bluuebunny/crossref_metadata_2025 huggingface dataset:
Progeny testing of Suffolk rams on three maternal breeds
Authors: Broadbent J. S. , Bowman J. C.
Published: September 2010

1. Six Suffolk rams (two purchased from each of three breeders) were each progeny tested on 10 Scottish Halfbred (Border Leicester ♂ × North Country Cheviot ♀), 10 Welsh and 10 Clun ewes. The progeny of the Clun ewes were reared at a different location from the progeny of the Halfbred and Welsh ewes.

2. Progeny were weighed at birth and every 3 or 4 weeks thereafter so that 56 and 112 day weights could be calculated. Growth rate was considered for the periods 0–8 weeks, 8–16 weeks and 0–16 weeks. The growth rates were corrected for birth type and sex, but not for birth weight. The growth rates of a ram's progeny for a ewe type were converted into a deviation from the mean of all progeny of that ewe type, and measured in standard deviation units. An overall deviation for all ewe types for each ram was also calculated; 0–16 weeks was considered the best period over which to compare ram progeny performance and the difference between the best and worst ram for this trait represented 0·81 of a standard deviation or a 10% increase in growth rate for the progeny of the best ram over the progeny of the worst ram. There was some evidence of ram × ewe-type interaction for this trait.

3. A number of progeny of each ram were sent to a central abattoir and dissected into commercial joints. All pieces were weighed and a total carcass value obtained by multiplying each joint weight by an average retail price per pound and summing. The total carcass value was converted to terms of yield in pence per pound. Subjective assessments were made for colour and texture of meat and for tenderness and flavour of cooked meat. There was little variation between ram progeny groups for any of the carcass traits.
The use of specialised sire and dam lines in selection for meat production
Authors: Smith Charles
Published: September 2010

Progress by selecting in a single line for overall merit is compared with the progress by selecting and crossing specialised sire and dam lines. The sire line is selected for growth and carcass traits, the dam line for number of offspring produced. The rate of improvement through specialised lines is never less than that in a single line and can be considerably greater but only i f there is an unfavourable genetic correlation between progeny number and performance and if there is a certain balance between the heritabilities and economic weights of the two sets of traits. In a sire line the selection may ignore progeny number without loss in efficiency but in a dam line progeny growth and carcass performance must be considered in addition to the number of offspring or else substantial losses in the efficiency of improvement may be suffered.

From estimates of the relative economic weights and relative heritabilities of number of progeny produced and the efficiency of feed conversion in several meat species it was concluded that selecting in specialised lines will have little advantage over selecting for overall performance in a single line.
The feed intake of milk cows I. Intake of winter rations during pregnancy and lactation and the influence of change to pasture
Authors: Holmes W. , Jones J. G. W. , Drake-Brockman R. M. , White N.
Published: September 2010

1. For 4 weeks before calving in December or January a group of 7 Ayrshire cows each received daily 6 lb. hay and silage to appetite, whilst a second group of 9 received the same roughages and 6–10 lb. concentrates. After calving, cows from both of the pre-calving treatments were placed in each of two post-calving groups of 8 cows. A High treatment received approximately 8 lb./day more concentrates at the same milk yield than the Low treatment. Both groups continued to receive 6 lb. hay/cow/day and silage to appetite. The cows were allowed to graze by day from 21 February and by day and night from 13 April. Hay, at 5 lb./cow/day and reducing rates of concentrates were offered until 8 May.

2. Individual feed intakes were estimated from faecal output and digestibility. Direct measures of the intakes of different treatment groups on indoor feeding agreed fairly closely with the mean individual estimates.

3. The digestible organic matter intake (DOMI) of 1,300 lb. cows in the last stages of pregnancy was increased from 10 up to 14–16 lb./day by giving 8–10 lb./day concentrates. Immediately after calving, the increases in DOMI compared with pre-calving levels were about 2.5 lb./day for cows which received concentrates before calving and 8.5 lb./day for cows which received no concentrates before calving.

4. When all cows had calved and were in full milk production there were no significant differences in DOMI, milk yield or rate of live-weight gain attributable to pre-calving treatment. Mean DOMI on the High and Low post-calving treatments were 23.8 and 19.4 lb./day, mean fat-corrected milk yields 44.5 and 38.8 lb./day and mean rates of live-weight gain 05 and nil lb./day, respectively.

5. DOMI increased by 0.7 and 4.9 lb./day for High and Low post-calving treatments when cows were turned out to night as well as day grazing, and milk yields increased by 1.0 and 2.2 lb./day respectively.

6. Regression equations relating animal production and feed intake, and substitution rates of concentrate usage were calculated. Faecal output and DOMI were closely related to milk yield. When additional concentrates were given the resulting increase in total DOMI was greater when the bulk feed was of low digestibility than when it was of high digestibility.
Repeatability and heritability of fertility in hill sheep
Authors: Purser A. F.
Published: September 2010

Lambing records of 3,500 Scottish Blackface ewes and 2,000 Welsh Mountain ewes were used for a study of repeatability of ewe fertility and litter size. The repeatability of litter size at birth (calculated as an intra-ewe correlation) was higher in both flocks (0.19 and 0.24 for Blackface and Welsh ewes respectively) than that for barrenness (0.09 and 0.08) or for number of lambs born per mating (0.07 and 0.10). Repeatability of the corresponding traits at weaning were generally about half these values.

