bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of young steers offered stack-treated ammoniated hay or untreated hay with or without a supplement
Authors: Gibb M. J. , Baker R. D.
Published: September 2010

An experiment was designed to establish the growth response of young housed steers to the feeding of stack-ammoniated low-quality hay, and to a range of different supplements for 16 weeks, and any carry-over effects during the following 24 weeks at pasture. Ammoniated hay was offered alone (TA), or with daily supplements of either 0·75 kg barley (TLB), 1·50 kg barley (THB), 0·1125 kg fish meal (TF), 0·75 kg or 1·50 kg of a barley-based concentrate (TLC and THC, respectively). Untreated hay was offered with either urea (UU) or with a daily supplement of 0·75 or 1·50 kg concentrates (ULC and UHC respectively).

Ammoniation increased the total nitrogen concentration of the hay from 13·4 to 24·2 g/kg dry matter, and resulted in a small increase in the organic matter digestibility measured in vivo (0·597 to 0·653), compared with that measured in vitro (0·572 to 0·667). Digestibilities of the fibre fractions, measured in vivo, were also increased by ammoniation (0·626 to 0·734, 0·637 to 0·761, 0·678 to 0·771 for acid-detergent fibre, neutral-detergent fibre and cellulose, respectively). Intakes of hay were reduced by supplementation, with the exception of TF, although total intakes were increased. During the housed period, live-weight gains of steers given ammoniated hay were 0·58, 0·71, 0·81, 0·69, 0·80, 0·86 kg/day for treatments TA, TLB, THB, TF, TLC, THC, respectively. The live-weight gains of steers offered the untreated hay were 0·49, 0·66, 0·87 kg/day for treatments UU, ULC, UHC, respectively. There was no carry-over effect of treatments on live-weight gains over the grazing season (mean 0·66 kg/day). It is concluded that when high levels of supplementation are available, no benefit is to be gained by ammonia treatment of ihe hay. However, without supplementation stack ammoniation of hay produces a marked improvememt in performance, compared with the addition of urea at feeding.
Responsiveness of ewe genotypes to varying nutritional management, and conventional genotype × environment interactions in sheep
Authors: Hohenboken W. D. , Clarke J. N. , Rattray P. V. , Smith J. F. , Wheeler M.
Published: September 2010

An experiment was conducted during 2 years to evaluate industry Coopworth, industry Romney and Waihora Romney ewes (a strain selected for 10 years for increased ewe productivity) in a variety of nutritional and management treatment combinations. Waihora Romneys were most productive with small and inconsistent differences between industry Romneys and Coopworths. Conventional cross-classified analyses of variance did not reveal large, consistent nor economically important ewe genotype × nutritional treatment or year interactions. Additional analyses were designed to investigate whether the ewe genotypes responded to changes in the nutritional and(or) management environment with similar quantitative changes in production. A sensitive genotype would be one that responded to environmental changes with relatively large changes in productivity; a stable genotype would be one whose changes in production in response to a variable environment were smaller. By several statistical procedures designed to assess relative ‘sensitivity’ v. ‘stability’, Waihora Romney ewes appeared to be the most stable, with industry Romney and Coopworth ewes similar in their sensitivity.
Food intake, growth and body composition in Australian Merino sheep selected for high and low weaning weight 6. Muscle-weight distribution
Authors: Perry Diana , Thompson J. M. , Butterfield R. M.
Published: September 2010

The change in muscle-weight distribution from birth to maturity was examined in rams and ewes from strains of Australian Merino sheep which had been selected for high or low weaning weight, and from a randomly bred control flock. The proportional distribution of total muscle weight among nine anatomically standardized muscle groups was determined for 34 mature animals. The growth of each group was then assessed relative to the growth of the total musculature, using data from 106 immature animals. Maturity coefficients were calculated separately for pre- and post-weaning growth. Several muscle groups exhibited a diphasic growth pattern.

