bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of partial neutralization with sodium bicarbonate or ammonia and the feeding of blood meal on the voluntary intake of a whole-crop barley silage by sheep
Authors: Wllkins R. J.
Published: September 2010

Silage made from a whole crop of barley was offered to sheep without neutralization or after partial neutralization to pH 5·4 to 5·5 with sodium bicarbonate or ammonia. In a further treatment the un-neutralized silage was supplemented with blood meal administered each day as a drench. Total organic-matter intake and nitrogen retention were significantly higher for the sheep receiving the blood meal supplement than for any of the other treatments, which did not differ significantly one from another. It is suggested that the intake of the un-supplemented silage was limited by a low uptake of amino acids from the intestine.
Differences between groups of lamb carcasses chosen for good and poor conformation
Authors: Jackson T. H. , Mansour Y. A.
Published: September 2010

Ninety-six lamb carcasses drawn from six batches of lambs commercially consigned to an abattoir were analysed for characteristics which may affect their economic value. From each batch carcasses were selected in equal numbers into two classes of ‘good’ or ‘poor’ conformation according to traditional standards. Carcasses selected for ‘good’ conformation were heavier (P<0·05) and fatter (P<0·05), slightly shorter in carcass length and hind leg length (P<0·05), greater in circumference (P<0·001) and width (P<0·001) of the hind leg, slightly greater in muscle weight (P<0·05) but no greater in bone weight than those of poor conformation. The yield of prime retail joints was similar in the two conformation classes but the ‘good’ conformation class had a higher proportion of loin and rib joints and lower proportion of hind leg joint (P < 0·01) although these differences were not considered to be of commercial importance. There was a lower proportion of the carcass fatty tissue in the hind leg joint of the ‘good’ conformation class (P < 0·05). Muscle-to-bone ratio and area of ‘eye muscle’ (M. longissimus thoracis) appeared to be little affected by selecting for conformation differences. Depth of fleshing as indicated by the weight of muscle in the hind leg per 10 cm length, was 40 g (6%) heavier in the carcasses of the ‘good’ conformation class. This contrasted with the much greater differences, between batches, of 290 g (40 to 50%). Between batches there were significant differences for all the measures taken except the yield of preferred retail cuts. In the main the batch differences were greater and commercially more important than the conformation class differences.
Prediction of the Energy Requirements for Growth in Beef Cattle 1. The irrelevance of fasting metabolism
Authors: Webster A. J. F. , Brockway J. M. , Smith J. S.
Published: September 2010

1. According to the Agricultural Research Council (1965) energy retention in cattle is predicted from metabolizable energy (ME) intake, the net availabilities of ME for maintenance (km) and for fattening (kf) and measurements made of fasting metabolism (F). The present experiments were designed to examine the validity of the use of F as a basis from which to predict energy retention.

2. Four British Friesian and four Aberdeen Angus steers were fed, from weaning to slaughter at about 450 kg, a barley-based, pelleted diet at two levels calculated to yield overall efficiencies of retention of ME of 20% and 10% respectively. Successive measurements were made of the energy balance of each animal at intervals of 4 to 8 weeks.

3. The metabolizability of the diet was measured for both sheep and cattle. In both species metabolizability was greater at the higher level of feeding. In sheep kf measured directly or estimated from metabolizability was 0·61.

4. Measured values for F in cattle agreed closely with values given by the Agricultural Research Council.

5. Basal metabolism in the growing animal (F') was predicted by extrapolation to zero intake of measurements made on animals in positive energy balance. Log F' during growth was proportional to log body weight0·73. Expressed in terms of the usual exponent of metabolic body size, F' was about 440 kJ/kg0·75 per 24 hr throughout growth. There were no major differences in F' attributable to breed or to level of food intake.

6. The results indicate that F is not a good basis from which to predict energy retention in steers.
Variations in immunoglobulin concentrations in Merino and Scottish Blackface lambs
Authors: Halliday R.
Published: September 2010

The concentrations of maternal immunoglobulin in 2-day-old lambs varied widely. They were significantly correlated with the lengths of pregnancy and the serum protein concentrations of the adult female sheep (ewes), but not with the colostrum immunoglobulin concentrations, nor with the weights or ratios of weights of the lambs and ewes. The mean concentrations were as high in Merino as in Blackface lambs.

Although there was some evidence that colostrum production was higher in ewes with twins than in ewes with single lambs, the immunoglobulin concentrations in the lambs fell significantly as litter size increased. They were significantly higher in male than in female twins, and in twins from litters containing both sexes than in twins from litters of one sex, but the difference between single males and females was not significant. Nor was the difference between the first and second born of each pair of twins. Twins and triplets born to ewes aged 7 years or more had particularly low concentrations. No other effects of the age of the ewe were found. The concentrations fell significantly as the date of lambing during the season advanced, and there were significant annual variations which could not be attributed to the weather. The correlation coefficients for the concentrations in lambs born to the same ewe in successive years were 0·309 and 0·298 (P < 0·001), respectively, for Merino and Blackface lambs.

