences in carcass fat content, there being a range of 30g/kg in carcass fat content between companies at equal weight and P2.

There was a further small improvement in precision from the addition of conformation assessments to weight, P2 and company (minimum residual standard deviation = 22·9 g/kg).

The study confirms earlier results which indicate that shape assessments are of limited value as predictors in the British pig population, due mainly to limited variation in lean to bone ratio. It also indicates that significant variation exists between companies in fat content at equal P2 and weight which is not explained by shape assessments.
An evaluation of the Hennessy and Chong Fat Depth Indicator, and the Ulster Probe, for use in pig carcass classification and grading
Authors: Kempster A. J. , Chadwick J. P. , Jones D. W. , Cuthbertson A.
Published: September 2010

The Hennessy and Chong Fat Depth Indicator and the Ulster Probe automatic recording instruments developed for measuring fat thickness were tested against the optical probe for use in pig carcass classification and grading.

Fat thickness measurements were taken using each probe 60 mm from the dorsal mid-line over the m. longissimus at the positions of the 3rd/4th lumbar vertebrae, 3rd/4th last ribs and last rib on a total of 110 hot carcasses covering the range of market weights in Great Britain. The standard deviation of carcass lean proportion at equal carcass weight was 35·4 g/kg.

The instruments differed little in the precision of carcass lean proportion prediction: residual standard deviation (g/kg) for the multiple regression with carcass weight and the best individual fat measurement for each probe were: last rib optical probe, 22·1; last rib Ulster Probe, 22·7; and 3rd/4th last rib Fat Depth Indicator, 21/6. Residual standard deviation (g/kg) for carcass lean proportion prediction from carcass weight and all three fat measurements in multiple regression were 21·3 optical probe, 21·3 Ulster Probe and 201 Fat Depth Indicator.

Similar mean fat measurements were obtained from the optical probe and Fat Depth Indicator, and for these instruments, but to a lesser extent for the Ulster Probe, the regression relationships with each other and with fat thickness measurements taken on the cut surface of the cold carcass were also similar.

The differences recorded in precision are unlikely to be sufficiently important to influence the choice of one probe rather than another.
The effect of ammonia treatment on the intake of straw and hay when offered with rations of concentrates to ewes in late pregnancy
Authors: Orr R. J. , Treacher T. T. , Mason V. C.
Published: September 2010

Finnish Landrace × Dorset Horn ewes were offered 300, 600 or 900 g fresh weight per day of concentrates and forage ad libitum from day 105 of pregnancy until lambing. Spring barley straw (S) or hay (H) was offered either untreated (U) or following treatment with anhydrous ammonia in an oven (T). Organic matter digestibilities (in vitro) were 0·42, 0·58, 0·42 and 0·60 and nitrogen contents were 7·2, 18·6, 12·0 and 25·0 g/kg dry matter for US, TS, UH and TH respectively. Forage intake did not differ between ewes carrying two or more foetuses but the small number of ewes carrying one foetus ate more straw (6·8 v. 4·5 g organic matter (OM) per kg live weight) than ewes carrying two or more foetuses. Ammonia treatment increased intake; the increase was larger on straw (4·6 v. 100 g OM per kg live weight) than on hay (9·0 v. 10·7 g OM per kg live weight). Replacement rates of forage by concentrates were -0·21, +0·06, -0·48 and +0·08 kg forage per kg concentrates for treatments US, TS, UH and TH respectively; only the value for treatment UH differed significantly from zero. On most treatments forage intake decreased as pregnancy progressed and the declines were greater when treated forages were offered. Concentrate level had a large effect on most aspects of ewe performance. Ewes offered treated forage gained slightly more weight in pregnancy (138 v. 104 g/day), had a slightly smaller decrease in body condition score (-0·54 v. -0·68) between day 105 and lambing but did not have greater lamb birth weights than ewes on untreated forage.
The influence of daily movement of gilts and the environment in which boar exposure occurs on the efficacy of boar-induced precocious puberty in the gilt
Authors: Pearce G. P. , Hughes P. E.
Published: September 2010

