bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of clover in the diet of grazed lambs on production and carcass composition
Authors: Vipond J. E. , Swift G. , Noble R. C. , Horgan G.
Published: September 2010

The effect of grazing clover on ewes and lambs was studied using nitrogen-fertilized grass (G) and grass/white clover pastures (GC) containing proportionately 0·18 clover. Carcasses of lambs grazed on GC were significantly heavier than carcasses of lambs grazed on G pastures. An interaction with weaning occurred. Carcasses from lambs grazed on GC for 53 days post weaning were 2·3 kg heavier (F < 0·01) but lambs slaughtered at weaning had similar carcass weights. Diet had no effect on relative joint components of carcasses. The effect of clover in the diet on carcass weight was attributed to higher levels of protein retention.

Analysis of the fatty acid composition of intramuscular and subcutaneous and perirenal lipids indicated small but significant effects of diet. Lean tissue lipids of lambs grazing clover showed significant increases in C18:2 and reduced C20: 5 fatty acids. In tissue fats there were small increases in C14:0, C16:0 and C18:2 with reduced C18:1 content.

Twin suckled lambs grazing GC for 94 days from turn-out in early April showed increased live-weight gain over lambs on G of 336v.287 g/day (s.e.d. 84;P< 0.001). Post weaning live-weight gain of lambs was 173 and 221 g/day on G and GC respectively. Sward height was maintained at 5.18 and 5.24 (s.e.d. 0.075) cm on G and GC paddocks by adjusting ewe numbers. GC pastures carried proportionately 0.82 of the stock on G pastures but output of lamb was similar at 1289 and 1247 kg/ha for G and GC respectively.

Results showed that the production penalty of lower stocking rate associated with grass/cloverv.grass fertilized with 190 kg nitrogen per ha was ameliorated by higher lamb live-weight gain and carcass weight without change in joint composition or nutritionally significant change in fatty acid composition of carcass tissues.
A note on heritability estimates for growth traits in male and female Romanov sheep
Authors: María G. A. , Boldman K. G. , van Vleck L. D.
Published: September 2010

A total of 1855 records were analysed using restricted maximum likelihood (REML) techniques to estimate heritabilities separately for males and females lambs on birth weight (BW), weaning weight (WW), 90-day weight (W90) and average daily gains birth to weaning (Cl) and weaning to 90 days (C2). An animal model including fixed effects of year × season, parity, litter size and rearing type; and random effects of direct genetic effect (h2D) and residual was applied. Estimates ofh2Dfor BWwere 048 (males) and 0·50 (females); for WW 0·35 (males) and 0·22 (females); for W90 0·21 (males) and 0·31 (females); for Cl 0·20 (males) and 0·25 (females); and for C2 0·18 (males) and 0·29 (females).
Effect of lamb growth rate and growth pattern on carcass fat levels
Authors: Chestnutt D. M. B.
Published: September 2010

A total of 252 lambs was subjected to two contrasting growth rates (high and low) for 7 weeks commencing at 6 weeks of age, factorially arranged with two contrasting growth rates (high and low) from 13 weeks to slaughter. Growth rate was controlled either by weaning lambs at 6 weeks and feeding indoors throughout on differing levels of a concentrate diet (84 lambs in experiment 1) or by grazing at differing sward heights up to weaning at 13 weeks after which weaned lambs were grazed at differing sward heights and where necessary housed from early October and offered differing levels of concentrate and silage (168 lambs in experiment 2). Lamb slaughter weights on each growth rate treatment covered the range 40 to 48 kg live weight.

Increasing the growth rate between 6 and 13 weeks from 213 to 320 glday in experiment 1 and from 191 to 291 g/day in experiment 2 did not significantly affect the fat depth measured at various locations throughout the carcass, the weight of perinephric and retroperitoneal fat, fat grade or the total lipid content of soft tissue dissected from the shoulder joint when lambs were taken to slaughter weights. Increasing the growth rate between 13 weeks and slaughter from 136 to 338 g/day in experiment 1 and from 99 to 146 g/day in experiment 2 significantly increased the depth of carcass fat and fat grade but, though lipid content of the tissue in the shoulder also increased, this difference was not significant.

Carcass fat depth, perinephric and retroperitoneal fat, fat grade and lipid content of the shoulder tissue increased as slaughter weight increased. The effect of carcass weight on carcass fat was greater on the high plane of feeding from 13 weeks than on the low plane. For example, mean fat depth increased by 0·52 mm/kg increase in carcass weight on the high plane compared with 0·13 mm/kg on the low plane.

Comparing the effect of plane of feeding and carcass weight on carcass fat depth the high finishing plane of feeding had an effect equivalent to an increase of 3·8 kg carcass weight. The equivalent figure for the depth of tissue over the 12th rib was 2·8 kg while in relation to fat grade the effect was smaller at 1·0 kg carcass weight.
Nitrogen and energy metabolism and serum constituents in lambs given broiler poultry litter processed by three deep-stacking methods
Authors: Rude B. J. , Rankins D. L. , Dozier W. A.
Published: September 2010