The mean concentration in lambs which died subsequently from infections was significantly lower than in the surviving lambs, but many lambs with very low concentrations survived.
The replacement of skim milk by cooked potato flour in milk diets for calves
Authors: Hinks C. E. , Peers D. G. , Armishaw Alison M.
Published: September 2010

1. A total of sixty, 7-day-old British Friesian male calves, reared on a conventional early-weaning system, were used in two experiments in which dried skim milk was partially replaced by levels of 7, 14 and 21 % cooked potato flour (CPF). In the first experiment the diets were iso-energetic but differed in total nitrogen contents, whilst in the second experiment, casein was used to make the diets iso-nitrogenous.

2. In both experiments, diets containing CPF depressed growth rate from 4 to 18 days on treatment (11 to 25 days of age) and reduced the firmness of the faeces. These effects were correlated with the concentrations of CPF in the diets, live-weight gain being depressed by 20%, and the firmness of the faeces by 14%, for each 10 % inclusion of CPF. After 18 days on treatment (25 days of age) these effects became less pronounced.

3. The overall performance of calves to weaning (after 35 days on treatment) was similar on all diets. Daily live-weight gains from 4 to 56 days and 35 to 56 days did not differ between treatments. 4. It was concluded that whilst the inclusion of CPF in the diets of milk-fed calves was unlikely to have any permanent effect on the live weight of calves at 5 or 8 weeks of age its use in milk diets for calves of less than 3 weeks of age must be limited if loose faeces are to be avoided.
A comparison of tissue development in Pietrain and Large White pigs from birth to 64 kg live weight 1. Growth changes in carcass composition
Authors: Davies A. S.
Published: September 2010

Female pigs of the Pietrain and Large White breeds, 18 from each, selected to form a logarithmic weight range, were dissected into their major carcass tissues. Relative to carcass growth, fat was the fastest developing tissue in both breeds; fat and muscle grew at a rate higher, and bone at a rate lower, than the carcass. The growth of bone relative to carcass growth was faster in the Large White; differences between breeds in the growth of muscle and fat were not significant. Muscle weights and muscle: bone ratios, estimated at the same empty body weight, were greater for the Pietrain over the entire body weight range studied. There was no significant difference in muscle: bone ratio between the Large Whites used in the present study and those dissected by McMeekan over 30 years previously. The breed difference in the proportion of muscle and bone at the same body weight is attributed to a greater maturity of the Pietrain.
A comparison of tissue development in Pietrain and Large White pigs from birth to 64 kg live weight 2. Growth changes in muscle distribution
Authors: Davies A. S.
Published: September 2010

Half carcasses of 18 Pietrain and 18 Large White female pigs were each dissected into 93 muscle units. An allometric analysis of the weight of these units relative to total muscle revealed increasing craniocaudal and distoproximal growth gradients, which were more pronounced in the Pietrain.

The greater total weight of muscle, shown previously for the Pietrain at any given body weight over the range studied, was not due to higher muscle weights in any particular region at birth, but at 60 kg body weight was due to heavier high impetus muscles. Heart weight relative to total muscle weight was higher for the Large White over the entire range.

It is concluded that for the animals studied the changes in muscle distribution are related to the functional demands of an increase in body size, and that the muscle distribution of pigs can differ between breeds.
A note on the growth of early-weaned Hampshire piglets
Authors: Whittemore C. T. , Illius A. W.
Published: September 2010

The appetite and growth of individually-fed, weaned Hampshire and Saddleback piglets and of Hampshire and Large White × Landrace piglets were compared in three experiments from 14 to 49, 28 to 55 and 21 to 45 days of age. There was a reduced rate of growth in the Hampshire piglets, which was not found to be related to any need of Hampshire piglets for a higher quality diet. Neither was there any reduction in the efficiency with which Hampshire piglets used ingested nutrients, nor a differential rate of deposition of any body component. Hampshire piglets ate less food than Saddleback or Large White × Landrace piglets and this reduced appetite was largely accounted for by the lower body size.
A note on the estimation of total lactation yield from production on a single day
Authors: Wood P. D. P.
Published: September 2010

The recording of total lactation yield for individual cows can be timeconsuming and costly. Periodic sampling at intervals throughout lactation offers an acceptable alternative, and a single day's production can be made to furnish a useful guide, by using an equation relating total to daily production.