About two-thirds of the ewes had sires recorded and were used for a heritability analysis. The heritability of litter size at birth in both flocks was higher (0.14 and 0.16 for Blackface and Welsh respectively) than either the heritability of barrenness (−0.03 and 0.03) or of numbers of lambs born per mating (−0.01 and 0.07).

It was concluded that the greatest improvement in numbers of lambs weaned would be obtained by selection on litter size at birth. There would be correlated changes in live-weight (genetic correlations of 0.44 and 0.78 for Blackface and Welsh respectively) but not in fleece weight (genetic correlations of 0.09 and −0.13).
The litter size and fertility of Finnish Landrace and Tasmanian Merino sheep and their reciprocal crosses
Authors: Land R. B. , Russell W. S. , Donald H. P.
Published: September 2010

Litter size (number of lambs born per female lambing) of adult female Finnish Landrace and Tasmanian Merino sheep mated to males of either breed was 2·9 and 1·0 respectively. Breed of ram had a direct effect on the conception rate of the ewes to which they were mated—22% of ewes mated to Merino rams returned to oestrus but only 10% of those mated to Finn rams—but not on their litter size.

A comparison of the reproductive performance of crossbred females with that of purebred contemporaries indicated that there was very little or no heterosis for litter size, the crossbreds being almost exactly intermediate between the parents. The proportion of females showing oestrus during the mating period, however, was lower in the Merinos than in the Finns and crossbreds. This was particularly noticeable in females put to the ram at around 6 months of age. Whereas 35 of 36 Finnish Landrace females and 46 of 49 crossbreds showed oestrus, only one of the 20 Merinos did so. At about 6 months of age therefore the crossbred females showed heterosis in the incidence of oestrus.
Analysis of production records from a lowland sheep flock 3. Phenotypic and genetic parameters for reproductive performance
Authors: Forrest P. A. , Bichard Maurice
Published: September 2010

Phenotypic and genetic parameters for reproductive performance in a flock of Clun Forest ewes have been estimated. Average litter size (ALS) appeared to be more repeatable than the number of lambs born per ewe mated and present at lambing (NLBEM), and the estimates obtained by regression (0·15 and 0·14) were slightly higher than those from the analyses of variance (0·12 and 0·09). The repeatability of barrenness was very low (0·05). It was concluded that little scope existed for the improvement of reproductive performance from a regular policy of culling.

Estimates of heritability by analysis of variance and a method for all-or-none traits were 0·12 and 0·11 for ALS, and 0·15 and 0·10 for NLBEM, whereas barrenness was less heritable (0·07). An estimate of 016 was found for the heritability of ALS performance over two years. The phenotypic correlation between body weight and reproductive performance were positive yet small (ALS:+0·16; NLBEM:+0·10), while at the genetic level ALS was more strongly related to body weight (+0·21) than NLBEM (-0·04). The genetic regressions indicated that an increase of 5 lambs per 100 ewes lambing would accompany genetic gain of 5 kg in ewe body weight, while an increase of 1 lamb per ewe lambing would lead to a correlated response in body weight of 5 kg.

Selection for ALS on the basis of dams' performance, within the flock studied, would be expected to yield a rate of progress of 2% per annum.
A note on the comparative performance of pigs sired by Pietrain/Hampshire and Large White boars
Authors: Smith W. C. , Lishman W. B.
Published: September 2010

Two Pietrain/Hampshire crossbred males and two Large White males were mated in equal numbers to 24 Large White females. Breed of sire did not affect litter size or total weight at birth or weaning. After weaning, on ad libitum feeding over the live-weight range 25 to 88 kg, the crossbred pigs grew more slowly to slaughter (5%) but with equal efficiency of live-weight gain. Crossbreds had higher carcass yields (3%) shorter carcasses (3%) and larger ‘eye-muscle’ areas (18%). Fat depths, joint proportions and cut-out values were not affected. The ‘eye-muscles’ of crossbreds were paler in colour and had a lower water-binding capacity than those of the purebreds, but pH1 values and transmission percentages did not differ.
Dominance patterns and positional behaviour of sheep in yards
Authors: Dove H. , Beilharz R. G. , Black J. L.
Published: September 2010

1. Observations were conducted to ascertain the social dominance structure in two small groups of castrated male Corriedale sheep. In these and a third group, the order of the sheep past a fixed point was recorded, when they were moving either voluntarily or under force. Records were also made of the way in which the sheep distributed themselves spatially in a confined area, relative to one or two men simulating yard work. In a fourth group divided into two sub-groups, the social dominance structure was determined before and after the subgroups were mixed, to assess the effect of mixing.

2. The small groups showed a distinct social dominance hierarchy of a linear type, similar to that found in cattle and pigs. The dominance status of individual animals was correlated with their body weight, wither height and height at hocks. Dominance status within a subgroup remained stable following the mixing of sub-groups.

3. The sheep adopted consistent positions in forced movement, and in relation to one or two men simulating yard work. There was no consistency in voluntary movement. Dominant animals did not lead the forced movement, were usually some distance from man, and were widely scattered from each other.

