bluuebunny/crossref_metadata_2025 huggingface dataset:
Moderate indoor exercise: effect on production and carcass traits, muscle enzyme activities and meat quality in pigs
Authors: Enfalt A. C , Lundström K. , Hansson I. , Karlsson A. , Essén-Gustavsson B. , Håkansson J.
Published: September 2010

The effects of moderate indoor exercise (running/walking up to 735 m, 5 days/week) on performance, muscle enzyme activities, carcass traits and technological meat quality were studied in 20 crossbred slaughter pigs during the fattening period. Non-exercised pigs were kept only in their pens and consisted of littermates (no. = 20). Blood samples for lactate analysis and muscle samples from m. longissimus dorsi (LD) and m. biceps femoris (BF) for analyses of the activities of lactate dehydrogenase (LDH), citrate synthase (CS), 3-OH-acyl-CoA dehydrogenase and hexokinase were collected at exsanguination. The initial pH was measured approximately 1 min after exsanguination in LD and BF. The carcasses were partially cut and then the back and ham were dissected into individual muscles. Carcass length and presence of osteochondrosis were recorded. Technological meat quality parameters measured were: surface reflectance, water-holding capacity, intramuscular fat (IMF), crude protein, dry matter, ash content, shear force, ultimate pH, pigment content and extractability of muscle proteins.

In comparison with the non-exercised pigs, the exercised pigs had slightly shorter carcasses, paler meat and higher drip loss values in LD and, in BF, a lower proportion of IMF and dry matter and higher pigment content. The CS and LDH activities differed between LD and BF muscles, as also did many of the technological meat quality traits.
Cold housing and computer-controlled milk feeding for dairy calves: behaviour and performance
Authors: Bøe K. , Havrevoll Ø.
Published: September 2010

In each of two experiments, 36 3 to 5-day-old dairy calves (male and female), were allotted to one of three groups: warm housing, milk feeding in teat-buckets twice a day (group 1); warm housing and computer-controlled milk feeding (group 2); and cold housing and computer-controlled milk feeding (group 3). The experiments were conducted from September until February. The daily gain in the first 4 weeks was lower for the calves in group 3 in both experiments and for calves in group 2 in experiment 2 because of lower food intake in this period. This was compensated for by an increased gain later. In spite of the different method of milk feeding, the activity rhythm was nearly equal among groups, but at week 6 and 10 the calves in group 1 spent more time with the head over the feeding table than the calves in the two other groups. The number of unrewarded visits per calf to the milk feeding station decreased from over 30 at week 4 to around 20 shortly before weaning. The frequency of sucking/licking pen-mates was almost negligible in all groups. In order to reduce the heat loss, the frequency of calves lying with body contact clearly increased by decreasing ambient temperature in cold housing.
The effect of melatonin on seasonal reproduction of indigenous and crossbred dairy goats in Greece
Authors: Zygoyiannis D. , Davies P. H. , Doney J. M.
Published: September 2010

The effects of melatonin implants, administered during anoestrus, on the time of onset of oestrus, conception rate and litter size in indigenous (Capra prisca) and crossbred dairy goats were studied on commercial farms in a hill region of northern Greece. In the 1st year, 192 indigenous and 86 crossbred does on one farm (farm 1) were each separated into treated (T) and control (C) groups. The T groups from each breed type were given implants of melatonin on 17 April and 6 May, respectively. Bucks were re-introduced to both T and C groups 5 weeks after implantation. Mean mating dates for indigenous goats were 6 July (s.e. 0·15) (T) v. 13 July (s.e. 0·24) (C). Corresponding dates for crossbreds were 31 July (s.e. 0·61) (T) v. 14 August (s.e. 0·87) (C). Treatment did not significantly affect conception rate. Mean kidding dates (from first service) were 6 December (s.e. 0·18) (T) v. 14 December (s.e. 0·28) (C) for indigenous and 31 December (s.e. 0·64) (T) v. 13 January (s.e. 0·82) (C) for crossbred goats. Litter size was higher in both T groups but the difference was not significant. In the 2nd year the indigenous flock on farm 1 was supplemented by two similar neighbouring farms. Farm 1 had both treated does and control does; farm 2 were all treated and farm 3 were untreated control does. In this year all bucks used on treated does were also implanted. All implants were given on 21 April. Mean mating dates were 21 June (s.e. 0·23) (1/T) v. 9 July (s.e. 0·36) (1/C), and 28 June (s.e. 0·09) (2/T) v. 19 July (s.e. 0·15) (3/C). Conception rate was high in all groups. Corresponding mean kidding dates were 22 November (1/T) v. 11 December (1/C) and 29 November (2/T) v. 22 December (3/C). Litter size was higher (F > 0·05) in T than in C groups.
A note on the effect of use of bovine somatotropin on the fatty acid composition of the milk fat in dairy cows
Authors: Polidori P. , Maggi G. L. , Moretti V. M. , Valfrè F. , Navarotto P.
Published: September 2010