Errors of estimation are affected by the degree of consistency of daily production, parity and individual herd management, so that estimates could be biased and have a standard error of nearly 20% if these effects are disregarded. Coefficients in the prediction equation must therefore be developed for individual herds.
Pre-puberal plasma luteinizing hormone concentrations and progesterone concentrations during the oestrous cycle and early pregnancy in Galway and Fingalway female lambs
Authors: Quirke J. F. , Gosling J. P.
Published: September 2010

Twenty-four young female sheep, 12 Galways and 12 Fingalways, were used to study the effects of breed and level of nutrition on pre-puberal plasma luteinizing hormone and progesterone concentrations throughout the oestrous cycle and during the first 35 days of pregnancy. The sheep were spring-born and were housed at the end of July when they weighed approx. 34 kg. Equal numbers of animals from each breed were fed on a concentrate diet either ad libitum or at a restricted level that was slightly above their estimated maintenance requirements. The Fingalways reached puberty 1 month earlier than the Galways (11 October ±4 days v. 10 November ±5 days). The restricted animals tended (P < 0·10) to reach puberty later than those fed ad libitum (1 November ±5 days v. 20 October ±4 days). Breed differences in the mean level of plasma progesterone on any day of the oestrous cycle were not significant. The mean daily plasma progesterone concentration was similar for the animals on the two planes of nutrition throughout the cycle, with the exception of day 11 when those fed ad libitum had a significantly higher level (P < 0·01). Plasma progesterone levels in the pregnant females between 5 and 35 days post mating were generally higher in Fingalways than in Galways and were not influenced by plane of nutrition. Plasma luteinizing hormone levels tended to be higher, during the 7 weeks before puberty, in Fingalways than in Galways and in animals fed ad libitum than in those on the restricted level of feeding.
A note on the comparative growth performance of pigs sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars
Authors: Lishman W. B. , Smith W. C.
Published: September 2010

The performance of progeny sired by Piétrain × Hampshire, Hampshire × Large White and Large White boars was compared over the live-weight range 28 to 65 kg. Feeding was twice daily to ‘appetite’ up to a maximum of 2·27 kg meal/day. Breed of boar did not influence rate or efficiency of live-weight gain, mid-line or internal fat depths nor muscle quality. Progeny of Pietrain × Hampshire and Hampshire × Large White sires, compared with those of Large White boars, had higher killing-out percentages (1·4 and 1·2 units) and larger eye muscles in cross-section (19·3 and 11·6%). Significant but small breed differences were noted in joint proportions of the carcass.
A note on the ovulation rate of sheep following treatment with clomiphene citrate
Authors: Land R. B. , Scaramuzzi R. J.
Published: September 2010

The use of the ‘anti oestrogen’ clomiphene to increase the ovulation rate of the sheep was investigated. Although in most trials clomiphene had a positive effect, this effect was small and inconsistent—especially n i relation to dose. It was concluded that the present approach would not lead to a simple technique to increase ovulation rate and the number of lambs born.
Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs
Authors: Quirke J. F.
Published: September 2010

Groups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.

Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.
Evidence for phenotypic change at the amylase I locus in cattle—an explanation of the apparent heterozygote excess
Authors: Archibald A. L. , Bradley J. S. , Spooner R. L.
Published: September 2010

The amylase (Ami) phenotypes have been determined in sera collected from 244 heifers before 6 months and after 2 years of age. Fifty of these animals exhibited a change in phenotype from Ami C to an apparent Ami BC with age. Using a modified electrophoretic technique these apparent heterozygotes were reclassified as Ami C(E). Eight hundred and nineteen cows, which had previously been shown to have a highly significant excess of heterozygotes at the Ami locus, were also retyped by this modified technique. The apparent heterozygote excess was not found as it was now possible to differentiate between Ami C(E) and Ami BC.
A note on the use of electronic doors for individual feeding of group-housed lambs
Authors: Cammell S. B. , Spooner M. C. , Thomson D. J.
Published: September 2010

1. Two groups of artificially-reared lambs were used to evaluate electronic equipment which allowed group-housed lambs individual access to their own food supply.

2. Trial group A comprised six lambs in a cross-over design between individual metabolism cages and group-housing with electronic doors to examine the effects of method of housing upon ad libitum food consumption. There were no significant differences in dry-matter intake although it was observed that food consumption was temporarily reduced during the training periods.

3. Trial group B comprised 16 lambs used to test established training techniques and to examine the effects of adaptation to electronic doors upon food consumption and live-weight gain over a period of 50 days. There was a reduced intake of food during days 1 to 7 which resulted in the daily dry-matter intakes and live-weight gains for days 8 to 50 and 15 to 50 being higher (P<0·01) than those for the total period (days 1 to 50). It was concluded that a minimum of 7, and preferably 14, days were required for training lambs and for adaptation to a diet provided through electronic doors.
Amino acid requirements of growing pigs. 1. Effects of reducing protein level in diets containing high levels of lysine
Authors: Taylor A. J. , Cole D. J. A. , Lewis D.
Published: September 2010

Sixty-four growing pigs, with equal numbers of females and castrated males, were fed diets containing from 10 to 17·6% crude protein but in which lysine was maintained at 0·95%. Over the 25 kg to 55 kg live-weight range studied, growth performance was unaffected by a reduction in crude protein level from 17·6 to 14·5%. Below 14·5% crude protein, daily live-weight gain and feed conversion ratio deteriorated linearly. Percentages of lean meat and fat in the middle joint showed similar trends. Significant sex effects were confined to carcass characteristics which indicated that the females produced leaner carcasses. It was concluded that below 14·5% crude protein a deficiency of the next limiting amino acid to lysine, or possibly non-essential nitrogen, depressed growth performance.
Season of birth and the response to hemicastration in lambs
Authors: Land R. B. , Drury D. J. , Fordyce Marjorie
Published: September 2010