Poultry litter has been used as an economical nitrogen (N) source in ruminant diets. However, litter must be processed to eliminate pathogens. Broiler poultry litter was processed by three different deep-stack methods: (1) uncovered, (2) covered with 0.1524 mm clear polyethylene, and (3) aerated by placing perforated pipe 1 m apart within the stack. Stack temperature was measured for 28 days. The litter was used to formulate experimental diets (186 g litter per kg), while the control diet contained urea as the N source. All diets contained 100 g/kg cottonseed hulls, 16 to 17 g/kg limestone, varying amounts of cracked maize and added retinol. The control diet contained 131 g/kg crude protein (CP) while the litter diets contained 125 g/kg CP. The diets were offered to 16 crossbred wether lambs (37 (s.e. 6·1) kg) in individual metabolism crates for 16 days. Blood was collected at the initiation and termination of the trial. Covering litter with plastic decreased temperature ivithin the stack (P < 0·05). Maximum temperature for the uncovered, covered and aerated stacks was: 68°C, 57°C and 72°C, respectively. Dry-matter intake and dry matter, energy and neutral-detergent fibre apparent digestibilities were not different (P > 0·05) among the diets. Apparent digestibility for N was less (P < 0·05) in lambs given uncovered and aerated litter than in those given the control diet. However, N apparent digestibility in lambs given covered litter was not different from that of those given the control diet. Gross energy and N retention of the four diets were not different (P > 0·05). Covering deep-stacked broiler poultry litter improved N digestibility by proportionately 0·15 compared with uncovered litter. Serum chloride was decreased while serum urea was increased (P < 0·05) in sheep consuming the litter-containing diets. Deep-stacked broiler litter should be covered in an air-tight manner in order to maximize its nutritive value.
Level and pattern of winter concentrate allocation in dairy cows: results in first lactation cows
Authors: Coulon J. B. , D'Hour P. , Garel J. P. , Petit M.
Published: September 2010

A total of 148 dairy cows in their first lactation and with a mean calving date of 6 December were used in a 4–year experiment. The experiment was designed to examine the effect of level and distribution of concentrate given during the winter period in addition to grass silage (ad libitum) and hay (4 kg/day) on total lactation performance. Each year the same five treatments were compared: three levels of concentrate supply during the winter period (H, M and L), and, for levels M and L, two different allocation patterns (standard (S) or flat rate (F)). Concentrate allocation was individually pre-determined according to expected milk production. During summer, all animals grazed together as a single group. During the experimental period (weeks 4 to 18 of lactation), concentrate and roughage intakes were 6·3, 5·0 and 3·6 kg dry matter (DM) per day and 9.;5, 9·6 and 10·0 kg DM per day in group HS, MS and LS respectively. Milk yield and protein concentration of group HS were higher than that of group MS (+1·3 kg I day and +1·0 g/kg) or LS (+3·0 kg/day and +1·7 g/kg). During winter, live-weight changes were +4, -26 and -39 kg for group HS, MS and LS respectively. Over the 40 weeks of lactation, the differences in milk production and concentrate supply were 193 kg and 196 kg DM between groups HS and MS, and 518 kg and 413 kg DM between groups HS and LS. There was no significant difference between groups S and F.
Crossbreeding Jersey with Ghana Shorthorn and Sokoto Gudali cattle in a tropical environment: additive and heterotic effects for milk production, reproduction and calf growth traits
Authors: Rege J. E. O. , Aboagye G. S. , Akah S. , Ahunu B. K.
Published: September 2010

Crossbreeding data involving Ghana Shorthorn, Sokoto Gudali and their Jersey F1s and backcrosses collected over a 16-year period were analysed to estimate additive and heterotic effects for milk production, reproduction and calf growth traits. Sokoto Gudali was significantly better than Ghana Shorthorn in all milk production traits. Calving interval and annualized milk production were better in Gudali than in the Shorthorn. The F1s had higher lactation milk yield, milked longer, produced their first calves earlier and had shorter dry periods and calving intervals than their corresponding purebreds. However, genotype was not significant for number of services per conception. Both F1s had higher average daily gain and weaning weight than their corresponding purebreds. Sokoto Gudali backcross (Jersey × F1) was significantly (P < 0·05) better than the F1 in lactation length. However, in Gudali crosses, there was no advantage in increasing the proportion of Jersey genes beyond 0·5 for milk production traits. Additive effects were significantly (at least P < 0·05) lower in the Shorthorn and the Gudali than in Jersey for milk production traits except proportion of butterfat. Heterosis estimates were significant (P < 0·01) for milk production traits for the Shorthorn but not for the Gudali. Heterotic effects were large and significant (at least P < 0·05) in improving annualized milk production in Shorthorn crosses, whilst none of the heterotic effects for reproductive traits was significant. At both 0 and 0·5 levels of Jersey inheritance, the Gudali was superior (P < 0·01) to the Shorthorn in birth weight, weaning weight and pre-weaning average daily gain. Heterotic effects for calf traits were positive and much larger in Gudali crosses than in Shorthorn crosses. In general, backcrosses were, at best, similar to the F1s implying that upgrading these indigenous breeds beyond 0·5 European inheritance may not be desirable.
Efficiency of energy utilization in cattle given food ad libitum: predictions according to the ARC system and practical consequences
Authors: Tolkamp B. J. , Ketelaars J. J. M. H.
Published: September 2010

Overall efficiency of energy utilization (i.e. total net energy intake as a fraction of metabolizable energy intake) in cattle given food ad libitum was calculated from information included in the United Kingdom energy evaluation system as published by the Agricultural Research Council. For growing cattle (live weight 250 kg), overall efficiency was estimated for five levels of diet metabolizability (ranging from q = 0·45 to q = 0·65) for each of two diet types: coarse/long roughage and fine/pelleted diets. The overall efficiencies varied from 0·58 to 0·62 and were not systematically affected by diet type or diet metabolizability. For lactating cattle (live weight 600 kg), overall efficiency was also calculated for five diets with metabolizability ranging from 0·45 to 0·65. Calculations were made for cows at equilibrium intake (i.e. zero energy balance) and at milk production levels proportionately 0·30 higher or lower than those attained at equilibrium intake. Overall efficiencies varied from 0·60 to 0·63 and were not systematically affected by diet metabolizability.

