bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of factors affecting the voluntary intake of food by cattle
Authors: McCullough T. A.
Published: September 2010

Six diets providing ratios of concentrate to hay of 100 : 0, 95 : 5, 90 : 10, 80 : 20, 70 : 30 and 60 : 40 were given ad libitum to 24 British Friesian steers. The hay (in the long form) was offered separately from the concentrates. From 91 to 136 kg live weight, as the proportion of hay in the diet increased, daily dry-matter intake decreased. Over the weight range, 136 to 363 kg live weight, the addition of small amounts of hay to the concentrate diet caused an increase in intake.
At 42 weeks of age a digestibility trial was carried out. Daily drymatter intake was maximal when the diet contained 80% concentrates. The apparent digestibility and mean retention time of the diets increased as the proportion of concentrates increased. Differences in estimated gut fill were not significant.
The diet consisting of concentrate only resulted in the lowest concentration of acetic acid and the highest concentration of propionic and butyric acids in the rumen liquor. Net-energy intake tended to increase as the proportion of concentrates increased from 60 to 90% but then remained fairly constant.
Haemoglobin variants in Indian sheep
Authors: Agar N. S. , Rawat J. S. , Roy A.
Published: September 2010

Haemoglobin types in three breeds of sheep were investigated. All three haemoglobin types—A, B and AB—were found to be present in the animals in two of the breeds examined, namely Bikaneri and Corriedale × Bikaneri (F1 generation). Mandia sheep had only Hb B and Hb AB types. Haemoglobin JB animals predominated in all the three breeds, the Mandia breed having the highest percentage of these animals. The possible significance of these findings is discussed.
Relative weight changes in the tissues of the gigot joint as Scottish Blackface castrated male lambs develop from weaning to maturity and an analysis of the observed individual variation
Authors: Jackson T. H.
Published: September 2010

Eighty-two Scottish Blackface castrated male sheep were used to test whether, from weaning to near maturity, the gigot grew exactly proportionally to the half carcass and whether the tissue in the gigot grew at the same rate as the respective tissue of the half carcass.

While slight deviations from exact proportionality of growth occurred, none could be adjudged significant or important. If the gigot does not grow directly proportionally to the half carcass the data suggested that the gigot tended to grow slightly more slowly than the total half carcass over this period. If gigot muscle does not grow proportional to the total muscle the data suggested that gigot muscle might grow slightly more slowly. If growth of bone tissue is not directly proportional between the gigot and the half carcass the tendency was for the gigot bone to grow slightly faster than total bone while the fatty tissue of the gigot showed a slight tendency to grow more slowly than the half carcass fatty tissue.
An economic appraisal of pig improvement in Great Britain 1. Genetic and production aspects
Authors: Mitchell G. , Smith C. , Makower M. , Bird P. J. W. N.
Published: September 2010

Estimates of the economic returns from pig improvement in Great Britain are substantial. Genetic improvement in the national pig improvement scheme from 1970 to 1977 was estimated, using two control herds, to be 76 (s.e. 10) pence per pig per year. Stocks from breeding companies were of a similar merit from 1975 to 1980, so both groups were combined in the economic evaluation. Annual costs were estimated at €2 × 106 and annual benefits at approximately €100 × 106. The use of crossbreeding in commercial production was also estimated to contribute approximately €16 × 10 per year. These substantial figures are the best estimates available for the benefits, but some of the deficiencies are discussed.
An economic appraisal of pig improvement in Great Britain 2. Factors affecting estimated benefits
Authors: Smith C. , Gibson A. , Mitchell G.
Published: September 2010

In a previous paper, pig improvement in Great Britain was assessed for the value of genetic improvements in growth-carcass traits. The benefits are substantial, estimated at €100 × 10 per year. Here, several factors that possibly affect these estimated benefits are examined. These include: 1. comparisons in production systems optimal to improved and to unimproved stocks; 2. interaction of station and farm performance; 3. changes in correlated traits, especially sow weight; and 4. uncertainty about future husbandry and marketing needs.

The conclusion is that, despite appreciable documentation and evaluation, and although the overall benefits are certainly large, there is room for uncertainty about the actual value of past pig improvement work in Great Britain.
A mixture of malt distillers' grains (draff) and pot ale syrup as a food for dairy cows
Authors: Castle M. E. , Watson J. N.
Published: September 2010

Twelve Ayrshire cows in a 16-week changeover design experiment were offered 8 kg hay per day together with a daily supplement of either: A, 8 kg concentrates; B, 6 kg concentrates and 4·5 to 50 kg draff/syrup mixture; or C, 4 kg concentrates and 9·0 to 10·0 kg draff/syrup mixture. The concentrate and the draff/syrup mixture had dry-matter concentrations of 872 and 385g/kg, and contained 229 and 255 g crude protein per kg dry matter respectively. Total daily intakes of dry matter were 13·77, 13·80 and 13·81 kg per cow for treatments A, B and C respectively, and were not significantly different. The mean daily milk yields for treatments B and C were 18·2 and 18·5 kg per cow respectively, and were significantly higher than the yield of 17·3 kg per cow for treatment A. The solids-not-fat and lactose concentrations in the milk, and the mean live weights, were also significantly higher for treatment C than for treatment A. Based on the differences in milk yield and composition between treatments, it was estimated that the metabolizable energy value of the draff/syrup mixture was 12·2MJ/kg dry matter. It is concluded that the draff/syrup mixture was a safe and acceptable food for dairy cows when it replaced half of the concentrate dry matter.
Growth, hormonal and metabolic response of post-pubertal entire male cattle to trenbolone acetate and hexoestrol
Authors: Galbraith H.
Published: September 2010

