bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of diets containing different levels of wheat straw on lamb performance, feed intake and digestibility
Authors: O'Donovan P. B. , Ghadaki M. B.
Published: September 2010

A total of 120, 6–7-month-old fat-tailed uncastrated Kellakui lambs were randomly allotted to three groups, given fattening diets for 93 days and then slaughtered. The diets contained 10 (A), 20 (B) or 30% (C) coarsely chopped wheat straw; the latter was increased at the expense of dried beet pulp. All diets contained 45% ground barley, 10% beet molasses and 1% ground oyster shells; there were minor adjustments in the cottonseed meal percentage to maintain a similar protein level in all diets.

The three diets were also given in sequence to six adult male Kizil (fat-tailed) sheep in a digestibility trial. Further digestion trials were made with chopped wheat straw given alone or supplemented with 400, 800 and 1200 g of a concentrate consisting of 75% dried beet pulp and 25% cottonseed meal; an all-concentrate treatment was also included.

Daily gain (g), feed efficiency (kg feed/kg gain) and dressing percentages for lambs given diets A, B and C were, respectively: 154, 9·78, 54·5; 159, 9·85, 53·5; 127, 11·30, 53·1. A significant decrease in daily gain occurred with the highest straw level and considerably more feed was required per unit of gain. Supplementing straw with 400 g of concentrate increased daily dry-matter intake per sheep from 645 g to 1214 g, with further but smaller increases at higher levels of supplementation. Almost linear increases were observed in dry-matter digestibility as more concentrate was given.
Growth rate, feed conversion ratio and carcass traits of Charolais × Holstein-Friesian and Hereford × Holstein-Friesian steers slaughtered at three different weights
Authors: Fahmy M. H. , Lalande Gaspard
Published: September 2010

Thirty one-year-old Charolais × Holstein-Friesian (CH) and Hereford × Holstein-Friesian (HH) steers averaging about 268 kg live weight were used to study the effect of increasing slaughterweight from the traditional 454 kg (1000 lb) to 544 and 635 kg (1200 and 1400 lb) live weight. The steers were fed a growing ration of grain, silage and hay until they weighed 68 kg (150 lb) below the assigned slaughter weight, followed by a finishing ration of grain mixture and maize silage given ad libitum. Average daily gain on the growing ration was 0·91 kg in CH, 14% higher than that in HH steers, while on the finishing ration HH steers, finished at 544 and 635 kg, made higher gains. CH steers were 7·9% more efficient than HH steers in feed conversion. Feed conversion efficiency (total dig. nutrients (kg) per kg live-weight gain) decreased by 10% and 19% respectively as slaughter weight increased to 544 and 635 kg. Live measurements showed that CH steers were generally longer, taller and wider at the hip, whereas HH steers had a greater depth of chest and width of shoulder. CH steers, slaughtered at different weights, had a higher percentage of round and shank, while HH steers had a higher percentage of all other wholesale cuts. Carcass measurements were generally higher in CH than in HH steers. CH steers had a higher percentage of muscle and bone, and lower fat, in the 12th rib. They also had larger areas of m. longissimus thoracis. Fat deposition over and in that muscle was much higher in HH than in CH steers. Under the conditions of this study, 544 kg was found to be the optimum slaughter weight for both groups. Slaughtering steers at 635 kg was found to be economically disadvantageous.
The effects of quantity and distribution of milk substitute on the performance and carcass measurements of artificially reared lambs
Authors: Penning P. D. , Treacher T. T.
Published: September 2010

Twenty-seven groups of Finnish Landrace × Dorset Horn lambs each of 2 castrated males and 2 females were offered daily quantities of 180, 248 or 343 g of milk substitute dry matter (DM) for 21, 29 or 40 days. Concentrate pellets were available ad libitum and from 22 days of age 150 g of hay per week was offered. When the mean live weight of a group reached 35 kg two castrates and one female from each group were slaughtered and the carcasses appraised.

The growth rate and daily concentrate intake of lambs from 48 days of age until slaughter (reported -in this paper) were not affected by previous treatment, but lambs weaned at 40 days had a higher food conversion efficiency in this period (0·266 kg gain/kg feed DM) than those weaned at 21 days (0·244) or 29 days (0·232).

Delaying weaning from 21 to 29 and 40 days reduced overall concentrate DM intake from birth to slaughter (from 88·15 to 81·09 and 73·39 kg) but increased growth rate (261, 276 and 288 g/day) and the conversion of total DM consumed to live weight (0·300, 0·311 and 0·350 kg/kg). Increasing the daily allowance of milk substitute from 180 to 248 and 343 g/day also reduced total concentrate intake (84·18, 80·74 and 77·71 kg). Growth rate and food conversion efficiency tended to increase and concentrate DM intake to decrease when the same total quantity of milk substitute was given over a longer period. Castrated males grew faster than females (290 v. 260 g/day).

Weaning age generally had a greater effect than daily allowance of milk substitute on carcass measurements. Fat in the carcass tended to increase with increasing weaning age and significant interactions between daily allowance of milk substitute and weaning age were found for some carcass measurements.
Meat production from pigs which have farrowed. 2. Carcass characteristics
Authors: Brooks P. H. , Cole D. J. A. , Jennings W. J. N.
Published: September 2010

The carcass characteristics of young adult female pigs (gilts) slaughtered after weaning their first litters have been investigated using three groups of 19 Landrace × (Landrace×Large White) gilts. In two treatment groups gilts were mated at their pubertal oestrus and suckled their piglets for 5 to 11 and 35 to 42 days respectively. These gilts were slaughtered on average 10 days after weaning. A third control group consisted of unmated gilts slaughtered at 118 kg live weight.