Selection for high and low weaning weight resulted in an increase and decrease respectively in total muscle weight in mature animals, but had no effect on mature muscle-weight distribution. There were no significant strain effects on maturing patterns of muscle groups, except during the pre-weaning growth of muscles around the spinal column and those connecting the thorax to the forelimb. When compared at the same stage of maturity there was little difference between the strains in muscle-weight distribution. However, at the same weight the larger mature-size strain had a more immature pattern of muscle-weight distribution.

The total muscle weight of mature rams was greater than that of mature ewes. Sex also had an effect on muscle-weight distribution at maturity for seven of the nine muscle groups. At maturity rams had a higher proportion of their muscle weight in those muscle groups associated with the neck and thorax, and a lower proportion in those associated with the limbs. Sex affected the pre-weaning maturing pattern of the muscles of the spinal column, and the post-weaning maturing pattern of all muscle groups, with the exception of those muscles associated with the distal hindlimb, the spinal column, and those attaching the thorax to the forelimb.
Feeding British rapeseed meals to pregnant and lactating ewes
Authors: Vincent Isobel C. , Williams H. Ll. , Hill R.
Published: September 2010

Three types of high glucosinolate British rapeseed meal (RSM) — extracted, expeller and extruded — were incorporated in ewe diets at 200 g/kg; soya-bean meal (SBM) at 165 g/kg replaced RSM in a control diet. Eighty housed Suffolk-Mule ewes were divided into four equal groups and given one of four diets, A (control SBM), B (extracted RSM), C (expeller RSM) or D (extruded RSM) for one reproductive cycle. Diets A and B were compared for a second season. The ewes were given a maximum of 2·5 kg diet per day during lactation. Barley straw was available ad libitum. The ewes were mated in November and December. Lambs were weaned at 42 days of age; they were given creep food similar in composition to their dams' lactation diets.

There were no dietary effects on ewes in overall health, live weight, oestrous activity, conception, number of lambs born alive or lamb birth weights. A mean of 1·6 lambs were weaned per ewe mated and 58% of these were twins, in year 1. In year 2, 1·8 lambs were reared and 79% were twins. The mean milk yield over the first 4 weeks of lactation was 3·2 1 and there were no significant dietary effects. Fat concentration in milk was very variable, but in general was slightly depressed by the RSM diets, significantly so at three sampling dates. Protein concentration was consistently lower in milk from RSM than SBM groups, significantly lower at four of the weekly samplings. Thiocyanate levels in plasma and milk were related to glucosinolate intake, but were not associated with any detrimental effects. At all sampling dates, values for RSM groups were significantly greater than for SBM ewes. Plasma thyroxine values were similar regardless of diet
Amino acid requirements of the growing meat rabbit 2. Comparative growth performance on practical diets of equal lysine concentration but decreasing levels of other amino acids
Authors: Schultze W. H. , Smith W. C. , Moughan P. J.
Published: September 2010

Over a 40-day period nine rabbits were each given one of nine isocaloric diets with progressively reduced amounts of crude protein (159 to 97 g/kg) but a fixed level of lysine; the latter was slightly below the higher of the National Research Council (NRC, 1977) and Societe de Chime Organique et Biologique (AEC, 1978) recommendations. The proportion of each other essential amino acid in the diet of highest crude protein concentration was close to a balance derived from the higher of each independently determined amino acid requirement given by NRC (1977) and AEC (1978), while the proportions in the two diets of lowest crude protein level were below those in a theoretical amino acid balance based on rabbit whole-body tissue composition. When an intersecting linear regression line model was fitted to growth performance data over the period, performance was found to be similar on the first six diets (159 to 123 g crude protein per kg) but further reductions in dietary protein were accompanied by a decline in growth rate and concomitant increase in food conversion ratio. Fitting of an asymptotic model to the data showed that growth performance first declined markedly between diets four and five (130 to 120 g crude protein per kg). These findings suggest that if a balance of essential amino acids relative to lysine, based on current amino acid recommendations, is adhered to in diet formulation for the growing rabbit, several of these amino acids will be in excess of requirement
Evaluation of beef breeds for rangeland weaner production in Zimbabwe 2. Productivity of crossbred cows and heterosis estimates
Authors: Tawonezvi H. P. R. , Ward H. K. , Trail J. C. M. , Light D.
Published: September 2010