To examine the influence of boar exposure environment and daily movement on the efficacy of boar-induced precocious puberty in the gilt, 60 Large White × (Large White × Landrace) prepubertal gilts from 12 litters were randomly allocated within litter to five treatment groups of six, in two replicates, at 145 days of age. Treatments were (1) control (no movement or boar exposure), (2) gilts moved to a boar pen and exposed to a mature boar, (3) gilts moved to a different pen and exposed to a boar, (4) gilts moved to a different pen only, (5) gilts moved to a vacated boar pen. Treatments occurred for 30 min/day for 75 days, or until pubertal oestrus was observed. Gilts showing pubertal oestrus were removed and slaughtered. Ovaries were examined to confirm reproductive status. Gilts failing to exhibit oestrus by 240 days of age were slaughtered and nominally ascribed a pubertal age of 245 days. Age at puberty was significantly earlier (P < 0·001) in treatments 2 and 3 involving boar exposure than in treatments 1, 4 and 5 not involving boar exposure. No significant difference was observed in the median gilt age at puberty between the two forms of boar exposure used in this experiment. Thus the efficacy of the boar effect does not appear to be significantly affected by the environment in which exposure to the boar takes place. Additionally, it is suggested that the stress of a daily pen change is insufficient to stimulate precocious puberty in gilts in the absence of boar contact.
A note on the effect of individual penning on the performance of fattening pigs
Authors: Patterson D. C.
Published: September 2010

Individual and group-penning, and entire male and female sexes were investigated in a factorial design. The size of group was five pigs. The diets were given to a scale based on live weight.

Individual penning gave significantly faster gains than group penning (679 v. 653 g/day, P < 0·01) but the improvement in food conversion ratio was not significant. Loin sample joints from individually-penned pigs had less lean and significantly more fat than did those from group-penned pigs. The faster growth rate and greater fatness of the individually-penned pigs indicated that more energy was retained by these animals and it was concluded that the greater retention of energy derived primarily from an apparently reduced metabolic heat production. The associated increase in initial growth rate was accentuated by the nature of the feeding scale.

There was some indication that boars did not grow as well as gilts in individual pens. Boars grew faster than gilts and converted food more efficiently to live-weight gain especially above 50 kg. They had lower killing-out yields and less fat than gilts.
Use of plasma hormone and metabolite levels to predict breeding value of young bulls for butterfat production
Authors: Sejrsen K. , Larsen F. , Andersen B. B.
Published: September 2010

The purpose of the experiment was to investigate the possibility of using concentrations of hormones and metabolites in plasma of potential breeding bulls early in life as indirect selection criteria for butterfat production. Sixteen Red Danish bull calves were included in the experiment, 10 were offspring of parents selected for high butterfat production for two or three generations, and six were from parents selected for low butterfat yield. The average estimated relative breeding values of the calves in the two groups were 111 and 91.

At 3·5 and 7 months of age blood samples were collected every 6 h during 2 days of ad libitum feeding, 5 days of fasting and 2 days of refeeding. The samples were analysed for glucose, urea, free fatty acids, insulin and thyroxine. At 3·5 months plasma concentrations of free fatty acids were significantly correlated with breeding value under all feeding conditions examined. The increase in plasma glucose during refeeding at both ages was positively related to breeding value. Plasma insulin during the 1st day of fasting was positively correlated with genetic merit at 3·5 months of age and negatively correlated at 7 months. Plasma thyroxine was negatively correlated with breeding value at both ages, but the correlation was only significant at 7 months. Multiple regression analyses showed that a large part of the variation in breeding value for butterfat production could be described by plasma levels of hormones and metabolites when more than one variable was included in the model. With six variables in the model 0·67 and 0·73 of the variation could be accounted for at 3·5 and 7 months of age respectively.