There was no significant difference in the killing-out percentage for the three groups. The carcasses of the gilts which farrowed contained significantly less fat (P<0·001) than those of the unmated controls. The carcasses of the farrowed gilts had significantly lighter middle sections (P<0·001) and significantly heavier shoulders (P<0·001) than the controls.

Despite the variations in tissue yield and distribution, the yield of prime joints for the gilts which had farrowed was only 0·62 percentage units less than that of the controls.

No commercially significant variations between groups in meat quality were observed.
Some consequences of high flock prolificacy in an intensive grassland sheep production system
Authors: Boaz T. G. , Tempest W. M.
Published: September 2010

An intensive sheep production system using flocks of 100 Scottish Halfbred (SHB), 100 Welsh Speckleface (WSF) and 100 Finn Blackface (FBF) ewes maintained by 8, 4 and 6 ha grassland respectively for a 5-year period, was investigated to establish the consequences of high flock prolificacy and the measures taken to achieve it, including PMS administration. Mating occurred in late October/November at ewe: ram ratios of 25 or 33: 1. Ewes were housed in winter and fed silage, with supplementary cereals in late pregnancy. Lambs in excess of 2 (SHB) and 1 (WSF and FBF) per ewe were artificially reared and fattened indoors; ewes and lambs at grass were rotationally grazed (with forward creep grazing by the lambs). Prolificacy in the SHB breed was 225 lambs born per 100 ewes mated for untreated ewes and 237 for hormone-treated ewes; 119 and 155 respectively for WSF ewes; and 255 for FBF ewes (all untreated). Lambs sold per 100 ewes mated were: for SHB, 200 and 177; WSF, 102 and 107; FBF, 201.

Good ewe condition and heavy live weights at mating were associated with appetite problems on silage in late pregnancy; PMS injection with a failure to secure conception rates above 80% at the critical oestrus and a markedly lower prolificacy for ewes conceiving at later oestruses; mating in the middle of the breeding season and March/April lambing with slow lamb growth rates on grass in July and August. Hormone-induced high prolificacy was associated with a greater proportion of large multiple litters than natural high prolificacy, and consequent smaller lamb birth weights and more perinatal mortality. There was a significant negative regression relating fleece weight with litter size. The results suggest the existence of an optimal level of prolificacy for the system employed.
The effect of an anabolic steroid on the performance and carcass measurements of gilts and barrows in the finishing stages of growth
Authors: Williams I. H. , Dunkin A. C.
Published: September 2010

1. An experiment involving 64 individually-penned pigs (32 females (gilts) and 32 castrated males (barrows)) was conducted over the live weight range 50 to 83 kg, to study the effects of a parenterally administered anabolic steroid upon the performance and carcass measurements of gilts and barrows given either a 15·0% or an 18·8% crude protein (CP) diet at two different levels.

2. The steroid significantly improved both daily weight gain (+5·2%) and food conversion ratio (+4·8%) of gilts and barrows.

3. There were no significant treatment interactions for either daily weight gain or food conversion ratio, but the data suggest that gilts responded to the hormone to a greater extent than barrows at the particular dose level of the steroid administered.

4. The steroid significantly improved the carcass, as assessed by linear backfat measurements, of pigs given the higher CP diet but had no effect upon carcass measurements of pigs given the lower CP diet.
Relationship between live weight, age and dry-matter intake for beef cattle after different levels of food restriction
Authors: Lopez Saubidet C. , Verde L. S.
Published: September 2010

Five groups of 24 Aberdeen Angus steers, initially 8 months old and 185 kg in weight were subjected to varying degrees of restriction of energy intake, by feeding them on diets containing 1·45 to 2·85 Meal metabolizable energy (ME)/kg dry matter (DM) for 16 weeks. During the realimentation period that followed, all animals were fed ad libitum on the diet containing 2·85 Meal ME/kg DM. When realimentation began the feed consumption of all animals, which had been markedly different, rapidly became similar. When compared at equal live weight the restricted animals had higher intakes than the controls; at an equal age, however, feed intakes were practically the same. This led us to discard compensatory feed intake as a possible explanation for compensatory growth. Age explained 65% of the variability in feed intake, live weight explained 43% and both parameters jointly explained 73%. It is concluded that in restricted and realimented animals, age is a better predictor of feed intake than live weight. Compensatory growth is attributed to a lower maintenance requirement in restricted animals because of their lower live weight at the beginning of the realimentation period.
A note on short term selection for birth weight in mice
Authors: Eklund J. , Bradford G. E.
Published: September 2010

A short-term selection experiment was undertaken to estimate the realized heritability for birth weight in mice.