Crossbred cows were evaluated for reproductive performance and live weight, and for pre-weaning growth and viability of progeny sired by seven unrelated breeds. They were also evaluated on overall productivity expressed as weight of weaned calf per cow mated per year, per 100 kg of cow per year and per 100 kg metabolic weight of cow per year. The cows comprised reciprocals of Africander with Mashona, Nkone, Brahman and Sussex, one-way crosses sired by Sussex out of Mashona, Nkone and Brahman dams, and by Charolais out of Africander, Mashona, Nkone, Brahman and Sussex dams. These represented sanga × sanga, sanga × zebu, Bos taurus × sanga, Bos taurus × zebu and Bos taurus × Bos taurus crossbred types. Bos taurus × zebu crosses were superior to other breed types for all the three productivity indices and for virtually all the individual components of these. There was little difference between the other four breed types in overall productivity of components of these. Differences between reciprocals were observed in sanga × sanga and sanga × zebu, cows with Africander dams being more productive than reciprocals with Mashona, Nkone and Brahman dams. The Bos taurus × Bos taurus cross was inferior in overall productivity primarily due to large cow weight and relatively low growth rate of progeny. Progeny sired by Friesian, Simmental and Brahman had higher weaning weights than those sired by Hereford, Aberdeen Angus, Africander and Tuli. Overall, heterosis was positive for all traits and averaged 0·15 for the three measures of cow productivity. Heterosis was three times higher in the Bos taurus × Bos indicus cross than in the Bos indicus crosses.
The response of store lambs to dietary supplements of fish meal 3. Effects of the preceding pattern of growth
Authors: Tayer S. R. , Bryant M. J.
Published: September 2010

Three diets containing 0, 45 or 90 g fish meal dry matter (DM) per kg diet DM were given to lambs in sufficient quantities to provide energy for maintenance and 150 g daily gain. The lambs grew directly from 30 to 40 kg live weight (C) or were given a maintenance diet only such that they remained at 30 kg live weight for 12 weeks before being allowed to proceed to 40 kg (R). The 48 lambs were slaughtered at 40 kg. Preliminary slaughter groups provided data upon the fleece-free empty body weights for both C and R lambs at 30 kg live weight.

There were no significant diet × growth pattern interactions. R lambs ate more DM (P < 0·01) and had greater fleece-free empty body gains (P < 0·01) than C lambs. The inclusion of fish meal in the diet increased fleece and offal weights (P < 0·05) and fleece-free empty body gains (P < 0·01). Much of the response was confined to the first increment of fish meal. The preceding growth pattern had little effect upon the response of the lambs to dietary supplements of fish meal.
Artificial insemination of farmed fallow deer (Dama dama): fixed-time insemination at a synchronized oestrus
Authors: Asher G. W. , Adam J. L. , James R. W. , Barnes D.
Published: September 2010

Two trials were conducted in 1986 on artificial insemination of female fallow deer at fixed intervals from the cessation of oestrous synchronization treatment. Semen had been collected previously from mature bucks by electroejaculation and extended in sodium citrate/egg yolk diluent.

In the first trial involving a comparison of the fertilization rates of fresh and frozen-thawed semen delivered intravaginally, 57 does each received a single intravaginal progesterone-releasing device (CIDRtype S, Carter Holt Harvey Plastic Products Group Ltd, Hamilton, NZ) for a 14-day period early in the 1986 breeding season. All does were inseminated intravaginally with either fresh (no. = 26) or frozenthawed (no. = 31) semen (85 × 106 motile spermatozoa per inseminate) at 48 h after CIDR removal. The apparent conception rates for the two types of semen were 65·4% and 64·5% respectively (P > 0·1) and the actual fawning rates were 500% and 48·4% respectively (P > 0·1).