Commencing on day 100 ± 10 of lactation, 10 Italian Friesian cows averaging 32·6 kg milk per day were injected biweekly with recombinant bovine somatotropin (BST), while 10 other cows averaging 33-4 kg milk per day were injected with a placebo. Cows were offered ad libitum a total mixed diet throughout the lactation. The experiment lasted 16 weeks; milk samples were taken before and 16, 62 and 91 days after the commencement of BST injection. The objective was to determine the impact of biweekly injections of BST on the synthesis and proportion of milk fatty acids, particularly on cis and trans isomers and on fatty acids with an odd number of carbon atoms (C15 and C17). A decrease in the proportion of shortchain (C4 to C14) fatty acids (P < 0·001) and an increase in the proportion of long-chain (C16 to C20) fatty acids (P < 0·001) were observed in the first period of the treatment. With regard to cis and trans isomers, a considerable increase of the cis isomers (P < 0·001), particularly C18.1cis9 (oleic acid) was observed, while differences in trans isomers were not statistically significant. Concentrations of C15 (pentadecanoic acid) were not affected but heptadecanoic acid (C17) concentration showed a considerable increase (P < 0·01) but only in the sample taken after 16 days.
The effect of concentrate level on the intakes of silages or hays by ewes in the 1st month of lactation
Authors: Orr R. J. , Treacher T. T.
Published: September 2010

In three experiments, four grass silages and four grass hays were offeredad libitum to a total of 164 Finn Dorset ewes rearing twins in the 1st month of lactation. In addition, one of three constant daily levels (300, 650 or 1000 g fresh weight per ewe) of a barley-based concentrate was offered. In the first experiment, replacement rate of silage with in vitro organic matter digestibility (OMD) of 0·65 was less than for hay (OMD 0·59), at –0·09 v. –0·62 g forage OM per g concentrates OM. Consequently, lamb growth rate was greater and ewe weight loss was less with increased concentrate level for the silage than for the hay. In the second experiment, the replacement rates of three silages (OMD 0·56, 0·60 and 0·67) were not significantly different (mean –0·29) and, once again, increased concentrate level gave significantly better ewe and lamb performance. Finally, the replacement rates for three hays (OMD 0·51, 0·59 and 0·72) were also not significantly different (mean –0·30). Equations are presented to predict the intakes of hays and silages by ewes in early lactation.
Effect of genotype on the morphological characteristics, chemical composition and feeding value of nine barley straws, and responses to soya-bean meal supplementation
Authors: Herbert F. , Thomson E. F. , Capper B. S.
Published: September 2010

Three experiments were conducted to investigate the effect of genotype on the morphological characteristics, chemical composition and feeding value of nine chopped barley straws, and responses of the feeding value to a supplement of soya-bean meal (SBM). In experiment 1, the straws were offered ad libitum to 12 wethers and measurements were made of straw intake and dry (DMD) and organic (OMD) matter digestibility using a balanced lattice design with three periods. Experiment 2 used the same experimental design but the straws were offered ad libitum with 200 g SBM. Experiment 3 measured the dry matter losses (DML) of ground straws from nylon bags placed in the rumen of three wethers. The extent (b) and rate (c) of DML were estimated using the equation DML = a + b(l – ect).

There were significant differences in the stem height (P < 0·001), leaf proportion (P < 0·001), and protein (P < 0·001) and modified acid detergent fibre (P < 0·01) concentrations between the straws. Significant (P < 0·05) effects of genotype on intake were seen but the variation in intake between them decreased when the protein supplement was added. Effects of genotype on DMD (P < 0·05) and OMD (P < 0·05) were seen in unsupplemented straws and differences of OMD (P < 0·05) were still apparent when SBM was given with straw. Although there were significant (P < 0·05) differences in DML after 48 h incubation, the constants b and c were similar (P > 0·05) across the genotypes. Protein concentration in the straw, although closely correlated with intake, appears to have less value as a predictor of feeding value than previously thought.
Feeding behaviour of pigs in groups monitored by a computerized feeding system
Authors: Young R. J. , Lawrence A. B.
Published: September 2010

Electronic feeding systems for progeny testing pigs, allow selection to occur under conditions found on commercial farms. This paper reports on the feeding behaviour of six groups of 10 pigs, balanced for sex and initial body weight (mean starting and finishing weight: 32·1 kg v. 68·5 kg), monitored on such a system, for an average of 38 days. These data represent 26 542 feeder visits for which the pen, identity of the pig, feeder entry and exit times, and the amount of food consumed are known. The results show significant time-of-day effects for frequency of feeder visits, feeding rates, mean feeder occupation time, mean food intake per feeder visit, total food intake and total feeder duration (all P < 0·001). A single peak in feeding behaviour was observed between 13·00 and 16·00 h. Significant pen effects were observed on all feeding variables (e.g. feeder occupation times P < 0·05) with the exception of total food intake (P > 0·05). Individual pigs were found to possess different types of meal regulation, as measured by prandial correlations. Pens were found to have significantly non-random sequences of feeder entries (e.g. yen 1, P < 0·001). The range of feeder visits (three to 69) observed, was higher than reported in any previous study. Physical performance on the system, in terms of gain in body weight and total food intake was best predicted by total feeder occupation time, suggesting that individual pigs could adapt to the physical and social constraints imposed by the system, by altering aspects of their feeding behaviour. The results suggest that feeder access competition resulting from social synchrony and facilitation strongly influenced the feeding behaviour of pigs on this computerized food intake recording system.
Immunomodulatory approaches for regulation of growth and body composition
Authors: Flint D.J.
Published: September 2010

Hormonal growth promoters (growth hormone (GH), β-adrenergic agonists, steroids) which improve growth rate and/or lean: fat ratios in the carcass have received considerable adverse publicity and are either banned or have no licence for their use in countries of the European Community. This has led to the development of a number of techniques, involving the use of antibodies, aimed at regulating metabolic processes involved in determining growth and body composition.