A cross of two strains was used as a base population, from which heaviest and lightest birth weight individuals were selected to initiate an up (JU) and a down (JD) selected line. Selection was applied on a within-litter basis for six generations. By the end of the experiment, the two lines differed by 0·20 ± 0·01 g. The heritability, estimated from the regression of cumulative response on cumulative selection differentials and adjusted to that of individual values, was 0·14 ± 0·02. Six-week body weight, averaged over both sexes, was higher in line JU than in JD by 1·0 ± 0·3 g at generation 6. Litter size was higher in line JU in every generation, the regression of the divergence between JU and JD on generation number being 0·13 ± 0·03.
Maternal effects and selection response with an application to sheep data
Authors: Hanrahan J. P.
Published: September 2010

The implications of genetic variation in maternal performance for the relative merits of common selection strategies have been investigated. If the accuracy of progeny testing is computed without taking maternal effects into account, the estimate is biased upward. This bias increases as the correlation between direct and maternal genetic effects decreases from positive to negative values. The relative efficiency of progeny and performance test selection is a function of the heritability of direct and maternal genetic effects and the correlation between them. In terms of genetic gain per unit time, progeny testing is almost always less efficient than performance testing. For sire line improvement progeny testing is relatively more useful but is still likely to be less efficient than performance test selection unless there is a negative correlation between direct and maternal genetic effects or the correlation between purebred and crossbred direct genetic effects is very low or negative.

Analysis of body weight at 6 and 14 weeks of age in Galway sheep has shown that maternal genetic effects are an important source of variation in this population.
The cellularity of backfat in growing pigs and its relationship with carcass composition
Authors: Wood J. D. , Enser M. B. , Restall D. J.
Published: September 2010

1. Using 12 castrated Large White pigs, the way in which the size and number of recognizable fat cells (i.e. > 6·0 μm) increases during growth from 26 to 109 kg live weight, and the relationships between fat cellularity and body fat content were determined.

2. Fat biopsy samples were taken at 87, 145 and 188 days of age from the shoulder region. This region grew rapidly in volume but was early maturing since its relative growth during the period of the experiment was low compared with other regions, particularly the mid-back to loin region.

3. The growth of fat that occurred during the experiment was due to increases in both the size and number of recognizable cells. There was no indication that the number of cells had become constant even at 188 days of age.

4. Subcutaneous or total fat expressed as a percentage of total dissectible tissue weight was related quite closely (r= 0·6 to 0·7, residual s.d. about 8% of mean fat percentage) to average fat cell size measured at 145 and 188 days. The number of cells at these times, defined as the number in a cylinder whose depth was known and whose cross-sectional area was 1 mm2on day 1, was not significantly correlated with whole body fatness.

5. Appetite was strongly linked to the rate of fat deposition and to the weight of fat at 188 days, but not to fat expressed in percentage terms. This was, however, closely related to the corrected food conversion ratio (r= 0·90, residual s.d. 2% of mean total fat percentage).

6. Fat thickness measured by ultrasonics before slaughter was no better as a predictor of percentage fat than average fat cell size.
Effectiveness of sequential selection in pig improvement
Authors: Hagenbuch P. , Hill W. G.
Published: September 2010

The effect on genetic improvement of a policy of sequential selection, in which breeding animals are retained for differing times, is investigated for a closed herd of pigs. Selection is practised for traits of the growing animal, either on phenotype or on predicted breeding value with account taken of parental age.

The following scheme gives near to maximum response over a wide range of values of parameters such as litter size, mating ratio and farrowing interval and of heritability. One out of every three or four females should be retained fora second litter and with continuous use of males about three out of every seven males should be retained after 3 months of use for a further 3 months. Such a scheme gives an improvement of only up to 3% over a procedure where all females are kept for two litters and all boars for 6 months, and progeny are selected without regard to parental age. The advantage of sequential selection becomes greater if sows are kept for more litters.
Growth of bovine tissues 2. Genetic influences on muscle growth and distribution in young bulls
Authors: Berg R. T. , Andersen B. B. , Liboriussen T.
Published: September 2010

Muscle weight distribution was compared by jointing and complete tissue separation of carcasses from 277 young male progeny of eight sire breeds and two dam breeds, serially slaughtered at 300 kg live weight, 12 months and 15 months of age. The sire breeds were Simmental, Charolais, Danish Red and White, Romagnola, Chianina. Hereford, Blonde d'Aquitaine and Limousin; the dam breeds were Danish Red and Danish Black Pied.

Growth impetus for muscle in each joint was established from the allometric equation (Y = aXb). Growth coefficients, b, were homogenous among breeds, indicating similar muscle development patterns over the range of weights studied. Growth impetus waves increased centripetally on the limbs, caudocephalically on the whole of the body (being more marked dorsally) and dorsoventrally on the trunk.

There were small but significant breed differences in the proportion of muscle in different joints at similar total muscle weight. They probably reflect differences in maturity and other minor functional influences. Chianina and Hereford crosses were the two extremes for muscle distribution with many of the remaining breed groups being very similar. Differences were already established by 300 kg live weight and muscle growth patterns were similar among breeds over the range of the experiment.
The use of sodium hydroxide-treated straw in rations for beef cattle
Authors: Cuthbert N. H. , Thickett W. S. , Wilson P. N. , Brigstocke T.
Published: September 2010

Sixty-four British Friesian castrated male cattle (steers) with an average starting weight of 292 kg and an average slaughter weight of 460 kg were used to compare compound diets containing 0, 10, 20 or 30% NaOH-treated straw. A basic diet of 1·8 kg hay, 1·8 kg barley straw and sugar beet pulp, on a scale rising from 1·4 to 2·8 kg according to live weight, was given throughout the trial. Compound diets were individually offered on a scale starting at 3·8 kg rising to 5·8 kg with an average intake of 4·9 kg/day. Treatments did not differ significantly in respect of live-weight gain, which ranged from 0·94 kg/day with the control to 0·97 kg/day with the 30% NaOH-treated straw compound. The grading of the animals, based on the Meat and Livestock Classification scheme, also showed no significant difference.