The response of post-pubertal entire male cattle (bulls) to implantation with trenbolone acetate and hexoestrol was studied in two experiments. In experiment 1, eight British Friesian bulls, weighing approximately 359 kg at the beginning of a 90-day experiment, were either sham-implanted or implanted with 45 mg hexoestrol, followed 21 days later with a further implantation of 300 mg trenbolone acetate. In experiment 2, 16 bulls (14 British Friesian and two Simmental < ♂ × (Hereford < 5 × Friesian ♀), weighing approximately 349 kg, were similarly untreated or implanted with 30 mg hexoestrol and 300 mg trenbolone acetate. Treatment with hexoestrol gave a small and non-significant increase in live-weight gain in both experiments. However, live-weight gain and efficiency of conversion of food into live-weight gain were significantly improved in both studies following implantation with trenbolone acetate (P < 0·05). Treated bulls had heavier carcasses and greater mean values for estimated carcass gain (P < 005 in experiment 2). Comparison of mean values for blood metabolites indicated significant differences in concentrations of plasma glucose, free fatty acids and cortisol, and serum total protein, growth hormone, insulin and prolactin. Mean values were significantly lower in treated animals for serum albumin in experiment 2 (P < 001) and for plasma urea in both experiments (P < 0·001; P < 0·05). Treatment with hexoestrol resulted in lower mean concentrations of plasma androgens. These were further reduced following treatment with trenbolone acetate (P < 0·01). The results suggest that the combination of trenbolone acetate plus hexoestrol may improve growth performance, by altering protein metabolism, in post-pubertal entire male cattle. The combination of trenbolone acetate plus hexoestrol appears to have more potent anabolic activity than the endogenous hormones of these animals.
The effects of partial weaning, movement and boar contact on the subsequent reproductive performance of lactating sows
Authors: Henderson Ruth , Hughes P. E.
Published: September 2010

Forty multiparous Large White × Landrace sows were randomly allocated to five treatment groups: (1) control (C) — no partial weaning, movement or boar contact, (2) partial weaning (PW) only — sow and litter separated for 12 h/day, (3) PW + boar contact (B) in the sow's pen (1 h/day), (4) PW + sow moved (M) to empty pen (1 h/day), (5) PW + sow moved to occupied boar pen (1 h/day). Treatments were imposed from day 10 post partum until weaning at day 35 (s.e. 1). All sows were generously fed throughout lactation (7 kg/day) and in the post-weaning period (3 kg/day). One sow (treatment 5) exhibited lactational oestrus and was mated on day 33 of lactation, while the remaining sows on treatments 2 to 5 had significantly reduced (P < 0·05) weaning to remating intervals relative to control sows (4·84 v. 6·63 days, respectively). Litter creep food intakes tended to be higher in PW litters than controls (512 v. 376 g/day; P > 0·05), whereas sow live-weight gains during lactation were significantly increased when PW was employed (+0·43 kg/day v. −0·13 kg/day for control sows; P < 0·001). Partial weaning significantly (P < 0·001) reduced litter weaning weights (74·8 v. 87·0 kg for controls). However, there were no significant treatment effects on individual piglet weaning weights, subsequent growth performance of the weaned litters, or the size of litter subsequently produced by the sows.
A note on the influence of methionine content in the diet of pigs from 21 to 49 days of age on their performance from 49 to 97 days of age
Authors: Leibholz Jane
Published: September 2010

One hundred and twenty-five boars were given diets containing five levels of methionine: 1·5, 1·7, 1·9, 2·1 and 2·3 g methionine per kg diet, from 21 to 49 days of age. The mean weight gain of the pigs given the diet containing 1·5 g methionine per kg was 71 g/day and this increased linearly to 346 g/day for the pigs given the diets containing 2·3 g methionine per kg.

From 49 to 97 days of age all pigs were given a commercial pig grower diet containing 160 g protein per kg. Live-weight gains over this period increased linearly from 477 to 689 g/day with increasing methionine content of the starter diets. There was no compensatory weight gain.
Environmental effects on bull performance test results
Authors: Simm G. , Smith C. , Prescott J. H. D.
Published: September 2010

Measurements of growth rate, food intake and food conversion efficiency on 235 Hereford bulls, from the first 4 years of a selection experiment, were used to assess the effects of rearing method, dam age and year/season of birth. Bulls were either reared artificially from birth to 84 days of age, or reared on their own dam to 84 or 168 days of age, to examine whether non-genetic effects on performance could be reduced by early weaning. All bulls were performance tested on ad libitum feeding from 200 to 400 days of age. Artificially-reared bulls had lower live weights at the start of test, which led to higher food conversion efficiency on test. Bulls reared naturally to 84 days of age were least affected by dam age and year/season of birth and performed as well as those weaned at 168 days of age. Earlier weaning of bulls entering central performance tests would reduce these environmental effects on performance, and may increase the accuracy of identifying bulls with genetically-superior growth and efficiency.
Effects on food intake, rumen development and live weight of calves of replacing barley with sugar beet-citrus pulp in a starter diet
Authors: Williams P. E. V. , Fallon R. J. , Innes G. M. , Garthwaite P.
Published: September 2010