The results of the experiment have to be considered with caution because only one sire was used per group, the parents were preselected, and the number of animals was small. The results, however, do indicate that plasma levels of hormones and metabolites in the early life of potential breeding bulls, measured after suitable physiological challenges, may be useful as selection criteria for butterfat production of their offspring.
Characterization of post-weaning traits of Simmental and Hereford bulls and heifers
Authors: Jenkins T. G. , Ferrell C. L.
Published: September 2010

Post-weaning growth, dry-matter intake, carcass characteristics, chemical composition of the 9th to 11th rib section and food conversion efficiency were evaluated for Simmental bulls (15) and heifers (18) and Hereford bulls (17) and heifers (14) from approx. 240 days of age to 470 days of age. Within each breed × sex sub-class, animals were assigned to one of three energy intake levels: (1) ad libitum, (2) 795 kJ metabolizable energy (ME) per kg0·75 per day and (3) 544 kj ME per kg0·75 per day.

Simmentals tended to exhibit higher post-weaning growth rate and consumed more dry matter than Herefords. At ad libitum intakes, efficiency estimates (gain/food) were greater initially but decreased more rapidly for Herefords than for Simmentals. No differences were observed in efficiency estimates between Herefords and Simmentals fed at 795 kJ ME per kg0·75 per day and both breeds fed at this level improved in efficiency as time on test increased.

Bulls tended to have greater growth rate, and consume more dry matter than heifers. At ad libitum food intake, bulls were more efficient than heifers and the decrease in efficiency of the two sexes was parallel. Heifers fed at 795 kJ ME per kg0·75 per day had a constant efficiency throughout the test while bulls improved in efficiency.
Relationship of lifetime productivity with mature weight and maturation rate in Red Poll cows
Authors: Marshall T. E. , Mohler M. A. , Stewart T. S.
Published: September 2010

Lifetime maternal records were collected from 116 Red Poll cows born over a 12-year period. Estimates of mature cow weight (A), maturation rate (K) and lifetime maternal performance characters (years in herd, YH; number of calves weaned, NC; total calf weight weaned, TW; total calf weight plus mature cow weight produced, TW + A; average calf weaning weight, AW; calf weight weaned per year in the herd, TWIYH and predicted cow metabolizable energy (ME) required per kg beef produced, MEITW + A) were calculated to study the relationship between cow growth characters and maternal performance. Calf weights were adjusted to a steer basis. Reproductive management practices consisted of breeding heifers to calve as 2-year-olds; cows failing to calve in two successive seasons were culled. Mean mature cow weight was 554 (s.e. 6) kg with a mean maturation rate of 0·059 (s.e. 0·001) per month. The correlation between A and K was −0·69. Means for lifetime maternal characters were: YH, 5·1 (s.e. 0·2); NC, 4·7 (s.e. 0·2); TW, 1187 (s.e. 54) kg; TW + A, 1741 (s.e. 55) kg; AW, 252 (s.e. 1·7) kg; TWIYH, 228 (s.e. 4·5) kg/year; and MEITW + A, 72 (s.e. 1·2) MJ ME per kg beef. The regression of maternal lifetime productivity measures on mature cow weight was quadratic for YH, NC, TW and TW + A with optimal cow weight being 606, 600, 605 and 628 kg, respectively. AW and MEITW + A were positive linear functions of cow mature weight. Regressions of YH, NC, TW, TWIYH and TW + A on K were negative linear functions. AW and MEITW + A were not significantly related to K.
The effects of dietary energy content on the response of dairy cows to body condition at calving
Authors: Jones G. P. , Garnsworthy P. C.
Published: September 2010

Four groups of six cows were fed from 12 weeks before calving to achieve condition scores at calving of 3·23 (F) and 1·98 (T). For the first 20 weeks of lactation all cows were given 10 kg/day of isonitrogenous (180 g crude protein per kg dry matter (DM)) compounds containing either a high (13·0 MJ/kg DM; HE) or a low (9·8 MJ/kg DM; LE) concentration of metabolizable energy, together with 3 kg/day molassed sugar-beet pulp and hay offered ad libitum.