A second trial with a further 64 British Friesian steers tested inclusion levels of 0, 30,45 and 60% treated straw in a compound diet. At the start of the trial, the cattle averaged 328 kg live weight and were slaughtered from 450 kg live weight. Animals were yarded in store condition and were given a combination of grass silage and compound diets according to a scale, based on live weight and a predicted performance of 1 kg live-weight gain per day. There were no significant differences between treatments in live-weight gain, which ranged from 0·97 kg on the control to 1·02 kg/day on the 45% NaOH-treated straw diet. There was some refusal on the 60% NaOH-treated straw diet in respect of twice daily allocations, with a few cattle on occasions not being able to consume the allowance in the 30 min provided. However, each feed allocation was always consumed before the next meal. There were no significant differences between treatments in respect of fat class, but cattle on the 45% treated-straw diet had statistically superior conformation compared with the control.
Efficiency of lean meat production by British Friesian and Jersey steers
Authors: Hind E.
Published: September 2010

1. Eight-one British Friesian and 44 Jersey steers was slaughtered at 1. 12, 24, 48 or 72 weeks of age. Those aged 24 weeks and over were reared on a standard complete diet offered ad libitum, and individual food intakes were recorded until slaughter when carcasses were dissected on an anatomical basis.

2. From 1 to 72 weeks British Friesians were on average 50% heavier than Jerseys and consumed 47% more food. Total lean tissue (L) increased 11-fold to 137 + 6·4 kg in the British Friesians and 16-fold to 84 ± 4·7 kg in the Jersey. L as a percentage of live weight rose to 32% ±0·6 in the British Friesians and to 29% ±0·8 in the Jerseys. Breeds did not differ significantly in average efficiency of growth of lean tissue in any period.

3. From 24 to 72 weeks, an allometric relationship held between L and total food consumed postnatally, F. The two breeds had the same allometric coefficient of 0·61. Current efficiency, 0·61 L/F, was thus proportional to cumulated efficiency, L/F. Allowance was made for the prenatal input, Fo, required to produce the newborn calf. An optimum slaughter point at which overall efficiency, L/(F+F0), reached a maximum occurred in each breed when postnatal input was 58% higher than prenatal input (F = 1·58F0). When the breeds had equal maximum efficiency the British Friesian: Jersey ratios for prenatal input, total food consumed and total lean produced were all 2·6:1.
A note on the physiological development of a red muscle from the ham region of the pork carcass
Authors: Swatland H. J.
Published: September 2010

Samples from a dark red area of the vastus medialis muscle were taken from eight Canadian Yorkshire-breed pigs after slaughter. Frozen transverse sections were tested for alkali-stable adenosine triphosphatase (ATPase) and the ratio of strong to weak reacting muscle fibres was determined from photomicrographs. The percentage of fibres with strong ATPase reactions was positively correlated (r = 0·82, P<0·01) with animal live weight. This growth-related change is in the opposite direction to that known to occur in the white longissimus dorsi muscle of the pork carcass.
A note on draught capacity in castrated and entire male buffaloes as reflected in some blood constituents
Authors: Nangia O. P. , Rana R. D. , Singh Narinder , Ahmad A.
Published: September 2010

Castrated and entire male buffalo calves of about 2 years of age were made to work by pulling a stone roller weighing 80 kg at a constant speed of about 3 km/h on even ‘Kachha’ ground for 3 h. Blood levels of lactic acid and pyruvic acid and the Icteric index increased, whereas blood levels of bicarbonate and proteins decreased in response to exercise. No change was observed in blood glucose or chloride levels. There was no difference in the concentrations of blood constituents of the two groups.
The effect of field wilting and mechanical treatment on the feeding value of grass silage for beef cattle and on beef output per hectare
Authors: Steen R. W. J.
Published: September 2010

Two experiments were carried out to compare three methods of harvesting grass silage for beef production. These involved (a) harvesting the grass directly with a flail forage harvester (b) pre-cutting the grass with a rotary mower and harvesting it with a precision-chop forage harvester without wilting and (c) pre-mowing and harvesting with a precision-chop forage harvester after field wilting for 36 to 80 h (experiment 1) or 20 to 24 h (experiment 2). Half of the grass harvested by each method received formic acid at a rate of 2·5 1/t while the other half received no additive. The silages were offered ad libitum and supplemented with 2·6 kg concentrates per head daily to 72 castrated male cattle in each experiment. The unwilted and wilted herbages had mean dry-matter concentrations of 163 and 273 g/kg at ensiling and all silages were well preserved. Harvesting silage with a precision-chop rather than a flail forage harvester produced only a small non-significant increase in intake (0·034) and performance (0·046) and did not affect carcass gain per ha. Field wilting for 36 to 80 h prior to ensiling (experiment 1) reduced animal performance by 0·08 and beef output per ha by 0·11. Wilting for 20 to 24 h in ideal weather (experiment 2) did not affect animal performance or beef output per ha compared with that produced by well-preserved, unwilted silage. There was no significant interaction between method of harvesting and additive treatment.
Weaning at birth: the effect on the reproduction of the sow
Authors: Varley M. A. , Atkinson T.
Published: September 2010