A number of these approaches have focused upon the GH axis, for example immunoneutralization of somatostatin (which normally inhibits GH secretion) to improve growth, the use of antibodies to GH which can enhance its effects in vivo and the development of antibodies which mimic the actions of GH. Although immunization against somatostatin has led to increased growth rates in a number of studies other studies have failed to demonstrate such an effect. A precise understanding of the mechanism of action of this approach is required before we can begin to understand why success is not assured. Antibodies which enhance GH action clearly do work reproducibly but the major problem in developing this approach is to produce an inexpensive peptide immunogen (its sequence derived from GH) which can be used to actively immunize animals so that their own antibodies enhance endogenous GH activity. Anti-idiotypic mimics of GH have also been produced which have GH actions in vivo but again this approach is of limited value until appropriate vaccines can be developed.

A different approach to the problem of excess fat deposition involves the use of antibodies directed against the plasma membranes of adipocytes in order to elicit their destruction and thereby limit the storage capacity for fat. This technique has been demonstrated in rats, sheep and pigs in both passive and active immunization techniques. Once again, however, this promising approach is limited by the lack of a commercially suitable vaccine. The identification of individual membrane proteins which are antigenic has been achieved and this provides the prospect of producing recombinant DNA-derived vaccines.

Whether these new approaches will be perceived as acceptable to the general public remains a serious concern and a potential limitation to their development as many would-be sponsors cut back their support for research in these areas.
Genetic and phenotypic relationships between conformation and production traits in Ayrshire heifers
Authors: Mrode R. A. , Swanson G. J. T.
Published: September 2010

First lactation records for production traits (milk, fat and protein yields) and 17 linear type traits for 7169 Ayrshire heifers were analysed to estimate genetic parameters for type traits and to examine the relationship between type and production traits. A multivariate restricted maximum likelihood procedure fitting a sire model with sire relationships included was used for all analyses.

Heritabilities for production traits were approximately 0·3 and genetic correlations among them were high (>0·84). The estimates of heritabilities for type traits were mainly low to moderate ranging from 0·04 to 0·42. Angularity (0·80), beef shape (0·49), foot angle (0·53) and stature (0·46) had higher heritabilities. Generally phenotypic correlations among type traits were lower than the genetic correlations. The highest negative genetic correlation was between rear legs side and rear legs rear (-0·95) and the highest positive correlation between chest width and beef shape (0·93).

Genetic correlations between type and production were low to moderate and were similar for milk, fat and protein yields. The genetic correlations between the production traits and chest width, udder depth and beef shape were negative but were positive between production and angularity, rear udder width and teat placement side.
A comparison of alternative index procedures for multiple generation selection on non-linear profit
Authors: Groen A. F. , Meuwissen T. H. E. , Vollema A. R. , Brascamp E. W.
Published: September 2010

Alternative index procedures for selection on non-linear profit are quadratic indices, desired gains indices, group or mate selection indices, or direct optimization of responses over multiple generations. In this study a multiple generation time horizon was considered and several linear, quadratic and desired gains indices were compared. Genetic and economic responses over multiple generations were calculated considering a quadratic profit function combining protein yield and days open.

Directly optimizing reponse over multiple generations was found to yield slightly higher economic responses (+ < l.5%) than stepwise (each generation) adjustment of a linear index. A constant linear index using base population averages and a quadratic index were found to be less efficient. The quadratic index was less efficient than the linear index when considering multiple generations. Desired gains indices allowed stabilization of base population average for days open, however, forcing considerable economic losses. Relative efficiencies of methods depended on the degree of non-linearity of the profit function.
Female-female influences on the duration of the post-partum anoestrous period in beef cows
Authors: Wright I. A. , Rhind S. M. , Smith A. J. , Whyte T. K.
Published: September 2010

Two experiments were conducted to determine whether female to female influences could reduce the duration of the post-partum anoestrous period in beef cows. In experiment 1, cows were housed from calving, either in individual stalls, which precluded physical contact with other cows (treatment I; no. = 19) or as a group, with a cow in oestrus introduced to the group twice per week (treatment G; no. = 18). The percentage of cows cycling by day 50 post partum was similar for both treatments, but at 91 days post partum was significantly higher (P <0·05) in the G than in the I cows (89% v. 58%).

In experiment 2, cows were housed in individual stalls from calving and exposed twice per week to either cervical mucus collected from cows in oestrus (treatment M; no. = 21) or distilled water (treatment W; no. = 24). The percentage of cows cycling by 70 days post partum was similar in both treatments but by 130 days there were significantly more (P <0·05) M cows cycling (86% v. 58%). In neither experiment were LH profiles at 22,43 or 64 days influenced by treatment.