4. Dominance status was closely related to positional behaviour.
Analysis of production records from a lowland sheep flock. 4. Factors influencing the incidence of successful pregnancy in young females
Authors: Bichard Maurice , Younis A. A. , Forrest P. A. , Cumberland P. H.
Published: September 2010

Over a 15-year period nearly 2000 young females were exposed to the ram at 6 to 9 months of age. These Clun Forest females were born between January and April in the Cockle Park experimental flock, and mated between October and December of the same year. On average nearly 42% of those present at lambing did not produce a lamb. Analyses are presented of the reproductive efficiency of these animals and of some of the possible causes of their failure to lamb. Observations in 10 of these years suggested that only 12% had not been mated and might therefore be assumed to be prepuberal. Age at first oestrus for those animals achieving puberty in their first autumn was inversely related to date of birth. The number which lambed increased by 1·1% per kg increase in live weight before mating.

In 3 years simple nutritional and housing treatments were applied to groups of female lambs. Feeding a cereal supplement to animals at pasture before, during and after mating, and housing 1 to 2 weeks after mating, appeared to increase the percentage which lambed. It is suggested that the effect was to reduce the amount of early embryo death caused by nutritional and climatic stresses on the normal grazing animal.
Growth in mice after selection on maize-milk diets
Authors: Bateman Nigel
Published: September 2010

Six lines of mice were fed distinctive fixed or shifting diets while being selected for fast growth in the first two weeks after weaning. The intention was to provide alternative routes for the improvement of growth with respect to a maize diet (100% maize) where controls grew 6 g, an optimum diet (76% maize, 24% milk) where controls grew 17 g, and a ‘milk’ diet (16% maize, 84% milk) where controls grew 12 g. After 10 generations of selection the lines, hybrids and unselected controls were compared on these and intermediate diets. Realized genetic correlations between growth on optimal and suboptimal diets depended on the feeding regime in which selection was practised, and were significantly higher in lines that were selected on suboptimal diets. When the selected lines were tested on unfamiliar suboptimal diets they were hardly better than controls, but on their own diets and also on the optimum diet were about 6 g heavier. Peak growth was never much greater than on 76% maize and was made on diets containing between 58% and 82% maize. With one exception, the hybrids grew on each test diet about as well as did the best selected line.

A genetic limitation was encountered on the optimum diet. The growth there of the mice selected on either milk or maize diets was not improved upon by the mice actually selected on the optimum diet.
The independent effects of live weight and body condition on fecundity and productivity of Icelandic ewes
Authors: Adalsteinsson S.
Published: September 2010

In an experiment carried out on five farms in 3 years and comprising 1221 annual weight records of adult ewes, an increased level of feedingwas comparedwith feeding according to farming practice. The higher feeding level started 6 weeks before mating andfinishedjust before lambing. Significant effects of feeding level on ewe live weight and body condition, ewe fecundity and the birth and weaning weights of lambs were found.

Ewe fecundity increasedlinearly with ewelive weight at 8 weeks prior t o mating (b=1·05 lambs/kg per 100 ewes), curvilinearly with ewe body condition score at 8 weeks before mating (maximum at score 3·32) and curvilinearly with weight gain from 8 to 2 weeks before mating (maximum at 2·3 kg gain). A 10% range in live weight, condition score and live-weight gain resulted in a predicted fecundity range of 21 lambs per 100 ewes alive at lambing. Changes in weight and condition score during the mating period did not affect ewe fecundity.
Genetic and phenotypic parameters of Australian Large White and Landrace boars performance-tested when offered food ad libitum
Authors: McPhee C. P. , Brennan P. J. , Duncalfe F.
Published: September 2010

Genetic analyses were carried out on 935 Large White and 767 Land-race boars performance-tested from 25 kg to 80 kg live weight under individual andad libitumfeeding conditions. Traits analysed were daily weight gain (GR), feed conversion ratio (FCR), daily feed intake (FI) and subcutaneous fat depth (F). Genetic parameters were estimated from sire components obtained by conventional hierarchical analyses of variance and covariance.

Large White pigs grew faster, had higher intakes of feed and utilized it more efficiently than Landrace. There was no breed difference in fat depth. Heritabilities, pooled over both breeds, were 0·36 ± 0·10, 0·27±0·08, 0·62±0·13 and 0·47±0·11 for GR, FCR, FI and F respectively. Noteworthy among the correlation estimates were strong and positive correlations between FI and the other three traits. A positive genetic correlation between GR and FCR arose from a very high coefficient of genetic variation for FI.