Testis diameter and body weight were recorded for 37 Finn-Dorset ram lambs born in winter and 38 born in summer 1977 from 8 to 24 weeks of age. Testis growth in summer-born ram lambs reared during a period of decreasing daylength was more rapid than that of winter-born lambs reared during a period of increasing daylength. Hemicastration at 12 weeks of age (19 of the winter-born and 18 of the summer-born lambs) increased the rate of growth of the remaining testis. Season of birth did not affect the response to hemicastration. It was deduced that the feed-back of gonadal hormones on gonadotrophin release was similar in both seasons.
The effect of level and system of concentrate allocation to January/February calving cows on total lactation performance
Authors: Steen R. W. J. , Gordon F. J.
Published: September 2010

A randomized block experiment using 108 British Friesian cows was conducted over a 2-year period to assess the effects of level and pattern of concentrate allocation during early lactation on the performance of cows which calve during January and February. The three concentrate levels were 280 (L1), 405 (L2) and 530 (L3) kg during a 74-day post-calving period, and the two systems of allocation were either a uniform daily allowance (uniform system) or a high input for the first 4 weeks after calving followed by a low input (high/low system). The animals had ad libitum access to medium-quality grass silage during the indoor period and in both years were turned out to pasture on 9 April. At pasture they were grazed rotationally in treatment groups at a stocking rate ranging from 6·4 cows ha-1 in the early-grazing season to 4·9 cows ha-1 in the late-grazing season.

Mean milk outputs for the indoor feeding period were: high/low system 1577 (L1), 1705 (L2) and 1764 (L3), uniform system 1583 (L1), 1676 (L2) and 1783 (L3) ±33·8 kg; and for the total lactation were high/low system 4625 (L1), 4906 (L2) and 5148 (L3), uniform system 4830 (L1), 4933 (L2) an d 5301 (L3) ±118·9 kg.There was no significant interaction between level and system of concentrate allocation. Feed intake, milk composition, animal live weight and body-condition data are also presented.
The relationship between heterozygosity and heterosis in reproductive traits in mice
Authors: McGloughlin Patricia
Published: September 2010

Continuous reciprocal backcrossing results in individuals which are 67% heterozygous, and which, assuming a linear relationship between heterozygosity and heterosis, would be expected to exhibit 67% of the heterosis found in Fi hybrids. An experiment was undertaken to investigate this relationship in the reproductive traits of mice. By crossing and repeated backcrossing in both directions using two unrelated strains of outbred mice, females were produced which were 25, 50, 75 and 100% heterozygous. The crossbred females and the two purebred strains (922 females in all) were mated to a sire line of a genetically distinct strain to standardize foetal heterosis. The reproductive performance of females with different percentage heterozygosity gave estimates of maternal heterosis. A significant positive linear relationship was found between heterozy-gosity and heterosis in litter size, total weight of litter and individual weight of progeny both at birth and at weaning. The relevance of these results for livestock breeding is discussed.
Carcass composition in four sheep breeds: the importance of type of breed and stage of maturity
Authors: Wood J. D. , MacFie H. J. H. , Pomeroy R. W. , Twinn D. J.
Published: September 2010

In order to investigate the effects of type of breed on carcass composition, an examination was made of 361 lambs from four breeds: Clun Forest and Colbred (termed ewe breeds); and Suffolk and Hampshire (termed ram breeds). The animals were in four carcass weight groups averaging 15, 17, 19 and 21 kg.

Percentage subcutaneous fat was influenced more by carcass weight than by breed, whereas both carcass weight and breed had similar effects on percentage lean. At the mean carcass weight of 18 kg, Colbreds, the leanest breed, had a similar value for percentage lean (about 57 % of carcass tissue weight) to the carcasses over all breeds weighing 15 kg; and Cluns, the fattest breed, had a similar value (about 54%) to those weighing 21 kg. Since the ram breeds were intermediate in composition between the two ewe breeds there was no effect of type of breed on carcass composition. The breed differences were related to eventual mature size and to the stage of maturity at each carcass weight, as judged by body length and bone weight measurements. However, Colbreds were bigger and leaner than published estimates of their mature weight suggested. Humerus weight was a good predictor of lean or total fat weight, explaining 83 % ofvariation when used as a predictor along with carcass weight.

Type of breed had a marked effect on internal fat deposition, the ewe breeds having heavier weights of both kidney knob and channel fat (KKCF) and caul fat (omental fat) than the ram breeds; and on the length oflimb bones, the ewe breeds having longer but thinner bones than the ram breeds. The order of the relative growth of the tissues and fat depots was: subcutaneous fat > caul fat > KKCF > intermuscular fat > lean > bone. Therefore, the internal fat depots were later maturing than intermuscular fat.

