bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal variation in testis diameter and sperm output of rams of breeds of different prolificacy
Authors: Islam A. B. M. M. , Land R. B.
Published: September 2010

Seasonal variation in testis diameter and sperm output was studied in five Finnish Landrace (Finn) and five Tasmanian Merino (Merino) rams, together with five crossbreds between these breeds (Finn-Merino), five selected phenotypically from the Finn-Dorset breed type for high juvenile testis diameter (Finn-Dorset-High) and four for low juvenile diameter (Finn-Dorset-Low). There was marked seasonal variation in testis diameter for each of the breed types. The time of the seasonal increase in testis diameter varied among the breed types, the Merino rams starting earliest—49 days before the Finns. The characteristics of seasonal variation in testis diameter thus showed similarity with the characteristics of seasonal variation in the reproductive performance of females of the breed type. Breed differences in response to season were also demonstrated by a significant breed by season interaction for sperm production, but there were no indications of a useful association between variation in sperm production and variation in the reproductive performance of related females. Overall, differences in adult testis diameter were small relative to those among juveniles.
Fertility of inseminations with two sperm concentrations in oestrus-synchronized cattle
Authors: Boyd L. J. , Smith G. F. , Wood P. D. P. , Craven J. , Melrose D. R. , Williamson J.
Published: September 2010

Two field trials were conducted to evaluate oestrus synchronization under farm conditions and to determine if increased sperm numbers per insemination would enhance fertility at the first synchronized oestrus. One hundred and seventy-seven previously unmated British Friesian females in 6 dairy herds and 236 suckler cows in 9 beef herds were used. Treated animals received 1·0 mg melengestrol acetate (MGA) daily for 14 days. Treated and control animals were inseminated with either 15 or 60 million sperm per first insemination.

Oestrus was synchronized in 94% of the treated dairy heifers and 66% of the treated suckler cows. Oestrus detection by herdsmen appeared to be much less precise in suckler herds than in the dairy herds.

First inseminations were given during a 21-day breeding period (commencing at withdrawal of MGA) to 97% of treated and 79% of control dairy heifers (P<0·01), and to 77% of the treated and 69% of the control suckler cows (P>0·05). On an average, first inseminations were given 10 days earlier to treated heifers and 7 days earlier to treated suckler cows than to their control counterparts. The 45-day non-return rate to first inseminations was 81% for control and 41% for treated dairy heifers (P< 0·001) and 69% for control and 46% for treated suckler cows (P>0·05).

Oestrus-synchronized animals required significantly more services than control animals during a 30-day breeding period. However, there was no difference between treated and control animals in the non-return rate to one or more services given during the prescribed 30-day breeding period.

Insemination with 15 or 60 million live sperm had no effect on the non-return rate of treated or control animals.
Variation in intake among group-fed pregnant Scottish Blackface ewes given restricted amounts of food
Authors: Foot Janet Z. , Russel A. J. F. , Maxwell T. J. , Morris P.
Published: September 2010

The intakes of concentrates and hay by individuals in three groups of ewes were estimated at three-weekly intervals in late pregnancy from faecal output; chromic oxide was incorporated as a marker in the concentrates. The groups were: (1) 16 mature ewes, (2) 16 2-year-old ewes, (3) eight mature and eight 2-year-old ewes. A constant daily hay allowance of 734 g dry matter (DM)/sheep was given but the concentrate was increased from an equivalent of 96 g DM/sheep at the beginning of the experiment to 435 g at the end. Individual concentrate intakes were most variable when the group allowance was small (CV over 50% in the mixed group) but variation decreased when amounts of concentrates were increased to contribute up to 47% of the total digestible DM intake. The CV for the total digestible DM intake ranged from 13 to 24%.

The younger sheep were at no disadvantage when penned with mature ewes. Intakes by individual ewes were compared with their calculated requirements and several twin-bearing ewes were shown to have a substantial energy deficit which was confirmed by their higher plasma ketone concentrations.

A major practical difficulty in group-feeding pregnant ewes is to ensure that the ewes with the highest foetal burden are adequately fed.
The effects of quantity and distribution of milk substitute on the performance of artificially reared lambs to forty-eight days of age
Authors: Penning P. D. , Cottrell K. M. , Treacher T. T.
Published: September 2010

Twenty-seven groups of Finnish Landrace × Dorset Horn lambs, each of two males and two females, were offered daily quantities of 180, 248 or 343 g milk substitute dry matter (DM) for 21, 29 or 40 days. The environmental temperature was 18°C during the first 21 days of rearing, and concentrate pellets and clean water were always available. From 22 to 48 days of age the lambs were offered 150 g of hay per week.

For lambs offered 180 g milk substitute DM, increasing the number of days before weaning increased the daily live-weight gain over the 47-day experimental period. For daily allowances of 248 and 343 g of milk substitute, greater gains were effected only by delaying weaning from 21 to 29 days.

Increasing the daily allowance of milk substitute DM had little effect on the daily gain of lambs weaned after 21 days but increased gain by lambs weaned at 29 days. For lambs weaned after 40 days growth rate was increased only by the first increment of milk substitute DM. Intake of solid food began when the lambs were 3 weeks old and total intake of concentrates was inversely related to total quantity of milk substitute DM consumed and in general was less when weaning was later.