In three experiments the effects of replacing barley with citrus or unmolassed beet pulp in starter diets for calves was examined. In experiment 1, 40 Friesian bull calves were offered to appetite from 14 to 91 days of age one of four complete pelleted diets, each of which contained 200 g ground straw per kg and n i which the ratio of barley to pulp (citrus and beet pulp in the ratio 1:1) was 100:0 (A); 67:33 (B); 33:67 (C) and 0:100 (D). All diets contained 12·1 MJ metabolizable energy and 187 g crude protein per kg dry matter (DM). Milk replacer containing 200 g fat per kg was offered once daily (0·44 kg/day) until day 49 when the calves were abruptly weaned. Up to weaning (days 14 to 49) and after weaning (days 50 to 91) intake of DM was significantly increased by replacing barley with pulp (P< 0·05). Intakes (kg DM per day) of diets A, B, C and D were 0·31, 0·44, 0·51 and 0·50 before weaning and 2·07, 2·08, 2·23 and 2·38 after weaning. Weight gains (kg/day) of calves given pulp tended to be higher before weaning (0·44v.0·58 for Av.mean of B, C and D) but lower after weaning (0·73v.0·68) than of calves given the cereal-based diet. In experiment 2, 65 calves were given diets similar to A and C except that the pulp was supplied totally by unmolassed beet pulp, they were given only 0·35 kg milk replacer per day and weaned on day 35. The results were similar to those obtained in experiment 1; between days 14 to 84 intake was higher (P< 0·05) and there was a tendency for weight gain to be higher in calves given the diet containing pulp. The DM digestibility of the diets decreased significantly with inclusion of pulp (P< 0·05); digestibility of nitrogen was severely depressed but there was an increase in digestibility of acid-detergent fibre. Growth rate was possibly restricted by the availability of nitrogen in diets containing pulp.
A note on the effect of scrotal wool cover on morphological changes in ram spermatozoa due to heat stress
Authors: Rathore Ashok K.
Published: September 2010

Variation in scrotal wool cover influenced the percentage of abnormal cells in the semen of rams exposed in the hot room. The percentage of abnormal cells was highest in the rams with maximum wool cover on their scrota, intermediate in those with scrota completely devoid of wool cover and minimum in those with intermediate (2 to 3 cm) scrotal wool cover.
A note on the effect of weaning age on lamb production
Authors: Sharafeldin M. A. , Ramadan I. A.
Published: September 2010

At birth, the Barki lambs used in this experiment were randomly allocated to three groups which numbered 133, 126 and 154 lambs of both sexes weaned at the ages of 10 weeks (Group I), 12 weeks (Group II) and 16 weeks (Group III) respectively.

The most pronounced differences between the three groups of lambs in their body weights took place at the age from 4 to 6 months. Group II lambs performed as well as or even slightly better than the other two groups, which leads to the conclusion that as far as the body weight of lambs is concerned there is no need to extend their suckling period more than 12 weeks.

The three groups of lambs varied little in their mortality rates from 2·5 to 12 months of age.
Resistance to body cooling in male and female sheep, and the effects of previous exposure to chronic cold, acute cold and repeated short cold shocks
Authors: Slee J.
Published: September 2010

Twenty-eight female and 26 uncastrated male Scottish Blackface sheep were shorn and subjected to two acute cold exposures one week apart. Between exposures and for one week before the first exposure the sheep were kept either at +30°C (thermoneutral), or at +8°C (subcriticai), or at + 30°C with daily short cold shocks. Food intakes were restricted.

Females showed significantly greater resistance to body cooling than males during both acute exposures.

Both males and females showed acclimatization (increased resistance to body cooling) as a result of the first acute exposure.

Exposure to +8°C for one week did not produce significant acclimatization. Exposure to +8°C for two weeks tended, in females only, to increase acclimatization above that resulting from the first acute exposure.

Daily short cold shocks reduced cold resistance and inhibited acclimatization in females, but had little effect in males.

The male sheep lost significantly more weight during treatment and became thinner than the females. It was suggested that this, and their low cold resistance, might be related to a lesser ability of males to store fat as a subsequent source of energy.
The Use of Chromic Oxide in the Measurement of Individual Feed Intake in Cattle Fed on Silage and Barley
Authors: Wilkinson J. M. , Prescott J. H. D.
Published: September 2010

1. Three experiments are reported in which chromic oxide, administered as a component of shredded paper at 09·00 and 16·30 hr daily, was used in the estimation of the faecal output of steers fed on silage and barley.

2. Four Friesian steers of 160 kg live weight were used in experiment 1. They were fed on grass silage ad libitum with controlled allowances of concentrate supplement. ‘Absolute’ recovery of Cr2O3 in total collections was 85–91%, though it was apparent that some faeces may have been lost from the total collections. ‘Relative’ recovery in grab samples was 97%.