The percentage of prime cuts in the carcass was not affected by carcass weight. Colbreds had significantly lower values than the other breeds. Suffolks had the lowest lean to bone ratio.
Protein requirements of male cattle fattened on diets differing in energy concentrations
Authors: Levy D. , Holzer Z. , Folman Y. , Bleiberg M. , Ilan D.
Published: September 2010

The effects of three levels of crude protein in the diet, 10, 12 and 14 %, on the performance of entire Israeli Friesian male cattle (bulls) during fattening, was studied in two experiments.

The bulls were 5 months old and 200 kg live weight, and 7·5 months and 250 kg, at the start of Experiments 1 and 2, respectively, and were slaughtered after 178 to 268 days (Experiment 1) or 156 to 166 days (Experiment 2) on trial, at a live weight of 430 to 480 kg.

In Experiment 1 mixed diets of two metabolizable energy concentrations (11·1 and 10·5 MJ metabolizable energy/kg dry matter) were used, each containing concentrates with 10, 12 or 14% crude protein content. In half of the treatments the crude protein content of the concentrate was increased by two percentage units for the first 61 days of the experiment. Daily live-weight gain was significantly higher at 14% and 16% crude protein than at 10% and 12% crude protein during the first 61 days for animals on the high energy diet, but liveweight gain was not affected by crude protein content on the low energy diet over this period, or at either energy concentration from 62 days to slaughter.

In Experiment 2 the diet consisted of concentrate, wheat straw and cotton hulls, giving a metabolizable energy concentration of approximately 10·55 MJ/kg dry matter. Daily live-weight gain did not differ significantly between concentrates containing 10, 12 or 14% crude protein, but carcass weight gain was higher at 12% and 14% crude protein than at 10% crude protein.

It is concluded that in order to ensure the best performance of bulls of the Israeli Friesian breed, diets with a high concentration of energy should contain 14% crude protein when fed to animals with a body weight of 200 to 300 kg, and 12% crude protein for heavier animals.
The effect of correction factors on response to selection in beef cattle
Authors: Jones L. P. , Hopkins I. R.
Published: September 2010

Progeny of younger dams grow more slowly than those of older dams. When the environmental effects of dam age are not allowed for in selection for growth rate, selection differentials and genetic responses to selection are reduced.

In a model herd, with cows aged 2 to 8 years, it was found that neglecting the dam age effects reduced genetic gains by about 15% when selection is for weaning weight, and by 11 to 7 % when selection is at an age of 12 to 20 months. Much of the reduction occurs because of the selection of higher proportions from genetically inferior groups.

If genetic differences among dam age groups are small the reduction is only 7% at weaning and less at older ages. The effect of ignoring calf age was also estimated. It was found that if calves born within a period of 33 days were compared and calf age was neglected, the response to selection for weaning weight would be reduced by about 6%.
A note on the effect of social rank on the feeding behaviour of young cattle on self-feed maize silage
Authors: Leaver J. D. , Yarrow N. H.
Published: September 2010

In two experiments young British Friesian cattle were allowed restricted access to maize silage on a self-feed system. Restrictions were imposed by either limiting the width of feed face per animal or by reducing the time available for feeding.

The social order of each group of cattle was determined by observing dominance-submission interactions between pairs of individuals. Dominance rank and angular dominance values were calculated for individuals in each group and related to silage intake, feeding time and rate of eating. Silage intake and rate of eating increased significantly with dominance value, and feeding time decreased although not significantly.
Pig courtship behaviour: pheromonal property of androstene steroids in male submaxillary secretion
Authors: Perry G. C. , Patterson R. L. S. , MacFie H. J. H. , Stinson C. G.
Published: September 2010

The influence of the odoriferous androstene steroids upon the response and courtship behaviour of gilts has been studied. These steroids are normally present in the submaxillary salivary glands of the boar, and have been shown previously to be an aid in the artificial insemination of gilts. Glands were excised from young boars after weaning, and at 6 months of age the ability of the boars to elicit a standing response from oestrous gilts was compared with that of littermate controls. In addition, a detailed record was made of behavioural activities performed by both gilts and boars, under a standard test procedure.

Analysis of the data showed that the presence of the glands was essential for normal behavioural patterns in both the females and the males. When confronted with a treated boar, the gilts were affected in three ways: approaching oestrus, they did not respond as early as they did to the controls; the intensity of their response was reduced; and it was held for a shorter period. The demeanour of the treated males was passive and unconcerned, i n contrast to the easily-aroused aggressive nature of the controls. The characteristic viscous salivary secretion was absent, and the scrotal sac was less pronounced and supported closer to the body.