The overall efficiency of conversion of total DM consumed to live weight was positively related to total milk substitute DM consumed and tended to be greatest when weaning was later. A daily allowance of 180 g milk substitute DM for 21 days gave the lowest food cost per unit of live-weight gain.

The incidence of navel sucking is discussed.
A note on the relationships between solid food intake, the volume of the abdominal organs, and external body measurements in calves
Authors: Hodgson J. , Cottrell K. M.
Published: September 2010

Regression equations derived from Jersey calves fed on either chopped or ground and pelleted dried grass indicated that the volume of the organs of the abdomen or abdomen plus thorax could be predicted from simple external body measurements. The prediction equations did not differ significantly between diets. It is suggested that this measurement may be of importance in studies on the voluntary food intake of ruminants.
Breed variation in lambing performance and lamb mortality in commercial sheep flocks
Authors: Wiener Gerald , Deeble F. K. , Broadbent J. S. , Talbot M.
Published: September 2010

Two surveys were conducted on commercial farms in England, Wales and Scotland to ascertain whether breeding contributed to variation in the number of lambs born per ewe, in lamb mortality and in the number of lambs remaining to be weaned per ewe. Each flock comprised two or more breed groups, but within flocks differences in breed were often quite small.

In one survey of 74 flocks (average size 198 ewes, comprising 175 breed groups) the lambing percentage averaged around 150% and the lamb deaths to weaning (including stillbirths) around 9%. Within flocks there were statistically significant differences in the number of lambs born and weaned per ewe attributable to the breed of lamb and of its dam and sire. Crossbreeding was associated with a higher weaning percentage. Lamb mortality differed significantly among breeds and crosses of lamb. Lambing performance varied with type of farm.

The second survey was a comparison of different crossbred types of dam, themselves the offspring of three breeds of sire and seven of ewe. Thirty flocks participated, providing 29 sets of records for 1-yearold females producing on average 120% lambs and losing through death (including stillbirths) 25 % of lambs born, and 10 sets at 2 years old, with 176 lambs per 100 ewes lambing and 11 % of the lambs born dying before 8 weeks old. Variation attributable to the crossbred type of the dam and to the breed of the dam's sire was significant for lambing and weaning percentage and the incidence of lamb mortality.
The fatty acid composition of backfat from Pietrain and Large White pigs
Authors: Wood J. D.
Published: September 2010

The fatty acid composition of backfat from Pietrain and Large White pigs was examined. Both the inner and outer layers of Pietrain backfat had higher concentrations of unsaturated fatty acids and lower concentrations of saturated fatty acids. Pietrains consequently had relatively soft fat.

A pair-feeding experiment was conducted with Large White and Pietrain pigs to determine whether these differences could be explained by the lower voluntary feed intake of Pietrains. The results showed that the Large Whites continued to accumulate relatively saturated fatty acids even at the lower level of feeding. It was concluded that the differences in the fatty acid composition of backfat reflect genetic differences in the capacity for fat deposition between the two breeds.
The effect of daylength and nutrition on the oestrous and ovulatory activity of Greyface ewes
Authors: Ducker M. J. , Boyd J. S.
Published: September 2010

The onset and duration of oestrous and ovulatory activity in 26 Greyface ewes receiving natural daylength changes were determined. Precise ovulation data were obtained by endoscopy and repeated observations of the ovaries of all ewes were made on 10 occasions from 15 July 1971 to 27 June 1972. The natural breeding season for these Greyface ewes was, on average, 22 September 1971 to 18 February 1972. There were significant seasonal changes in the mean ovulation rate of the ewes which appeared to be inversely related to seasonal changes in natural daylength.

An abrupt decrease in artificial daylength of 11 -43 hr applied on 22 June 1971 to 28 similar Greyface ewes advanced their mean onset of oestrous activity by 23 days. The decrease in artificial daylength also advanced the occurrence of ovulation in these ewes. The highest mean ovulation rate of the ewes receiving the decrease in artificial daylength was at least as high as the peak mean ovulation rate measured in the control ewes.

At most stages of the experiment, the plane of nutrition had no significant effect on either oestrous or ovulatory activity in the ewes.
Post-natal follicle development and fleece changes in two selection lines of Scottish Blackface sheep
Authors: Ryder M. L.
Published: September 2010

Fleece and skin samples were taken at intervals from birth to 86 days from Scottish Blackface lambs born into one line selected for hairiness, another for fineness and an unselected control line. The birthcoats in the Hairy line were longer than those in the Fine line, and had a predominance of Plateauo and Pi fibre type arrays, whereas P2 and P3 arrays predominated in the Fine line. The Hairy group had significantly more halo hairs and hairy-tip curly-tip fibres, but significantly fewer histerotrichs.

Most secondary follicles had fibres by 56 days, and development appeared to be faster in the Control than in the other two groups. The Hairy and Control groups had consistently high percentages of primary medullation, whereas the Fine group had a peak at 14 days. The Fine group had consistently low secondary medullation, whereas it increased in the Hairy and Control lambs, apart from a set-back at 28 days.

