bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy utilization by Hereford and Simmental males and females
Authors: Ferrell C. L. , Jenkins T. G.
Published: September 2010

Post-weaning metabolizable energy intake, growth of empty-body chemical components and efficiencies of energy utilization were evaluated for Hereford intact males (17) and females (16) and Simmental intact males (15) and females (16) during a 212-day feeding period. Within each breed × sex subclass, animals were assigned to one of three levels of metabolizable energy (ME) intake: (1) 544 kJ/kg M0·75 per day, (2) 795 kJ/kg M0·75 per day, and (3) ad libitum. Body composition of each animal was estimated at the beginning and end of the feeding period by deuterium oxide dilution.

Protein and water gain of Hereford and Simmental cattle were similar at restricted levels of intake but were greater for Simmental than for Hereford cattle at ad libitum intakes. Similarly, rates of protein and water gain tended to increase more rapidly in response to increased energy intake by males than by females. Hereford males gained fat and energy slightly more rapidly than Hereford females, but Simmental males gained fat and energy at slower rates than Simmental females.

Males had higher maintenance requirements and tended to use ME with less efficiency for maintenance and gain than females. Hereford cattle had lower maintenance requirements and used ME with greater efficiency for both maintenance and gain than Simmental cattle.
Relationships between some estimates of growth hormone and prolactin secretion and rates of accretion of constituents of body gain in rams
Authors: Klindt J. , Jenkins T. G. , Leymaster K. A.
Published: September 2010

Relationships between estimates of some factors affecting growth hormone (GH) and prolactin (PRL) secretion and rates of deposition of fat, protein and ash and rate of gain were investigated in Suffolk ram lambs. Factors affecting secretion were determined from measurements made by radioimmunoassay on blood samples collected at 15-min intervals during a 6-h period at a body weight of 43 to 58 kg. Depositional traits were estimated over the period of growth from 32 to 73 kg. The endocrine secretory measurements were adjusted statistically for weight at blood sampling. The only single endocrine secretory measurement that significantly correlated with a growth or depositional trait was frequency of GH peaks which was negatively related to rate of ash accretion. Multiple regression analysis was used to estimate the association between endocrine secretory measurements and rates of gain and accretion. R2 values were 0·43, 0·29, 0·42 and 0·70 for average daily gain and accretion rate of protein, fat and ash, respectively. Models with minimal error mean squares contained linear, quadratic and/or crossproduct terms for the independent variables, thus suggesting nonlinear relationships of the hormones in the mediation of rate and pattern of growth. These results emphasize the value of assay of multiple samples from each animal, the subsequent estimation of secretory characteristics and the use of expanded statistical models to determine the relationship present in the system under investigation.
The feeding value of straw from different genotypes of barley when given to Awassi sheep
Authors: Capper B. S. , Thomson E. F. , Rihawi S. , Termanini A. , Macrae R.
Published: September 2010

Barley straw constitutes up to half of the dry-matter intake of Awassi sheep in areas of Syria where the rainfall is 200 to 350 mm. The genotype of barley planted could therefore, through the nutritive value of its straw, significantly affect flock production levels. Selection of suitable barley genotypes may have greater economic potential as a means of improving roughage feeding quality in these areas than chemical or physical processing.

The voluntary intake and digestibility of the unsupplemented straw of three genotypes of barley was evaluated with Awassi castrated male sheep. The voluntary organic-matter (OM) intakes of handharvested Beecher, Arabic Abied and ER/Apam straw were 22·2, 34·7 and 27·0 g/kg M0·75 per day and OM digestibility coefficients were 0·39, 0·44 and 0·42. The factors affecting voluntary intake and digestibility appeared to be the proportions of leaf and stem. Beecher straw had less leaf and more stem than the other two genotypes. The chemical composition and in vitro cellulase digestibility of the leaf indicated that it had a higher potential feeding value than stem.

ER/Apam appears to be an example of a genotype which under dry environmental conditions combines higher barley grain yields with more acceptable straw feeding value than several other genotypes evaluated.
Effect of ionophores on the accumulation of copper in the livers of sheep
Authors: van Ryssen J. B. J. , Barrowman P. R.
Published: September 2010

Lambs were allocated to three treatments: control (C), monensin (M) and lasalocid sodium (L) in a concentrate diet containing 36 mg copper per kg food. After 2 months deaths from copper toxicity occurred and the trial was terminated. All lambs were slaughtered. The mean liver copper concentration (mg/kg dry matter) of 1907 in the M treatment was higher than the mean concentrations of 1342 and 1229 in the C and L groups respectively (P < 0·01). Total liver copper was 234, 260 and 230 mg and the retention of dietary copper in the liver was 93·5, 108·5 and 93·3 g/kg for the C, M and L treatments respectively. These differences were not significant. From reduced liver size (as a proportion of body weight) and high copper levels in the kidneys, it was concluded that the group given monensin had accumulated copper to a level closer to the toxicity threshold than the other two groups.
A comparison of the early behaviour of intensively and extensively reared calves
Authors: Kerr Sheila G. C. , Wood-Gush D. G. M.
Published: September 2010