In the second trial involving an investigation of the feasibility of laparoscopic intrauterine insemination, 55 does were synchronized as for the first trial. At 56 to 58 h from CIDR removal, the does were anaesthetized and laparoscopically inseminated with frozen-thawed semen (85 × 106 motile spermatozoa per animal) by direct injection into both uterine horns. Anaesthesia was reversed immediately following artificial insemination. The apparent conception rate was 47·3% and the actual fawning rate was 41·8%.

Data from both trials indicate that reasonable fawning rates can be obtained for artificially inseminated fallow deer. Between 11 and 25% of does expected to fawn did not and this may represent embryonic mortality attributable to the method of oestrus/ovulation synchronization.
A note on the apparent digestibility of fodder beet roots in sheep
Authors: Sabri M. S. , Offer N. W. , Roberts D. J.
Published: September 2010

Six castrated male sheep were used to measure the apparent digestibility of fodder beet roots when included at two concentrations (610 and 490 glkg) in a feeding regimen in which the only other component was a standard complete diet of known digestibility. Mean digestibility coefficients for organic matter and gross energy for the beet were calculated to be 0·962 and 0·953 respectively. Digestible and metabolizable energy values (MJIkg DM) were calculated to be 16·0 and 13·1 respectively.
Reproductive performance, body weight and body condition of breeding sows with differing body fatness at parturition, differing nutrition during lactation, and differing litter size
Authors: Yang H. , Eastham P. R. , Phillips P. , Whittemore C. T.
Published: September 2010

One hundred and two Large White × Landrace Fl hybrid sows were allocated over four parities in a factorial design to two levels of target P2 backfat thickness at parturition (20 mm, F v. 12 mm, T), two levels of lactation feeding {ad libitum, H v. 3 kg/day, L), and two sizes of sucking litter (six v. 10). Sows attained 13 mm P2 when first mated at 126 kg live weight. Fatness (P2, mm) at weaning was significantly influenced by target fatness at parturition (14·2 v. 9·3), lactation feeding level (13·7 v. 10·0), and litter size (12·7 v. 11·0). Changes in backfat (P2, mm) during 28-day lactation were significantly influenced by target fatness at parturition (—5·0 v. —2·5), lactation feeding (-2 0 v. —5·4), and litter size (—2·9 v. -4·6). Sow live weight (kg) at weaning was significantly influenced by target fatness at parturition (211 v. 192), lactation feeding (218 v. 186), and litter size (208 v. 196). Changes in live weight (kg) during 28-day lactation were significantly influenced by target fatness at parturition (—26 v. — 12), lactation feeding (—5 v. —31), and litter size (—12 v. —25). With multiparous sows only, total food intake during 28-day lactation was negatively related to total food intake in pregnancy. Change in backfat (P2, mm) during 28-day lactation = -0·28 - 0·27 P2 at parturition + 0·04 lactation food intake — 0·50 litter size. Change in live weight (kg) during 28-day lactation = -3·8 — 0·15 live weight post partum + 0·36 lactation food intake — 3·3 litter size. Sows with target fat levels of 20 mm P2 at parturition had better food conversion efficiencies than sows with target fat levels of 12 mm. Target fatness at parturition, and especially lactation food intake, but not litter size, significantly influenced the interval (days) from weaning to oestrus in parity 1 (9·1 v. 14·2 and 7·8 v. 15·3, but 11·6 v. 11·5), while n i subsequent parities only litter size influenced the interval (days) from weaning to oestrus (6·0 v. 8·0). Birth weight (kg) of piglets was influenced only marginally by target fatness at parturition (1·4 v. 1·2) in parity 1, and not by the other factors, or in subsequent parities. Piglet growth rate was affected by both target fatness at parturition and litter size, but by lactation feeding level only in the last week of lactation. The relationship between fatness at weaning (mm) and the weaning to oestrus interval (days) for primiparous sows can be expressed as 26·6 — 1·28 P2. High level feeding in lactation imparted production and efficiency benefit in both primiparous and multiparous sows, while pregnancy feeding to a target of 20 mm rather than 12 mm at parturition was of benefit for primiparous sows.
A note on the digestibilities of nitrogen and amino acids in meat, skimmed-milk and fish meals in young pigs
Authors: Green S.
Published: September 2010