Up to 56 days the Fine group had no fibre shedding in the skin, and the Hairy group had most, although the incidence in any sample was less than 2%. There was more follicle inactivity at 86 days, and the Fine group then had most.
An investigation of the anabolic effects of androstenedione in young ruminants
Authors: Johnson C. L. , Wilkinson J. M.
Published: September 2010

Three experiments were carried out to investigate the anabolic effects of androstenedione administered at various levels to female and castrated male lambs in one experiment and to entire and castrated male calves in two other experiments. Significant increases in growth were not effected in normally fed animals but a sex × dose level interaction was detected in female lambs. Under normal husbandry conditions androstenedione appears to have little application in meat production.
Feeding dried poultry waste for intensive beef production
Authors: Oliphant J. M.
Published: September 2010

Dried poultry waste was substituted for soya and fish meals in an intensive beef ration to ascertain if it was a satisfactory alternative source of nitrogen and in an attempt to reduce the cost of production. The experiment was conducted over 3 years in each of which groups of autumn-born British Friesian male castrates were taken from 150 kg live weight to slaughter at 400 kg on various rations. The treatment rations were made isonitrogenous with the control (14·5% crude protein). When the crude protein of the poultry manure was low (24%) it was necessary to include 27·6% in the diet and poor performances resulted. For manures of 30 % crude protein, or when urea was added to equalize the nitrogen content of diets containing up to 17·5% manure, performance was not markedly different from that shown with control diets. There was a considerable saving in the food cost at the prices ruling when the experiment was conducted and it was concluded that the use of dried poultry manure could increase the profitability of intensively produced beef.
Pre-pubertal mammogenesis in the sheep 3. The effects of restricted feeding or daily administration of bovine growth hormone and bromocriptine on mammary growth and morphology
Authors: Johnsson I. D. , Hart I. C. , Turvey A.
Published: September 2010

In crossbred female lambs reared on a concentrate diet between 8 and 20 weeks of age, a restriction in food intake to 40 g/kg body weight per day decreased live-weight gain (155 g/day) compared with that in control lambs fed ad libitum (284 g/day) and significantly reduced final live weight and the size of the mammary fat pad (P < 0·001). However, restricted lambs at 20 weeks had more total parenchymal deoxyribonucleic acid (DNA; 54·7 v. 47·5 mg) occupying a greater mass of mammary fat pad (17·0 v. 13·2 g) than control lambs (P > 0·10). Restricted feeding had little effect on mean plasma growth hormone (GH) concentrations at 12 and 18 weeks of age, but decreased plasma insulin and prolactin concentrations.

In lambs fed ad libitum, daily subcutaneous (s.c.) injections of 0·1 mg bovine pituitary GH per kg live weight between 8 and 20 weeks of age significantly increased daily live-weight gain (347 g/day; P < 0·001) and also increased total mammary parenchymal DNA (71·2 mg; P < 0·10) and the mass of fat pad occupied by parenchymal tissue (20·6 g; P < 0·05), compared with the control treatment. Daily s.c. injection of bromocriptine (1 mg/day) had no effect on either body or mammary growth, but tended to reduce the effects of bovine GH when given in combination. Secretory activity was observed in the parenchymal tissue of the eight lambs receiving bovine GH alone, and also in five control lambs and three lambs receiving bromocriptine alone. Three lambs that had attained puberty by 20 weeks of age had the poorest mammary development of their respective treatment groups.

Mammary gland development at 20 weeks of age was significantly correlated across treatment means with plasma GH concentrations estimated at 18 weeks of age (r = 0·95; P < 0·05), but no correlations of similar magnitude were found between individuals within treatments at 20 weeks. Strongest correlations were found among 8-week-old lambs, where mammary parenchymal DNA was positively correlated with mean plasma GH (r = 0·62) and the GH:insulin ratio (r = 0·79) and negatively correlated with the prolactin:GH ratio (r = -0·65).
Voluntary intake, health and performance of lactating ewes fed on turnips with or without straw supplement
Authors: Valderrábano J. , Uriarte J. , Muñoz F.
Published: September 2010

The effect of cereal straw supplement on turnip diets has been studied in Romanov × Rasa Aragonesa ewes in early lactation. Measurements were made of level of intake, blood characteristics and performance under pen-fed and grazing conditions. Barley straw supplementation resulted in a proportional increase of 0·1 in turnip intake to give daily intakes of 82 and 94 g organic matter per kg M0·75 for pen-fed and grazing ewes respectively.

Ewes fed on turnips showed a significant decrease in red blood cell numbers, haemoglobin and packed cell volumes though remaining within the range considered as normal for this species. Heinz bodies were present in proportionately up to 0·25 of erythrocytes and no clinical symptoms were observed.