3. Diurnal variation in Cr2O3 excretion was investigated in experiment 2 with four yearling Friesian steers. Faeces were sampled in three 24-hr periods at each natural defaecation. A significant and consistent diurnal variation was observed, with the lowest concentration of Cr2O3 occurring during the night. Concurrent grab samples taken at 09.15 and 17.00 hr over four days gave estimates of cr2O3 in the faeces which were 16·27% higher than the mean concentration for the three 24-hr sampling periods.

4. Day-to-day variation in the Cr2O3 content of grab samples was examined in experiment 3 with eight yearling Friesian steers. Four steers received 3·63 kg/head per day of barley supplement and four received 1·81 kg. Both groups were offered silage of 25% dry matter ad libitum. Faeces were sampled per rectum twice daily at 09.15 and 17.00 hr over four-day sampling periods. The degree of day-to-day variation was small and tended to be random.
The effect of cobalt supplementation, as an oral drench or pasture treatment, on the growth of lambs
Authors: Griffiths J. R. , Bennett R. J. , Bush R. M. R.
Published: September 2010

In a trial to investigate an ill-thrift problem in lambs on an Exmoor farm frequent oral drenching with cobalt sulphate was compared with pasture spraying. There were two groups of twin lambs reared respectively on sprayed and unsprayed pasture. One partner from each twin set was drenched with cobalt sulphate every two weeks. There were no significant differences in live-weight gain up to weaning time. Thereafter there was little difference in the progress of the twins on sprayed pasture. On the unsprayed pasture, however, the drenched lambs had gained an average of 9 lb live weight more than their partners over a period of 15 weeks but were still about 7 lb lighter than the lambs on sprayed pasture.

Blood vitamin B12 concentration, assayed with Lactobacillus leichmannii, was not well correlated with the treatment of the groups and all values were above commonly accepted critical levels.
Some effects of including differently processed barley in the diet of the growing pig: 2. In vivo gastric pH changes
Authors: Lawrence T. L. J.
Published: September 2010

1. In vivo gastric pH changes were studied, in 6 pigs fitted with permanent gastric cannulae, under ‘basal conditions’ (i.e. when no food was given) and when diets containing 85% of differently processed barley were given either twice daily or at frequent intervals of time in an attempt to simulate ad libitum feeding systems. Before inclusion in the diet the 85% of barley had either received no processing (i.e. was given as the whole grain) or had been processed in one of the five following ways: (a) ground through a (1·56 mm) screen (b) ground through a (4·68 mm) screen (c) ground through a (9·36 mm) screen (d) coarsely crimped (e) cold rolled.

2. Relative to the ‘basal’ determinations the systems of feeding which gave food at frequent intervals of time induced higher overall mean pH values than did those which gave food twice daily, while between the six differently processed diets those containing the smaller particles of barley tended to give higher overall mean pH values than did those containing the coarser particles.

3. The validity of the results is discussed in the context of the techniques used and some possible implications in terms of animal health are briefly discussed.
Proceedings of the 50th meeting of the british society of Animal Production: University of Newcastle upon Tyne, 8-11 September, 1969
Authors: T. J. C. D.  , M. B.  , J. H. D. P.
Published: September 2010

THE theme of the meeting was ‘Beef Production’. The first day was devoted to seven invited papers on carcass quality. This was followed by a whole day tour of north Northumberland including the inspection of beef calf production enterprises on five farms. Suckled calf production was also the subject of the four invited papers presented the next day and the meeting concluded with a visit to Cockle Park Experimental Farm.
Further studies on the voluntary food intake of Bos Indicus, Bos Taurus and crossbred cattle
Authors: Ledger H. P. , Rogerson A. , Freeman G. H.
Published: September 2010

1. The voluntary dry-matter intake, water intake and rate of live-weight gain of indigenous, exotic and crossbred cattle on low- and medium-roughage diets have been compared under similar conditions of management.

2. At similar live weights and on similar diets exotic cattle usually have a higher food intake than indigenous animals.

3. When roughage was freely available the voluntary dry-matter intake of both types of cattle increased.

4. Water intake was closely related to dry-matter intake and varied with the nature of the diet. The ratio of water to dry-matter intake was not affected by live weight and varied only slightly between the different types of cattle.

5. Exotic cattle were generally more efficient than indigenous cattle of comparable live weight in converting food into live-weight gain; crossbred animals were intermediate. It is suggested that this largely reflects their higher intake of food relative to their maintenance requirement.

6. One group of indigenous animals that were initially mature but under weight gained weight as quickly, and converted their food as efficiently, as did exotic animals.
Effects of air temperature on body temperatures and sensible heat loss of Friesian and Jersey calves at 12 and 76 days of age
Authors: Holmes C. W.
Published: September 2010

1. Measurements have been made of sensible heat flow, body temperature and some hair coat characteristics, at 10 different air temperatures, on each of 24 Friesian and Jersey calves aged 12 and 76 days.

2. Minimum values for thermal conductance of the trunk tissues were 29·5 and 37·3 kcal/m2.hr per °C for the 12-day-old Friesian and Jersey calves respectively; corresponding values for the 76-day-old calves were 22·5 and 19·9 kcal/m2.hr per °C.

3. Weight of hair per m2 surface area was greater for Friesian calves and for younger calves; Friesian calves had longer hair and deeper coats. Coat depth increased at low temperatures in all calves.