This study involved two groups of calves, one group consisted of eight Angus × (Friesian × Hereford) calves born in the late summer and kept with their dams in the field. The other group consisted of 20 autumn-born Friesian calves kept indoors in individual stalls. Similar ethograms and techniques were used to study their behaviour up to 8 weeks of age, thus allowing comparisons to be made of the proportion of time spent in various activities, as well as changes in the sequences of behaviour with age. In general, the activity of the calves of both groups showed a similar trend in development. However, the field calves spent significantly more time in investigatory behaviour while the confined calves showed a significantly higher frequency of investigatory behaviour and indulged in more self grooming. The analysis of behavioural sequences showed few differences in focal points or direction of transitions from one behavioural pattern to another, suggesting that the integration of activities into developing motor patterns in the calf is determined ontogenetically with little modification by the environmental factors encountered in this study. However, the confined calves showed a greater mean number of transitions per hour. The findings are discussed in relation to the welfare of the confined calf.
Varietal differences in rumen degradation of barley, wheat and hard wheat straws
Authors: Ramanzin M. , Bailoni L. , Beni G.
Published: September 2010

The rumen dry-matter degradation of straw from nine varieties of barley, nine varieties of wheat and seven varieties of hard wheat was studied to provide further information on varietal differences and their relationships with agronomic characteristics.

In all the cereals there were significant differences in in situ dry-matter disappearance between varieties. The range of differences was lower in hard wheat varieties compared with the other cereals. There were no significant correlations between straw degradability and plant height, days from sowing to heading and grain production and quality. Lignin concentration was significantly correlated to straw degradability (r = −0·937 in barley, −0·675 in wheat and −0·987 in hard wheat).

Leaf had lower concentrations of lignin and higher degradability than stem in barley and wheat but the two fractions were similar in hard wheat straws. The differences in degradation between the most and the least degradable straw varieties of each cereal species were mainly due to differences in degradability of both the fractions whereas the role of leaf and stem proportions was of minor importance.
Animal production and food: real problems and paranoia
Authors: Blaxter K. L. , Webster A. J. F.
Published: September 2010

The scientific and technological expansion of British agriculture between the mid 1930s and mid 1980s can be attributed primarily to the provision of favourable and stable prices and only secondly to government support of research and development. These conditions have changed. Most government-funded research in agriculture is now directed to the new biological sciences, molecular biology and transgenics. It is uncertain whether those at the frontiers of biotechnology are aware of the limits and constraints placed on animal production. Equally, it is uncertain whether the commercial supply services to agriculture will be prepared to meet the costs of transferring this new technology into production. These real problems facing agriculture are amenable to rational solutions. Of greater concern are food scares whipped up by pressure groups and government responses taken in the absence of, or in defiance of, scientific evidence.

Two examples are considered, one trivial, the other deadly serious. The first involves the recommendation that pregnant women ‘should not eat liver’ based on an unpublished report of a single case of birth defects. The second example chosen for discussion is the alleged causal relationship between the intake of saturated fatty acids (SFA) and coronary heart disease. The inadequacy of the simple distinction between saturated and unsaturated fats is briefly reviewed in the light of new knowledge relating to specific SFA, monounsaturates and the distinction between polyunsaturates of the linoleic and linolenic series. Evidence from large epidemiological studies is marshalled to demonstrate that there is no good case to support the conclusion of the Committee on Medical Aspects of Food Policy (COMA, 1984) that the nation's diet should be changed to reduce the proportion of saturated fats. The Department of Health is invited to recall COMA to reconsider their recommendations in the light of new evidence.
Effect of feeding whole and rolled barley to steers in the morning or afternoon in diets containing differing proportions of hay and grain
Authors: Mathison G. W. , Engstrom D. F. , Macleod D. D.
Published: September 2010

A 2 × 2 × 2 factorial experiment was conducted with 128 growing-finishing steer calves to examine the effects of feeding whole v. rolled barley in diets containing either a constant proportion of concentrate (0·67) or proportionately 0·33 concentrate for 56 days followed by 0·90 concentrate for 83 days, with the concentrate being given at either 08.00 or 15.30 h. Steers given hay at 08.00 h and concentrate at 15.50 h grew proportionately 0·05 faster (P < 0-05) and had better dry matter (DM): gain ratios (P < 0·05) during the first 56 days than those given concentrate at 08.00 h and hay at 09.00 h. By the end of the trial steers fed at 15.50 h had similar daily gains to steers fed at 08.00 h but required proportionately 0·02 less DM: gain (P <0·05). No significant difference in gain was detected between steers given whole (1·30 kg/day) or rolled (1·38 kg/day) barley, but those given whole barley ate proportionately 0-08 more DM daily and had a proportionately 0-15 poorer DM: gain ratio (P < 0-05). The digestibility of diets containing whole grain was reduced (P < 0-05). Thirty-six steers given whole barley bloated compared with nine given rolled barley (P < 0·05). No significant differences were found either in DM intake or in final proportion of concentrate in the diet between steers given the diet containing proportionately 0·67 concentrate throughout the feeding period and those given the variable concentrate diets. There was a trend for DM: gain ratios to be poorer for steers given the constant proportion of concentrate (6·89 v. 6·65).
The influence of the fat concentration of the diet on the response by dairy cows to body condition at calving
Authors: Garnsworthy P. C. , Huggett C. D.
Published: September 2010