The mean milk yield of cows receiving compound HE (27·7 kg/day) was higher (P > 0·05) than that of cows receiving compound LE (25·6 kg/day). Cows in group FHE yielded 27·0 kg/day, compared with 25·5 kg/day for FLE (P > 0·05); cows in group THE yielded 28·4 kg/day compared with 25·17 kg/day for TLE (P <0·05). After peak lactation, milk yields were maintained better in group THE but declined at a faster rate in group TLE than in groups FHE and FLE. Neither dietary energy concentration nor condition score at calving significantly affected milk composition (butterfat 43·5, protein 29·1, lactose 50·2 g/kg). Cows receiving compound HE consumed significantly (P < 0·001) more energy (208 MJ/day) than cows receiving compound LE (188 MJ/day). Over the first 10 weeks of lactation, changes in condition were –0·83, –0·88 +0·08 and –0·25 (s.e.d. 0·22, P < 0·05) condition score units for cows in groups FHE, FLE, THE and TLE respectively.

It is concluded that with diets of high energy concentration intake is mainly limited by physiological mechanisms so that thin cows eat more than fat cows and produce similar amounts of milk. With diets of lower energy concentration, intake is limited by rumen capacity and thin cows eat the same as fat cows. This results in increased fat mobilization and a slight decrease in milk yield by cows which are fat at calving but the limited fat reserves of cows which are thin at calving are insufficient to compensate for reduced energy intake so large reductions in milk yield are observed.
Effects on performance and behaviour of mixing 20-kg pigs fed individually
Authors: Rundgren M. , Löfquist I.
Published: September 2010

The effects of mixing on agonistic behaviour and performance were studied in 90 individually fed pigs, grouped at a mean live weight of 23 kg by one of the following three methods: (1) six unmixed littermates; (2) three pigs from each of two litters; and (3) one pig from each of six litters. Unmixed animals (treatment 1) did not fight and the mode of fighting differed between treatment 2 and 3. Mixing decreased daily weight gain in the period 23 to 100 kg for barrows, but not for gilts. For gilts, food conversion efficiency was negatively correlated with the number of received attacks in the observation period (80 min after mixing), and for the barrows to fighting injury scores.
A comparison of draught cattle (Bos indicus) and buffaloes (Bubalus bubalis) carting loads in hot conditions
Authors: Anne Pearson R.
Published: September 2010

Two pairs of cattle and two pairs of buffaloes carted loads, in wooden wheeled local carts, 16 to 17 km over the same flat route on village tracks. One team worked each day in temperatures of 24 to 37°C for a total of 6 days per team.

Body temperature, respiration rate and stepping rate in one animal from each pair and work done and distance travelled were monitored.

Buffaloes and cattle started work at speeds of 1 m/s or more. Cattle kept this up for most of the day whereas the buffaloes showed a steady decrease in speed over the day to speeds of less than 0·9 m/s in the last hour. Body temperature of the buffaloes increased during work. By 3-5 h, increases of up to 3·5°C in starting values could be seen. It was necessary to stop and let the buffaloes wallow for at least 20 min to allow them to cool off before they would continue to work. During wallowing body temperature decreased to or below values seen at the start of the day's work. Unlike the buffaloes, the cattle showed changes of less than 1°C in body temperature during work. Respiration rates of buffaloes increased at least two-fold as they began panting usually after 1·5 to 2·5 h. Respiration rates of the cattle could also increase up to three-fold during work. The results have shown that in well fed animals there is little to choose between buffaloes and oxen in daily work output. Estimated daily energy expenditures by the buffaloes and cattle on working days were similar, 1·75 to 1·79 and 1·74 to 1·78 × maintenance, respectively. However, buffaloes usually took longer to achieve the work, as time had to be allowed for wallowing. This is seen as the main disadvantage of using buffaloes for carting on longer routes.
Breed and sex differences among equally mature sheep and goats 4. Carcass muscle, fat and bone
Authors: Taylor C. S. , Murray J. I. , Thonney M. L.
Published: September 2010