The results indicate that cervical mucus of cows in oestrus contains pheromone(s) which can reduce the postpartum anoestrous period in beef cows with extended anoestrous periods.
The influence of food intake and allyl trenbolone administration during lactation on plasma steroid concentrations and the reproductive performance of multiparous sows
Authors: Costa A. N. , Varley M. A.
Published: September 2010

An experiment was made to examine the effects of food intake and an orally active progestagen on plasma steroid concentrations and subsequent reproductive performance of multiparous sows. Thirty-five multiparous Landrace × Large White sows were assigned to one of four treatments immediately after parturition. Treatment H-AT sows were offered a high level of food intake throughout lactation: 3·5 kg of a diet containing 160 g/kg dry matter (DM) of crude protein and 13 MJ digestible energy per kg DM given twice daily. Treatment H+AT sows were offered the same food intake as H-AT sows and in addition they were given 20 mglday of allyl trenbolone (AT) mixed with the morning feed. Treatment L-AT sows were given 1·5 kg of the same diet offered twice daily during lactation and treatment L+AT sows were also offered this lower level of food intake and given AT. The respective levels of food intake were offered to sows from the 1st day of lactation onwards until weaning at 21 days post partum. Litter weights at weaning were influenced significantly by feeding level (P< 0·001) and also by AT administration (P<0·05). Sows on the high level of feeding had the heaviest litters and food-restricted sows had the lightest litters. AT treatment depressed litter weight at weaning. There was no effect of food level or AT on the plasma concentrations of progesterone or oestrogens during lactation. There was a highly significant (P<0·001) difference in mean plasma oestrogen concentration between high (H-AT and H+AT) and low (L-AT and L+AT) fed groups during early pregnancy in the subsequent cycle. Sows given a combination of high energy in lactation and AT (H+AT) exhibited shorter intervals from weaning to oestrus than both groups of food-restricted (L-AT and L+AT) sows fP<0·01) but treatment had no significant effect on either the farrowing rate or on the subsequent litter size. It is concluded that despite significant changes in the live weight and condition of sows and changes in steroid hormone concentrations due to food intake and the administration of allyl trenbolone, there were no significant effects on reproductive performance.
Selection for components of efficient lean growth rate in pigs 4. Genetic and phenotypic parameter estimates and correlated responses in performance test traits with ad-libitum feeding
Authors: Cameron N. D. , Curran M. K.
Published: September 2010

Genetic and phenotypic parameters and correlated responses in performance test traits were estimated for populations of Large White (LW) and British Landrace (LR) pigs tested in Edinburgh and Wye respectively, to four generations of divergent selection for lean growth rate (LGA), lean food conversion (LFC) and daily food intake (DFI) with ad-libitum feeding.

There were differences between the two populations in genetic parameters, as LW heritabilities for growth rate, daily food intake and backfat depths were higher and the correlation between growth rate and backfat was positive for LW, but negative for LR. However, heritabilities, genetic and phenotypic correlations were generally comparable between selection groups, within each population. Genetic and phenotypic correlations indicated that animals with high daily food intakes were faster growing, had positive residual food intakes (RFI), were fatter with higher food conversion ratios. RFI was highly correlated with daily food intake and food conversion ratio, but phenotypically independent of growth rate and backfat, as expected.

Selection for LGA, in LW and LR populations, increased growth rate (54 and 101 g/day), but reduced backfat (−3·9 and −2·0 mm), food conversion ratio (−0·23 and −0·25) and total food intake (−11·8 and −12·6 kg). There was no change in daily food intake in LW pigs (−19 g/day), but daily food intake increased in the LR pigs (69 g/day). With selection for LFC in LW and LR populations, there was no response in groivth rate (9 and 9 g/day), but backfat (−4·1 and −2·1 mm), total (−6·6 and −11·8 kg) and daily food intake (−90 and −172 g) were reduced, as animals had lower food conversion ratios (−0·13 and −0·22). LW and LR pigs selected for DFI ate more food in total (6·8 and 5·9 kg) and on a daily basis (314 and 230 g), grew faster (94 and 51 g/day) and had higher food conversion ratios (0·12 and 0·13). Backfat was increased in LW pigs (3·7 mm), but not in the LR population.

In general, efficiency of lean growth was improved by increasing groivth rate, with little change in daily food intake from selection for LGA, but was primarily due to reduced daily food intake with selection on LFC.
Milk production from grass silage diets: effects of the composition of supplementary concentrates
Authors: Aston K. , Thomas C. , Daley S. R. , Sutton J. D.
Published: September 2010

Thirty-six British Holstein-Friesian cows were offered 9 kg dry matter (DM) daily of one of 12 concentrates together with grass silage ad libitum in a cyclical change-over design experiment during lactation weeks 8 to 22. The carbohydrate source in the concentrates was either mainly starch, mainly digestible fibre or a 1:1 mixture. Each concentrate type was formulated to provide 120, 160, 200 or 240 g crude protein (CP) per kg DM and similar metabolizable energy concentration. Silage contained 142 g CP per kg DM, in vivo digestible organic matter was 0·690 kg/kg DM, pH 4·4 and ammonia-N 172·2 g/kg total nitrogen.

Silage intake increased as fibre replaced starch in the concentrate. Apparent digestibility of organic matter and energy were highest for starch-based concentrates, but there was no effect of carbohydrate source on yields of milk and milk solids. Milk protein concentration was depressed by feeding mixed or fibrous carbohydrates.