Twenty-four Friesian dairy cows were divided into two groups of 12 between 12 and 18 weeks prior to calving and fed to achieve condition scores at calving of 3·2 (F) or 2·3 (T). For the first 11 weeks of lactation, six cows from each group (H) were given daily 9 kg of a high-fat compound (acid ether extract (AEE) 96 g/kg dry matter (DM)), 3 kg molassed sugar-beet pulp and hay ad libitum. The other six cows in each group (L) were given 10 kg of a low-fat compound (AEE 29 g/kg DM), 2 kg sugar-beet pulp and hay ad libitum. Allowances of compound and sugar-beet pulp were designed to provide equal amounts of energy, neutral-detergent fibre and protein. The fat source used in compound H was a calcium salt of palm acid oil (Megalac®).

DM intake was not affected by treatment but fat intake was significantly higher on diet H (P < 0·001). Group TH had higher intakes of digestible energy (DE) than group FH (249 v. 229 MJ/day; P < 0·05), but condition at calving did not affect DE intake with diet L (FL = 230, TL = 233 MJ/day). Milk yield was not significantly affected by treatment, although cows in group TL tended to yield less milk than other groups (28·3, 27·3, 28·0 and 24·3 kg/day for FH, FL, TH and TL respectively). The concentration of milk fat was higher and of milk protein lower with diet H compared with diet L (milk fat 48·1, 42·2, 42·9 and 39·6; milk protein 28·0, 31·0, 28·4 and 30·5 g/kg for FH, FL, TH and TL respectively). Loss of condition score was greater for cows in group F (0·65 units) than for those in group T (0·04 units). Within group F, loss of condition tended to be greater with diet L.

It is concluded that the increased intake of fat with diet H tended to decrease loss of condition in cows that were fat at calving but increase milk yield in cows that were thin at calving. It also tended to increase milk fat concentration but decreased milk protein concentration.
A note on the effects of pattern of food intake and body condition on the duration of the post-partum anoestrous period and LH profiles in beef cows
Authors: Wright I. A. , Rhind S. M. , Whyte T. K.
Published: September 2010

An experiment was conducted to determine the effect of level and pattern of food intake in post-partum beef cows on the length of the post-partum anoestrous period and associated luteinizing hormone profiles. Forty-six multiparous cows were allocated at calving to one of three feeding regimes: 55 MJ metabolizable energy (ME) per day throughout (LL), 145 M] ME per day throughout (HH), or 55 M] ME per day until 6 weeks post partum and then 145 M] ME per day thereafter (LH). The duration of the post-partum anoestrous period was assessed from plasma progesterone profiles. Luteinizing hormone profiles in the peripheral circulation were determined at weeks 3, 6, 8 and 11 post partum from samples collected every 20 min for 10 h.

Feeding regime had no effect on either the length of the post-partum anoestrous period, being 99, 89 and 91 (s.e.d. 12·2) days for the LL, LH and HH cows respectively, or on any aspect of luteinizing hormone pulsatility. Body condition at calving was negatively correlated with the duration of the post-partum anoestrous period, each unit increase in body condition at calving being associated with a decrease in the post-partum anoestrous period of 86 (s.e. 21·8) days. Luteinizing hormone pulse frequency at 6 weeks post partum was positively correlated with body condition at calving.

This experiment confirms the importance of body condition at calving in influencing the duration of the post-partum anoestrous period and indicates that level and pattern of feeding post partum has little effect when cows calve at a body condition of approximately 2·25.
Asymptotic response to selection on best linear unbiased predictors of breeding values
Authors: Dekkers J. C. M.
Published: September 2010

Formulas were derived to predict asymptotic response to selection on best linear unbiased predictors (BLUP) of breeding values that account for selection-induced gametic phase disequilibrium, also known as the ‘Bulmer’ effect. Breeding programmes in populations of infinite size and with discrete generations were considered. For two-path breeding programmes with equal male and female accuracy of selection, relative reductions in response due to gametic phase disequilibrium were independent of heritability. Reductions in response depended only on intensities of selection and ranged from 0·22 to 0·27 when selected proportions were less than 04 for both males and females. With unequal accuracy of males and females, relative reductions in response depended on the ratio of accuracies, in addition to selection intensities. For given selection intensities, reductions were up to proportionately 0·08 larger with unequal accuracies than reductions obtained for equal accuracies. Relative reductions in response for breeding programmes with four paths of selection depended on intensity and accuracy of selection in each path, but were within a range similar to that observed for two-path programmes. Gametic phase disequilibrium will, therefore, not greatly affect ranking and relative differences among alternative breeding programmes.