Males and females from Soay, Welsh Mountain, Southdown, Finnish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and a breed of feral goats were slaughtered when proportionately 0·40, 0·52, 0·64 or 0·76 of mature live weight. On average, carcasses contained 583 g muscle, 243 g fat and 174 g bone per kg. Individual cuts (four commercially higher-valued and six lower-valued cuts of the shoulder, rib, loin and gigot joints) ranged from 375 to 670g muscle, 129 to 625 g fat and 0 to 294 g bone per kg.

Allometric coefficients are given for 32 traits. The distribution of bone in the carcass joints changed little as animals matured but carcass muscle and fat distributions changed significantly.

Breeds differed significantly in proportion of carcass muscle, fat and bone and also in their distribution. Welsh Mountain, Southdown, Wiltshire and Oxford Down all deposited carcass fat about three times more rapidly than did the Soay, goat, Finnish Landrace and Jacob. The Oxford Down had the lowest proportion of muscle (514 g/kg) and most fat (317 g/kg). The Southdown had least bone (148 g/kg) and the feral goat most muscle (662 g/kg). Southdown and Soay had the most muscle in commercially higher-valued cuts and Jacob and feral goat the least. Males had significantly more of their muscle in the neck and shoulder and significantly less in the gigot and flank.

As breed size increased, proportion of carcass muscle and bone decreased and proportion of carcass fat increased. These breed regressions were attributed to the small but exceptionally lean feral Soay and goat breeds, rather than to a failure of genetic size-scaling. There were no significant trends with breed size among the domesticated breeds.
Breed and sex differences among equally mature sheep and goats 5. Lipid in dry tissue
Authors: Taylor C. S. , Murray J. I. , Thonney M. L.
Published: September 2010

Males and females from Soay, Welsh Mountain, Southdown, Finnish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and a breed of feral goats were slaughtered when proportionately 0·40, 0·52 0·64 or 0·76 of mature live weight. Lipid concentrations in dried tissue were obtained for perirenal fat, omental plus mesenteric fat, subcutaneous fat, carcass muscle plus associated intermuscular fat, carcass bone and offal (pelt, head, feet and organs). Lipid varied from 260 g/kg dry matter (DM) for bone to 968 g/kg for perirenal fat.

As animals matured, lipid concentration increased in the dry matter of all tissues except bone, most rapidly in offal and least in intra-abdominal fat. The increases were highly correlated with the associated increases in proportion of dissected fat.

Breeds differed significantly in lipid concentration in the DM of all tissues examined. Breeds with a high lipid concentration in DM of one tissue usually had high concentrations in all other tissues. The Oxford Down had the highest concentration, and the Soay and feral goat the lowest. Males had slightly lower concentrations in all tissues except internal fat.

As breed size increased, mean lipid concentration (at the same stage of maturity) also increased in the DM of all tissues except bone. These breed regressions were attributed to the sampling of breeds, the smallest breeds being the exceptionally lean Soay and feral goat. Among the domesticated breeds, there were no signficant trends with breed size.
Breed and sex differences among equally mature sheep and goats 6. Breed correlations for body composition and food conversion efficiency
Authors: Taylor C. S. , Murray J. I. , Thonney M. L.
Published: September 2010

Breed means are given for 40 traits relating to food conversion efficiency and body composition at the same stage of maturity in seven breeds of sheep and a feral goat breed. In terms of breed means, food intake and food conversion efficiency were genetically correlated, as were most traits associated with fatness or leanness.

Highly inter-correlated measures of breed fatness were proportion of fat in the carcass, proportion of total carcass fat found in the rib plus loin, the fat : muscle ratio and the lipid concentration in the dry matter of all tissues except bone. Dressing proportion was highly correlated with all these measures of fatness.