In order to compare the digestibilities of amino acids in meat, skimmed-milk and fish meals, isonitrogenous, semi-purified diets containing these foodstuffs were given to five castrated male pigs, of 13 kg live weight, with ileo-rectal anastomoses. Apparent digestibilities were calculated as (amino acid consumption —Heal digesta amino acids)Iamino acid consumption. In the order, meat, milk and fish meal, digestibilities were: of N, 0·80, 0·84, 0·88 (s.e.d. 0·021); of lysine, 0·84, 0·94, 0·94 (s.e.d. 0·011); of threonine, 0·81, 0·86, 0·91 (s.e.d. 0·017); of methionine, 0-86, 0·94, 0·94 (s.e.d. 0·006). In vitro solubility of N in 0·2 gll solution of pepsin and hydrochloric acid was 0·93 (s.e. 0·003) for meat, 0·97 (s.e. 0·001) for milk, and 0·95 (s.e. 0·001) for fish meal. In conclusion, the digestibilities of essential amino acids were greater in the milk and fish meals, than in the meat meal.
A long-time ambient temperature diluent for boar semen
Authors: Revell S. G. , Glossop C. E.
Published: September 2010

Semen was collected from boars of proven fertility and diluted with Zorpva base using the antibiotic treatments: benzylpenicillin and streptomycin; polymixin B; tylosin; neomycin; gentamycin; kanamycin or lincomycin and spectinomycin. The last combination provided an economical treatment with enhanced quality and preservation of motility. The addition of trehalose (1 g/1) and potassium chloride (0·25 g/1) improved the preservation of acrosomes. The resulting ‘Reading’ variant was compared with Zorpva at days 4 to 6 of storage in a split ejaculate trial using 40 sows slaughtered 9/10 weeks after insemination. Conception rates were significantly higher using Reading (16/20) compared with Zorpva (8/20; P < 0·05) and the effect was particularly marked at days 5 and 6. The mean number of embryos per pregnant sow was 11·6 (Reading) v. 9·4 (Zorpva), representing 51% and 42%, respectively, of ova shed, as measured by counting corpora lutea.
Effects of lactational level on reactivation of ovarian function, and interval from parturition to first visual oestrus and conception in high-producing holstein cows
Authors: Harrison R. O. , Young J. W. , Freeman A. E. , Ford S. P.
Published: September 2010

Data were collected on 19 high-producing Holstein dairy cows from day 20post partumuntil they were either determined pregnant or reached 150 dayspost partum. Blood metabolites (progesterone (P4), glucose, beta-hydroxybutyrate (BHBA) and free fatty acids (FFA)) were related to the interval from parturition to first luteal phase, first visual oestrus and conception. Prior to data analysis, cows were divided into two groups based on their 120-day milk production and designated as below herd average (BHA; no. = 9) or above herd average (AHA; no. = 10). Average 120-day milk productions for BHA, AHA and herdmates (no. = 56) were 3932 (s.e. 157), 4841 (s.e. 60) and 4353 (s.e. 96) kg, respectively. Days from parturition to first luteal phase were not different between the BHA and AHA groups (31·7 (s.e. 1·7) and 31·5 (s.e. 6·9), respectively). In contrast, days from parturition to first visual oestrus and to conception oestrus were less for the BHA group than for the AHA group (46·8 (s.e. 4·6) and 76·9 (s.e. 7·5)v.67·7 (s.e. 5·2) and 102·5 (s.e. 9·2) days, respectively (P< 0·05)). Further, average glucose concentration from day 20 to first luteal phase was higher (P< 0·05) for the BHA group than for the AHA group (64·1 (s.e. 1·6)v.58·4 (s.e. 1·6) mg/dl). From day 20 to first visual oestrus, plasma glucose concentration increased while BHBA and FFA declined; all three metabolites then remained relatively constant until conception. These data suggest that as the amount of milk a dairy cow produces increases, the interval from parturition to first visual oestrus and conception increases. These data are consistent with a suppression of oestrus behaviour rather than with a delayed interval to ovarian cyclicity.
Developing breeding objectives for australian beef cattle production
Authors: Ponzoni R. W. , Newman S.
Published: September 2010