Silage intake increased on average by 0·13 kg DM per additional 10 g/kg CP in the concentrate. The digestibility of the diet was not affected by increasing CP except for nitrogen. Milk yield increased by 0·028 kg per additional g/kg CP in the concentrate and there were linear effects ofCP on yields of milk solids.

As CP increased, milk fat concentration tended to rise with starch but was depressed both overall and by offering mixed or fibrous carbohydrates. In contrast milk protein concentration increased with mixed and fibrous carbohydrates but not with starch.

It is concluded that when silage is given ad libitum with 9 kg/day concentrates, CP level has more effect than source of carbohydrate on milk production.
Body-weight loss, blood and rumen fluid characteristics and nitrogen retention in lambs in negative energy balance offered diets with differing glucogenic potential
Authors: Moloney A. P. , Moore W.
Published: September 2010

The effects of altering the glucogenic potential of the diet of wether lambs (initial body weight 56·4 kg) offered an energy allowance of 0·25 that required for maintenance on body-weight loss, nitrogen retention and blood and rumen fluid parameters were examined. Whole barley was offered alone or substituted on an isoenergetic basis with 40 or 120 g of a blend of glucose precursors (polyhydric alcohols, propylene glycol, sodium propionate) absorbed on to palm kernel meal (acetona meal), to 36 lambs (no. = 12 per treatment) for 8 weeks. Substituting barley with 40 g acetona meal had a small but non-significant effect in decreasing body-weight loss and plasma aspartate amino transferase activity and in increasing plasma insulin concentration. Increasing the glucogenic potential of the diet by substituting barley with 120 g acetona meal decreased body-weight loss in the early phase of the study, decreased plasma concentrations of non-esterified fatty acids and increased the proportion of propionate in volatile fatty acids in rumen fluid, plasma aspartate amino transferase and gamma-glutamyl transferase activities and plasma insulin concentrations. Increasing the glucogenic potential of the diet did not affect nitrogen retention or plasma glucose concentration. It is concluded that increasing the glucogenic potential of the diet of lambs resulted in an increase in metabolic efficiency at the onset of negative energy balance which was mediated through a change in plasma insulin concentration. The absence of a significant difference in body-weight loss between the diets in the latter part of the study reflects the lack of sustained ketosis.
A note on the estimation of economic values for selection indices: a response
Authors: Melton B. E. , Willham R. L. , Heady E. O.
Published: September 2010

Various procedures for estimating the economic values required to weight characteristics in multitrait selection have been proposed. Some, despite their theoretically sound foundations, are frequently misinterpreted. One such method involves the derivation of economic values based upon accepted economic theories of the firm, profit maximization, and the concepts of marginal economic behaviour. An amplified and more rigorous presentation of this method and its theoretical basis is presented that confirms the basic propriety of the method, clarifies the misinterpretations surrounding its application, and offers additional insights into the potential fallacy of less economically rigorous alternatives.
An analysis of the variation in the lean tissue distribution of sheep
Authors: Wolf B. T.
Published: September 2010

The distribution of lean tissue between eight standard joints was examined in 956 crossbred lambs slaughtered at constant live weights of either 35 or 40 kg. The sire breeds used were the Dorset Down, Ile-de-France, Oldenburg, Oxford, Suffolk and Texel. Sire breed did not have a significant effect on the proportion of total carcass lean found in the higher-priced joints but did show significant differences in the proportion of total carcass lean found in individual joints, with a maximum difference of 7·7 g total lean per kg joint being recorded. Similarly, small but significant effects due to ewe age (1 to 3 years), rearing type (single, twin, triplet), sex (male castrate, female) and weight of total lean were reported for the proportion of total carcass lean found in different joints.

Heritability estimates ranged from 0·07 (s.e. 008) to 0·65 (s.e. 0·16) for the proportion of total lean in the best-end neck and higher-priced joints respectively. Phenotypic standard deviations of 5·8g/kg and 17·9g/kg were reported for the proportion of total lean found in the best-end neck and the higher-priced joints respectively. The genetic correlations between the proportion of total lean in each of the higher-priced joints and the proportion of total lean in the higher-priced joints combined were positive. A genetic correlation of 017 (s.e. 0·20) was found for the relationship between average daily gain from birth to slaughter and the proportion of total lean in the higher-priced joints.
The influence of breeding management efficiency on dairy herd performance
Authors: Bailie J. H.
Published: September 2010

Computer simulation was used to measure the effects of breeding management efficiency in block calving dairy herds and in those with a long mating season of 9 months. In particular, the effects of varying levels of oestrus detection and conception rates were assessed, and the product of these two parameters defined as the fertility factor. As the fertility factor increases from 20 to 50, where the mating season extends to 9 months, the mean calving index for the herd decreased linearly from 393·5 to 373·6 days and the culling rate for failure to conceive declines in curvilinear fashion from 0·196 to 0·006. Concurrent with the decrease in calving index, mean annual milk yield and margin over purchased food increase, with the herd commencing calving in January showing a more marked response than the herd commencing calving in October. When overall replacement rate is also taken into account, the margin over purchased food net of herd depreciation per cow, at 1979/80 prices, changes from £270·7 to £315·2 in the January herd compared with £275·9 to £315·8 in the October herd. For each day change in calving index associated with alteration in fertility factor, there is a change of £2·24 for the January herd and £2·01 for the October herd in margin over purchased food net of herd depreciation.