These results suggest that elimination of the white, frothy saliva normally containing and dispersing the androstene steroids not only reduces the boar's ability to command and elicit a full sexual response from oestrous gilts, but it also reduces his own libido. In conjunction with previous work, these studies provide evidence for the pheromonal properties of androstenone and androstenol.
A note on milk intake of piglets measured by tritium dilution
Authors: Yang T. S. , Howard B. , Macfarlane W. V.
Published: September 2010

The milk intake of two litters of suckling piglets was measured by the turnover of tritium-labelled body water. The estimated intakes of a litter of seven piglets agree with the current knowledge of milk yield from sows, which generally rises to a maximum at the 3rd week and then declines. With a litter of four, intake rose continuously from the 1st to the 6th week. Since piglets are often weaned at 3 weeks of age, this method has few disadvantages n i practical use. During the estimation of water turnover the total body water of individual piglets can also be obtained so that information on body composition (solids, protein, fat and ash) can be derived. The efficiency of conversion of milk by piglets can thus be calculated.
Induction of puberty in gilts 1. The effects of rearing conditions on reproductive performance and response to mature boars after early puberty
Authors: Paterson A. M. , Lindsay D. R.
Published: September 2010

Attainment of puberty and the ovulation rates for the first three oestrous cycles were studied in gilts reared to 160 days alongside contemporary castrate or entire males before introducing them to mature boars.

Gilts which were introduced to the boars at 160 days of age reached puberty at younger ages and lighter weights than isolated gilts. Rearing treatment did not affect the age of puberty. Gilts which were isolated from boars after 160 days of age reached puberty earlier if they had been reared with entire rather than castrate contemporary males. The interval from introduction of the boars to first oestrus was related to age and weight at the time of introduction.

Ovulation rate at the pubertal oestrus was the same in both isolated groups, and higher in both these groups than for gilts induced into early puberty by boars. Ovulation rate increased at the second and third oestrous cycle and groups differed only at the first oestrus. In a second experiment, the reproductive performance of gilts approximately 218 days of age experiencing either their first, second or third oestrus was studied. No differences were found among the groups and the conclusion is that in gilts of similar age and weight the oestrous cycle at which mating takes place does not affect reproductive performance.
A note on the housing of intact male and female pigs together in the same pen during the growing period to bacon weight
Authors: Barber R. S. , Braude R. , Mitchell K. G. , Thomas Joanne
Published: September 2010

A feeding trial was carried out, using 180 pigs, to assess the effect on performance when intact male and female pigs were housed together in the same pens from 20 to 90 kg live weight. There were no significant differences in daily feed intake, rate of growth or feed: gain ratio between pigs from mixed-sex pens and pigs from single-sex pens. Carcass measurements indicated slightly leaner carcasses for intact male pigs whether housed in separate pens or together with female pigs, while female pigs likewise had a significantly higher dressing percentage.
A note on a comparison of crossbreds from two prolific sheep breeds
Authors: Boaz T. G. , Jones R. , Smith C.
Published: September 2010

Two groups of crossbred ewes, produced by crossing the Scottish Blackface with two prolific sheep breeds, the East Friesian and the Animal Breeding Research Organisation Dam Line, were compared in good lowland conditions over three ages (2 to 4 years) from 1976 to 1978. The East Friesian crossbred ewes were heavier, had larger, heavier litters and had heavier lambs at weaning. More of their lambs were slaughtered directly off their dams, at heavier weights and at earlier ages. The total weight of lamb sold per ewe was about 15% higher than for the Dam Line crossbred ewes.
The effect of daylength on the growth of lambs 3. Level of feeding, age of lamb and speed of gut-fill response
Authors: Forbes J. M. , Brown Wendy B. , Al-Banna A. G. M. , Jones R.
Published: September 2010

Four experiments, each with 24 growing sheep, were carried out to investigate the effects of 8- or 16-h daylengths on growth and carcass characteristics. In the first two experiments, with 6- to 9-month-old castrated males, and 3- to 5-month-old female and castrated male animals, pair feeding of a concentrate feed was adopted. Live-weight gains were significantly greater under 16-h daylength, but carcass weights were not significantly increased because most of the live-weight difference was due to gut-fill. Carcass weights and measurements suggested that long daylength stimulated the growth of non-fat tissues at the expense of fat.

The third experiment compared castrated males fed either ad libitum or restricted to a daily ration proportional to each animal's own weight from 6 to 9 months of age. Food intake was higher in the ad libitum sheep but not significantly so. Weight gains were, however, significantly greater with ad libitum feeding and long daylength, compared with restricted feeding and short daylength, respectively. Gut-fill was greater in those kept in 16 h daylength and the small advantage in carcass weight was not significant. Carcass characteristics were not markedly affected by daylength, while carcass weight and fatness were higher following ad libitum feeding than restricted feeding.

In the fourth experiment 12 female sheep, aged 9 months, were individually rationed according to live weight and slaughtered after 4 weeks exposure to 16- or 8-h daylengths; another 12 were slaughtered after 7 weeks of treatment. Gut-fill was significantly greater in long daylength at both slaughter times, showing that the effect of daylength on gut fill has occurred within 4 weeks of the start of treatment, while live weight has not been observed to be affected at this stage in any experiment in this series.