It is concluded that, in practical cattle production systems with ad libitum feeding, the net energy content of food may be estimated at 0·6 of the metabolizable energy content (or 0·5 of the digestible energy content), irrespective of diet type, diet metabolizability or productive function.
Influence of stocking rate and faeces deposition in the pen at different temperatures on skatole concentration (boar taint) in subcutaneous fat
Authors: Hansen L. L. , Larsen A. E. , Jensen B. B. , Hansen-Møller J. , Barton-Gade P.
Published: September 2010

The aim of this work was to investigatethe effect of stockingrate (0·6 m2 per pig or ≥1·2 m2 per pig) and faeces plus urine deposition on skatole concentration (boar taint)in subcutaneousfat. The study utilized pens with concrete flooring and different environmental temperatures.

The experimental material consisted of 144 cross bred male and female pigs in each of two experiments. One experiment was carried out in the summer (temperature ≥ 22°C) and one in the winter (temperature approx. 17°C in the pig house). In both experiments, stocking rate and faeces deposition were kept constant up to first delivery to the abattoir. Then stocking rate and faeces deposition were changed to the opposite treatment a week before the last three of the four deliveries to the abattoir.

The experiment confirmed the hypothesis that the pigs which lay in their faeces plusurine in pens with the high stocking rate for at least a week had a higher skatole level in subcutaneous fat than pigs kept clean in pens with the low stocking rate. It was feasible within a week before slaughter to increase or lower the skatole level by changing the treatment of the pigs.

Male and female pigs showed similar differences. Air temperature (season) had a significant influence on skatole level. The level was significantly higher in subcutaneous fat at hight emperatures in the summer experiment compared to the winter experiment despite the fact that the pigs with high stocking rate in the winte rexperiment were as heavily fouled with faeces and urine as those in the summer experiment.

Skatole concentrations in faeces of individual pigs were not influenced by different temperatures or treatments, and there was no significant correlation between the skatole level in faeces and in subcutaneous fat.

High skatole levels in subcutaneous fat seemed to have a genetic component.

It is hypothesized that skatole from faeces plusurine (excreta) especially at temperatures of 30° Cor more may pass through the skin of the pig and/or that skatole in a gaseous form may be absorbed through the lungs.
A note on the effects of dietary inclusion of a yeast culture on growth and ruminal metabolism of lambs given diets containing unground pelleted molassed dried sugar-beet pulp and barley in various proportions
Authors: Rouzbehan Y. , Galbraith H. , Rooke J. A. , Perrott J. G.
Published: September 2010

Twenty-eight Suffolk-cross male castrated lambs aged 7 to 8 months, initial live weight 36 (s.e. 149) kg were given four diets which contained unground pelleted molassed sugar-beet pulp and rolled barley (940 g/kg, fresh weight basis) in the following proportions either A, 0·8 to 0·2 or B, 0·5 to 0·5, with 60 g soya-bean meal per kg. Diets A and B were offered with or without a yeast culture product Yea-Sacc. Diets zvere offered twice daily to appetite with 100 g hay per head. Yeast culture had no effect on any measurement made (P > 0·05). Lambs given diet B consumed more dry matter (DM), grew faster and had superior food conversion efficiencies (all P < 0·01). Rumen fluid taken 3 h after feeding contained higher concentrations of ammonia (F < 0·01), total volatile fatty acids (F < 0·001) and acetic acid (F < 0·001) in samples from lambs given diet A. Rumen fluid samples collected before the 10·00 h meal, produced more gas from diet A than diet B after 6 and 24 h in vitro incubation (F < 0·001) suggesting the presence of more undigested food. When ground diets were incubated, more gas was produced from diet A after 6h (F < 0·05) but not after 24 h fP > 0·05). It is suggested that diet B supported faster growth of the lambs as a result of faster rate of digestion, higher DM intake and superior food conversion.
Influence of a hormonal preparation containing glucocorticoids (dexamethasone esters), progestagen (chlormadinone acetate) and oestrogen (ethinyl oestradiol) on testosterone, insulin-like growth factor-1 (IGF-1), IGF-binding proteins and spermatogenic cells in finishing bulls
Authors: Renaville R. , Massart S. , Lognay G. , Devolder A. , Sneyers M. , Marlier M. , Severin M. , Burny A. , Portetelle D.
Published: September 2010