Thirty-six Landrace × Large White sows were allocated at random to one of three treatment groups. Sows on treatment A (no. = 6) did not lactate at all and the piglets from these sows were removed at birth. Sows on treatment B (no. = 15) lactated for 1 day after parturition and sows on treatment C (no. = 15) acted as controls and lactated for 42 days. The reproductive performance of each treatment group was recorded and all sows were bled every 2nd day from parturition to 30 days post partum. All blood samples were assessed for oestradiol-17β and progesterone concentrations. In treatments A and B, a high proportion of anoestrous sows was seen (0·28). None of the sows in treatment C became anoestrous. The mean interval from weaning to the onset of oestrus for treatments A and B (19·0 (s.e. 6·5) days and 19·7 (s.e. 3·8) days respectively) were not significantly different, while that for treatment C (5·6 (s.e. 0·4) days) was significantly shorter (P < 0·01). The number of piglets born alive at the subsequent farrowing for treatments A, B and C respectively was 7·3 (s.e. 0·8), 9·1 (s.e. 0·8) and 10·5 (s.e. 0·67) (P < 0·05). The calculated annual sow productivity (piglets born alive per sow per year), excluding the first litter born, for treatments A, B and C respectively was 18·4, 22·8 and 22·9. Weaning at, or close to, parturition did not, therefore, influence sow productivity compared with weaning after 6 weeks of lactation.
Selection indices for terminal sires to improve lean meat production from sheep in the United Kingdom
Authors: Parratt A. C. , Simm G.
Published: September 2010

Selection indices to improve lean meat production of terminal sire breeds of sheep were derived. An aggregate breeding value which comprised growth rate, killing-out proportion and carcass lean proportion was examined. Selection criteria included growth rate and ultrasonic or X-ray computer tomography (CT) estimates of carcass composition. Correlations betwen the index and the aggregate breeding value were about 0·38 for indices using ultrasonic fat measurements, and about 0·40 for those using CT measurements. Dropping ultrasonic or CT measurements from the indices reduced the correlations with the aggregate breeding value by only about 0·01 and 002 respectively, indicating that selection on growth rate alone under current economic conditions was highly efficient. Changes in economic weights, and genetic parameters had little effect on the efficiency of selection. The total national discounted value of returns from a single round of selection on the indices was expected to be between £6 and £30·5 million, depending on penetration rates of improved stock, the breeding scheme used, and with a time horizon of 20 years.
A genetic analysis of body weight traits in young Bauscat and Giza White rabbits
Authors: Khalil M. H. , Afifi E. A. , Owen J. B.
Published: September 2010

The effects of various genetic and environmental factors on body-weight traits were studied in 3051 records of Bauscat (B) and Giza White (G) rabbits in the period from October 1976 to September 1983. Sixty-five sires and 289 dams were used for analysis of data of body weight at 6 weeks and bi-weekly up to 12 weeks of age. Year and month of birth exerted a pronounced effect on body weights of rabbits. Sex differences on the other hand were small at all ages studied and no pattern of parity effects was observed. Effects of litter size at birth were significant for 6-week weight but not for weights taken at later post-weaning ages. Body weights at the four ages studied decreased as litter size at weaning increased. Litter-weight effects on body weights decreased significantly as the age of the rabbit advanced. Sire and dam affected significantly most of the body-weight traits studied. The proportion of variance attributable to both sire and dam components for all body weights studied in G rabbits were generally larger than those in B rabbits. Heritabilities from sire and dam components of variance for body weights n i B rabbits were substantially lower than the corresponding estimates in G rabbits. Genetic and phenotypic correlations among body weights at all ages studied were positive and of moderate or high magnitude, and tended to decrease in value as the differences between the two ages increased.
Toxicity induced by poultry litter consumption: effect on measurements reflecting liver function in beef cows
Authors: Silanikove N. , Tiomkin D.
Published: September 2010

During clinical investigation of a commercial herd it was found that intake of supplemented poultry litter (PL) by beef cows at >10 kg/day, was associated with severe cachexia and a mortality rate of between 10 and 20% of cows. Postmortem analysis of 40 fresh carcasses and elevated serum levels of cholesterol, bilirubin, alkaline phosphatase, glutamic oxaloacetic transaminase and sorbitol dehydrogenase in cachetic cows indicated that the cows suffered severe liver damage. The interrelationship between liver damage and PL intake was subsequently investigated in three groups of 20 beef cows each, consuming 0, 3 and 10 kg PL respectively. As determined by the serum indices, intake of 3 kg PL seemed to be sufficient to cause liver damage, although these cows appeared healthy.