Breeds with a high proportion of subcutaneous fat did not necessarily have a low proportion of intra-abdominal fat. A low proportion of carcass fat in the rib plus loin was associated with a high proportion in the shoulder (inter-breed correlation —0·7): both were measures of leanness. Muscle : bone ratio was not correlated with fatness or leanness. Slower maturing, larger breeds had slightly more bone, less fat and more lean in their higher-priced cuts. Breeds with heavier fleeces were fatter (0·7). The food conversion efficiency of a breed was largely independent of its body composition.
The effect of feeding saltbush and sodium chloride on energy metabolism in sheep
Authors: Arieli A. , Naim E. , Benjamin R. W. , Pasternak D.
Published: September 2010

The effect of consumption of saltbush and sodium chloride on energy metabolism in sheep was investigated. Twenty-four Awassi wethers were fed at maintenance level and allotted to three treatments: saltbush (Atriplex barclayana), salt (NaCl) and control. Daily mineral intakes with these diets were 149, 158 and 57 g, respectively. The saltbush had been irrigated with an equal-part mixture of seawater and fresh water and contained 15 g nitrogen and 310 g ash per kg. Energy and nitrogen balance were conducted using indirect calorimetry. The disappearance of organic matter and nitrogen from saltbush in the rumen was studied by the polyester bag technique.

Water intake of animals fed a high salt diet was 2·9 times higher and urine excretion was 3·7 times higher than in the control. Digested energy was proportionately 0·616 of dietary gross energy in the saltbush treatment, and 0·700 and 0·707 in the salt and control treatments respectively. Metabolizable energy (ME) was proportionately 0·795, 0·786 and 0·815 of digested energy, and heat production was 1·135, 1·043 and 0·867 of ME in the saltbush, salt and control treatments, respectively. The calculated values for digestible energy, ME, and net energy for maintenance on the saltbush diet were 5·02, 3·77 and 0·54 MJ/kg dry matter.

It is suggested that the low energetic utilization of saltbush is related to its low digestibility and the associated increase in energy expenditure, which are apparently related to mineral metabolism in the rumen. To maintain sheep on saltbush diets efforts should be made to lower the mineral content of this shrub.
Ultra-violet irradiation of fattening pigs
Authors: Walker-Love J. , Laird R. , Thomson J. M. , Gray K. W.
Published: September 2010

1. Ninety-six Large White fattening pigs, 8-10 weeks old at the beginning of the trial were used to study the effects of ultra-violet irradiation (22½ hours daily) with and without oxytetracycline supplements of the diet. All meal fed was fortified with vitamin D.

2. Under the conditions of this trial ultra-violet irradiation was without effect. Oxytetracycline supplementation resulted in significantly higher live-weight increases, lower age at slaughter and improved feed conversion.

3. No significant treatment differences were recorded for any of the carcass measurements.

4. Ultra-violet irradiation did not reduce the number of ‘thumping’ pigs nor the degree of lung damage by virus pneumonia, whereas ‘thumping’ was significantly less on the oxytetracycline treatments.

5. The results are discussed in relation to vitamin D requirements and the presence of virus pneumonia.
Milk yield and butterfat percentage of twin and single-born cattle under experimental and field conditions
Authors: Watson J. H.
Published: September 2010

1. A comparison has been made of 305-day lactation milk yields and butterfat percentages of twin and single-born cattle under experimental and field conditions. Experimental two-egg twins, as judged from within-pair variances, were four times as variable as one-egg twins. Two-egg twins in the experimental herd were more alike than twins in dairy herds in fat percentage due to more frequent butterfat testing. Variance of milk yield within pairs was the same in both experimental and farm twins.

2. Twins and half sisters in dairy herds had similar within-pair variances for milk yield and fat percentage. Full sisters, of necessity non-contemporary, differed more in yield than twins and half sisters; significantly so in the latter comparison.

3. The between-pair variance components for experimental twins were high, relative to twins in herds. In experimental twins, breed differences, lack of culling and uniform treatment were probably contributing causes, and also more frequent observation of fat percentage during lactation. Twins n i dairy herds had greater between-pair variances than full sisters.