Growth-promoters are banned by the European Community, but different hormonal cocktails are still illegally used. This experiment was therefore conducted to evaluate the effects of one of the most currently used cocktails on some hormonal parameters and spermatogenesis in finishing bulls in an attempt to provide a suitable screening technique for their illegal use. Sixteen double-muscled Belgian White Blue finishing bulls (mean ivcight: 535 (s.d. 37) kg) were blocked into control (C; no. = 7) and treated (Dex; no. = 9) groups. Animals were treated i.m. with the hormonal preparation (dexamethasone isonicotinate and phosphate, chlormadinone acetate and ethinyl oestradiol) on day 0, day 15 and day 30. Animals were slaughtered on day 45. Three h before each treatment and just prior to slaughter, jugular blood samples were collected to monitor the testosterone (T) response to an i.v. injection of gonadotropin releasing hormone (GnRH) (0·5 fig GnRH per kg body weight). Testicular tissue was also collected at slaughter. Plasma T and insulin-like growth factor-1 (IGF-1) concentrations were measured by radioimmunoassay. IGF-binding proteins (IGFBPs) were evaluated using Western ligand blotting. Daily weight gains were lower in the control group (1·29 (s.d. 0·13) kg for C v. 1·60 (s.d. 0·39) kg for Dex) but the difference ivas not significant. After treatment, spermatogonia, spermatocytes, spermatids and spermatozoa disappeared from the testis and seminiferous tubules consisted only of Sertoli cells; these observations suggest that treated animals were sterile. Moreover, plasma T concentrations in response to GnRH stimulation were suppressed fP < 0·001) in the Dex group between day 15 and day 45 (mean maximal responses: 5·4 to 7·9 μg/l in C group v. < 0·2 μg/l in Dex group at day 15, 30 and 45). Treatment did not show any prominent effect on plasma IGF-1 levels but increased IGFBPS band intensity. In conclusion, treatment with a cocktail containing dexamethasone esters, chlormadinone acetate and ethinyl oestradiol for a short period induced a number of changes in finishing bulls luhich might be possible to develop as a screening method for the identification of illegally treated animals.
Selection for components of efficient lean growth rate in pigs 3. Responses to selection with a restricted feeding regime
Authors: Cameron N. D. , Curran M. K. , Kerr J. C.
Published: September 2010

Responses to four generations of divergent selection in pigs for lean growth rate (LGS) with restricted feeding were studied. The selection criterion was designed to obtain equal correlated responses in growth rate and carcass lean content, measured in phenotypic s.d. Animals were to be performance tested in individual pens with a mean starting weight of 30 kg for a period of 84 days. Daily food intake was equal to 0·75 gig of the daily food intake for pigs offered food ad-libitum. In the high, low and control lines, there ivere 1250 Large White-Edinburgh (LW) pigs and 875 British Landrace-Wye (LR) pigs. Each selection line consisted of 10 sires and 20 dams, with a generation interval ofl year.

After four generations of selection, cumulative selection differentials were 5·9 and 4·8 phenotypic s.d. for LW and LR populations, with similar responses, 1·8 (s.e. 0·17) phenotypic s.d. Mean weight at the end of test, growth rate and backfat depths at the shoulder, mid back and loin were 89 kg, 712 g/day, 26,13 and 13 mm for LW and for LR pigs were 87 kg, 683 g/day, 28,10 and 10 mm. High line pigs were heavier at the end of test (4·3 (s.e.d. 1·4) kg and 4·0 (s.e.d. 1·6) kg) for LW and LR populations, with corresponding responses in growth rate (54 (s.e.d. 16) g/day and 47 (s.e.d. 18) g/day). Responses in the three backfat depths were −4·1 (s.e.d. 1·2) mm, −2·6 (s.e.d. 0·7) mm and −2·9 (s.e.d. 0·7) mm for LW and −2·2 (s.e.d. 0·05) mm, −2·2 (s.e.d. 0·4) mm and −2·4 (s.e.d. 0·5) mm for LR populations. Responses in weight off test and backfat depths were symmetric about the control lines.

Heritabilities for LGS were 0·34 and 0·28 (s.e.d. 0·5) for the LW and LR populations, when estimated by residual maximum likelihood. Common environmental effects for LGS were 0·11 (s.e. 0·03) for LW and 0·17 (s.e. 0·04) for LR. Heritabilities for growth rate and average backfat depth were similar for LW and LR populations (0·17 and 0·29, s.e. 0·05), as were common environmental effects (0·10 s.e. 0·04). Average phenotypic and genetic correlations between growth rate and backfat, for LW and LR populations, were small (0·15 (s.e. 0·03) and −0·06 (s.e. 0·16), respectively).

Responses to selection and genetic parameter estimates demonstrate that there is substantial genetic variation in growth and fat deposition when pigs are performance tested on restricted feeding.
Effect of nitrogen supply on the retention and excretion of nitrogen and on energy metabolism of pregnant sows
Authors: Everts H. , Dekker R. A.
Published: September 2010

To reduce nitrogen excretion (NEx) the effect of nitrogen supply on nitrogen retention (NR) and NEx was studied in pregnant sows during three parities. A nitrogen supply of 40 g/day (treatment L) was compared with 62 g/day (treatment C) during day 0 to 85 of pregnancy. In the last month of pregnancy nitrogen supply on treatment L was 50 g/day and on treatment C 74 g/day. Faecal digestible lysine supply followed the same pattern as nitrogen. Nitrogen and energy balances were measured during mid pregnancy (day 50 to 60; no. = 22) and late pregnancy (day 105 to 112; no. = 60). During mid pregnancy treatments had a minor affect on NR and energy metabolism. NEx on treatment L was proportionately about 0·40 lower than on treatment C. During late pregnancy NR was lower on treatment L than on treatment C. NEx on treatment L was proportionately reduced by 0·35 compared with treatment C. In parity 1 the lower NR on treatment L was compensated by a higher fat gain. Results indicate that nitrogen and faecal digestible lysine supply on treatment L were close to minimal requirement in late pregnancy. Assumed values for maintenance requirement of nitrogen (0·45 g N per kg M0·75) and efficiency of ingested nitrogen to NR (0·6) were in line with the results of the balance trials. The observed nitrogen retention of sows, especially during mid pregnancy, permits a reduced nitrogen supply to reduce NEx.
Effect of triple versus double mating on sow productivity
Authors: Tilton J. E. , Cole D. J. A.
Published: September 2010