Overall these experiments show little stimulating effect of long daylength on growth, and a large effect on gut-fill.
The composition of body-weight changes in underfed lactating beef cows
Authors: Chigaru P. R. N. , Topps J. H.
Published: September 2010

The effects of reducing the feed intake of 12 winter-calving (Hereford male × British Friesian female) cows to the maintenance level for 6 weeks from week 10 of lactation were investigated during two consecutive lactation periods. Initially, six cows were in their first and six in their third lactation. In each year the period of ‘underfeeding’ was preceded by a period of ‘adequate feeding’ (maintenance plus milk production requirements) and succeeded by a period of ‘refeeding’ (2 × maintenance). Changes in body water, estimated by the dilution of tritiated water and deuterium oxide at the end of each feeding period, were used to calculate changes in body tissue. Milk yield during the period of ‘adequate feeding’ indicated that individual cows differed markedly in milk production potential. During ‘underfeeding’ milk yield was related to lactation potential. Cows of higher potential tended to maintain higher yields than those of lower potential but in doing so they incurred higher body-weight losses. The ‘refeeding’ period did not result in significant increases in milk yield. The weight losses during ‘underfeeding’ consisted mainly of fat but some cows apparently mobilized relatively large amounts of protein. More fat per unit body weight loss was mobilized by the heifers than by the cows, which, on the other hand appeared to mobilize relatively more protein. On ‘refeeding’, only a few cows were able to achieve complete tissue repletion.
A note on regional variations in the seasonality of milk production in dairy cattle
Authors: Wood P. D. P.
Published: September 2010

Mean daily milk yield, fat concentration and protein concentration in the milk of 579 303 British Friesian, 6 608 Shorthorn, 27 374 Ayrshire, 19 529 Jersey and 19 760 Guernsey cattle were recorded monthly from August 1978 to July 1979 inclusive, and classified by breed, parity, stage of lactation, and five geographical areas according to the location of the herd. Parameters of the function Y(n) = anbecn were estimated for each breed/parity/area group for yield, fat concentration and protein concentration (b and c describe the shape of the curve, a is a scalar, n the week of lactation and e the base of natural logarithms). Systematic deviations from the function were associated with the season of production, reflecting the spring and summer flush of milk yield. Fat and protein concentrations also exhibited seasonal variations from the underlying curve. After correction for the seasonal fluctuation in production, there was no variation in total yield, fat concentration or protein concentration associated with the month of calving.
A note on a possible association between plasma β-carotene levels and conception rate in a group of winter-housed dairy cattle
Authors: Jackson P. S.
Published: September 2010

Three groups of winter-housed Friesian cows were fed according to maintenance and production requirements on dairy cake and poor quality hay for 5 weeks (5 cows), 4 weeks (4 cows) or 2 weeks (3 cows). They were then treated as one group with two injections of 500 μg cloprostenol 11 days apart to synchronize oestrus, followed by insemination 72 and 96 h after the second treatment.

Blood samples were taken for β-carotene estimation 1 day before the first cloprostenol injection, 3 days before the second injection, and the day after the second insemination. Conception was confirmed by rectal examination. Haematological parameters and metabolic profiles for all 12 cows were in the normal range and condition scores showed no correlation with time of conception. However, plasma β-carotene levels declined rapidly and uniformly between the three sample points for all cows. The individual animal means were directly correlated with length of time on the described diet and with time of conception (P<005). A theory of β-carotene involvement in ovarian function is advanced.
A note on the eating quality of pork from lean pigs
Authors: Wood J. D. , Mottram D. S. , Brown A. J.
Published: September 2010

Sixteen pork carcasses were purchased from those exhibited in Class 146 at the Royal Smithfield Show 1978 (i.e. pork carcasses of 48 to 61kg dead weight, age <5 months). Eight had thinner backfat than the average for the class (‘very lean’ group with 6 mm fat over m. longissimus at the last rib and estimated lean content in side of 63%), while eight had thicker backfat than the average (‘lean’ group with 12 mm fat over m. longissimus at the last rib and estimated lean content in side of 57%). Both groups were leaner than the national average. The carcasses were returned to the Meat Research Institute for eating quality assessments. Muscle quality was similar in both groups. Toughness (assessed instrumentally), tenderness and flavour (assessed by taste panellists) were also similar. Juiciness was lower in the ‘very lean’ group but was not matched by higher cooking losses and the difference was considered to be relatively unimportant. In conclusion, the eating quality of pork is maintained at very low values of carcass fatness.
Beef production from silage 1. The voluntary intake and live-weight gain of beef cattle given red clover silage
Authors: Thomas C. , Aston K. , Gibbs B. G. , Tayler J. C.
Published: September 2010

1. The primary growth of a tetraploid red clover was cut from 17 to 19 June and ensiled with formic acid at 3·81/t fresh crop (F), equal volumes of formic acid and formalin at 9 11/t (67 g formaldehyde per kg crude protein) (FF) or wilted and ensiled without additive (W). The silages were given ad libitum either alone or with supplements of dried grass or barley/fish meal at 6·7 g dry matter per kg live weight to 45 British Friesian male castrates, initially 3 months old and 104 kg live-weight.