Selection indexes emphasising efficiency of lean growth were constructed using some or all of the 4 traits as measured variables. Their use is expected to reduce FI and GR on feeding ad libitum. The results indicate the need to select pigs on the same level of feeding as that used in production.
A comparison of different predictors of the lean content of pig carcasses 1. Predictors for use in commercial classification and grading
Authors: Kempster A. J. , Evans D. G.
Published: September 2010

Carcass measurement and dissection data for 1176 pigs were used to examine the suitability of different measurements for predicting carcass lean percentage in commercial classification and grading. Three carcass weight groups with means of 47, 72 and 93 kg, were analysed separately. Similar results were obtained and those for the 72 kg group are given in this abstract. The s.d. of percentage carcass lean in this group was 3·84. Visual conformation score, carcass length and m. longissimus depth were valueless as predictors (residual s.d. of carcass lean percentages were 3·84, 3·77 and 3·80 respectively). Fat thickness measurements taken on the exposed surface of the split carcass provided a less precise prediction (best residual s.d.=2·89) than fat measurements taken over the m. longissimus using the optical probe (best residual s.d. = 2·20). The probe measurements were taken 6·5 cm from the dorsal mid line at fixed positions along the carcass from 4/5th cervical vertebrae to the 5/6th lumbar vertebrae. Precision of prediction showed a regular pattern with highest levels at the last rib (the P2 position currently used in the Meat and Livestock Commission classification scheme) and at the 13th rib, with lower values anteriorly and posteriorly. These two measurements in multiple regression were more precise than any other pair of measurements for predicting both percentage carcass lean (residual s.d. = 2·16) and the lean percentage in individual primal joints.
A note on the effect of climate on fertility in pigs in the Padana Valley of Italy
Authors: Enne G. , Beccaro P. V. , Tarocco C.
Published: September 2010

The outcome of 37 563 matings of pigs in the Padana Valley of Northern Italy over a 4-year period was studied. The results show a marked reduction in fertility in the hottest months when a fertility rate of less than 50% was found.

Separate studies of sows and gilts show a similar development in the dynamics of the phenomenon, with, however, a time change.
Models of heat production and critical temperature for growing pigs
Authors: Bruce J. M. , Clark J. J.
Published: September 2010

1. A deterministic model for thermoneutral heat production of growing pigs on barley-based diets has been developed and validated. The model variables are live weight (20 to 100 kg) and metabolizable energy intake (not less than maintenance). The root-mean-square error for 62 data is 049 MJ/day (3·2%).

2. A deterministic model for heat production of growing pigs below their critical temperature has been developed and validated. The model variables are: air temperature, air velocity, floor type, live weight (20 to 100 kg), and group size. The root-mean-square error for 78 data is 0·77 MJ/day (5·6%).

3. The two heat production models are combined to give a model for the lower critical temperature for growing pigs.

4. These models may be used to quantify and compare the effects on energy balance of different combinations of nutrition and environment. They should help to clarify the issues when practical decisions in pig production are made and should also help in the design of nutritional and physiological experiments.
Sow service in lactation: an analysis of data from one herd
Authors: Petchey A. M. , Jolly G. M.
Published: September 2010

Observations were made on a pig herd where sow service in lactation had been practised for 2 years. Sows and their litters were grouped and a boar later introduced. Of the 49% of sows mated in lactation 78% conceived. Sow and litter data were subjected to multiple regression analyses which indicated that lactational oestrus was more likely to occur for sows farrowing at the end of the calendar year, and for sows with smaller litter sizes. Sows mated in lactation showed a smaller weight change from the end of the previous pregnancy to weaning than those first showing oestrus after weaning. It is suggested that these weight changes in lactation and the seasonal relationship to lactation oestrus may be related to weight gain achieved by the sow in the previous pregnancy. Sows mated early in lactation had piglets with lower weaning weights and sows mated in late lactation had greater weaning weights than piglets whose dams showed oestrus after weaning.
The administration of sugar solutions to pigs immediately prior to slaughter 1. Effect on carcass yield and some muscle and liver characteristics
Authors: Fernandes T. H. , Smith W. C. , Armstrong D. G.
Published: September 2010

Three experiments, involving a total of 84 pigs of approximately 90 kg live weight, were undertaken to determine the effects of feeding sugar solutions immediately prior to slaughter on carcass yield, liver weights, ultimate pH of the musculature and some chemical characteristics of muscle and liver. In the first, where water-only (14 h) prior to slaughter, or access to a solution of either glucose syrup (12 h) or sucrose (12 h) followed by water-only (2 h) were the treatments, sugar feeding did not influence carcass yield. Liver weight was increased with glucose (39%) and markedly so with sucrose (77%). Livers from sugar-fed pigs had higher glycogen and lower protein concentrations. Glucose reduced muscle ultimate pH (0·2 to 0·4 units) but sucrose had little effect. In the second study various sugars were tested (pure glucose, glucose syrup, sucrose and fructose) and pigs had access to solutions of them for 4 h and water-only thereafter for 10 h prior to slaughter. All sugar treatments increased liver weight and reduced muscle ultimate pH relative to water-only before slaughter. The final experiment involved access to varying amounts of a glucose syrup solution for 4 h followed by water-only (10 h). In comparison with ‘water-only’ prior to slaughter, an intake of some 250 g hexose equivalent reduced muscle ultimate pH (0·2 to 0·3 units) and increased liver weight but a response in carcass yield required in excess of 1000 g hexose equivalent.
The influence of age at first boar contact on puberty attainment in the gilt
Authors: Kirkwood R. N. , Hughes P. E.
Published: September 2010

Thirty-six Large White × (Large White × Landrace) young female pigs (gilts) were allocated to one of nine treatments. These were 30 min daily boar contact from 125, 132, 139, 146, 153, 160, 167, 174 or 181 days of age. Gilts were fed so as to maintain them on a pre-determined growth curve, gaining 0·45 kg per day. Once puberty had been detected, gilts were mated at the next (second) oestrous period and subsequently slaughtered 20 days post coitum.