The average weight gain of lambs reared by the grazing ewes was 173 g/day. However, growth rates of lambs and weight losses of ewes on turnip diets were lower than expected from the performance of animals on a control diet based on barley, lucerne and straw.
Food intake, milk production and body-weight change of milking cows given complete diets to appetite
Authors: Poole D. A.
Published: September 2010

In each of 2 years, 20 Friesian cows were given either a low-energy or a high-energy complete diet to appetite during weeks 3 to 20 of lactation. The diets for trial 1 contained concentrates, lucerne silage and chopped grass hay in the proportions 33:47:20 or 58:29:13. In trial 2, concentrates and lucerne silage were mixed in the proportions 38:62 or 75:25. These mixtures had energy concentrations of 10·2 or 11·2 and 10·3 or 11·9 MJ metabolizable energy per kg dry matter (DM) and crude protein concentrations of 144 or 160 and 140 or 157 g/kg DM in the low- and high-energy diets of trials 1 and 2 respectively.

Cows offered the low-energy diet consumed less DM daily (14·5 v. 17·4 (P < 0·001) and 15·2 v. 18·2 (P < 0·001) kg DM per day in trials 1 and 2). Daily milk yields were lower with low-energy diets (19·2 v. 22·3 (P < 0·001) and 18·7 v. 24·2 (P < 0·001) kg/day in trials 1 and 2), and there were significant differences between treatments in milk composition and live-weight changes.

The correlation between food intake and milk yield during weeks 3 to 20 was moderately strong (r2 = 0·58). Variation in food utilization efficiency between diets and parity groups was small in comparison to variation within parity groups.

During weeks 21 to 44 of lactation the cows were at grass. In trial 2, but not in trial 1, cows previously given the low-energy diet gave less milk (1999 v. 2644 (P < 0·001) kg) but gained more live weight. There were also differences in the composition of milk produced in this period.
Muscle weight distribution in lambs: a comparison of entire male and female
Authors: Butler-Hogg B. W. , Brown A. J.
Published: September 2010

The carcasses of 15 ram and 15 ewe lambs of the Dorset Down breed, weight range 12 to 23 kg, were separated into individual muscles, bones and fat depots.

At the same carcass weight (16-8 kg) the ram lambs contained 41 g more muscle per kg, but there were few important differences between sexes in individual muscle weights; 65 of the 72 muscles differed in weight by less than 10 g.

The distribution of total muscle weight between eight anatomical groupings differed significantly between the sexes; ewes had proportionately more muscle in the proximal pelvic limb (8 g/kg) and less in the neck (7 g/kg) and distal thoracic limb (1 g/kg). Despite these small differences in muscle-weight distribution in higher-valued joints in favour of the ewe lambs, each of their joints contained less muscle than those of ram lambs.

In these lambs, reared under commercial conditions in the United Kingdom, there were no signs of gross morphological differences which could result in their disqualification for the Variable Premium of the European Economic Community Sheepmeat Regime. In particular the m. splenius cervicus was a very small proportion of total muscle in both sexes (1·5 and 2·5 g/kg for ewe and ram respectively).
The effect of breed of sire on the urinary excretion of phosphorus and magnesium in lambs
Authors: Field A. C. , Woolliams J. A. , Woolliams Carol
Published: September 2010

Seventy-eight lambs, 9 weeks of age, the offspring of sires of the Scottish Blackface, East Friesland, Finnish Landrace, Suffolk and Texel breeds mated to Scottish Blackface females, as a common maternal breed, were given a barley-fish meal diet containing 1-6 g magnesium and 5·9 g phosphorus per kg dry matter for 13 weeks. Urinary excretion of Mg and P was estimated from the ratio of Mg or P to creatinine in spot samples of urine. A relationship between creatinine excretion and live weight was obtained using total urine excretion from a sample of 20 lambs, two of each sex from each sire breed group. Good agreement was found between the actual and predicted urinary excretion of minerals by the 20 lambs on three occasions.

The effect of sire breed on urinary excretion of P was significant (P< 0·05) and the breed types ranked, in descending order of excretion rate, Texel, Blackface, East Friesland, Finnish Landrace and Suffolk, with a four-fold difference in excretion rate between Texel and Suffolk. This difference in urinary excretion of P was taken as evidence of breed differences in efficiency of absorption of dietary P.

Urinary excretion of Mg was correlated with the intake of Mg. The mean estimated efficiency of absorption of dietary Mg varied, over the three occasions, from 0·42 to 0·50 and from 0·39 to 0·45 for total collections and for spot samples of urine respectively. Individual variation in the estimated efficiency of absorption within sires was not significant whereas that between sires was significant (P< 0·05). Heritability was estimated to be 0·62 (s.e. 0·30).
Cumulative selection differentials and realized heritabilities with overlapping generations
Authors: James J. W.
Published: September 2010

It is shown that a commonly used method of calculating cumulative selection differentials in experiments where generations overlap is biased, and consequently leads to biased estimates of realized heritability. In one example, the heritability was underestimated by about one-fifth. Since genetic variation in a given progeny crop may be increased by genetic differences between parental age groups, realized heritability estimated by regression may not agree with base population estimates. An alternative form of analysis is proposed to allow for this effect.
A note on a partial adjustment model to describe lactation curves
Authors: Hoekstra Janneke A.
Published: September 2010