Gametic phase disequilibrium had a larger effect on response with selection on BLUP than on phenotype, which is largely due to larger relative reductions in accuracy of selection with BLUP. Despite larger relative reductions, asymptotic response to selection on BLUP is expected to be larger than selection on phenotype.
Electrocardiogram parameters of piglets during housing, handling and transport
Authors: Villé H. , Bertels S. , Geers R. , Janssens S. , Goedseels V. , Parduyns G. , van Bael J. , Goossens K. , Bosschaerts L. , de Ley J. , Heylen L.
Published: September 2010

Telemetric techniques for the monitoring of physiological parameters during housing, handling and transport may help producers to reduce mortality and improve meat quality. In order to know the reliability of electrocardiogram parameters as stress indicators, piglets (12 to 23 kg) being different with respect to the halothane gene (homozygous halothane sensitive (nn) and non-sensitive (NN), heterozygotes (nN)), and thus different with respect to stress susceptibility, were monitored with an ambulatory ECG device during housing, handling and transport. Skeletal muscularity of all animals was measured with an ultrasound device.

Heterozygotes and homozygote halothane sensitive piglets had a higher muscularity, but only the homozygotes had a higher ST-elevation from the isoelectric line of the QRST-complex of the electrocardiogram when measured within housing conditions. This means a different propagation of the electric current related to the activation of the ventricle. Halothane gene carriers (Nn and nn piglets) had a statistically significant higher mean maximal heart rate during housing conditions. During handling heart rate rose by 14·8%, 0·61% and 42·9% respectively for NN, nN and nn piglets, with nn piglets having the highest values. During transport these measurements were respectively 6·88%, 3·66% and 9·7% higher for lines NN, nN and nn as compared with those in housing conditions. Heart arrhythmicity parameters were not different between housing and transport, but during handling up to a 23-fold increase could be observed.

Heart rate and arrhythmicity parameters may generate reliable information to monitor stress during housing, handling and transport of piglets through genotypes and skeletal muscularity.
The assessment of a crop husbandry technique in terms of animal production
Authors: Blaxter K. L. , Wilson R. S.
Published: September 2010

1. The energy value of three hays cut at three stages of maturity was. measured by calorimetric methods and, in addition, the amounts of the hays consumed voluntarily by sheep were measured. Voluntary intake was alsa measured when 200, 500, 800 and 1,200 g. of pelleted concentrates were given.

2. The metabolisable energy values of the three hays measured at the-maintenance level were 2·45, 2·26 and 2·16 kcal./g. for cuts 1, 2 and 3-respectively (cut 1 being the earliest). The net energy values for fat production were 0·96, 0·85 and 0·68 kcal./g. respectively.

3. The apparent digestibility of the hays fell with increasing intake, but supplementation with concentrates increased their apparent digestibility.

4. The voluntary intake of the hays given as the sole food was 70, 62 and 57 g./kg. W0·73 for the three cuts, respectively. When concentrates were given in increasing amounts, the intake of cuts 2 and 3 increased to maxima of 65 g. and 64 g./kg. W0·73 respectively and thereafter declined. With cut 1, intake of hay declined even with the smallest intake of concentrates. Voluntary intake of the hays was maximal when the protein content of the whole ration was 8·5%.

5. When no supplement was given the digested energy per sheep per day supplied by cut 1 was 64% greater than that supplied by cut 3. When 800 g. concentrates were given, however, the ration including the early cut of hay provided only 2% more energy than that including the late cut.

6. It is shown that if hay were given as the sole food cut 3, which produced 57% more weight of crop per acre, would provide 38% more metabolisable energy/acre and 11% more net energy (starch equivalent)/acre than would cut 1. The late cut would also enable 92% more sheep to be kept feeding to maximal appetite on an acre of produce. However, the total live-weight gain per acre would be only 25% of that obtained with thefirstcut.

7. Comparable calculations have been made for the experiments in which concentrates were given. It is shown that here too optimal times of cutting can only be assessed in terms of estimates of animal production.
Inbreeding arising through artificial insemination and natural service in Welsh black cattle
Authors: Watson J. H.
Published: September 2010

Current rates of inbreeding due to A.I. and natural service are estimated in Pedigree Welsh Black cattle.

Since 1948, 27 sires have been used in A.I., 16 of which have a common male ancestor. Four sire-son pairs and two pairs and one trio of half-brothers have been in recent use. Two-thirds of the bulls and heifers bred by A.I. and registered in 1960 were sired by 4 bulls. Since 1954 progeny of two A.I. sires who are father and son, were preferred for registration.

Pedigree analysis of a sample of 128 bulls showed that those bred by A.I. were, on average, 2·80% inbred, compared with 2·32% for those from natural matings. In a sample of 166 heifers corresponding values were 0·82% and 1·17%.

One herd, through natural service, contributed 12% of the genes of a sample of bulls and heifers. Four other herds were outstanding for the number of males they provided. The average inbreeding of their young, registered bulls was estimated to be 7·04%.

The widespread use of the descendents of one bull, both in A.I. and natural service, led to 94 cases of inbreeding in the third and fourth ancestral generations of the pedigrees of animals in the sample.