4. The air temperatures at which the ears became vasoconstricted were 18·8 and 21·8°C for the 12-day-old Friesian and Jersey calves respectively; the corresponding values for the 76-day-old calves were 10·1 and 17·8°C. Vasoconstriction occurred in the back legs at a lower air temperature than in the ears or on the trunk surface.

5. The intake of dry matter as fresh grass was 1·15 kg/day for Friesians and 0·72 kg/day for Jerseys, aged 76 days; the Friesians weighed 74 kg and the Jerseys 59 kg at this age.
A note on the effect of Broken Mouth on the performance of Scottish Blackface hill ewes
Authors: Gunn R. G.
Published: September 2010

On a hill farm, 376 Scottish Blackface ewes with all permanent incisor teeth present (whole mouth) at 53 months of age were compared with 118 ewes having one or more of these teeth missing (broken mouth). By 46 months, ewes becoming or already broken-mouthed were significantly lighter in weight and although at their third lambing they gave birth to the same number and weights of lambs as whole-mouthed ewes, their twin lambs were significantly lighter in weight from about three weeks of age onward. At their fourth lambing, broken-mouthed ewes produced and reared significantly fewer lambs and of lighter weight than their whole-mouthed contemporaries. Grazing of turnips increased the incidence of ewes with broken mouths.
A note on the apparent digestibility of energy and protein in dried poultry excreta
Authors: Lowman B. G. , Knight D. W.
Published: September 2010

The nutritional value of dried poultry excreta was investigated by determining the apparent digestibility of dry matter, organic matter, nitrogen, energy and copper in five diets containing 0 to 100% of this feed. Dried poultry excreta supplied 20·21% apparently digestible crude protein and approximately 1·57 or 1·74 Mcal of metabolizable energy per kg dry matter.

The copper in dried poultry excreta was found to be less digestible than the copper in barley. It is concluded that, as far as copper levels are concerned, dried poultry excreta are safe for ruminants, and are a source ofcheap protein. More detailed work is needed to determine the metabolizable energy of the material accurately.
Factors affecting accuracy in the evaluation of progeny tests of growth rate in cattle
Authors: Wood P. D. P.
Published: September 2010

Two progeny tests for beef, one using 452 calves brought centrally to a test centre, the other using 768 calves commercially fattened on 81 farms, were compared to isolate environmental sources of variation. It was concluded that appreciable reduction of error variance ensued from the use of a growth curve, the maintenance of pen identity, and the removal of variation due to pens and months of birth. The fixed effects model underlying the experimental design on the centre yielded relatively robust estimates of variance components.
Studies on protein utilization by ewes during lactation
Authors: Robinson J. J. , Forbes T. J.
Published: September 2010

A total of 64 Border Leicester × Greyface ewes were offered eight diets comprising four levels of digestible crude protein and two levels of metabolizable energy (ME) intake during gestation. After parturition the ewes on each gestation treatment were offered a high or low level of ME intake at a constant level of crude protein intake. Nitrogen balances were carried out on all ewes during weeks three and four of lactation.

Digestibility coefficients and output of nitrogen in the milk measured during the lactation balance periods were not significantly affected by the gestation treatments. Body nitrogen balance during lactation was significantly affected by the level of protein offered during gestation.

Empirical equations relating digestible crude protein intake and ME intake to milk nitrogen production and body nitrogen balance indicated that a digestible crude protein intake of 7·9 g/kg W0·75 per day and a ME intake of 220 kcals/kg W0·75 per day resulted in the production of 0·70 g milk nitrogen per kg W0·75 or approximately 100 g of milk per kg W0·75. The corresponding level of body nitrogen retention was 0·162 g/kg W0·75 per day and showed no consistent trend due to level of protein intake during gestation.
A note on the estimation by simulation technique of the optimal colostrum dose and feeding time at first feeding after the calf's birth
Authors: Kruse V.
Published: September 2010

Computer simulations using parameters based on results from experiments showed that by chance a certain frequency of hypo-gammaglobulinaemia would always occur. This was due to variations in birth weight, concentration of immunoglobulin in the ingested colostrum, amount of colostrum offered, and age at first feeding. It was not necessarily associated with an absorption block as sometimes postulated. The probability of an individual getting hypogammaglobulinaemia can be minimized by early feeding of a large quantity of colostrum at the first feeding after birth.
The voluntary intake and utilization of roughage–concentrate diets by sheep. 2. Barley and soya bean meal supplementation of hay diets
Authors: Crabtree J. R. , Williams G. L.
Published: September 2010

Three levels of soya bean meal (0%, 25% and 50% of the intake of hay dry matter) combined with three levels of pelleted barley (0%, 50% and 100% of the intake of hay dry matter) in a factorial arrangement of treatments were offered to Welsh Mountain ewe lambs receiving hay ad libitum for 14 weeks.