In another experiment, six beef cows were stall-fed a diet giving separate access to PL and wheat straw. PL intakes were 3·1,4·7 and 6·0 kg/day. Ruminal ammonia concentration was three to five times higher than the estimate of that required for maximal fermentation in the rumen. The high pH values (6·81 to 6·97) found are optimal for absorption of ammonia from the rumen. The combination of excess absorption of ammonia from the gut and low metabolizable energy intake might have been the cause of liver damage.
The effect of feeding supplements in the autumn on the reproductive performance of grazing ewes 1. Feeding fixed amounts of supplement before and during mating
Authors: Gunn R. G. , Milne J. A. , Senior A. J. , Sibbald A. M.
Published: September 2010

The effects on reproductive performance offeeding supplements to ewes grazing predominantly perennial ryegrass swards before and during mating which started in mid November were examined with approximately 200 Scottish Blackface ewes in each of three experiments. In two experiments, ewes were offered no supplement (C), 600 g barley (S(B)) or 500 g barley + 100 g white-fish meal (S(B + FM)) per head per day from 3 weeks before until 3 weeks after the start of the mating period. Ewes in experiment 1 were grazed on different areas and in experiment 2 were rotated around these areas on a 12-day cycle. Initial herbage allowance in both experiments was 40 to 50 kg organic matter per ewe and stocking rates ranged from 10 to 14 ewes per ha. Ewes in experiment 3 were rotated around the same areas on a 10-day cycle at a stocking rate of 18 ewes per ha and offered either no supplement (C) or 600 g barley (S(B)) per head per day when live weight started to decrease or sward height declined to 3·5 cm, whichever occurred first. Both of these occurred shortly after the start of mating. Sward height fell from mid October and throughout November and was between 3 and 4 cm at the start of mating in all experiments.

There were no differences in response to the (S(B)) and (S(B + FM)) treatments in live weight, body condition or reproductive performance in experiments 1 and 2 and the effects of supplementation were examined with these treatments pooled.

Supplementation had very little effect on live weight, resulting in higher values only in experiment 1 but did produce higher body condition in all experiments. This occurred by the start of mating in experiment 1 but not until mid December in experiment 3 and early January in experiment 2.

A significant increase in the number of lambs born per ewe lambing was obtained from supplementation when the data from experiments 1 and 2 were combined (P < 0·05). There was no response in reproductive performance to supplementation in experiment 3. It was concluded that supplementation in the pre-mating period can improve reproductive performance when sward height declines from 6 to 3·5 cm but that supplementation in the post-mating period may not, even when the sward height is below 3·5 cm.
Comparison of the Duroc and Large White as terminal sire breeds and their effect on pigmeat quality
Authors: Edwards S. A. , Wood J. D. , Moncrieff C. B. , Porter S. J.
Published: September 2010

The experiment examined the effect of breed, diet and sex on pig performance and carcass quality. Eight sires of the Duroc and Large White breeds each produced four experimental litters. Two boar and two female pigs from each litter were reared under standard conditions to 38 kg and then one of each sex was allocated to each of two finishing diets. These were cereal-based diets with and without 16 g/kg soya oil. Following slaughter at 80 kg, loin chops taken from half of the pigs (two litters per sire) were subjected to detailed investigation of physical, chemical and organoleptic characteristics. Lifetime live-weight gain was similar for both breeds but Duroc-sired pigs had greater voluntary food intakes and poorer food conversion efficiencies in the finishing stage. They also had greater killing-out proportions (775 v. 755 g/kg, P < 0·001) and backfat thickness at slaughter (284 v. 27·2 mm at P1 + P3, P < 0·05). Fat firmness measured by penetrometer at 4°C was lower in Duroc-sired pigs (738 v. 792 units, P < 0·001). The proportion of extractable intramuscular lipid was greater in chops from Duroc-sired pigs (13·8 v. 10·4 g/kg, P < 0·001). There were no significant effects of breed or diet on the eating quality of the grilled chops as assessed by a trained taste panel and a consumer panel.
A note on the ease of handling and flight distance of Bos indicus, Bos taurus and their crossbreds
Authors: Kabuga J. D. , Appiah P.
Published: September 2010

Ease of handling (time to enter and exit scales and dip, and temperament scores) and flight distance were studied in Bos indicus and Bos taurus cattle and their crossbreds. At one research station (LS), 20 cows and 20 female calves, each of N'dama and West African Shorthorn (WASH) cattle were used. At another research station (BRS), 15 cows each of N'dama, Holstein and their crossbreds (NH) were used for the study. In addition a further 20 cows and 20 female calves of the N'dama breed were studied at BRS for comparison with the N'dama at LS. There were no significant differences in ease of handling and flight distance between N'dama and WASH and between N'dama at LS and at BRS. There were significant differences between N'dama, Holstein and NH cows in ease of handling and flight distance. Cows took a shorter time to enter but generally a longer time to exit a scale, had a shorter flight distance and a lower temperament score (P < 0·01) than calves.
Effect of varying weight gain during the last trimester of gestation on productivity of beef heifers
Authors: Whittier J. C. , Clanton D. C. , Deutscher G. H.
Published: September 2010

An experiment was conducted using medium-sized crossbred beef heifers to study how manipulation of weight gain in late gestation affected production. Forty heifers were fed individually to gain according to one of three regimens for an approximate 90 day period prior to parturition: (1) 1·2 kg gain per head per day for 45 days followed by no gains for 45 days; (2) 0·6 kg gain per head per day for the entire period; (3) no gain for the first 45 days followed by 1·2 kg gain per head per day for the last 45 days. Milk production was measured by weighing of calves before and after suckling at 30, 60, and 150 days post partum. Heifers were weighed, measured for heart girth and hip weight, and visually scored for condition at the start, middle and end of the feeding period to quantify growth and condition changes. Heifers that had a high rate of gain for a short time produced more milk in early lactation than heifers that gained at a slower rate for a longer time pre-partum (P < 0·05). Calf weaning weights and dam reproductive performance were unaffected (P < 0·05) by pre-partum weight gain. It is concluded from these results, that as long as the recommended weight gain is achieved during late gestation, the timing of the weight gain is not critical to sustain productivity.
Blood and tissue lipid composition and lipase activity in wether lambs treated with trenbolone acetate combined with oestradiol-17 β at two different live weights
Authors: Singh S. B. , Scaife J. R. , Galbraith H.
Published: September 2010