A sequential procedure for the development of breeding objectives for beef cattle improvement is presented. The procedure is general, and could be used for other types of domestic livestock. The development proceeds in four phases: (1) specification of the breeding, production and marketing system; (2) identification of sources of income and expenses; (3) determination of biological traits influencing income and expense; (4) derivation of the economic value of each trait, based on discounted gene flow methods. As an example, a breeding objective is developed for a pure breeding herd from which male calves are marketed at 9 months of age and surplus heifers are sold at 15 months of age. Situations examined included: (1) the effect of discounting on the breeding objective (income and expense per year v. discounting at 0, 5 and 10%); (2) the effect of ignoring the economic value for food intake in the objective; (3) the effect of inclusion of yearling weight or the deletion of calving date from the selection index. In general, correlations between objectives for discounting and income and expense per year were greater than 0·95, whereas correlations between indices were greater than 0·85. Setting food costs equal to zero shifted emphasis from reproduction to growth traits, with a consequent increase in food intake. The addition of yearling weight to the index caused a small increase in the accuracy of the index, whereas the deletion of calving date had a large effect, halving the accuracy of the index. The practical implications of the results are discussed.
A note on the influence of routine induction of parturition by administration of a synthetic prostaglandin analogue on productivity in the rabbit
Authors: Ubilla E. , Rodriguez J. M.
Published: September 2010

The effect of routine induction of parturition on some reproductive and productive parameters during a year-long trial in 50 California doe rabbits allocated in two groups of 25 animals (treated and control), was studied. Intramuscular injections of 50 ug of the synthetic analogue of prostaglandin F2ct (Etiproston), were given at 10.00 h on day 29 of pregnancy. Control animals were untreated. When compared with the controls, treated does showed a significant reduction in the individual weight of pups at birth (49·7 (s.e. 0·41) and 52·2 (s.e. 0·53) g), number born dead per litter (0·42 (s.e. 0·11) and 0·81 (s.e. 0·16)), and parturition interval (42·9 (s.e. 1·5) and 53·5 (s.e. 1·7) days), and an increase in both sexual receptivity on days 6 to 9 post partum (70·4% and 43·0%), and in the conception rate to remating on days 6 to 7 post partum (82·2% and 66·6%), respectively. Litter size at birth, overall conception rate, mortality from birth to weaning, litter weight at 21 days, litter size at weaning, milk production, and mortality of does were not affected by the prostaglandin treatment.
Evaluation of eleven cattle breeds for crossbred beef production: performance of progeny up to 13 months of age
Authors: Baker R. L. , Carter A. H. , Morris C. A. , Johnson D. L.
Published: September 2010