In the block calving herd, increases in fertility factor are reflected mainly in changes in culling rate for failure to conceive from 0·292 to 0·033, and not in margin over purchased food.
A note on the estimationin vivoof body fat in cows using deuterium oxide or adipose-cell size
Authors: Robelin J.
Published: September 2010

Two methods of estimating body fatin vivoin cattle, namely measurement of body water by dilution of deuterium oxide and subcutaneous adipose-cell size, were studied in mature cows and compared with a classical method based on dissection of a sample joint.

Total body fat, measured after complete dissection of 12 dry cows, varied between 64 and 185g/kg body weight. Rib fat and adipose-cell diameter were related positively, while body water was related negatively to total body fat. The equations for prediction of total body fat were sufficiently accurate (s.d. = 10·1 to 11·5 g total body fat per kg body weight) to warrant further examination, and adipose-cell diameter was as accurate as body water.
The influence of nutrition in early life on growth and development of the pig 2. Effects of rearing method and feeding level on growth and development to 75 kg
Authors: Campbell R. G. , Dunkin A. C.
Published: September 2010

1. Fifty-seven piglets were used to study the effects of rearing pigs on the sow or artificially on a low or high level of feeding between 1·8 and 6·5 kg live weight and either a low or high level of feeding between 6·5 and 20 kg live weight on growth and development to 75 kg live weight.

2. The artificially reared pigs fed at the higher level grew more rapidly (P < 0·05) and were fatter (P < 0·05) at 6·5 kg live weight than their more restrictedly fed counterparts. The pigs reared on the sow grew at the same rate as the artificially reared pigs fed at the low level but at 6·5 kg live weight were as fat as the artificially reared pigs fed at the higher level.

3. Between 6·5 and 20 kg live weight the artificially reared pigs previously fed at the lower level grew more rapidly (P < 0·05) than their more liberally fed counterparts which in turn, grew at a faster rate (P < 0·05) than pigs previously reared on the sow. However, nutrition prior to 6·5 kg live weight had no influence on performance or body composition subsequent to 20 kg live weight.

4. Raising the level of feeding between 6·5 and 20 kg live weight increased growth rate (P < 0·05) and body fat content at the latter weight (P < 0·05). However, subsequent to 20 kg live weight, the pigs previously fed at the lower level exhibited more rapid and efficient growth (P < 0·05) and at 75 kg live weight were leaner (P < 0·05) than those fed more generously between 6·5 and 20 kg.

5. At 6·5 kg live weight the pigs reared on the sow contained less deoxyribonucleic acid (P < 0·05) in the m. adductor than pigs from either of the two artificially reared groups. Muscle deoxyribonucleic acid at 20 and 75 kg live weight was unaffected by nutrition before 6·5 kg live weight or level of feeding between 6·5 and 20 kg live weight.
The influence of nutrition in early life on growth and development of the pig 3. Effects of energy intake prior and subsequent to 10 kg on growth and development to 30 kg live weight
Authors: Campbell R. G. , Dunkin A. C.
Published: September 2010

1. Forty-two piglets were used to study the effects of a low, medium or high level of energy intake (1·0, 1·4 and 1·9 MJ gross energy per kg W0·75per day respectively) from 1·8 to 10 kg live weight and a low or high level of energy intake (1·4 and 1·8 MJ digestible energy per kg W075 per day respectively) subsequent to 10 kg live weight on growth performance, body composition and the cellularity of muscle and subcutaneous adipose tissue to 30 kg live weight. During both live-weight periods all pigs received the same daily intake of crude protein.

2. Raising energy intake in the period prior to 10 kg live weight increased (P< 0·-05) growth rate, body fat content and fat cell size but reduced food conversion efficiency, body protein and water (P< 0·05) and muscle deoxyribonucleic acid. These effects on body composition and muscle deoxyribonucleic acid at 10 kg live weight were still evident at 30 kg live weight.

3. Subsequent to 10 kg live weight, pigs previously given the lowest energy intake deposited protein and fat at a faster rate and exhibited more rapid and efficient growth (P< 0·05) than pigs previously given the high energy intake.

4. At 30 kg live weight pigs given the two higher levels of energy intake before 10 kg live weight contained less deoxyribonucleic acid (P< 0·05) in subcutaneous adipose tissue and had larger (P< 0·05) fat cells than those given the lowest energy intake before 10 kg live weight.

5. The effects of energy intake subsequent to 10 kg live weight on growth performance, body composition and the cellularity of muscle and adipose tissue were qualitatively the same as those for the period 1·8 to 10 kg live weight.
The development of solid food intake in calves 3. The relation between solid food intake and the development of the alimentary tract
Authors: Hodgson J.
Published: September 2010

1. Jersey calves were fed on milk substitute at the rate of 10% of live weight per day for 5 weeks and were offered either chopped dried grass or ground, pelleted dried grass to appetite. Calves were slaughtered at birth and after 5, 6, 7, 9 and 12 weeks on experiment, and the weights of the component parts of the alimentary tract and their contents were measured.