Thirty-two Border Leicester ♂ × Scottish Blackface ♀ wether lambs aged about 5 months, were divided on the basis of live weight such that group G1 contained the 16 lightest lambs and group G2 the 16 heaviest lambs. Lambs in group G1 were subdivided equally at random to be either sham-implanted controls (group C1) or to be implanted with 35 mg trenbolone acetate (TBA) + 5 mg oestradiol-17β (OE) (group T1) at 24 kg initial live weight. Lambs in group G2 were also subdivided into two groups (C2 and T2) and similarly treated approximately 1 month later at 37 kg initial live weight. Animals were offeredad libitum, a diet containing an estimated 12·5 MJ metabolizable energy and 140 g crude protein per kg dry matter. The experimental treatments lasted for 60 days.

Samples of pre-heparin plasma were analysed for free fatty acid (FFA) and triglycerides (TG). Post-heparin plasma was analysed for lipoprotein lipase (LPL) activity. Samples of subcutaneous (SCAT), perinephric (PNAT), mesenteric (MAT) and intermuscular (IMAT) adipose tissue, liver and muscle, taken immediatelypost mortem, were analysed for total lipid concentration and fatty acid composition. Comparisons were made for the main effects of hormonal treatment and live weight.

Plasma FFA concentrations in heavier lambs (group G2) were significantly higher than in group G1 from week 1 pre-implantation to week 3 post implantation. Compared with group G1, animals in group G2 had significantly higher plasma TG concentrations at weeks 1, 2, 5 and 8 when data was analysed using pre-implantation values as covariates. The lipid concentration was lower in group G1 than in group G2. In group G1 compared with group G2 there were greater proportions of C12:0 and C18:2 in SCAT and C16:1 in PNAT and lesser proportions of C18:0 in SCAT and PNAT.

Significant effects due to hormonal treatment were recorded for plasma TG at weeks 1, 5, 6, 7 and 8 mainly due to increases in group T1 compared with group C1. Hormonal treatment increased the proportions of C12:0, C15:0, C16:1 and C18:1 in SCAT and C16:1 and C18:1 in IMAT; reduced the proportions of C16:0 and C18:0 in SCAT and C18:0 in MAT and IMAT and reduced the ratio of saturated to unsaturated fatty acids in SCAT and IMAT and to a lesser extent in MAT.
Rumen degradation of straw 4. Selection and degradation of morphological components of barley straw by sheep
Authors: Bhargava P. K. , Ørskov E. R. , Walli T. K.
Published: September 2010

Experiments were made to study the proportion, chemical composition, and rumen degradability of the morphological components of barley straw (Corgi variety) and to study the selection of these components by sheep. The proportions in the harvested straw dry matter (DM) as leaf blade, leaf sheath, stem and chaff were 128, 314, 500 and 58 g/kg DM, respectively. The different components of straw on analysis proved to have very different concentrations of nitrogen and neutral-detergent cellulase digestibility. The leaf blades had the highest and the stems the lowest values. The degradabilities of DM in the components and in the whole straw were determined by measuring DM loss from samples incubated in nylon bags for various periods in the rumen of sheep. Responses were measured using the mathematical model p = a+b (1–e−ct) where p is DM loss, (a+b) potential degradability, c the rate constant of DM loss and t is the time of incubation. DM losses decreased in the order leaf blades > leaf sheath > whole plant > chaff > stems. Leaf blades also had the highest potential degradability and rate of degradation.

In another trial, five sheep were offered unchopped barley straw ad libitum. There were five treatment periods in which sheep were allowed to leave uneaten proportionately 0·2, 0·3, 0·4, 0·5 and 0·7 of the straw on offer for assessing the animal's selection of the morphological components of that straw. The amount of leaf blade in the material consumed increased in largely a linear (P < 0·01) fashion with the amount of excess allowance. The proportion of stem eaten varied conversely. The selection of leaf sheath was less apparent. Little stem was consumed until the proportion of leaf blade in the food available decreased below proportionately 0·4. The practical significance of the study is discussed.
Genetic parameters of test day records of British Holstein-Friesian heifers
Authors: Pander B. L. , Hill W. G. , Thompson R.
Published: September 2010

Estimates of genetic parameters for test day records of yields of milk, fat and protein and concentrations of fat and protein were obtained on 47 736 British Holstein-Friesian heifers in 7973 herds, progeny of 40 proven (to improve connectedness) and 707 young sires (comprising about one-fifth of the progeny), using multivariate restricted maximum likelihood methods with a sire model.

Heritability estimates for lactation yields of milk, fat and protein and concentrations of fat and protein were 0·49, 0·39, 0·43, 0·63 and 0·47, respectively. Estimates for individual test day records of these traits ranged from 0·27 to 0·43, 0·16 to 0·34, 0·22 to 0·33, 0·11 to 0·48 and 0·21 to 0·43, respectively. Generally, heritability estimates for test day records were lowest at start and highest in mid lactation.