Eleven sire breeds were evaluated in New Zealand from the performance of their calves at two sites using Aberdeen-Angus cows, and at a third site using Angus and Hereford cows. The experiment was carried out over 5 years, generating a total of 4519 calves by 161 different sires. There were seven recently imported sire breeds, Blonde d'Aquitaine, Charolais, Chianina, Limousin, Maine Anjou, Simmental (including strains from four countries) and South Devon, and four local breeds, Angus, Friesian, Hereford and Jersey. Overall, 92% of calves survived at birth and through to weaning, with a range from 86% for the Charolais sire breed to 96% for the Friesian and Jersey breeds. The proportion of calves (from cows aged 3 years and over) experiencing birth difficulty averaged 8·6% and ranged from 17·7% for the Charolais, 15·1% for the Chianina and 13·7% for the Maine Anjou, to 2·3% for the Hereford and 0·9% for the Jersey. Birth weights by sire breed had a range of 7·2 kg, proportionally 0·23 of the mean for the Hereford × Angus cross. The birth weights of calves by imported sire breds were greater than those of calves sired by local breeds by 4·7 kg. Sire breeds were ranked in approximately the same order for the weights of calves at weaning (5 months of age) and at 13 months of age. As a proportion of the mean for the Hereford × Angus crosses, there was a range due to sire breed of 0×17 for weaning weight and 013 for 13-month weight. As a group, the imported sire breeds had calves with 13-month weights 11·5 kg heavier than Hereford × Angus or 250kg heavier than straightbred Angus calves; proportionally these advantages in weight were 005 and 011, respectively. There was no evidence of any major interaction between sire breed and location. The heritability estimates ranged from 0·01 to 0·05 for calving difficulty and survival traits, from 0·13 to 0·33 for live weights and from 0·06 to 0·12 for pre-weaning live-weight gains. For gestation length the estimate was 0·48.
The effect of Haemonchus contortus infection on haematological parameters in young Merino sheep and its significance for productivity
Authors: Albers G. A. A. , Gray G. D. , Jambre L. F. Le , Barger I. A. , Barker J. S. F.
Published: September 2010

Faecal egg counts, haematocrits, erythrocyte potassium contents and serum iron concentrations were determined in 1005, 3- to 5-month-old Merino lambs infected with a single dose of 11 000 Haemonchus contortus larvae. Live-weight gain and wool growth also were recorded. Lambs were infected in six different groups over a 3-year period. When infections were terminated after 5 weeks, faecal egg counts in the six infected groups had reached a peak of 5170 to 20 339 eggs per g (average 12 909), haematocrits had declined to between 196 and 309 ml/1 (average 233), erythrocyte potassium contents had risen to between 16·7 and 37·5 mequiv. per 1 (average 31·5) and serum iron concentrations, in some cases following an erratic course, had dropped to between 0·512 and 1·546 mg/1 (average 0·946).

Of the three haematological parameters, haematocrit correlated best with faecal egg count (r = 0·7 in four of six infected groups). However, in two groups with low faecal egg counts this correlation was much lower (r = 0·3). Erythrocyte potassium concentration and serum iron concentration significantly correlated with variability of haematocrit not accounted for by faecal egg count, suggesting that both erythropoiesis and iron availability influence the degree of anaemia.

The effect of H. contortus infection on productivity of lambs was best predicted by haematocrits: for each further 0·01 proportional decrease in haematocrit, a 0·03 reduction of live-weight gain over a 9-week post-infection period, a 0·007 reduction in clean wool growth and a 0·004 reduction in fibre diameter over a 4- to 9-week period were observed. Some evidence was obtained indicating a tolerance level of anaemia at approximately 280 ml/1 packed cell volume.
The effect of melatonin implants on breeding activity and litter size in commercial sheep flocks in the UK
Authors: Haresign W. , Peters A. R. , Staples L. D.
Published: September 2010

Two trials were undertaken to investigate the effects of treating seasonally anoestrous ewes with melatonin implants on date of first oestrus and other aspects of reproductive performance.

Trial 1 involved a total of 368 Mule ewes and 79 Scottish Blackface ewes on five farms, approximately half of which were treated with a single subcutaneous implant of melatonin (Regulin®), containing 18 mg melatonin, between 23 July and 6 August 1986 and the remainder acted as untreated controls. Treatment had no significant effect on the date of first oestrus or conception rate in Mule ewes, although it increased the number of Scottish Blackface ewes mating (92% v. 73%) and the number of mated ewes conceiving (69% v. 54%) in a 5-week mating period, resulting in significantly more treated ewes lambing (63% v. 37%; P < 0·01). Litter size was higher in 4/5 flocks, although this only reached statistical significance in one Mule flock and the Scottish Blackface flock.