It is concluded that the short term consequences of using a small number of bulls in A.I. measured in terms of inbreeding, are no different from those in natural service and that inbreeding depression in traits of commercial importance would be undetectable.
Heritability of milk yield at different environmental levels
Authors: VanVleck L. D. , Bradford G. E.
Published: September 2010

Milk production records from 5740 first lactation Holstein-Friesian daughter-dam pairs were studied to determine if heritability was related to herd production level. Heritability from daughter-dam regression was essentially constant at 10 environmental levels based on either the dam's or daughter's herdmate deviation from season average yield. The heritability estimate over all levels of yield was 0·43 (with standard error 0·03) which is higher than most estimates. Estimates of heritability from paternal half-sib correlations for four environmental levels and based on data from 2568 daughters of A.I. sires generally increased as the herd production level increased. The highest half-sib estimate was 0·42 and the lowest 0·17. Daughter-dam estimates from the same data were essentially constant over the four herd levels.

Total variation increased as herd level increased, in agreement with previous reports.

Heritability was found not to differ between seasons of calving.
Effects of various low protein diets on the distribution of ruminal nitrogen and on the nitrogen required for maintenance of African sheep
Authors: Elliott R. C. , Topps J. H.
Published: September 2010

1. Four groups of diets made up with differing proportions of roughage and concentrates were each givenad lib. to 4 Blackhead Persian wether sheep. The four diets in each group contained approximately 4, 6, 8 and 10% crude protein. The distribution of nitrogen in the rumen at various times after feeding and the nitrogen balance of the sheep were measured.

2. Total N and ammoniacal N content of the rumen liquor were both closely related to the N content of the diet. Diurnal changes in the concentrations of these components were most marked with the diets which had the highest concentration of protein, and consisted of rapid increases after feeding followed by declines later in the day. Each group of diets produced characteristic patterns of change and these changes appeared to be related to the proportion of concentrates in the diet.

3. With sheep given poorly digested veldt grass, very low in protein, levels of ammonia in the rumen were unusually high. This effect was thought t o be due to the recycling of urea and its conversion to ammonia in the rumen.

4. The amounts of digestible N required by the sheep for N equilibrium differed between groups of diets. High apparent requirements of digestible N were associated with relatively high ruminal ammonia levels, but the latter were not considered to be the cause of high requirements.

5. On all groups of diets, sheep were in N equilibrium only when their intakes of total digestible nutrients (TDN) were adequate for maintenance. This indicates that the protein requirement for maintenance was a function of protein content and TDN content of the diet and the effect of these factors on voluntary intake of TDN.
Long- and short-term effects on intake of pelleting a roughage for sheep
Authors: Greenhalgh J. F. D. , Reid G. W.
Published: September 2010

1. Four groups of eight castrated male lambs, weighing initially about 37 kg, were fed ad libitum for 18 weeks on: C, chopped dried grass throughout; P, pelleted grass throughout; C/P (or P/C), the two forms alternated every 3 weeks; or C + P, both forms on offer.

2. Daily dry-matter intake (g/kg W0·75) was 58·2 for treatment C and 814 for treatment P; thus the long-term difference in intake was 40%. However, in the alternated sheep, dry-matter intake was 53·6 g/kg W0·75 for chopped grass and 86·5 g for pelleted; this short-term difference (61%) was significantly greater than the long-term difference. Dry-matter intake for treatment C+P was 84·9 g/kg W0·75; after the first week, chopped grass comprised only 10% of this. Dry-matter digestibility coefficients (%) were: C, 740; P, 61·4 and C+P, 62·0.

3. The sheep were killed in week 19 and the dimensions of digestive organs and their contents were adjusted to an animal of 50 kg empty body weight. The weight of the reticulo-rumen was greater for C (1·30 kg) than for P (0·94) or C+ P (1·05), C/P and P/C being inter-mediate (1·15). The water-filled volume of the rumen was proportional to weight, except that C/P (alternated sheep finishing on pelleted grass) had low volumes. Reticulo-rumen fill was greater for C (7·28 kg) than for P (3·97) or C+ P (4·53), P/C (5·90) and C/P (4·34) being intermediate. There were no other significant differences in organs or contents.

4. Gains in empty-body weight (g/day) were: C, 112; P, 181; C/P and P/C, 126; C + P, 195.
The economics of calving intervals
Authors: James A. D. , Esslemont R. J.
Published: September 2010

A computerized mathematical model was used to test the economic effect of changing calving intervals under typical high-yielding (63701 per 305 days for mature cows) herd conditions at 1976 prices. The effect of month of first calving was also tested in a herd where four lactations are assumed to follow at equal calving intervals.

Under the prescribed conditions, cows should calve at 320-day to 360-day intervals (with two exceptions) to maximize the annual margins over concentrates, but the month of the initial calving affects the absolute level of margins over concentrates markedly (maximum £382·10 for 365-day interval for November calving, minimum £318·10 for April). This means that complete knowledge of the main input-output factors is required before recommendations can be made for an individual cow. The change in margin over concentrates for each day's delay in conception varies widely, with rates of loss as high as £1·80 per day's delay occurring.
The influence of restricted physical contact with pigs during rearing on the sexual behaviour of the male domestic pig
Authors: Hemsworth P. H. , Beilharz R. G.
Published: September 2010

Three groups of five male pigs (boars) were reared from an early age under various social conditions. The sexual and social behaviour of the boars was studied from 31 to 56 weeks of age. Boars individually reared from 3 to 12 weeks of age in adjacent wire-mesh pens had similar copulatory performance to that of group-reared boars. However, an apparently important component of courting behaviour, ‘nosing activity’, was significantly reduced (P<0·05) amongst those boars individually reared from 3 weeks of age in adjacent wire-mesh pens. Social behaviour appeared to be unaffected by the rearing treatment.
Effect of flaked maize in diets for early-weaned pigs on performance to 6 weeks of age
Authors: McCracken K. J. , Eddie S. M. , Walker N.
Published: September 2010

Four experiments were conducted to study the performance of pigs weaned at 10 days on to diets containing different amounts of flaked maize.