4. Experimental MZ twins had an intra-class correlation for milk yield of 0·88 and DZ twins of 0·67 which was much higher than for twins on farms. Farm twins and half sisters had correlations for milk yield of 0·37 and 0·31, to be compared with 0·20 in full sisters. Corresponding values for fat percentage were 0·40, 0·35 and 0·25 on farms as against 0·88 and 0·65 for MZ and DZ twins at the experiment station. These differences between experimental and commercial pairs were largely attributable to differences in between-pair variance.

5. There is no evidence from experimental or commercial data that twins produce less milk than single-born cows.

6. Differences between farms increased the within-pair variance in yield and decreased the intra-class correlation of twins and half sisters but had less effect on full sisters.
An analysis of the Entebbe herd of Nganda cattle in Uganda
Authors: Mahadevan P. , Marples H. J. S.
Published: September 2010

In the herd of Nganda cattle at the Government Livestock Experiment Station, Entebbe, Uganda, it was found that of the known environmental factors affecting milk production, the more important ones were age (in lactations) and length of the calving interval preceding the second and third lactations. The correlations between performance in different lactations of the same animal were high for lactation milk yield (0·73) and average daily milk yield (0·62) and low for calving interval (0·21) and dry period (0·15). The repeatability of lactation length was intermediate (0·42). The heritability values were around 0·3 for the weight measurements, around 0·2 for yield characteristics and around 0·1 for length of lactation and age at first calving.

The sires used in the breeding programme at Entebbe made little impact on production performance in the herd. The estimated genetic improvement in milk yield through selection of dams of cows was also low. It is argued from comparison with results from other parts of the tropics that superior genotypes for milk production are difficult to come by among indigenous cattle in these areas and that we should therefore look for other opportunities and methods to move ahead faster in the future.
The regulation of food intake by sheep
Authors: Blaxter K. L. , Wainman F. W. , Wilson R. S.
Published: September 2010

1. A series of experiments with adult sheep were carried out in an attempt to place on a quantitative basis the generalisation that the voluntary food intake of ruminants increases with the quality of the fodder they are given.

2. Methods of determining voluntary intake free of subjective bias were developed. It was shown that voluntary intake varied with a fractional power of body weight close to 0·734. The length of time necessary to establish stable intakes was 12–15 days and the number of times fresh food was offered each day had no apparent effect on intake.

3. It was found that voluntary intake of long fodders was related to the apparent digestibility of their energy, increasing rapidly as digestibility increased from 38% to 70% and thereafter more slowly.

4. The giving of concentrated food resulted in a drop in the voluntary intake of fodder. With high quality hay 100 g. concentrates replaced 100 g. hay. With poor quality hay, 100 g. concentrates replaced 47 g. of hay.

5. The passage of three widely different hays through the gut was measured and the poorest passed most slowly. Calculations showed that the dry matter content of gut contents was the same for all three materials irrespective of their quality.

6. It was shown that an increase in digestibility of 10 units in the range 40–60% resulted in considerable increases in the total amount of energy apparently digested and in equivalent increases in daily gain.

7. The digested energy consumed/day/kg. W0·734 (E) can be related to voluntary intake (I) g./day/kg. W0·734 by the equation:—

E=4·(I—31)

which provides a rapid and easy method of assessing fodder quality under conditions of ad libitum supply.

8. The results are discussed and it is shown that under ad libitum feeding conditions an increase in the nutritive value of unit feed from 50 to 55, i.e. by 10%, increases body gain by 100%.
Heritability of chemical fat content in the loin muscle of baconers
Authors: Duniec H. , Kielanowski J. , Osińska Zofia
Published: September 2010

Data on carcasses of 352 Large White baconers by 44 boars were taken from reports of Progeny Testing Stations to estimate the heritability of chemical fat in the loin muscle and of fatty tissue content in the carcass, and their phenotypic and genetic correlations.