Two hundred Landrace × Large White sows were used to evaluate the influence of mating to Landrace or hybrid boars, at different intervals and with different frequencies, on subsequent reproductive performance. Sows were allocated at random to either a mating on each of the first 2 days of oestrus (double mating), two matings on the 1st day and one on the 2nd, one on the 1st day and two on the 2nd or single matings on each of the first 3 days of oestrus. All triple mating systems increased number of piglets born and born alive, with mating on 3 consecutive days significantly influencing these parameters compared with double mating (P < 0·05). Number of piglets weaned and mean piglet weaning weight were not affected significantly by treatment. Breed of boar used did not influence significantly any of the factors measured.
Effects of trenbolone acetate and resorcylic acid lactone on protein metabolism and growth in steers
Authors: Griffiths T. W.
Published: September 2010

Twenty-four castrate male cattle were used in two nutritional balance and slaughter experiments to measure the effects of two implantations with 300 mg trenbolone acetate and 36 mg resorcylic acid lactone over the live-weight range 250 to 400 kg. Control and implanted animals were pair-fed barley-based diets of differing protein concentration in the first experiment and the lower protein diet at two levels of feeding in the second experiment.

Daily live-weight gain and nitrogen retention were significantly increased by implantation in both experiments. The carcasses of implanted animals contained significantly more lean meat and a higher proportion of meat in the forequarter. The edible portion of these carcasses contained significantly more protein and water and less fat.

Live-weight gain and carcass composition were not influenced by dietary protein intake. Increased feeding level improved live-weight gain, suggesting that a higher metabolizable energy intake would give an increased response to implantation.
The energy value to ruminants of malt distillers' draff, and of a mixture of draff and pot ale syrup
Authors: Wainman F. W. , Dewey P. J. S.
Published: September 2010

Two foods, distillers' wet draff and draff plus pot ale syrup, containing 207 and 256 g crude protein per kg dry matter respectively, were given as sole food at the maintenance level to four adult wether sheep. Two of the sheep were given draff and two draff plus syrup for a 28-day period; the treatments were then changed over for a second period. The copper contents of the foods were 17 and 30mg/kg dry matter for the draff and draff plus syrup respectively. Sheep are particularly susceptible to copper and care should be taken when feeding such by-products, but during these short-term trials there was no evidence of copper poisoning. Energy losses in the faeces and urine were measured for all sheep, and methane losses were measured in closed-circuit respiration chambers for two sheep on each treatment. The metabolizable energy values of the foods were 10·8 (s.e. 0·15) and 12·5 (s.e. 0·15) MJ/kg dry matter for the draff and draff plus syrup respectively. The proportions of gross energy intake lost as methane were 0·029 for the draff and 0·042 for the draff plus syrup; these were much lower than the values predicted by the commonly used equation.
Changes in body composition relative to weight and maturity in large and small strains of Australian Merino rams 3. Body organs
Authors: Butterfield R. M. , Zamora J. , James A. M. , Thompson J. M. , Reddacliff K. J.
Published: September 2010

Maturing patterns are established for 26 body organs using data from 35 rams of two strains of Merinos of different mature size (97 and 120 kg).

The proportion of shorn full live weight represented by each structure at maturity was very similar for all organs except the head, hide and distal limbs which were relatively heavier in the small strain. and small intestine and blood which were relatively heavier in the large strain.

All organs were early maturing relative to shorn full live weight except the hide and the penis plus bladder, which matured at the same rate as live weight. The maturity coefficients differed between strains only for the head, thyroid and omasum.

Differences in the proportion of live weight comprised by each organ in the two strains were compared at the same shorn full live weight and at the same proportion of mature shorn full live weight. Differences in the various portions of the alimentary tract and other internal organs, with the exception of the kidneys, which were evident in comparisons at the same weight, were reduced when compared at the same proportion of maturity. The difference between strains for head, hide and distal limbs was greater at equal maturity than at equal weight suggesting a functional relationship to body weight rather than to ultimate mature body size.

It was concluded in genetic comparisons of animals of different mature size, the most appropriate basis of comparison of relative organ weight will be at the same proportion of mature live weight.
Growth and backfat depth of pigs kept at a high temperature
Authors: Holmes C. W.
Published: September 2010

1. Two experiments have been carried out to determine the effect of a high air temperature, 32·33°C, on growth and backfat depth of pigs, by comparison with a thermo-neutral air temperature, 22·24°C. The diet consisted predominantly of whey, since it was expected thatthis would enable appetite to be maintained at the higher temperature.

2. Food intake was reduced by 5% to 7% during the period of exposure to 32°C in Experiments 1 and 2 respectively. Growth rate and FCE were reduced significantly only in Experiment 2.

3. Backfat depths measured above the eye muscle were significantly increased by the hot treatment in both experiments; those measured on the split carcass were consistently greater for the hot treatment.
The influence of a bio-active feed supplement (hormonexa) on the performance and carcass quality of bacon pigs
Authors: Laird R. , Walker-Love J.
Published: September 2010

Three trials, each involving 24 pigs, were conducted to assess the value of Hormonexa as a feed supplement for pigs slaughtered at 90 kg live weight. Rations were compounded from a variety of feeding stuffs to different protein levels and the pigs were fed on various nutritional planes. Hormonexa was added to these rations at the rate of 1·32 kg per 1000 kg meal.

In all three trials growth rate and food conversion efficiency were not affected significantly by the addition of the supplement. There was a tendency for the pigs receiving the supplement to be slightly leaner but in only 1 out of 39 measurements of fat thickness was the difference between control and supplemented pigs statistically significant (P< 0·05).