Digestibilities of dry matter and energy of flaked maize were found to be 0·87 for pigs between 11 and 16 days of age.

Starter diets containing 0, 250 or 375 g flaked maize/kg, given from 10 to 35 days, resulted in growth rates of 254, 254 and 213 g/day respectively and the reduction with the high level of maize was significant (P< 0·001). Feed conversion ratio was unaffected by treatment and averaged 1·08.

When the starter diets were replaced at about 24 or 27 days by a cereal-based diet containing 200 g dried skim milk/kg there were no significant differences in performance between 10 days and 10 kg live weight due to starter diet, and growth rates were similar t o those obtained when the starter diets were given to 35 days. However, there was a consistent trend of lower food intakes, poorer feed conversion ratio and, consequently, poorer growth during the immediate post-weaning period on the starter diet containing 375 g flaked maize/kg.
Effects of magnesium supplements on the digestion of forages and milk production of cows with hypomagnesaemia
Authors: Wilson G. F.
Published: September 2010

1. Ground forages were digested in vitro in rumen liquor supplemented with four concentrations of magnesium as MgSO4-7H2O (5, 20, 80, 320mg Mg/1) to determine the effects of magnesium on organic matter digestibility. A medium concentration of magnesium (generally 80 mg/1) resulted in optimum digestion although there was a large interaction between forage type and the response to magnesium.

2. Supplements of MgSO4-7H2O (2g Mg/day) increased the apparent digestibility of two types of hay fed to sheep, the difference being significant for poor quality hay (P<0·05).

3. The milk production of hypomagnesaemic cows given supplementary magnesium either orally, by rectal infusion, or by subcutaneous injection was compared. Plasma magnesium concentrations were increased to a similar and significant extent (P<0·01 ) but a significant increase in milk and fat production occurred only in the orally treated cows (P<0·05).

It was concluded that a dietary magnesium deficiency results in reduced rumen fermentation and hence poor production, as well as hypomagnesaemia. It was suggested that the effects on performance of other mineral deficiencies may also be mediated in part through depressions in rumen digestion.
Effect of various light regimes on lamb production by Rambouillet and Suffolk ewes
Authors: Vesely J. A. , Bowden D. M.
Published: September 2010

Six production cycles, each of 212 days' duration, were completed with Rambouillet and Suffolk ewes. One group of each breed was maintained under natural light conditions (control) and three groups of each breed were under the influence of various light treatments applied regularly in a rhythmic fashion within each production cycle. Comparison of conception rates between production cycles, breeds, and treatments showed that only in production cycle 2 (mating in June) were the conceptions in control ewes of both breeds significantly lower than those in ewes on altered light treatments. The most meaningful result was the effect of light treatments on prolificacy. Treatment 3 (106 days with 16-h light per day and 106 days with 8-h light per day) gave significantly higher prolificacy than control and treatments 1 (106 days with 8-h light per day starting 65 days before mating) and 2 (42 days with 16-h light per day, then light reduction at 21 min/week for 160 days). Rambouillet and Suffolk control ewes produced annually 179 and 174 lambs per 100 ewes exposed to rams. Corresponding productions were 200 and 197 for treatment 1, 193 and 226 for treatment 2, and 223 and 242 for treatment 3.
Performance of pigs given diets containing different levels of triticale
Authors: Nishimuta J. F. , Sunki G. R. , Rao D. R.
Published: September 2010

Sixty crossbred female and male castrate pigs were randomly allocated to five treatments in which 0, 20, 40, 60 and 80% of the ground maize in grower and finisher diets was replaced by triticale on an equal weight basis.

Pigs receiving the basal maize growing diet (0% tritcale) gained less than pigs fed the triticale diets (P<0·05). Pigs given the diets in which 20% of the maize was replaced by triticale gained significantly more than those given the other diets (P<0·05). Increasing replacement in the grower diets beyond 20% resulted in a linear decrease in consumption and weight gains (P<0·05). Feed conversion was similar for all diets which contained triticale.