2. The use of formaldehyde reduced the concentration of fermentation acids and of ammonia-nitrogen in the silage. Wilting the crop increased silage dry-matter content by 74g/kg fresh weight but this silage had the highest concentration of fermentation acids and of ammonia-nitrogen.

3. Digestibilities of diets containing silage FF were lower than those of diets containing silages F and W except when silage FF was supplemented with dried grass (interaction P <0·05).

4. The intake of silage W was on average higher than that of silages F and FF (P < 0·001). Supplements of barley/fish meal and dried grass depressed silage intake to a similar extent (P <0001). When silages were given as the sole feed, calves consuming silage F had higher live-weight gains than calves given silages FF and W (P <001). This effect was not apparent when silages were supplemented with barley/fish meal, but with a supplement of dried grass the calves given silage FF grew more slowly than those given silages F and W.

5. The results are discussed in relation to the possible effect of treatments on the supply of rumen-degradable protein and of amino acids to the animal.
Physiological attributes as possible selection criteria for milk production 2. Plasma insulin, tri-iodothyronine and thyroxine in bulls
Authors: Osmond T. J. , Carr W. R. , Hinks C. J. M. , Land R. B. , Hill W. G.
Published: September 2010

Insulin, thyroxine and tri-iodothyronine concentrations were measured in samples of blood from 175 Friesian bulls, aged between 2 and 7 years, which were being progeny-tested for milk production. Least squares regression coefficients were estimated for these hormone levels on time of day and time after feed at sampling and age of bull. Correlations between hormone levels and Improved Contemporary Comparisons of the bull, a measure of his daughters' milk production, did not differ significantly from zero, suggesting that simple spot estimates of levels of these hormones in bulls would not supply useful predictors of daughters' production.
Starling damage on farms using the complete diet system of feeding dairy cows
Authors: Feare C. J. , Wadsworth J. T.
Published: September 2010

Most farms that were feeding complete diets to dairy cows in the east midlands lost barley to starlings during the 1978/79 winter and more outdoor than indoor feeding sites were infested. The maximum total loss recorded on any one farm was 11 -881, this being 9% of the 1321 of barley presented to the cattle. The presentation of ground barley, rather than rolled barley, reduced the quantity of grain removed by starlings but the proofing of buildings i n which cattle are fed complete diets is suggested as the most effective means of preventing this food loss.
A note on the influence of boar age on its ability to advance puberty in the gilt
Authors: Kirkwood R. N. , Hughes P. E.
Published: September 2010

Twenty-four Large White × (Landrace × Large White) gilts were allocated to one of four treatments such that one gilt from each of the litters was on each treatment. Three of the treatments involved 30-min daily contact with a boar, the boar being either (1) 2 years of age, (2) 11 months of age, or (3) 6·5 months of age, at the start of the trial. The fourth group were controls, receiving no boar stimulation.

The experiment began at a gilt age of 165 days and continued until puberty was detected. The gilts were slaughtered 5 days after puberty was reached.

The results indicate no significant difference for age at puberty between gilts exposed to the 2-year- or 11-month-old boars (182·0 v. 181·6 days respectively), although both were significantly younger at puberty than gilts exposed to the 6·5-month-old boars or having no boar contact (P<001) (206·0 v. 203·0 days respectively).
Milk production from silage 2. The influence of the digestibility of silage made from the primary growth of perennial ryegrass
Authors: Thomas C. , Daley S. R. , Aston K. , Hughes P. M.
Published: September 2010

1. The primary growth of perennial ryegrass (Lolium perenne cultivar Endura) was cut on 23 May (high digestibility) and 23 June (low digestibility) and ensiled with an additive consisting of equal volumes of formic acid and formalin to supply 30 g formaldehyde per kg crude protein. The silages were given ad libitum, together with 6·3 kg dry matter per day of a barley/soya bean supplement, to 24 British Friesian cows over weeks 4 to 18 of lactation.

2. The delay in cutting the primary growth led to an increase in grass yield from 3·78 to 6·94t dry matter per ha but a depression in the content of digestible organic matter in the silage dry matter from 748 to 639 g/kg. However, the effect of the digestibility of the silage on the digestibility of the total diet by the cows was small. The silages contained low levels of fermentation acids and ammonia-nitrogen.

3. The digestibility of silage did not influence silage dry-matter intake in early lactation but in mid lactation the intake of the low-digestibility silage declined whilst that of the high-digestibility silage increased slightly.

4. Cows given silage of high rather than low digestibility produced significantly more milk (high, 28·0 v. low, 24·7kg/day, P < 0·01 ) of lower fat content (high, 36·1 v. low, 41·0 g/kg, P < 0·01 ) but higher protein content (high, 31·5 v. low, 29·4g/kg, P < 0·05). Cows given silage of low digestibility lost more live weight than cows given silage of high digestibility but the effect was not significant.