No benefit from this feed supplement has been demonstrated in terms of animal performance or carcass quality under a range of feeding systems.
The control of appetite in lactating cows
Authors: Monteiro L. S.
Published: September 2010

A closed-loop system is proposed for the control of voluntary food intake in lactating cows, and an expression is deduced relating the response of food intake to changes in milk yield and body-weight gain.

A closed-loop system necessarily involves a delay in the response to changes in production. The rate of increase of food intake is there- fore slower than the rate of increase in milk yield. The consequent deficit in energy during the rising part of the lactation curve is met by the mobilization of body reserves, which are partly accounted for by losses in body weight. During the declining part of the lactation the delay effect leads to an excess of energy intake and to the replacement of body reserves and, consequently, of body weight.

The expression deduced from the model was fitted to four different types of lactation curve corresponding to long and short lactations of Friesians and Jerseys fed ad libitum on a complete diet. The expected food intake based on the control model was contrasted with a linear regression model. The former gave a better account of the variation in food intake in all four types of lactation.

The total change in body weight during lactation was partitioned between changes in weight due to the mobilization and replacement of reserves and gain directly attributable to food intake. There was, in general, good agreement between the observed losses in weight occurring at the beginning of lactation and those predicted from the mobilization of reserves for milk production.

The physiological implications of the model and the values estimated for the parameters are discussed.
Growth and herbage consumption of grazing Merino and Border Leicester lambs reared by their mothers or fostered by ewes of the other breed
Authors: Langlands J. P.
Published: September 2010

Eight Border Leicester castrated male lambs (wethers) were fostered on to 8 Merino ewes (MB) at birth, and 10 Merino wethers were fostered on to Border Leicester ewes (BM). Two additional groups of 10 wethers consisted of Border Leicester lambs (BB) and Merino lambs (MM) reared by their natural mothers. The lambs and ewes grazed together and growth rate, and milk and herbage consumption of the lambs were recorded.

Live-weight gains to weaning at 74 days were 275, 245, 204 and 184 g/day for groups BB, MB, BM and MM respectively. Lambs reared by Border Leicester ewes received more milk and consumed less grass than lambs of similar genotype reared by Merinos, but BM lambs consumed less milk than BB lambs. Merino lambs also consumed less grass than Border Leicester lambs.

It was concluded that Merinos grew more slowly than Border Leicester lambs primarily because of their lower voluntary food intake. The lower milk production of Merino ewes was considered to be of secondary significance since if herbage is available ad libitum, lambs with high voluntary intakes will compensate for the lack of milk by consuming more forage.
A note on seasonal fluctuations in milk production
Authors: Wood P. D. P
Published: September 2010

Records from 161 lactations completed in the year ended September 1969 were obtained from a herd of British Friesians kept indoors all the year round and fed grass silage with a concentrate supplement. Seasonal variation in milk production from the herd was compared with that from cattle traditionally managed.

After allowing for variation due to parity, season of calving, and stage of lactation, there was a tendency for milk production to be stimulated during periods of feeding grass consumed in a rapidly growing state. Seasonal variation was considerably less evident in the indoor herd than in the traditionally managed samples.
The distribution of body fat in Scottish Blackface and Finnish Landrace lambs
Authors: McClelland T. H. , Russel A. J. F.
Published: September 2010

Seven Scottish Blackface and seven Finnish Landrace wether lambs were slaughtered over the weight range 26 to 41 kg. Total chemical fat deposition in relation to fleece-free empty body weight was found to be similar for both breeds, pooled data giving the significant relationship y = 1·28+0·46x, where y was the percentage chemical fat in the fleece-free empty body and x the fleece-free empty body weight.

Statistically significant differences in the rate of chemical fat deposition in different depots were found between breeds. The Scottish Blackface was found to deposit relatively more fat in muscular plus associated fatty tissue than the Finnish Landrace while the reverse situation occurred in respect of fat deposition in omental plus mesenteric fatty tissues and perirenal fatty tissues.

No breed differences were found in the rate of deposition of subcutaneous fat or fat in bone or in the remainder (head, skin and viscera).
Influence of social conditions during rearing on the sexual behaviour of the domestic boar
Authors: Hemsworth P. H. , Beilharz R. G. , Galloway D. B.
Published: September 2010

Three groups of six young male pigs (boars) were reared from 20 days to 7 mo of age under one of the following social conditions: a mixed sex group; an all-male group; or social restriction, without physical and visual contact with other pigs. The sexual behaviour of the boars was studied from 7 to 13 mo of age. The total number of copulations and the sum of all the courting behaviour activities were significantly greater (P<0·01) for the boars reared in the all-male and the mixed sex groups than for those reared in social restriction. Growth rate to 30 weeks of age, testicle size and semen quality were not affected by rearing treatment.
A note on the relationship between live-weight gain during calfhood and subsequent performance of intact male calves of the Israeli-Friesian breed
Authors: Folman Y.
Published: September 2010

Live-weight gains were recorded for 459 intact male (bull) calves kept in 17 groups on three farms. The correlation coefficient between weight gained during the first 110 to 130 days of life and that gained during the subsequent period until slaughter was r = 0·53 (n = 459; P < 0·001). It is suggested that with bulls, nutritional and other factors which increase live-weight gain during the rearing period to about 4 mo of age may have a positive effect on subsequent performance to slaughter.
Performance of crossbred sheep from a synthetic Dam Line
Authors: Smith C. , King J. W. B. , Nicholson D. , Wolf B. T. , Bampton P. R.
Published: September 2010

The performance of traditional Border Leicester × Blackface cross- breds (Greyfaces) was compared with Blackface crosses from a synthetic Dam Line developed from four breeds; Finnish Landrace (47%), East Friesian (24%), Border Leicester (17%) and Dorset Horn (12%). The Dam Line crosses were lighter (−10%), showed earlier sexual maturity, were more prolific (+12%) and weaned more lambs (+13%) than the traditional crosses but had similar litter weights and flock survival. The lambs from the Dam Line crosses grew more slowly (−5%) (comparing twins with twins and singles with singles) but their carcass composition and carcass grades were similar to those from the traditional crosses.