Dhanoa and Le Du (Animal Production 1982, 34: 243–247) proposed a model in which the milk yield in a particular week is described by a weighted average of a straight-line target yield and the yield in the preceding week. It is demonstrated that the weight parameter × in this model is partially determined by the time from calving to peak yield and hence does not represent correlation between successive yields satisfactorily.
Effect of body condition at calving on tissue mobilization, development of fatty liver and blood chemistry of dairy cows
Authors: Reid I. M. , Roberts C. J. , Treacher R. J. , Williams L. A.
Published: September 2010

An experiment was performed with two groups of nine British Friesian cows to compare the effect of calving in fat or thin condition on (1) the mobilization and functional activity of subcutaneous adipose tissue, (2) the mobilization of skeletal muscle, (3) the development and resolution of fatty infiltration of the liver and (4) the chemistry and haematology of blood. Sampling was performed at various times during the dry period and subsequent lactation. There were no differences between groups in the amount of adipose tissue mobilized between 4 weeks before and 26 weeks after calving. The lipogenic and lipolytic capacities of isolated adipocytes were also not different between groups at any time although major changes occurred in both over the calving period and during early lactation. Acetate oxidation to carbon dioxide was higher in adipocytes isolated from thin cows particularly after calving. More muscle fibre area was lost in the fat cows compared with the thin cows between 4 weeks before and 4 weeks after calving and the fat cows had greater infiltration of fat in the liver at 1 and 4 weeks after calving than the thin cows. The mean white-cell count was lower and the packed-cell volume was higher in the fat cows than in the thin cows at 1 week after calving. The major differences between groups in blood composition were increased concentrations of copper, non-esterified fatty acids, bilirubin and enzymes such as ornithine carbamyl transferase in the fat cows after calving. These results suggest that fat and thin cows respond differently to the metabolic demands of early lactation and that some of these differences render fat cows more susceptible to disease.
Effects of ambient temperature and head cooling on energy expenditure, food intake and heat tolerance of Brahman and Brahman × Friesian cattle working on treadmills
Authors: Thomas C. K. , Pearson R. Anne
Published: September 2010

Energy expenditure, food intake and some physiological reactions of Brahman and Brahman × British Friesian cattle working on an inclined treadmill at 33°C were studied. The effect of work at a lower ambient temperature (15°C) and local cooling of the head region while at 33°C were also investigated. Whilst walking up a 6° gradient at 1 m/s, animals expended about four times as much energy as when standing. Heat production during work (W/kgM0·75) was similar in both breeds and was not influenced by the treatments imposed. Crossbred animals showed significantly higher respiration rates and sweating rates than the Brahmans immediately after working for 30 min at 33°C. Food intake and body-weight changes in the crossbreds at 33°C compared with Brahmans provided further evidence that these animals were less tolerant of the conditions. Head cooling during work appeared to reduce depression in food intake associated with work at 33°C in both breeds although it had no effect on physiological changes.
Metabolic rate and rewarming speed of hypothermic neonatal lambs given thermal assistance or added insulation
Authors: Robinson J. B. , Okamoto M. , Young B. A. , Christopherson R. J.
Published: September 2010

To evaluate passive and active methods for rewarming hypothermic lambs, the rectal temperature of 19 neonatal lambs (4·9 (s.e. 0·34) kg) was reduced to 35°C by cold water immersion. Metabolic responses and change in rectal temperature were monitored as the hypothermic lambs recovered with added insulation in a 20 to 25°C air environment, or with thermal assistance provided by an infrared heat lamp, or through immersion in 38°C water. During the first 12 min of rewarming, the rise in rectal temperature in all treatment groups was linear, however it was more rapid with the lambs immersed in warm water (0·26°C/min;P< 0·05) as compared with the insulated lambs (0·21°C/min) and the lambs rewarmed with a heat lamp (0·22°C/min). During this 12-min period, the insulated lambs produced metabolic heat more rapidly than did the warm-water lambs, 13·6v.11·1 (s.e. 0·67) W/kg, respectively(P< 0·05). These data indicate that there was a substantial influx of heat which contributed to the increase in body temperature of the lambs immersed in warm water. Stabilization of rectal temperature occurred after 18 to 20 min in all treatment groups. The lambs recovered in all treatment groups, in addition, no clinical problems were observed in any of the lambs during the tests or subsequently when they were returned to their dams.
Artificial rearing of piglets: the administration of two sources of immunoglobulins after birth
Authors: Varley M. A. , Maitland Alison , Towle Alison
Published: September 2010

Sixty Landrace × Large White piglets were removed from their mothers at birth and allocated to one of five treatments. Treatment A piglets were controls and did not receive any form of passive immunity after birth. Treatment B piglets were given by intraperitoneal injection 20 ml equine serum derived from horses previously hyperimmunized against porcine pathogens. Treatment C piglets received the same equine serum given orally. Treatment D piglets were given 20 ml pooled pig plasma by intraperitoneal injection. Treatment E piglets received the same pig plasma given orally. All piglets were reared to 2 weeks of age in an artificial-rearing device and were automatically fed a liquid diet every hour. Overall survival to 2 weeks of age was 90% (54/60) but treatment did not affect survival. The overall survival after 6 weeks of age was 47% (22/47) deaths being due to a variety of systemic disorders. Overall daily gain to 2 weeks of age was 143 g/day and the food/gain ratio was 0·88. Treatment did not affect performance. The concentrations of immunoglobulin class G (IgG) in the blood were measured at 42, 49 and 56 days of age. There were no differences between the treatment groups in IgG concentrations.
A note on the estimation of the chemical body composition of sows
Authors: King R. H. , Speirs Elizabeth , Eckerman P.
Published: September 2010