When barley was not given, soya bean meal added at 25% of the hay intake increased hay voluntary intake from 287 g/day to 412 g/day but hay intake was depressed to 339 g/day by a further increase in the level of soya bean meal. When barley was given, soya bean meal did not affect hay intake. With one exception, an increase in barley reduced hay intake, with the result that there were no differences between treatments in the digestible energy intakes of lambs receiving barley at each level of soya bean meal. In general, it was found that an increase in the concentrate allowance (barley + soya bean) reduced hay intake, whereas an increase in the crude protein content of the concentrate increased hay intake. The relationship between live-weight change, metabolizable energy intake and live weight was examined by regression analysis. Although live weight and voluntary intake were unrelated at the start of the experiment, a positive relationship emerged as the experiment progressed.
Crossbreeding beef cattle in Western Uganda 3. Genetic analysis of body weight
Authors: Trail J. C. M. , Sacker G. D. , Fisher I. L.
Published: September 2010

Genetic influences on body weights, taken at three-monthly intervals from birth to two years, were measured in the progeny of Angus, Boran and Red Poll bulls mated to Ankole, Boran and local Zebu cows. At two years old, progeny of Angus and Red Poll sires were 9% heavier than progeny of Boran sires. Progeny of Boran dams were 15% heavier than progeny of Zebu dams and 8% heavier than progeny of Ankole dams at two years. Differential performance by progeny of Ankole dams in different years suggested that genetic × environment interaction might be of some importance, and indicated the necessity of testing breed types over several years. Low and variable heritability estimates of weight-for-age up to two years old, and significant hybrid vigour effects on weight, indicated that in this environment, exploitation of hybrid vigour could be of great importance. Repeatability estimates for calf pre-weaning weights averaged 0·42.
Crossbreeding beef cattle in Western Uganda 6. A note on hybrid vigour in Red Poll–Boran crosses
Authors: Sacker G. D. , Trail J. C. M. , Fisher I. L.
Published: September 2010

Hybrid vigour effects were measured on weights at birth and at 3, 6, 9 and 12 months, in crosses between Red Poll and Boran cattle. Means of crossbred weights were superior to means of purebred weights by 9·7% at birth and by 26·4% to 29·7% at 3–12 months. Boran cows had superior mothering ability to Red Poll cows, judged by the early growth of reciprocal cross calves, and lost less body weight over a nine-month lactation period.
Population study of abortion in cattle with special reference to genetic factors
Authors: Wijeratne W. V. S. , Stewart D. L.
Published: September 2010

The incidence of abortions over a period of eight years was studied in 107 393 progeny of 100 bulls belonging to five dairy and three beef breeds of cattle. The calving records related to the first four artificial inseminations on females with fresh or frozen semen.

The average frequency of abortion was 2·12%. Differences in rates of abortion between the breeds of sire were statistically significant although this may be confounded with the breed of dam. The highest incidence was from matings by bulls of the Channel Island breeds and the least from matings to Ayrshire bulls.

The rates of abortion increased with the number of inseminations necessary for conception.

There was a slightly higher incidence of abortions among twin births than among singles.
A note on non-genetic factors affecting body weights of Bikaneri sheep (Magra strain)
Authors: Chopra S. C. , Acharya R. M.
Published: September 2010

The least squares analysis on birth, weaning, 6-month and yearling weights in Magra lambs showed that years of lambing, age and weight of dam at lambing and sex of lamb significantly affected all the body weights except the age of dam which did not significantly affect 6-month and yearling weights. Adjustment of these weights for significant effect will be necessary in obtaining estimates of genetic and phenotypic parameters.
The long-term suppression of heat in cattle with implants of melengestrol acetate
Authors: Roche J. F. , Crowley J. P.
Published: September 2010

The effectiveness of silastic rubber implants impregnated with melengestrol acetate (MGA) to suppress heat in heifers being finished for beef was tested. Nine uniparous females received MGA implants, nine received 0·5 mg MGA orally and eight similar non-treated animals served as controls for a 110-day experimental period. Based on occurrence ofheat and ovarian examination during treatment and at slaughter, the silastic implants were effective in suppressing heat throughout the experimental period. The animals with implants also had a significantly higher rate of daily gain than the controls (P<0·1). In a second experiment the implants were effective in suppressing heat but the increase in daily gain did not reach significance. Silastic implants of MGA are effective for the long-term suppression of oestrus in finishing heifers and their effective life span is sufficiently long for use under commercial farming conditions.
A note on the effect of time of weaning and weight at slaughter on feed utilization of intensively fed lambs
Authors: Ørskov E. R. , Fraser C. , Gill J. C.
Published: September 2010

Fifty-four Suffolk × North Country Cheviot lambs were weaned at either 25, 33 or 41 days of age and slaughtered at either 35, 45 or 55 kg live weight.

Increasing the age at weaning reduced the growth check, increased creep feed consumption and decreased food required for fattening. For each kg increase in weight at slaughter there was an increase of 0·035 kg in dry matter required per kg gain. The female lambs had lower growth rates, lower efficiency of food utilization and a higher killing-out percentage than male lambs.

For the most efficient utilization of food, lambs should be weaned at about 33 days of age.
Effects of shelter, exposure and level of feeding over winter on the productivity of Welsh Mountain ewes and lambs
Authors: Robinson W. I. , Brown W. , Lucas I. A. M.
Published: September 2010

Pregnant Welsh Mountain ewes were kept over winter on a hill. All were penned individually, either in a shed or out of doors. In Experiments 1 and 2 different levels of digestible organic matter (DOM) were given in each environment and in Experiment 3 only a single level was offered. In Experiment 2 all ewes were grazed together after lambing; in Experiment 3 some from each treatment were moved to a shed after lambing and their milk yields recorded between 10 and 15 days later.