An assessment of the relative biological efficiency for meat production of the two crossbred types indicated an advantage of about 10 to 12% in favour of the Dam Line crossbred type.
Lactation curves of Holstein-Friesian and Holstein-Friesian x Gir cows
Authors: Madalena F. E. , Martinez M. L. , Freitas A. F.
Published: September 2010

Linear y = a′ + b′x and gamma type y = ea−cx xb models for the lactation curve (y = daily production on day x of lactation) were adjusted to daily production records of 870 lactations. Within- lactations pooled R2 = 0·71 and R2 = 0·74 were respectively obtained for the linear and gamma type models, the latter being preferred for further analyses on account of its general validity under varied circumstances.

The parameters a, b, c of individual gamma type lactation curves were analysed by least squares within a subset of 634 lactations from Holstein-Friesian (HPB), 1/2 HPB: 1/2 Gir (F1) and 3/4 HPB: 1/4 Gir (B1) cows. Crossbreds had both higher initial production and higher persistency of lactation than purebred cows. F1's had higher initial production than B1's, both groups having similar persistency of lactation. Cows calving during the rainy season had higher initial production than cows calving in the dry season, which, however, had more persistent lactations. Parity affected only the initial production a parameter, which was lower for first calvers, while the other parity classes had similar a values.
The effect of altering the hormone status of ewes on the outflow rate of protein supplements from the rumen and so on protein degradability
Authors: Ngongoni N. T. , Robinson J. J. , Kay R. N. B. , Stephenson R. G. A. , Atkinson T. , Grant I. , Henderson G.
Published: September 2010

Four experiments were carried out on individually penned Finn Dorset and Suffolk × Finn Dorset ewes receiving complete diets of milled hay and concentrates and rationed at various levels below voluntary intake. In the first experiment, 20 non-pregnant non-lactating ewes were each given daily 1·6 kg food and injected intramuscularly with either isotonic saline (control), progesterone plus oestrogen (20 mg + 80 ng per 24 h) to mimic hormone status in pregnancy, bromocriptine (1 mg per 12 h) to suppress plasma prolactin, or thyrotrophin releasing factor (TRF) to elevate plasma concentrations of prolactin and the iodothyronines. Fractional outflow rates of chromium-mordanted fish meal from the rumen were estimated from the rate of excretion of chromium in faeces and were proportionately 0·25 higher for ewes given TRF than for controls (P < 0·025). None of the other treatments had a significant effect on outflow rate.

In experiment 2, fractional outflow rates from the rumen were determined during July (long daylength) and again during December (short daylength) in 12 ewes that had their seasonal pattern of plasma prolactin modified by removal of their anterior cervical sympathetic ganglia. Another 12 sham-operated ewes were used as controls. Neither the seasonal changes in prolactin nor their modification by cervical ganglionectomy significantly affected outflow rate.

Twelve non-pregnant non-lactating ewes were used in the third experiment to test the effects of mid-winter shearing (mean ambient temperature −4°C) on fractional outflow rates from the rumen and on the plasma concentrations of prolactin, thyroxine (T4) and cortisol. Shearing caused a drop in plasma prolactin, gave proportional increases (P < 0·05) of 0·47 and 0·16 in T4 and cortisol respectively and gave a 0·12 increase (P < 0·01) in the outflow rate of chromium-mordanted fish meal from the rumen. The increases in T4, and outflow rate were sustained for at least 2 weeks.

For experiment 4, 22 ewes each suckling two lambs were used in three trials to see if variation between ewes in milk production and in lamb growth rate was correlated with variation in outflow rate from the rumen. The only significant correlation (r = 0·68, P < 0·01) was between outflow rate and lamb growth rate for the eight ewes in trial 1. The results of all four experiments are discussed in relation to the mechanisms by which non-dietary factors, via their effect on the rate of outflow of digesta from the rumen, may alter the quantity of protein reaching the abomasum and the likely significance of this alteration on animal performance.
Reproduction in the gilt 7. Exposure of young gilts to the same mature boar and relocation: effects on the attainment of puberty
Authors: Eastham Philippa R. , Cole D. J. A.
Published: September 2010

Twenty-four Landrace × (Landrace × Large White) gilts were randomly allocated at a mean age of 70 days to each of two rearing treatments which were: (1) housing gilts with other gilts but in complete isolation from other pigs; or (2) housing gilts with fence-line contact with a mature boar. At 160 days of age all gilts were relocated, treatment 1 gilts being adjacent to a mature boar for the first time while treatment 2 gilts were adjacent to the same mature boar with which they had had contact during rearing. In addition, the gilts on each treatment were exposed to full contact with this boar for 30 min/day. There were no significant differences between the treatments in age (176 and 185 days) or weight at puberty (81·9 and 82·6 kg), in the interval from relocation and full boar contact to puberty (11 and 16 days) and in ovulation rate at the pubertal oestrus (11·6 and 11·5).