The basal finisher diet, and the diet with 20% of the maize replaced, promoted better feed consumption and weight gain than the diets in which 40, 60 and 80% of the maize was replaced by triticale during the finishing phase and for the entire 109-day growing-finishing period. Carcass quality grade was higher for pigs fed the basal diet and the diet in which 20% of the maize was replaced by triticale (P<0·05 ) but there were no differences in the other parameters of carcass quality, nor in the composition, cooking quality and organoleptics,. of the longissimus muscle. Fatty acid profiles of the longissimus muscle indicated that palmitic and oleic acids were significantly higher (P<0·05 ) and linoleic and palmitoleic significantly lower (P<;0·05) in pigs given the basal and 20% replacement diets than in pigs given the other diets. The results show that triticale could replace maize partially (up to 20%) in diets for pigs.
A note on the relationship between live weight and the incidence of oestrus in Hereford heifers
Authors: Cohen R. D. H. , Garden D. L. , Langlands J. P.
Published: September 2010

The incidence of oestrus in 603 Hereford heifers with a mean age of 545 days (range 515 to 575) was related to live weight (range 130 to 376 kg). Observations were ranked in order of ascending live weight and the percentage of heifers showing oestrus was calculated for consecutive 10 kg increments in live weight from 130 to 380 kg. The percentage showing oestrus was subjected to the probit transformation (Y, probit units) and was then related to live weight (X, kg):

It was predicted that 50% of the heifers showed oestrus at 231 ± 1 kg, and that 5% and 95% showed oestrus at 187 and 280 kg respectively.
Some aspects of the energy and nitrogen metabolism of boars, gilts and barrows given diets containing different concentrations of protein
Authors: Holmes C. W. , Carr J. R. , Pearson G.
Published: September 2010

Four diets which varied in crude protein concentration from 140 to 240 g crude protein per kg dry matter were given to gilts in experiment 1, and two diets containing 140 and 200 g crude protein per kg dry matter were given t o boars and barrows in experiment 2. Two levels of feeding were offered in both experiments and energy and nitrogen balances were measured at 30 and 90 kg live weight in both experiments, and also at 50 kg in experiment 1. Nitrogen intake had a small negative influence on energy retention by pigs of all sexes, an effect which was independent of the large positive effect of metabolizable energy intake. The ratio of metabolizable energy concentration to digestible energy concentration decreased in association with increases in crude protein concentration of the diets. The results show that comparisons of feeds on the basis of their digestible energy concentrations would lead to overestimation of the energy values of those containing high protein concentrations. Live weight (or age) and metabolizable energy intake exerted positive influences on the amount of energy retained per kg live-weight gain, whereas nitrogen intake exerted a negative influence. Values for energy retained per kg live-weight gain predicted from multiple regression equations, together with calculated values for maintenance and net efficiency, were used to predict the energy retention and growth rate of pigs in various circumstances.

Nitrogen retention increased in association with increases in nitrogen intake for pigs of all sexes at 30 kg live weight; there was also a corresponding increase for boars at 90kg live weight, but not for gilts or barrows at this weight. Boars retained more nitrogen than did barrows at 30 and 90 kg live weight only if given the diet with the higher concentration of protein.

Metabolizable energy intake appeared to exert a small positive influence on the nitrogen retention by pigs of all sexes at 90kg live weight; however, it appeared to have no influence on nitrogen retention by pigs at 30kg live weight.
A note on the accuracy of an ultrasonic technique for selecting cattle of different breeds for slaughter at equal fatness
Authors: Kempster A. J. , Owen M. G.
Published: September 2010

In the first phase of the Meat and Livestock Commission's beef breed evaluation programme, cattle were slaughtered at a fixed subcutaneous fat percentage in carcass. Slaughter point was determined from fat areas measured over the m. longissimus at the 10th and 13th ribs by the Scanogram ultrasonic machine.

The accuracy of the slaughter procedure was examined using data for 1367 cattle from the first 3 years of the programme. Subcutaneous fat percentage predicted from the ultrasonic measurements was compared with the percentage estimated by visual assessment of carcass fat cover. The s.d. of the difference between the two was 1·65.

Data for a subset of 313 cattle were used to examine the relationships between the ultrasonically measured fat areas and actual subcutaneous fat percentage obtained by dissection. The residual s.d. for the prediction of subcutaneous fat within breed and production system was 1-18.

The level of accuracy achieved was considered to be satisfactory within the context of the beef breed evaluation programme.
The effect of climatic housing and level of nutrition on the performance of calves
Authors: Williams P. E. V. , Day D. , Raven A. M. , McLean J. A.
Published: September 2010

Five hundred and seven British Friesian × Ayrshire bull calves were reared on a once-daily milk replacer feeding system from approximately 6 to 72 days of age in four naturally ventilated, unheated calf houses differing in design and degree of insulation. Environment within the calf houses was monitored each hour. Differences in design and degree of insulation produced small but significant differences in internal house temperature, humidity and air movement which had no measurable effect on calf daily live-weight gains.

Calves receiving 0·6 kg/day compared with 0·3 or 0·4 kg/day of milk replacer plus concentrates ad libitum ate less concentrates but had higher daily live-weight gains (0·56 compared with 0·49 kg/day respectively) (P < 0·001). Rations supplying similar amounts of metabolizable energy from varying proportions of milk:concentrate resulted in comparable live-weight gains. Results suggest that calf viability was affected by level of nutrition and that low levels of milk replacer feeding resulted in higher mortality. Naturally ventilated, unheated calf houses were demonstrated to be suitable for rearing calves in south-west Scotland.
The influence of nutrition on reproduction in the ewe 1. Effects on ovulation rate, follicle development and luteinizing hormone release
Authors: Haresign W.
Published: September 2010

Two groups of 15 ewes in store body condition were either given a maintenance level of feeding or a twice-maintenance level (flushed) during the course of one oestrous cycle. Five ewes from each feeding level were slaughtered at 0, 18 or 48 h after the onset of the oestrus at the end of the treatment period and measurements were made of the luteinizing hormone content of their pituitary, the luteinizing hormone concentration in their blood plasma, their ovulation rates, and ovarian follicle numbers and sizes.