Present day sows, particularly young sows, have smaller fat reserves than they did 10 to 20 years ago (Whittemore, Franklin and Pearce, 1980). Consequently, changes in the sows' body reserves during pregnancy and lactation have become much more critical in evaluating various nutritional strategies. The interpretation of many experiments designed ot investigate the effects of nutrition of the sow would be enhanced if changes in the body composition of the animal could be determined.
Effects of offering silage overnight in the early grazing season to autumn-calved cows
Authors: Aston K. , Daley S. R. , Gibbs B. G.
Published: September 2010

Three experiments were conducted in the early grazing seasons of 1982–84 inclusive. Autumn-calved lactating British Friesian cows grazed a perennial ryegrass pasture either by strip grazing to leave 80 mm residual herbage (SG) or by rotationally grazing six paddocks on a fixed pre-determined cycle (PG). They were offered grazing only or grazing and average quality grass silage (S) or a 1: 1 mix of silage and ensiled brewers' grains (SB) given individually overnight in a cubicle house.

In experiment 1, cows received treatments SG or SGS. The intake of silage dry matter (DM) was 4·3 kg/day and the estimated intakes of herbage DM from measured animal performance were 15·2 and 8·9 kg/day respectively. Milk yields were 18·4 and 15·3 kg/day, the concentrations of fat and protein in the milk were 38·0, 41·8 and 33·3, 30·8 g/kg and live-weight change was +679 and +348 g/day for treatments SG and SGS respectively.

For experiment 2, cows received treatments SG, PG or PGS and grazing stocking rates were 5·2, 5·5 and 11·0 cows per ha respectively. Silage intake was 6·1 kg/day DM and the estimated intakes of herbage DM were 14·2, 15·3 and 7·7 kg/day respectively. Milk yields were 18·2, 18·2 and 16·1 kg/day, the concentrations of fat and protein were 41·6, 39·8, 42·3 and 33·3, 33·0, 30·4 g/kg and live-weight change was +325, +540 and +161 g/day for treatments SG, PG and PGS respectively.

For experiment 3, cows received treatments PG, PGS or PGSB and grazing stocking rates were 5·8, 11·6 and 11·6 cows per ha respectively. The intakes of silage and silage plus brewers' grains DM were 6·5 and 8·5 kg/day. The estimated intakes of herbage DM were 14·2, 7·2 and 7·3 kg/day, milk yields were 18·7, 14·6 and 18·9 kg/day, the concentration of fat and protein in the milk were 37·3, 42·1, 40·3 and 33·4, 32·6, 32·9 g/kg and live-weight change was +425, +415 and +441 g/day for treatments PG, PGS and PGSB respectively.

The results show that offering silage overnight allowed grazing stocking rates to be doubled, raised the concentration of fat in the milk and depressed the yields of milk and protein. When brewers' grains were given with the silage, yields of milk fat and protein were greater compared with when silage was offered alone and the yield of fat was greater than for herbage alone.
Concentrations of blood constituents in genetically high and low milk-production lines of British Friesian and Jersey cattle around calving and in early lactation
Authors: Gibson J. P. , Field A. C. , Wiener G.
Published: September 2010

Differences between Friesians and Jerseys and between progeny of high and low contemporary comparison (CC) sires were sought by examining nine blood constituent concentrations around first and second calvings and during lactation. A total of 1359 samples from animals at first lactation and 1148 samples at second lactation were collected. All animals were individually fed a complete pelleted dietad libitum. Blood constituents analysed were free fatty acids (FFA), ketones, glucose, calcium, magnesium, copper, phosphorus, albumin and globulin. All nine constituents showed marked changes around parturition and early lactation and several constituents showed changes with age. Jerseys had higher average copper and albumin levels and lower globulin levels than Friesians at both lactations and higher FFA concentrations at second lactation. Changes in plasma concentrations of FFA, ketones and glucose around calving were consistent in suggesting that Jerseys and progeny of high CC sires had a substantially greater energy deficit in early lactation than Friesians and progeny of low CC sires at the first but not the second lactation. Predicted requirementsv. recorded intakes suggested that the Jerseys and high CC progeny had the greater energy deficit at both lactations. Although the incidence of hypocalcaemia was nearly zero, changes of calcium and magnesium concentrations were consistent with reports of Jerseys being more susceptible to hypocalcaemia in later life.