The interval from first boar contact to puberty was significantly longer (P<0·05) amongst gilts first exposed to a boar at ages below 139 days. Amongst gilts older than this the interval was similar. Though the 174- and 181-day groups were significantly older at puberty (P<0·05) no significant differences were observed amongst the younger age groups. Synchronization of pubertal oestrus appeared to be better for the 160- and 167-day groups, with three out of four gilts reaching puberty within an 8-day period. There was no indication that weight at puberty, ovulation rate, percentage embryo survivval, or number of viable embryos at 20 days post coitum were affected by treatment.

From the results it appears that the optimal gilt age at which to commence boar contact, in terms of age at puberty, interval from first boar contact to puberty and synchronization of the pubertal oestrus, is in the age range 160 to 170 days.
Further studies on the response of lactating ewes to dietary protein
Authors: Robinson J. J. , McHattie I. , Cortes J. F. Calderon , Thompson J. L.
Published: September 2010

Four experiments were made during early lactation on individually penned Finnish Landrace × Dorset Horn ewes, each suckling two lambs. In Experiment 1, 14 ewes of mean body weight 74 ± 2·4 kg received daily, 1·9 kg dry matter, 20 MJ of metabolizable energy and 300 g of crude protein from a diet (H) containing hay, barley and fish meal. Reduction of the daily crude protein intake of half the ewes to 225 g by replacing fish meal with barley (diet L) in week 2 of lactation resulted in a decrease (P< 0·01) in daily milk yield of 0·53 kg (17%) compared with no change for ewes remaining on diet H. The effect was reversed by returning the ewes to diet H at the end of week 3. In Experiment 2 the use of four ewes fitted with abomasal cannulae showed that the additional non-ammonia nitrogen reaching the abomasum when fish meal was given was used with an efficiency of 0·51 for the production of milk nitrogen. In Experiment 3, involving 20 ewes, a restriction in protein intake for more than 10 days in early lactation by replacing the fish meal with barley depressed subsequent milk yield. In Experiment 4, 24 ewes were given either fish meal, soya bean meal or groundnut meal as protein supplements. In early lactation fish meal was superior by 0·40 and 0·43 kg of milk per day to soya bean meal and groundnut meal respectively, and this was attributed to the greater quantity of non-ammonia nitrogen reaching the abomasum in the fish meal compared with the soya bean meal and groundnut meal supplements. The commercial significance of the results is discussed.
Haemoglobin type and reproductive performance of sheep grazing oestrogenic pastures
Authors: Walker S. K. , Obst J. M. , Smith D. H. , Hall G. P. , Flavel P. F. , Ponzoni R. W.
Published: September 2010

The effect of haemoglobin types A and B on reproductive performance of ewes grazing oestrogenic pastures was studied in four commercial flocks in 1973 and in an additional five in 1974 (a total of nine flocks). The number of ewes lambing per ewe mated differed significantly (P< 0·05) between mating types (male AA × female AA, male AA × female AB, male BB × female AB and male BB × female BB). Differences between mating types in the number of lambs born per ewe exposed to the ram and in the number of lambs weaned per ewe exposed to the ram bordered on significance (0·05<P<0·1). Matings involving BB sires were superior to matings involving AA sires. This finding differs from previously published evidence on this topic. There were no significant differences in lamb mortality or in the number of lambs born per parturition. Reproductive performance did not differ amongst ewe genotypes. Age of dam, farm and year had significant effects on most of the reproductive characteristics studied. Three significant interactions (P<0·05) involving mating type were found: mating type × age on number of ewes lambing per ewe exposed to the ram, mating type × farm on number of lambs born per parturition and mating type × year on lamb mortality. Due to the relatively small differences observed in reproductive performance between mating types it is concluded that selection for haemoglobin type is unlikely to overcome the problem of low reproductive performance in sheep grazing oestrogenic pastures.
The effect of sub-clinical nematode parasitism on reproductive performance in the sow
Authors: Pattison H. D. , Smith W. C. , Thomas R. J.
Published: September 2010

Ten sows were each infected with 300 000 larvae of Oesophagostomum dentatum after weaning their second litter, and subsequent per formance over one parity was compared with that of 10 ‘worm free’ controls. Mean worm burden in the sows when slaughtered immediately after weaning, was 13 480 ±2377. From service to weaning of the litter the mean body weight of worm-free sows increased (+11·3 kg) whereas that of infected sows declined (—13·1 kg) and at slaughter the carcasses of infected sows had lower depths of backfat. Worm-free sows averaged 12·8 pigs born of which 11·3 were born alive, corresponding values for infected sows being 12·4 and 9·5. Worm infection reduced birth weights by 15% but differences were not significant. Litters were equalized at eight pigs shortly after birth, and subsequent weaning weights were 10·5 % lower in those of infected sows despite a 29 % higher consumption of creep feed. Clinical disease was never observed in the infected sows, and no parasitic infection was found in the piglets. It is concluded that sub-clinical infections of O. dentatum in sows may be of economic significance.
A model for calculation of the energy requirements of the pregnant ewe
Authors: Geisler Pamela A , Jones C. Merryl
Published: September 2010