‘Flushed’ ewes had a significantly higher ovulation rate (260, s.e. 0·24 v. 1·80, s.e. 0·20; P <0·05), although there was no significant difference in either pituitary luteinizing hormone content or plasma luteinizing hormone concentrations at oestrus.

Analysis of the patterns of ovarian follicle distribution suggest that flushing ewes for one oestrous cycle might increase ovulation rate by preventing the late atresia of large follicles in the last 30 h before ovulation.
A note on haemoglobin type and reproductive performance of ewes grazing oestrogenic pastures
Authors: Walker S. K. , Obst J. M. , Smith D. H. , Hall G. P. , Flavel P. F. , Ponzoni R. W.
Published: September 2010

Field data were analysed in an attempt to identify factors contributing to differences between haemoglobin types n i the proportion of ewes lambing per ewe exposed to the ram in flocks grazing oestrogenic pastures. The number of ewes mated and the proportion of ewes failing to conceive to first service per ewe exposed to the ram were analysed. Neither was found to significantly differ between matings of different haemoglobin type. It is concluded that differences in reproductive performance between haemoglobin types could possibly result from differences in embryo survival.
Disruption of teat preferences and retardation of growth following cross-fostering of 1-week-old pigs
Authors: Horrell I. , Bennett Josie
Published: September 2010

Twenty sows and their litters were observed at regular intervals over the 1st week post partum to determine piglet-teat relationships. At 7 days of age, three piglets were exchanged between five pairs of litters, the other 10 litters remaining intact as controls. Observations of sucking were continued for another week. All piglets were weighed at 3, 7 and 14 days of age. Cross-fostering disrupted the teat sucking relationships of the whole litter compared with those of control litters, but the probability of sucking at the same teat in the 2nd week as in the 1st was less in fostered piglets than in their non-fostered littermates. The weight gain of fostered piglets during the 2nd week was reduced to 79% of that in their non-fostered littermates. Both disruption of sucking and reduction in weight gain were greater in those piglets that had to compete, on their foster mother, for the teat they preferred during the 1st week than for those whose teat was free.
The effects of level of feeding of sows during pregnancy. III. Body composition
Authors: Elsley F. W. H. , Macpherson R. M. , Lodge G. A.
Published: September 2010

1. Four groups of three litter-sister Large White gilts were given during four successive pregnancies a daily meal allowance of either 2·70 kg (High), 1·35 (Low) or 1·35 kg for 76 days followed by 2·70 kg until parturition (Low-High). During 8-week lactation periods all received the same daily allowance of 1·8 kg meal plus 0·35 kg for each piglet suckled.

2. On the 100th day of the fourth pregnancy all sows were slaughtered. The major internal organs were weighed and measurements recorded of the length of carcass and backfat thickness at shoulder, midback and loin. The carcasses were then separated into bone, skin, subcutaneous fat and muscles plus intermuscular fat. The weights of radius-ulna, tibia-fibula, humerus and femur were recorded.

3. In each of the treatment groups the live-weight changes of the sows in the fourth pregnancy were almost identical to those in the third pregnancy.

4. The mean total carcass weights for the High, Low and Low-High sows were 154, 92 and 110 kg respectively, and the mean subcutaneous fat contents of the carcasses 14, 4 and 6 kg respectively.

5. The relative proportions of the weights of the organs to carcass weight, weight of bone to weight of muscle plus intermuscular fat, and the weight of individual bones to total bone weight were relatively unaffected by the treatments after allowance had been made for total carcass weight.

6. The implications of the changes in body composition on the lifetime reproductive performance of sows are discussed.
Intensive beef production. 9. A note on the performance of Friesian and Ayrshire steers fattened on a cereal diet
Authors: MacLeod N. A. , Macdearmid A. , Kay M.
Published: September 2010

In parts of the United Kingdom, considerable numbers of Ayrshire bull calves are slaughtered at birth or shortly after. These animals, if fattened intensively on a cereal diet, could provide a valuable addition to the beef produced from the dairy herd if their rate of live-weight gain, carcass composition and feed conversion efficiency provided an economic return. At the prevailing purchase price of calves and cost of feed the profit margin would appear to compare favourably with that from other dairy steers. The data from an economic survey of barley beef units in the North of Scotland by Clark (1966) show, on the basis of surplus per head (i.e. gross margin less other costs) that the greatest margin was achieved by a unit whose livestock was entirely comprised of Ayrshire steers.
The assessment of pig meat paleness by reflectance photometry
Authors: MacDougall D. B. , Cuthbertson A. , Smith R. J.
Published: September 2010

A portable EEL reflectometer was modified to measure the variations in the brightness of pig meat. The instrument was calibrated spectrophotometrically with reference to the luminous reflectance of standardized materials and selected meat samples. A very satisfactory level of agreement between the instrument and the visual assessment of muscle paleness was found in an investigation involving 251 pigs.