2. There were close correlations between the weights of the sections of the alimentary tract or their contents and the solid food intake at slaughter, total solid food intake, or empty body weight of the calves. There were no consistent changes with age in the DM concentration or the density of the digesta in any section of the alimentary tract except the abomasum, or in the digestibility or mean retention time of the diets.

3. Grinding and pelleting the diet increased the DM concentration but did not affect the density of the digesta. The increase in the weight of rumen contents per unit increase in dry-matter intake was much greater for chopped than for pelleted diets. The reverse was true for the contents of the abomasum and small intestine. There were relatively small variations between diets in the predicted weight of rumen contents, total digesta, or the volume of organs in the abdomen, at the within-diet mean levels of dry-matter intake.
Effects of nutrition in pregnancy and in lactation on milk yield in ewes
Authors: Treacher T. T.
Published: September 2010

1. Dorset Horn ewes were fed individually to make high (H) and low (L) gains in weight in the last 6 weeks of pregnancy. The gains were 20% (H) and 10% (L) of the live weight in week 14 of pregnancy for ewes with twin foetuses, and 16% (H) and 6% (L) for ewes with a single foetus. Three levels of intake imposed during lactation were denned as low (L) 15·0, medium (M) 22·5, and high (H) 30·0 g of feed dry matter/kg of ewe live weight in week 14 of pregnancy. The lambs were removed 12 to 16 hours after parturition and the ewes were machine-milked twice daily for the first 6 weeks of lactation.

2. Ewes making low gains in pregnancy produced lambs with slightly lower birth weights but the difference was not significant for either twins or singles. Pregnancy treatment had no effect on milk yield or live-weight change in lactation, but fat content was increased in milk from ewes on the H treatment in pregnancy (8·06% v. 7·46%).

3. Level of feeding during lactation did not significantly affect milk yields. The total yields in the first 6 weeks of lactation were (L) 49·4 kg, (M) 60·8 kg and (H) 62·7 kg. However, there were significant effects on milk composition. The treatment means for fat content were (L) 8·34%, (M) 8·05% and (H) 6·84% and for solids-not-fat content were (L) 10·04%, (M) 10·37% and (H) 10·82%.

4. Live-weight losses in lactation were (L) 9·1 kg, (M) 6·3 kg and (H) 3·2 kg.
Cycles of wool follicle activity in some shetland sheep
Authors: Ryder M. L.
Published: September 2010

The wool growth cycle in three rams and three ewes was studied by taking monthly wool and skin samples for periods up to 3 years. The percentage of inactive follicles and of medullated fibres was recorded, fleece length was measured and change in fibre diameter and pigmentation between summer and winter was investigated.

Casting of the fleece appeared to depend more on the thinning of fibres than on the proportion with brush ends, casting in some instances taking place with only 30% brush ends, while not in others with as much as 70% follicle inactivity.

Follicles began to become inactive in both sexes in September following the autumnal equinox. The secondary follicles had a greater proportion of inactivity (mean of 45% compared with 20% in the primaries) but tended to regrow earlier, and regrowth in the rams tended to begin before that in the ewes. Regrowth as a whole began from January to March. Subsidiary cycles of inactivity of about 2 months' duration were evident.

Maximum growth in length occurred between April and October. A difference in mean diameter of only a few microns could be detected between summer and winter. Maximum medullation occurred in July in the rams and August in the ewes. Decrease in pigmentation in winter was brought about by a lowering of the density of pigment granules within the fibres.
The effect of food restriction on subsequent voluntary intake of pigs
Authors: Owen J. B. , Ridgman W. J. , Wyllie D.
Published: September 2010

A total of 64 nine-week-old pigs were used in two experiments to study the influence on feed intake, growth and carcass quality of dietary restriction at various ages or live weights. Two diets of different energy content were given throughout each experiment, which was divided into four periods on either an age or weight basis. Feed was restricted or offered ad libitum during each of the first three periods, all pigs being fed ad libitum during the last period.

Compensatory intake following a period of feed restriction occurred at most stages of growth but was most marked in the early stages. Compensation when it occurred took several weeks to develop fully and persisted for some time, often after an intervening period of ad libitum feeding. Increased gains resulted from increased intake although some of the early compensatory gains could not be fully explained by increased intake.

There were few appreciable differences between the pigs on the highand those on the low-energy diets. However, in the early stages the latter did not show the same response in intake following restriction as did the former (but in experiment I the latter were considerably lighter).