A computer program is described which allows the calculation throughout pregnancy of the energy requirements of a ewe of any weight carrying any number of foetuses. The calculations rely on a prediction of potential lamb birth weight, from which a foetal growth curve of weight against time from conception is generated. Tied to the foetal growth curve are the growths of the placenta and fluids, while growth of the uterus is related to the ewe's weight at mating. Weights are converted to energy through energy density curves applicable through pregnancy for each component. An efficiency factor converts this energy requirement into a metabolizable energy requirement. With assumptions on the maintenance requirements for the ewe-foetus system, the total requirement for energy during pregnancy is calculated.

Predictions from the model are compared with other estimates of energy requirements available in the literature. The sensitivity of the predictions of energy requirements for the pregnant ewe to variations in the assumptions made in the construction of the model is discussed. The most important assumptions are those on the maintenance requirements for the ewe-foetus system. Effects on the predicted energy requirements of varying either the efficiency for foetal growth or the gestation length are also discussed.
The effects of additions of sodium hydroxide and a concentrated solution containing urea, calcium, phosphorus, sodium, trace elements and vitamins on the intake and digestibility of oat straw by beef cows
Authors: Bass Jean M. , Fishwick G. , Hemingway R. G. , Parkins J. J.
Published: September 2010

Eight pregnant beef cows and four rumen-fistulated cows were given 1·67 kg barley dry matter per day and 5·1 kg chopped oat straw dry matter treated by one of four different methods. The straw treatments (given in a 4 × 4 Latin square design) were (A) nil, (B) sodium hydroxide (25 g/kg straw, dry matter basis), (C) a fully soluble liquid supplement containing urea, calcium, phosphorus, sodium, trace elements and vitamins (40 g/kg straw, dry matter basis), and (D) sodium hydroxide plus liquid supplement. In the absence of liquid supplement 0·3 kg per day of the straw dry matter was not consumed, and with the sodium hydroxide plus liquid supplement treatment the cows would have consumed more straw than was offered. Sodium hydroxide increased the digestibility of the straw organic matter from 0·46 to 0·50 (P <0·05), and this was further increased to 0·53 (P <0·01) for the combined sodium hydroxide plus liquid supplement treatment. The calculated metabolizable energy intakes from straw were increased from 31 (nil) t o 36 by either the sodium hydroxide or liquid supplement treatments (P <0·05) and to 41 by the combined treatments (P <0·001). Sodium hydroxide tended to increase the concentrations of n- and iso-butyric acids in the rumen liquor.
The relative efficiency of food utilization of British Friesian entire male and castrate male cattle at two levels of feeding
Authors: Griffiths T. W.
Published: September 2010

A combined nutritional balance and comparative slaughter experiment using 20 animals compared entire male and castrate male cattle when pair-fed at high and medium levels of feeding and slaughtered at a constant 400 kg live weight. The carcasses were dissected into lean meat, separable fat, and bone, and the edible portion of the carcass was further analysed for crude protein, fat and water.

There were no significant differences between entire and castrate animals in their ability to digest energy, nitrogen or modified acid detergent fibre. The mean metabolizable energy values (MJ/kg dry matter) of the diets were 10·6 for castrates and 10·9 for entire animals. Live-weight and carcass gains (kg/day) for each treatment were respectively: entire high feeding level, 1·10, 0·69; entire medium feeding level, 0·91, 0·57; castrate high feeding level, 0·92, 0·57; castrate medium feeding level, 0·79, 0·48. Castrate carcasses contained significantly (P < 005) less lean meat and more separable fat. The edible portion of these carcasses also contained significantly (P < 0·05) more total fat but less protein and water than entire carcasses. Daily carcass protein gain was significantly higher for entire animals (P < 0·001) but daily energy gain was not significantly different. The most efficient conversion of dietary metabolizable energy and crude protein to either live weight or carcass meat production was obtained by the use of entire animals and the high level of feeding.
Conception rates of beef cattle in Botswana following synchronization of oestrus with cloprostenol
Authors: Buck N. G. , Light D. , Makobo A. D.
Published: September 2010

In three trials conducted in 3 successive years, Africander, Brahman, Tswana, Tuli and crossbred cattle were injected intramuscularly with 500 jug of cloprostenol on two occasions 11 days apart to synchronize oestrus. The cattle were inseminated 72 and 96 h after the second injection. Controls of the same breeds were exposed to natural service for a period of 22 days. In all trials the conception rate to natural service was significantly higher (P < 0·01).

Conception rates to both breeding methods were highest in Tuli and crossbred cattle and lowest in the Africander and Brahman. Non-lactating cows showed higher fertility than suckling cows and maiden heifers.