Estimates of genetic correlations among yields of a trait on different test days ranged from 0·57 to 0·99, and for fat and protein concentrations from 0·34 to 0·99, the correlations being highest for adjacent tests. Phenotypic correlations were lower than genetic correlations. Genetic correlations of test day records with corresponding lactation traits were high (0·76 to 0·99), being highest in mid lactation.

Genetic correlations of test day milk yield with test day yields and concentrations of fat and protein throughout the lactation were similar to those for complete lactation.

The high heritabilities of test day yields and their high genetic correlations with complete lactation, except for the first 1 or 2 test days, suggest that lactation performance may be predicted from test days in early and mid lactation.
Effects of genotype and stocking density on post-weaning daily gain and meat production per hectare in cattle
Authors: Mezzadra C. , Escuder J. , Miquel M. C.
Published: September 2010

With the objective of determining genetic × environmental interaction for beef production under direct grazing conditions, measured as both individual average daily gain (ADG) and per ha (PROD), 160 steers were utilized through 2 years, from two breeds of different growth potential, and four stocking rates (SR) tending to establish different nutritional environments. The breeds were Aberdeen Angus (A) and high-grade Limousin crossbred (L) and the SRs established were 2·25, 2·87, 3-50 and 4·13 steers per ha. The pasture where the steers grazed was Festuca arundinacea. Response variables were analysed by least-squares using a fixed model of year, breed, SR and their two-way interactions. There were highly significant effects (P < 0·01) of the interaction of breed × SR for ADG and PROD. Quadratic and linear regressions (P < 0·01) were adjusted for PROD and ADG on SR respectively using the least-squares means. The proportional superiority of L on A at the lowest SR was 0·27, while at the highest SR the situation was reversed, A gained proportionately 0·32 more weight than L. These results indicated that under limiting conditions of nutrition as generated at the highest SR in this experiment, the small-sized individuals tended to produce meat more efficiently both individually and per ha, the opposite situation being true when nutritional conditions were not restrictive.
Effects of rapid inbreeding and of crossing inbred lines on the growth of linear body dimensions of sheep
Authors: Wiener G. , Lee G. J. , Woolliams J. A.
Published: September 2010

Sheep of three hill breeds and the crosses among them were closely inbred for four generations to create five levels with inbreeding coefficients 0·0 (F2/O2), 0·25 (I1,), 0·375 (I2), 0·50 (I3), and 0·59 (I4). Inbred females were also mated to unrelated inbred males of the same breed or crossbred type to produce line-crosses (LC). Mating was arranged so that the effects of inbreeding on the individual could be differentiated from maternal inbreeding. A total of 2369 animals were available up to 78 weeks of age and 1062 to the age of 4 years. This study examines the effects on six linear body dimensions and draws comparison with the effects on body weight. There were significant reductions in the size of the body dimensions with increasing inbreeding but the maximum depression was usually at the I2 stage for individual inbreeding and the I3 stage for maternal inbreeding. Most of the linear and many of the non-linear effects of inbreeding of the individual were significant and the effects of maternal inbreeding were also significant in a majority of cases. Inbreeding effects were more marked for relatively late-maturing parts (shoulder and hook widths) than for early-maturing (cannon bone and tibia lengths) with head width and body length intermediate but closer to the early-maturing parts. This was seen separately at each age, and in the effects of advancing age. By 78 weeks of age, the effects of inbreeding of the individual on absolute size had increased with age and by 4 years of age, in spite of a small recovery in size relative to F2/O2, was still greater than in early life. The effects of maternal inbreeding became progressively less with advancing age relative to non-inbreds. The changes with inbreeding could not be explained by dominance effects alone and epistasis is therefore likely also to be involved.
Effect of calving date on lifetime productivity of cows in a winter-calving Aberdeen Angus herd
Authors: Garcia Paloma J. A. , Alberio R. , Miquel M. C. , Grondona M. O. , Carrillo J. , Schiersmann G.
Published: September 2010

Lifetime productivity of 408 Aberdeen Angus cows from the Estacion Experimental Agropecuaria (EEA) of Balcarce, Argentina, was analysed during the 1972 to 1983 period according to their date of calving. Cows were allocated to two groups: one group of early first calving (Fl) when cows calved within the first 25 days of the calving period; the other, of late first calving (F2) when cows calved after that date. Independently using similar criteria, the effect of date of second calving on lifetime productivity was analysed in the same cows, groups SI and S2. Early first calving cows weaned more kg of calf when their first four calvings were considered than cows of late first calving (659 v. 628 kg). The same tendency was observed when cows were compared according to their second calving date (653 v. 634 kg). Differences in weaning weight between calves from early and late cows were only significant for the first calving (group Fl v. F2) and for first and second calving (group SI v. S2). This fact was a consequence of the shorter initial calving interval for late cows (F2 and S2) so that subsequent ages of their calves at weaning were similar to early cows (Fl and SI). Groups F2 and S2 cows had first and second calving intervals respectively of 351 and 356 days, while groups Fl and SI cows had intervals of 372 and 371 days. It is concluded that the date of the first calving and the high overall reproductive performance of the herd contributed to a high concentration of early calvings and a high productive efficiency.