No effects on carcass quality were demonstrated under the conditions of these experiments.
The effect on litter size of increased feed intake during the oestrus period in the sow
Authors: Brooks P. H. , Cole D. J. A.
Published: September 2010

A field trial was conducted at 13 centres to investigate the effect of increasing feed intake on the day of mating on litter size of sows. From weaning to mating, control animals received 1·8, 2·3 or 2·7 kg food/day depending on the managemental procedure of the centre. Flushed animals were fed in the same way except on the day of mating when their feed allocation was doubled. Flushing did not significantly affect litter size when the overall results of all centres were considered (447 sows). Results for individual centres were also examined. A significant response to ‘flushing’ was obtained at only one of the 13 centres, where increasing feed intake from 2·7 to 5·4 kg on the day of mating significantly (P < 0·05) increased litter size by 1·3 ±0·52 pigs born.
A note on the effect of castration upon the development of the skin in the pig
Authors: Vold E. , Moen R. A.
Published: September 2010

The macroscopically measured thickness of the skin of bacon-weight pigs has been found to differ between entire boars and castrates. The histological analysis showed that this difference can be attributed to a significantly stronger development of the dermis in the boars compared with the castrates.
A note on the growth and carcass characteristics of castrated male pigs fed on a ration containing diethylstilboestrol and methyltestosterone
Authors: Walker N.
Published: September 2010

A control diet was compared with a diet containing 2 mg diethylstil-boestrol (DES) plus 2 mg methyltestosterone (MT) per kg air-dry feed, the hormone treatment extending either from 20 to 84 kg live weight or from 50 to 84 kg live weight. The experiment contained 20 blocks, each of 3 littermate castrated male pigs individually penned and fed to a restricted scale. Hormone supplementation had no effect on growth performance and significantly affected car-cass characteristics only when given for the longer period. Killing-out percentage, backfat thickness and percentage subcutaneous fat plus skin in the gammon joint were reduced and carcass length, percentage bone and percentage lean in the gammon joint were increased when the supplement was given over the longer period.
Effect of deliberate dietary mismanagement upon the incidence of diarrhoea in homebred calves
Authors: Burt A. W. A. , Irvine Sheila M.
Published: September 2010

The effects of dietary treatments designed to increase the incidence of diarrhoea were studied in two experiments with Ayrshire calves. In the first experiment, as a control a normal milk replacer was fed to calves at a rate of 170 g powder in 1·71 litre of water given twice daily. When the amount of powder was increased to 425 g in 1·71 litre of water, faeces consistency and intake of dry concentrates, decreased. When the amount of water was increased to 2·85 litre with 170 g of milk replacer each feed, the consistency of the faeces decreased. Inclusion of 2 % sodium citrate or 50% whey powder in the milk replacer tended to reduce live-weight gain in the period 0 to 32 days but did not increase the incidence of diarrhoea.

In the second experiment, the normal milk replacer and the replacer containing 50% whey powder were both given at 425 g powder in 1·71 litre water each feed without adverse effects upon performance. Clinical diarrhoea was virtually absent in both experiments and it was concluded that the homebred calf reared carefully in a good environment and given antibiotics prophylactically for 3 days is relatively resistant to substantial changes in the composition and methods of feeding of milk replacers.
Ground and pelleted straw and hay for fattening Israeli-Friesian male calves
Authors: Levy D. , Amir S. , Holzer Z. , Neumark H.
Published: September 2010

The performance of Israeli-Friesian male calves on six rations, including two levels (15% and 30%) of ground wheat straw and oatvetch hay in pelleted mixtures, and the same two levels of ground straw in non-pelleted mixtures, was examined.

Daily live-weight and carcass gain were higher on the lower level of both roughages. The differences in performance on hay and straw were insignificant. Feed intake was higher on the 15% level of both roughages when pelleted but the energy conversion ratio was higher on pelleted rations of both levels of straw.

The dressing percentage was higher for animals on pelleted rations. There was no significant difference in percentage fat trim, percentage bone or percentage saleable meat in the carcasses. There was 20% more kidney, pelvic and cod fat on the lower level of roughage.

The digestibility of organic matter was higher on rations with the lower level of roughage, and on the pelleted rations compared with the non-pelleted at equal level of roughage. This was not the case for the digestibility of crude fibre. Nitrogen retention was significantly higher on the lower levels of straw and on the pelleted rations of a similar level, and was higher on hay rations than on straw rations. Ration differences in the molar proportions of volatile fatty acids in the rumen liquor were detected.

Pelleting appeared to improve the nutritive value of straw.
The influence of supplements of energy and protein on the intake and performance of cattle fed on cereal straws
Authors: Andrews R. P. , Escuder-Volonte J. , Curran M. K. , Holmes W.
Published: September 2010

In two experiments the effects of several levels of supplementary energy and of protein on the voluntary intake of long straw by young cattle of 200 to 300 kg weight were studied.

In Experiment 1, 40 cattle were used to compare 4 protein levels and 5 energy levels. At the lowest protein level (diets containing 6·6% crude protein or less) intake of straw was low at all energy levels and the live-weight gain of the cattle was not increased by the energy supplements. There was no difference in performance between the other 3 protein levels, which gave whole diets containing 8·8% crude protein or more in the dry matter. Supplements of 5 to 9 g concentrates per kg live weight reduced straw intake only a little, and increased gains.

In Experiment 2, 40 cattle were used to compare barley and oat straw alone and with 2 levels of protein and 2 levels of energy supplement; one of the latter was higher, 12 g concentrate per kg live weight, than any in Experiment 1. The digestibility of the diets was determined. The results showed no difference in animal performance between oat and barley straw and agreed in general with Experiment 1. The low-protein, high-energy combination (6·4% crude protein in the whole diet) was frequently refused and gains on this treatment were low; at the higher protein level, when protein supply was adequate, straw intakes were less than on the lower energy level with adequate protein. Long straw could supply 35 to 45% of the daily energy requirements of young growing cattle.