Vasectomized bulls used in one trial were shown to be useful in the selection of breeding cows suitable for oestrus synchronization. Further studies are justified to maximize the benefits of a potentially valuable method of breeding beef cattle in ranching conditions.
Genetic size-scaling rules in animal growth
Authors: Taylor C. S.
Published: September 2010

Striking similarities are known to exist in the growth processes of different mammalian genotypes. Two genetic size-scaling rules formally summarize these well-established similarities. In consequence, experimental results in one breed or species can often provide an excellent quantitative guide to biological relationships in other species. Despite strong genetic similarity, much genetic diversity usually remains.
Genetic and environmental influences on beef cattle production in Zambia 2. Live weights for age of purebred and reciprocally crossbred progeny
Authors: Thorpe W. , Cruickshank D. K. R. , Thompson R.
Published: September 2010

Live weights from birth to 3·5 years are reported for beef cattle reared under ranching conditions in Zambia. The 809 cattle were purebred Africanders, Angonis, Barotses and Borans and the reciprocal crossbreds of the latter three breeds born in 2 years. All animals born in the 1st year and half the males born in the 2nd year grazed natural grassland. The remaining males and all females born in the 2nd year received, in addition, dry season supplementary feed from 1·5 years of age.

The interaction of genotype with year-of-birth was important but not the interactions of genotype with management or sex. Purebred progeny of the introduced Africander breed were heavier than the progeny of the indigenous Angoni and Barotse breeds in both year-of-birth groups, but only heavier than progeny of the introduced Boran breed in the first group. On average, the Africander progeny had live-weight advantages of about 16% and 10%, and the Boran progeny advantages of about 12·5% and 5·5% over the purebred Angoni and Barotse progeny respectively. Heterosis estimates tended to increase with age, reaching levels of about 5 to 6% in the Barotse/Boran crosses at and after 1·5 years. Heterosis was not shown by the other crosses. The Barotse and Boran breeds had similar maternal effects which were superior to those of the Angoni breed.
Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs
Authors: Mavrogenis A. P. , Louca A. , Robison O. W.
Published: September 2010

Data on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.
A note on the effects of forced air movement and environmental temperature on weight gain in the pig after weaning
Authors: Mount L. E. , Start I. B. , Brown D.
Published: September 2010

Twenty-six groups of four or eight pigs of mean initial weight 23·2 kg and mean age 84 days were exposed to environmental temperatures of 8, 12, 16 or 20°C under still-air conditions (wind-speed = 0·1 m.s−1) or of 12CC with wind-speeds of 0·45 or 0·8 m.s−1. The animals were fed at a fixed level close to three times their maintenance requirement, with water ad libitum, and were weighed weekly over a 7-week period. Variation in temperature between groups from 8 to 20°C had no significant effect on weight gain, but increasing wind-speed to 0·8 m.s−1 at 12°C resulted in reduced weight gain.
A note on the growth performance and carcass composition of Texel- and Suffolk-sired lambs in an intensive feeding system
Authors: Latif M. G. A. , Owen E.
Published: September 2010

Sixteen male and 16 female lambs were used to compare the performance and carcass composition of Texel- and Suffolk-sired lambs out of Finnish Landrace × Dorset Horn ewes. Lambs were weaned at 6 weeks of age and individually fed an all-concentrate diet ad libitum to slaughter at 30 kg (females) and 36 kg (males). At slaughter, offal weights were recorded and carcass left sides jointed and dissected.

Breed types did not differ in weight at weaning, growth iate, age at slaughter, daily feed intake or feed conversion rate. Texels had heavier carcasses (17·2 v. 16·4 kg: P <0·01) and higher dressing percentages (50·7 v. 49·2: P <0·05) than Suffolks. Texel-cross carcasses had 2·9% more lean (P <0·05), but 3·8% less total fat CP <0·01).

The results indicate the suitability of Texel-sired lambs for intensive lamb production.
Physiological attributes as possible selection criteria for milk production 1. Study of metabolites in Friesian calves of high or low genetic merit
Authors: Tilakaratne N. , Alliston J. C. , Carr W. R. , Land R. B. , Osmond T. J.
Published: September 2010

The use of variation in metabolism to predict genetic merit for milk production was studied using 42 Friesian calves: 11 ♀♀, 10 ♂♂ were the offspring of four bulls with high (H), and 11 ♀♀, 10 ♂♂ of four with low (L) improved contemporary comparison (ICC) values (mean = + 402 kg and − 276 kg respectively). The animals were 14 or 15 weeks of age at the start of the study and treated similarly throughout.

Blood samples were collected: I—in relation to feeding; II—at set intervals; III—during a 44-h fast; and IV—following the sudden introduction of an energy metabolite (sodium propionate), and then refeeding. Plasma concentrations of β-hydroxybutyrate, glucose, urea, free fatty acids, total proteins and albumin were measured in all samples.

Blood characteristics apparently differed among animals, particularly protein and urea (repeatability 0·74 and 0·62 respectively).

The progeny of high ICC bulls had lower levels of urea during fasting (H = 4·70, L = 5·62P< 0·05) but higher levels of free fatty acids (H = 578, L = 492 μ equivalents/l;P< 0·05). There was a small difference in total protein (H = 69·7, L = 66·8 g/l,P< 0·05) but the other metabolites showed no significant ICC group difference.

In general, sex of the animal did not influence the metabolites.