The heritability of the chemical fat content in the loin muscle was found to be 0·50, that of the fatty tissue content in the carcass 0·69. The genetic correlation between the characteristics under study seems to be very low (rA = 0·11), and their phenotypic correlation, though significant statistically, was also found to be low (about 0·2).
The effect of parenterally administered iron upon the growth of piglets reared on concrete
Authors: Walker Elizabeth A. , Taylor J. H.
Published: September 2010

1. Four fitter-mates from 20 litters on each of 3 farms were divided equally and distributed at random between two treatment groups. Each piglet was injected intramuscularly with 2 c.c. of an iron preparation between 1 and 2 days of age. The control group received an iron-dextran complex which provided 150 mg. of iron per piglet and a second group received an irondextrin complex which provided 200 mg. of iron per piglet.

2. The body weight and the level of haemoglobin in the blood of each piglet were measured at 1, 8, 15, 22, and 56 days of age and the incidence and cause of disease and mortality were recorded.

3. The level of haemoglobin in the blood of both groups was comparable throughout the experiment.

4. At the 22nd and 56th day, the group receiving 200 mg. of iron was approximately 6% heavier than the group receiving 150 mg. of iron. These differences were highly significant at the 0·1% level.

5. From each of 3 additional litters, 3 piglets received no supplementary iron while 5 piglets received 200 mg. of iron provided by the iron-dextrin complex. The three whole litters were slaughtered on days 3, 8, and 22 respectively. The mean level of iron per 100 g. of liver and spleen within the untreated group on the above occasions was 5·8, 5·8, and 3·7 mg. respectively, compared with 72·9, 55·1, and 17·6 mg. respectively within the treated piglets. The differences were highly significant at 0·1 % level.
Specialised sire and dam lines. II. The choice of the most profitable parental combination when component traits are genetically additive
Authors: Moav Rom
Published: September 2010

Detailed graphic and algebraic procedures were outlined for finding the most profitable parental combination among a group of lines when genetic additivity of component traits is assumed.

Profit was expressed as a linear function of productivity and a reciprocal function of reproductivity. The non-linearity and the unequal contributions to profit of the sire and dam lines were exploited in order to minimise both reproduction and production costs.
Studies on the nutritive value of the diet selected by grazing sheep. I. Differences in composition between herbage consumed and material collected from oesophageal fistulae
Authors: Langlands J. P.
Published: September 2010

Freshly-cut forages and lucerne chaff were given to penned sheep fistulated at the oesophagus. The feed given and the samples obtained through the fistula were analysed for in vitro digestibility, nitrogen, ash, phosphorus, sodium, potassium and calcium. Organic matter digestibility was predicted from the in vitro determination.

Three regression equations were calculated relating predicted organic matter digestibility of the feed to the digestibility of the extrusa sample. The most precise of these equations had a residual standard deviation of ±3·4 units.

The relationship between the nitrogen contents of the feed and sample was calculated. The equation did not pass through the origin but the differences in nitrogen content between feed and extrusa were small over the range 4·69 to 1·28% N included in this study. The nitrogen and calcium contents of the feed could be estimated from the sample with errors of ±7·5 and 9% respectively. The sodium, potassium and ash contents of the diet could not be reliably estimated from an oesophageal sample.
A note on the relationship between the rate of secretion of saliva and the rate of swallowing in cows at rest
Authors: Bailey C. B.
Published: September 2010

The variations that occur in saliva flow in cattle at rest may affect digestive processes in the reticulo-rumen (Bailey and Balch, 1961). To learn more about the effects of variations in saliva flow on digestion, it would be of value to have a reliable method of measuring saliva flow in intact animals. Stevens and Sellers (1959) showed that emptying the rumens of cows altered the rate at which saliva was swallowed and suggested that this was a result of changes in the rate of secretion. The rate of swallowing was measured during the course of experiments on saliva secretion described earlier (Bailey and Balch, 1961). Those earlier values are here analysed to study the relationship between rate of secretion of saliva and rate of swallowing.