In a second experiment, 72 gilts were reared with fence-line contact with a mature boar and at 160 days of age, half were relocated adjacent to a novel mature boar and the other half remained in the rearing house next to a novel boar with all gilts receiving full boar contact for 30 min/day. Significantly more relocated gilts reached puberty during the experimental period (25/32) than gilts which were only exposed to contact with a novel boar and not relocated (12/31) (P < 0·001) and those relocated gilts were significantly younger (187 v. 225 days; P < 0·001) and lighter (75·4 v. 93·9 kg; P < 0·001) at puberty and the induction interval was significantly shorter (20 v. 89 days; P < 0·001) compared with gilts on the second treatment.
A note on the effect of adipocyte size onin vitrolipogenesis from acetate and lactate in subcutaneous adipose tissue of large- and small-frame beef steers at 6 months of age
Authors: Rule D. C. , Beitz D. C. , Hood R. L.
Published: September 2010

Beef producers no longer emphasize excessive fat deposition in market cattle. Recent research findings in human health suggest that our diets should contain less fat because of the cardiovascular diseases that seem associated with greater intakes of fat. Large-frame cattle slaughtered at the same chronological age as small-frame cattle have leaner carcasses and a correspondingly greater proportion of carcass protein (Arnold, Hentges and Trenkle, 1985). Determining early in life whether a type of cattle will become obese, therefore, would be of great benefit to cattle producers. Arnoldet al. (1985) reported that, at 6 months of age, large-frame steers were significantly leaner than small-frame steers.
Effects of a β-andrenergic agonist on growth performance, body composition and nutrient retention in finishing pigs fed normal or low amounts of protein
Authors: Bracher-Jakob A. , Blum J. W.
Published: September 2010

In earlier studies with pigs the P-adrenergic agonist Ro 16·8714 ((3-AG) enhanced the efficiency of nitrogen (N) retention. Therefore effects of Ro 16·8714 were studied on growth rate, body composition, N, fat and energy retention in pigs fed isoenergetically, but given different amounts of protein (112 or 138 g/kg diet) without (groups LP and NP) or with 60 mg Ro 16·8714 per kg diet (groups LPP and NPP) from 60 to 100 kg live weight. Weight gain (898, 927, 855 and 810 g/day in NP, NPp, LP and LPp) decreased, whereas food: gain ratio (2·94, 2·82, 3·04 and 3·24 kg/kg in NP, NPP, LP and LPP) was increased by low protein intake (P < 0·05) and both weight gain and food conversion were modified by the interaction (P × P) of protein intake and Ro 16·8714 (P < 0·05). Killing-out proportion (820, 830, 830 and 830 g/kg in groups NP, NPp, LP and LPP) was modified by protein intake and Ro 16·8714 (P < 0·05). Carcass growth rate (760, 814, 748 and 723 g/day in NP, NPP, LP and LPP) was modified by protein intake and by P × p (P < 0·05), while non-carcass growth rate (90, 77, 76 and 56 g/day in NP, NPP, LP and LPP) was changed by protein intake and by Ro 16·8714 (P < 0·05). Compared with NP, weights of kidneys (−0·025 kg), small intestine (−0·26 kg) and large intestine (−0·17 kg) were decreased by low protein feeding, and weights of heart, spleen and stomach decreased in response to Ro 16·8714 (-002, -0·02 and -0·06 kg; P < 0·05) while both low protein intake and Ro 16·8714 reduced liver weight (−0·12 and −0·23 kg, respectively; P < 0·05) and blood volume obtained at slaughter (-0·12 and -0·23 kg; P < 0·05). Carcass N (1813, 1970, 1786 and 1825 g in NP NPp, LP and LPP) increased in response to Ro 16-8714, but was reduced by low protein intake (P < 0·05), while noncarcass N (330, 309, 312 and 285 g in NP, NPp, LP and LPP) was decreased by both low protein intake and Ro 16-8714 (P < 0·01). Carcass and non-carcass fat (22·1, 19·9, 23·4 and 23·0 kg, respectively 1·51, 1·41, 1·59 and 1·68 kg in NP, NPp, LP and LPP) increased with low protein feeding (P < 0·05), but were not significantly influenced by Ro 16·8714. The efficiency of N retention (295, 363, 321 and 327 g/kg N retained: N intake in NP, NPp, LP and LPP) was enhanced by Ro 16·8714 (P > 0·05) whereas the efficiency of energy retention was not influenced by Ro 16·8714 and protein intake. In conclusion, an adequate intake of protein is necessary for optimum expression of many, but not all, effects of the P-adrenergic agonist Ro 16·8714.
Absorption and metabolism of [U-14C] acetic acid in growing pigs
Authors: Latymer Eva A. , Keal H. D. , Low A. G.
Published: September 2010

By tracing14C after an injection of [U-14C] sodium acetate into the caecum of pigs, it was found that proportionately 0·93 of the acetate injected was absorbed. About 0·25 of the administered acetate was recovered in the body 96 h later. It is assumed that the remainder was oxidized during this period and exhaled as carbon dioxide.

The14C initially predominated in plasma lipids, but it progressively shifted over the 96 h to plasma proteins. In the lipid fraction of blood plasma there was a continuous shift of14C from triglycerides and free cholesterol to cholesterol esters over the 96-h period of measurement.

In the body most of the14C was recovered in the fat, liver and intestinal wall. The highest concentration of14C was in the bile, especially in glycine-conjugated bile acids.

It was shown that the absorbed acetate was a source of energy to the pigs and it was recycled and metabolized into more complex components in the body during 96 h.