In a fourth experiment on low land, pregnant ewes were either housed or kept in an exposed or a sheltered paddock. All were grazed together after lambing.

The results indicated that the requirement of indoors penned sheep to maintain body weight and produce a single lamb is 9·5 g DOM/kg live weight per 24 hr at 16 weeks pre-partum, rising to 15·0 g DOM/kg live weight per 24 hr at 1 week pre-partum. A 10% weight loss during pregnancy would be expected in ewes receiving 75 to 80 % of these requirements. Low intakes during pregnancy reduced wool growth and lamb birth weights.

Outdoor exposure reduced pre-partum ewe weight by about 1·5 kg, and so was equivalent to a 10% reduction in daily DOM intake. The magnitude of this effect was not changed significantly by level of feeding. Exposure did not affect wool growth and its influence on lamb birth weight and growth was variable.
The seasonality of reproductive performance of Merino sheep in Britain
Authors: Tempest W. M. , Boaz T. G.
Published: September 2010

A study has been carried out to determine the length of the breeding season and the feasibility of lambing twice a year in Merino sheep in Britain.

Six groups of 18 ewes were exposed to rams at monthly intervals, and twice per year, from April 1969 to June 1970. A well-defined breeding season, from August to January, was found, and its shortness, linked with the inability of the ewes to conceive immediately post partum, prevented lambing twice in the year.
The influence of age at first calving and winter feeding management as yearlings on calf production from beef Shorthorn cows
Authors: Bernard C. S. , Fahmy M. H. , Lalande G.
Published: September 2010

The effects of age atfirstcalving (2 v. 3 years) and the winter feeding management as yearlings (roughages v. roughages supplemented with meal) on conception rate, calving performance (survival and weights) and lifetime production were studied on 76 beef Shorthorn cows bora from 1956 to 1958 at the Lennoxville Research Station. Conception rates averaged 89 %, and were not influenced by treatments. Calf mortality from birth to weaning was 1·5 and 0·6% higher among the calves out of the cows which had calved first at 2 years old and cows not supplemented, respectively, but the differences were not significant. Calves born to cows calving first at 2 years were 0·8 and 7·7 kg (P>0·05) lighter at birth and weaning respectively than those born to cows calving first at 3 years of age. The effect of feeding regime of the cows as yearlings on the weights of calves at birth and at weaning was non-significant.

In cows calving annually up to 8 years of age in this trial the lifetime production of those calvingfirstat 2 years of age was greater by 40 kg than of those calving first at 3 years of age, although the advantage was greater in earlier years.
Onset of oestrus and fertility of dairy heifers and suckled beef cows treated with prostaglandin F2α
Authors: Hafs H. D. , Manns J. G. , Drew Bridget
Published: September 2010

Suckled cows (average 70 days post partum) and British Friesian dairy heifers (13 to 24 months of age) were injected intramuscularly with prostaglandin F2α (PGF2α) on two occasions 12 days apart, to synchronize oestrus and ovulation. The cattle were inseminated twice, 70 and 88 hr after the second injection.

Injections of 20, 30 or 40 mg of PGF2α were equally effective in 59 heifers; after the first injection, 11 failed to show oestrus during the following 10 days and 10 began oestrus within 36 hr. The majority of the heifers (59%) began oestrus during the 3rd or 4th day after the first injection of PGF2α. After the second injection of PGF2α, all but two heifers showed oestrus and the majority (88%) began oestrus in 3 to 6 days.

Injections of 30 or 60 mg of PGF2α were equally effective in 66 suckled cows; after the second injection of PGF2α, 68% of the cows began oestrus from the 3rd to the 6th day but 10 (15%) cows failed to show oestrus.

Fertility was highest among heifers and cows which began oestrus during 3 to 5 days after the second injection of PFG2α, 54% of the treated heifers and 42% of the treated cows calving during the expected intervals. Nineteen of the 20 control heifers were mated and 25 of 33 control cows were observed in oestrus and inseminated during 3-week or 25-day breeding periods. Eleven (55%) control heifers and 14 (42%) control cows calved during the expected intervals. Thus, fertility of the treated cattle inseminated at predetermined intervals after PGF2α was equivalent to that in the controls.
The performance of early-weaned calves offered a high dry-matter silage supplemented with concentrates or dried grass
Authors: Marsh R.
Published: September 2010

In two experiments a high dry-matter silage (36·8% DM) was offered ad libitum, together with a supplement of a conventional concentrate or cobs of dried grass, to young British Friesian castrated male (steer) calves. The silage was readily acceptable to the calves and was preferred to the dried grass. Intakes of silage DM were significantly higher (P<0·001) when supplemented with dried grass than when supplemented with concentrates, but daily gains were significantly (P<0·001) lower by 0·15 kg. The lower daily gains supported by the silage/dried grass diet were related to lower intakes of digestible organic matter (DOM); efficiency of utilization of silage/dried grass DOM was similar to that of concentrate/silage DOM. The results are discussed in relation to recommended levels of production for calves in a semi-intensive beef system.
The comparative performance of purebred and crossbred boars in commercial pig production
Authors: Lishman W. B. , Smith W. C. , Bichard M. , Thompson R.
Published: September 2010