Despite large differences in milk yield, differences in plasma concentrations between animals classified as either high or low achieved yielders within their genetic class were generally smaller than differences between progeny of high and low CC sires.
Adrenal function in lambs treated with androgenic and oestrogenic growth stimulants
Authors: Sillence M. N. , Thomas K. M. , Anil H. , Redfern E. J. , Rodway R. G.
Published: September 2010

Three experiments were carried out in which plasma cortisol concentrations were measured hourly in lambs treated with various anabolic steroids. In the first experiment, female lambs were implanted with trenbolone acetate (TBA) and plasma cortisol was measured for 24-h periods 4 weeks after implantation and 1 week after reimplantation. Plasma cortisol levels were unaltered 4 weeks after treatment, but were found to be significantly lower 1 week after retreatment. On this occasion, peak concentrations of cortisol after ACTH challenge were also reduced by TBA. In the second experiment, female lambs were implanted with a mixture of TBA and oestradiol and plasma cortisol measured 1 and 4 weeks later. Results were similar to the first experiment although the reduction in plasma cortisol was less. In the third experiment, castrated male lambs were implanted with either TBA, TBA plus oestradiol or a long-acting oestradiol implant. In this experiment, only oestradiol affected plasma cortisol levels, causing a large elevation. All three treatments stimulated growth. Measurement of bound and free cortisol concentration in the third experiment indicated that oestradiol treatment tended to increase the proportion of cortisol present in the free form.

These results suggest that an inhibition of cortisol secretion may be important in the anabolic response of female sheep to TBA. In the male, however, cortisol concentrations are naturally lower and are not further reduced by TBA treatment.

Plasma insulin concentrations were also measured in the castrated males. Neither TBA nor the combined implant altered insulin levels, but oestrogen treatment resulted in a small increase in insulin. The diurnal pattern of plasma insulin closely paralleled that of cortisol.
Oestrus synchronization and fertility in ewes: a comparison of three methods
Authors: Beck N. F. G. , Davies M. C. G. , Davies B. , Lees J. L.
Published: September 2010

Two experiments were designed to test the efficacy of two different methods of administering prostglandin F2α-tham salt for oestrous synchronization in mature cyclic ewes maintained under normal husbandry conditions. The effect of these agents on ewe fertility and lambing performance was also assessed.

A total of 180 Clun Forest ewes were used in this investigation conducted during the 1983 and 1984 breeding seasons. In the 1983 breeding season, 80% of ewes treated with a single injection of 20 mg prostaglandin F2α-tham salt were mated by fertile rams within a 3-day period, compared with 100% of ewes treated with progestagen pessaries or 23% of ewes treated with saline. Returns to service for the three groups were 23%, 3% and 16%, respectively. In 1984, a single injection of 20 mg prostaglandin F2α-tham salt resulted in oestrus synchronization in 73% of treated ewes, compared with 27% of saline-treated controls and 97% of ewes given two injections of prostaglandin F2α-tham salt, 11 days apart. Returns to service following these treatments were 36%, 6% and 20%, respectively. There was no difference between treatments in lambing performance.

The results indicate that acceptable levels of oestrus synchronization and fertility can be obtained with a single injection of 20 mg prostaglandin F2α. Furthermore, two injections of 20 mg prostaglandin F2α given 11 days apart produce levels of synchronization of oestrus comparable to those previously obtained with commercially available progestagen pessaries.
Metabolic control and future opportunities for growth regulation
Authors: Reeds P. J.
Published: September 2010

The last 10 years have seen a significant expansion in the scope of attempts to manipulate the growth of animals (Buttery, Lindsay and Haynes, 1986). The expansion of interest has been driven by a number of factors, both economic and theoretical. At the economic level the need to develop energetically and economically efficient strategies of animal production has been coupled with a renewed awareness of the implications for human health of excessive intakes of saturated fats. Emphasis then has switched from the maximization of weight gain as an end in itself towards a need to promote protein deposition at any given intake and, at the same time, to reduce the fat content of meat and meat products. These twin objectives might be achieved by one of three strategies: the promotion of protein deposition alone, because at any given rate of weight gain this will tend to minimize the rate of fat deposition (the so-called repartitioning effect); the reduction of fat gain (an approach that has received particularly close attention by those concerned primarily with human obesity); or ideally the simultaneous promotion of protein accretion and depression of that of fat.
Livestock production in central Mali: environmental factors affecting weight in traditionally managed goats and sheep
Authors: Wilson R. T.
Published: September 2010

A study of the factors affecting weight in traditionally managed goats and sheep in central Mali was undertaken during 1978–84. Sheep were heavier than goats at all ages. Birth weights of goats (2·2 kg) were significantly affected by year and season of birth, parity, type of birth, sex and system (rain-fed millet or irrigated rice). Lamb birth weights (2·9 kg) were affected by all these sources of variation except year. System did not exert a significant influence on kid weights at 30 (4·3 kg), 90 (7·5 kg) or 150 days (10·5 kg) but the random effects of flocks and dams and the fixed effects of season, year, parity, type of birth, sex and the interaction of season × year were all significant at all three ages except for year at 30 days. Lamb weights (5·7, 11·1 and 15·5 kg) were significantly affected at all three ages by all sources of variation except season × year effects at 90 and 150 days. Repeatabilities of lamb weights were higher than of kids, probably due to milk being taken for human consumption from goats. There were few significant effects at post weaning to 730 days except those related to sex. Post-partum weights of goats (26·0 kg) were not affected by system, by the type of parturition nor by the sex of the young but were affected by season and year of parturition and by parity. Ewe post-partum weights (30·6 kg) were affected only by system and parity. Changes in weight over the year, pooled for 7 years, in specific age and sex groups averaged proportionately about 005 above and below the annual mean. Weights of mature animals were about 0·05 lower in 1984 than in 1978. Seasonal and long-term effects on weight are much less marked in small ruminants than in cattle under the same management system in the central Mali environment and the allocation of future research effort should take into consideration the relative advantages of the two types of stock.
The use of product traits such as lean growth rate as selection criteria in animal breeding
Authors: Simm G. , Smith C. , Thompson R.
Published: September 2010