Results suggest that calves with different potentials for milk production vary in aspects of energy and nitrogen metabolism; the possibility of using these as criteria for genetic selection for milk production is discussed.
A comparison of machine-milking and the calf-suckling technique as methods of measuring the milk yield of beef cows
Authors: Somerville S. H. , Lowman B. G.
Published: September 2010

The milk production of 14 Hereford × British Friesian females in their second lactation (cows) and 36 in their first lactation (heifers) was measured at three levels of nutrition either by machine-milking twice a day, without the use of exogenous oxytocin, or by a calf-suckling technique. Machine-milking significantly increased the number of cows drying-off within 150 days of parturition (i><0·05) and significantly reduced milk yields compared with the calf-suckling technique (P< 0·01).

The 150-day cumulative milk yields of the heifers were not significantly affected by method of milking, but the coefficient of variation of milk yield was significantly greater in the machine-milked group(P< 0·05). One machine-milked heifer dried-off within the first 150 days of lactation.

There was no evidence of an interaction between method of milking and plane of nutrition in either the cows or the heifers.

It was concluded that measuring the milk production of beef cows by machine-milking, without the use of exogenous oxytocin, may be unreliable. Factors influencing the usefulness and reliability of the calf-suckling technique are discussed.
The effects of breed, crossbreeding and other factors on variation in fleece and skin traits
Authors: Woolliams J. A. , Wiener G.
Published: September 2010

Breed and crossbreeding significantly affected variation in 10 fleece, follicle density and fibre diameter traits in 12-week-old lambs. The breeds involved were the Scottish Blackface, South Country Cheviot, Welsh Mountain, Lincoln Longwool, Southdown and Tasmanian Merino, but the last only by rams.

The Southdown came closest to the Merino in affecting density and diameter traits although the Merino crosses remained clearly distinguishable by their high follicle density. The Lincoln and Blackface crosses were notable for their long fibres and the Blackface crosses also had the least dense follicle and coarsest primary fibres. The coarsest secondary fibres were from Lincoln and Cheviot crosses. Heterosis estimates were obtained for crosses involving the Blackface, Cheviot, Welsh and Lincoln breeds. Significant heterosis was present in a wide range of traits but was not apparent in all crosses. Maternal differences were evident for many of the traits but with density these differences were apparently related to maternal effects on live weight of the lamb. The sex of the lamb, its birth type and rearing and its 12-week live weight significantly affected many of the traits.

Among breeds and crosses a strong relationship was found between fibre density and average fibre diameter. The relationship suggested that breed variation in total fibre area per unit area of skin was small compared with the breed variation in its components. Fleece weight per unit area was most closely related to mean fibre length.
A note on the effect of monensin and amicloral in steer diets
Authors: Horton G. M. J.
Published: September 2010

The effects of feeding monensin and amicloral at 33 and 1500 mg/kg of diet, respectively, were investigated in two experiments using 330-kg steers. Monensin and amicloral, either alone or in combination, increased the digestibility of organic matter and crude fibre compared with a control diet (P< 0·001). Crude protein digestibility was increased by monensin (P< 0·001). Use of monensin and amicloral, alone or in combination, increased molar proportions of propionic acid by 22% on average (P> 0·05), and monensin decreased butyric acid by 37% (P< 0·05).

Ruminal ammonia concentrations were lower in steers fed monensin (P< 0·05). Steers fed monensin consumed 6 % less feed, gained 9 % more weight (P< 0·05) and utilized feed 14% more efficiently (P< 0·05) than control animals. Amicloral, either alone or with monensin, lowered feed intake by 11 % (P< 0·05), had no effect on average daily gain and improved feed efficiency by about 12% (P< 0·05). There were no treatment effects on any of the carcass parameters.
Diurnal variation of progesterone levels in milk and milk fat of crossbred cows during the oestrous cycle and early pregnancy
Authors: Batra S. K. , Pahwa G. S. , Suri A. K. , Pandey R. S.
Published: September 2010

Changes in progesterone levels in milk and in milk fat were measured by radioimmunoassay in nine crossbred cows for 40 days after insemination. On average, progesterone in milk was minimal: 1·10μg/l at the morning milking (M) and 1·63μg/l at the evening milking (E) on the day of oestrus; this increased to 15·72 μg/l at M and 22·8 μg/1 at E on day 13 after insemination, and thereafter declined to 0·99 μg/l at M and 1·12μg/l at E on the day that the next oestrous cycle commenced in non-pregnant cows. In pregnant animals the level was maintained, and fluctuated from 1505 to 19·60μg/l at M and 18·09 to 23·01 μ/1 at E up to 40 days of pregnancy.

The average progesterone concentration in milk fat was 18·9μg/l at M and 24·1 μl at E on the day of oestrus, and rose to a peak of 141·7μ/l at M and 153·8μg/1 at E on day 13 after insemination. It continued to increase and fluctuated between 160·6 and 195·8μg/l at M, and 161·1 and 225·6μg/l at E, in pregnant animals, but dropped to 12·0μg/1 at M and 16·7 μg/l at E on the day of the succeeding oestrus in those animals which failed to conceive. Progesterone concentration in milk and in milk fat was significantly higher in evening samples than in morning samples (P<0·05).