An investigation was undertaken to evaluate the crossbred boar per se, and also to assess the value of including the American Hampshire into a first-cross sire. Groups of three boars were placed on each of 20 farms. Each group contained a purebred white (Landrace or Large White), a crossbred white and a crossbred Hampshire boar. Co-operators were asked to obtain at least six litters by each boar, record their performance to weaning, and provide a sample of the progeny of each boar to be reared under standard conditions to slaughter at 90 kg live weight. Breeding of the boars did not affect either the level or variability of litter performance. Differences in performance and carcass traits between the progeny of purebred and whitecross boars were found only for ‘eye-muscle’ area and fat depth ‘C’. Pigs sired by Hampshire-cross boars had carcasses which were 2% shorter than those from white boars.
A note on the effect of the discount rate and length of the accounting period on the economic value of genetic improvement in cattle populations
Authors: Cunningham E. P. , Ryan Joan
Published: September 2010

The discounted gene flow method was used to study the effect of varying financial discount rates and accounting period on the present value of the genetic merit conferred by each insemination.

Over the range from 8% to 16%, each 1% increase in the discount rate reduces the value of the dairy and beef consequences of an insemination by about 5% and 4% respectively, Virtually all of the economic benefit arising from an insemination is complete within 20 years, with about 90% of it being realized in the first 10 years and 98% in the first 15 years.
Genotype-environment interaction in milk production under Danish and Bulgarian-Czechoslovakian conditions
Authors: Petersen P. H.
Published: September 2010

First lactation records from 971 daughters of 93 Red Danish Milk-breed bulls exported as pregnant heifers from Denmark to 4 Bulgarian and 21 Czechoslovakian herds were analysed and compared to results from corresponding half-sib groups under Danish field progeny tests. Average butterfat production in East European tests was 75% of that in Danish tests.

The results indicate that the true genetic variance and the heritabilities for milk yield, fat content and butterfat yield are higher under the Danish conditions than under the corresponding East European conditions. The genetic correlations between the two environments are estimated to be 0·91, 0·97 and 0·79 for milk yield, fat content and butterfat yield, respectively. Because of insufficient correction for environmental effects, these estimates are considered to be lower than the true parameters.

It is concluded that selection of proven sires in the Danish main population for use in the small East European subpopulations will result in a higher genetic improvement rate than will sire testing and selection within the subpopulations.
Effects of breed of cattle on energy requirements for growth
Authors: Chestnutt D. M. B. , Marsh R. , Wilson J. G. , Stewart T. A. , McCullough T. A. , McCallion T.
Published: September 2010

With the object of comparing the energy requirements of cattle of different breeds a total of 108 animals, representing three maturity types, were individually fed at two levels of intake over three 12-week periods commencing at 250, 375 and 500 kg live weight in a co-ordinated experiment. The three breeds compared were Aberdeen Angus cross, Hereford × British Friesian and British Friesian. Animals were offered a 50:50 hay: concentrate ration at two levels of feeding; one level was designed to give 0·7 kg gain daily and the other 75 to 80% of this intake.

Though the relative performance of breeds differed at the three centres, overall average live-weight gain did not differ significantly between breeds. Feed conversion efficiency dropped from 8·55 kg dry matter per kg gain in the first period to 16·95 kg in the third period, but differences in conversion ratio between breeds were not significant.

Carcass measurements taken at slaughter immediately after the third test period indicated higher killing-out percentages and higher fat percentages in the Angus cross than in the British Friesian with Hereford × Friesian intermediate. Differences in energy needs for gain among the three breeds, predicted by apportioning ME intake to maintenance and gain using a multiple regression technique, were greater than differences calculated from carcass composition and published energy requirements for fat and protein deposition. The limitations of the use of the multiple regression technique for this purpose are discussed.
Effect of dietary energy content at different stages of growth on performance of intact male cattle
Authors: Levy D. , Holzer Z. , Ilan D.
Published: September 2010

Six groups of Israeli-Friesian intact male calves were studied over growth periods of 200 to 300 kg, 300 to 400 kg, and 400 to 500 kg live weight. Different ratios (85: 15, 70: 30 and 50: 50) of concentrate to roughage were compared. Two groups received the same ratio (85: 15 or 70: 30) throughout the experiment. In the other groups, the proportion of concentrates was progressively increased or decreased.

Live-weight gain in the first period ranged from 759 to 1013 g/day, i n the second period from 1095 to 1239 g/day and in the third period from 831 to 922 g/day. Overall rate of gain was highest in the groups receiving a constant ratio, regardless of the ratio used. Increasing the proportion of concentrates as the calves became heavier, which is common practice in Europe, did not improve performance and decreasing the proportion reduced performance. Only at 200 to 300 and at 400 to 500 kg live weight did a concentrate percentage higher than 50 result in improved performance.

Dry-matter intake, relative to live weight, was higher with a ratio of 70: 30 than with one of 85: 15 or of 50: 50 in each period. Animals on a constant ratio of concentrates to roughage gave the most efficient conversion of feed energy to live weight.

There were no significant differences in dressing percentage or in carcass composition.