In meat animals there is some interest in lean growth rate or lean food conversion efficiency as selection criteria. These traits may be estimated as the product of growth rate (or efficiency), killing-out proportion and carcass lean proportion. When used as selection criteria these product traits do not require estimates of genetic parameters or economic values for component traits. Hence, they may be more stable, and of longer-term use than classical economic selection indices. The purpose of this study is to compare expected responses to selection on product traits with expected responses from selection, either on individual component traits, or on an economic selection index. Formulae were derived for predicting the phenotypic and genetic correlations between a product and one component, and for predicting the heritability of the product trait; these depend on the coefficients of variation and heritabilities of components, and on the genetic correlations among them. When the coefficient of variation of one component is much higher than that of the other, (× 3), this component will tend to dominate the product trait. In cattle and sheep, and to a lesser extent in pigs, killing-out proportion and leanness are usually less variable than growth rate or efficiency. Thus, in many cases, there is little loss in response in lean growth (or lean efficiency) from selection solely on growth rate (or efficiency) regardless of leanness. Although product traits do not require derivation of economic values, their component traits do have implied economic values. Often more appropriate weightings will be given to components by using an economic selection index, even when economic values and genetic parameters are not estimated precisely.
A note on concentrate energy source for dairy cows in mid lactation
Authors: Sloan B. K. , Rowlinson P. , Armstrong D. G.
Published: September 2010

The forage: concentrate ratio in the diet is known to influence the fermentation characteristics in the rumen (Sudweeks, Ely, Mertens and Sisk, 1981). Increasing the proportion of concentrates in rations fed to dairy cows has been shown to narrow the acetate plus butyrate: propionate ratio in the rumen (Sutton, 1981) with an associated depression in milk fat concentration (Ørskov, Reid and McDonald, 1981). The magnitude of the effect, on milk yield and composition, of increasing the concentrate proportion in the ration has been shown to be dependent on feeding level (Sutton, 1981), and the number of meals of concentrate per day (Johnson, 1979) and also may be influenced by dietary protein level and source (Ørskov et al., 1981).
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight 5. Adipocyte volume and number in the dissected fat partitions
Authors: Thompson J. M. , Butterfield R. M. , Reddacliff K. J.
Published: September 2010

The cellular characteristics of dissected carcass (subcutaneous and intermuscular fat) and non-carcass (kidney fat, omental and mesenteric fat) fat partitions were examined at maturity in a total of 34 rams and ewes from flocks of Peppin Merino sheep selected for high (weight-plus) or low (weight-minus) weaning weight and from a randomly bred control flock. Strain and sex effects on the rate of change in adipocyte volume in each fat partition relative to the change in chemical-fat weight in that partition, were examined in 60 immature animals.

Selection for high or low weaning weight had no effect on adipocyte volume in the mature animals, with the increased weight of fat in the weight-plus animals due to an increased number of adipocytes in the dissected fat partitions. Consequently, hyperplasia had a greater contribution to increases in chemical-fat weight in the weight-plus, compared with the weight-minus animals.

Mature ewes had larger and fewer adipocytes in the subcutaneous and intermuscular partitions than the mature rams, whereas there was no difference between the sexes in adipocyte volume in the kidney, omental and mesenteric fat partitions. Mature ewes had fewer adipocytes than the mature rams in the subcutaneous, intermuscular, omental and mesenteric fat partitions. With the exception of the kidney fat partition, there was no sex effect on the relative contribution of hypertrophy to increases in chemical-fat weight of the dissected carcass and non-carcass fat partitions.
Protein growth in pigs
Authors: Whittemore C. T. , Tullis J. B. , Emmans G. C.
Published: September 2010

Estimates were made of total body protein in 45 unimproved crossbred pigs slaughtered serially between 20 and 200 kg live weight. Allometric functions were used to estimate protein weight at any given body weight and the Gompertz function was used to express live-weight changes in relation to time and to predict weight at maturity. Predicted values for daily protein retention increased rapidly from 20 kg to attain, at around 75 kg live weight, maxima of 130 g for entire males, 120 g for females and 105 g for castrated males. Between 45 and 110 kg live weight rates of protein retention were maintained within 10 g of the maximum rate. Mature live weights were estimated to be 240, 215 and 225 kg for entire males, females and castrated males. The allometric exponents for whole body protein as a function of body weight were 0·963 (s.e. 0·025), 0·927 (s.e. 0·021) and 0·850 (s.e. 0·049) for entire males, females and castrated males respectively.