A total of 2116 ewes from 17 commercial flocks were used in trial 2, approximately half of which were Suffolk/Suffolk-cross ewes and the remainder Mule/Mule-cross ewes. Implantation with melatonin occurred between 22 June and 24 July 1987. Flocks with over 100 ewes were divided into three equal-sized groups and treated with either 18 mg melatonin (one implant of Regulin, 36 mg melatonin (two implants of Regulin given at the same time) or acted as untreated controls. Flocks with less than 100 ewes contained only the 18 mg melatonin and untreated control groups. Treatment with melatonin significantly advanced the date of first oestrus in most flocks of both breeds (P < 0·05) but the magnitude of this effect was variable. Significant (P < 0·05 at least) increases in ‘potential’ (from scanning) mean litter size (+0·13 to +0·18) and actual mean litter size (+0·11 to +0·14) resulting from treatment with melatonin were apparent in ewes of both breeds when the data were pooled across all flocks, but only in 4/17 of the individual flocks.

These results indicate that treatment with melatonin implants may be a simple and effective way of advancing the breeding season and enhancing litter size of early lambing flocks under commercial farming conditions in the United Kingdom, but treatment must be given >60 days before the start of the natural breeding season for benefits in date of first oestrus to be manifest.
Mechanical stimulation of rumen fill and alimentary behaviour in sheep
Authors: Baumont R. , Malbert C. H. , Ruckebusch Y.
Published: September 2010

The effects of an increase of rumen fill obtained with polystyrene cubes, and able to stimulate mechanically the rumen wall were investigated on alimentary behaviour and reticulo-rumen motility in sheep. The introduction through a rumen cannula of a volume of polystyrene cubes equal to one-quarter of the ruminal pool size depressed the daily intake of both low-quality cocksfoot hay and good-quality lucerne hay (P < 0·05). Surprisingly, the time spent ruminating was slightly increased and the frequency of contractions during rumination was significantly increased (P < 0·05). In addition, in the sheep fed enterally with a liquid into the rumen, either the mechanical stimulation of the rumen dorsal wall or the introduction of hay (200 g) into the rumen, induced a rumination molility pattern. It is concluded that the intensity of mechanical stimulation of the dorsal sac of the rumen by food particles, which depends upon rumen fill, reduces the time spent eating to increase the duration and intensity of rumination.
Efficiency of MOET nucleus breeding schemes in selecting for traits with low heritability in dairy cattle
Authors: Teepker G. , Smith C.
Published: September 2010

Theoretical rates of genetic response are calculated for adult multiple ovulation and embryo transfer (MOET) nucleus breeding schemes and conventional breeding systems in dairy cattle. For a single trait breeding objective, the relative responses with MOET schemes decline as the heritability falls and the number of progeny in the progeny test scheme increases. Selection for an aggregate breeding objective of milk yield and another trait, for different values of heritability, correlation and relative economic importance, is also examined. Generally, the overall response of efficient MOET schemes exceeds the progress of an efficient conventional breeding scheme with 50 to 100 daughters per bull. Only if the relative economic weight for the lowly heritable trait exceeds 0·60 and the progeny test is on 200 offspring are conventional systems superior. Testing additional paternal half-sib groups from a MOET scheme gives a considerable extra response, especially when lowly heritable traits have a dominating economic importance.
Relationships between pre-weaning growth, post-weaning growth and mature body size in Chios sheep
Authors: Mavrogenis A. P. , Constantinou A.
Published: September 2010

The study examined early measures of growth and their relationships with mature body size. Data on 792 purebred females of the Chios breed, born and reared on two experimental farms between 1978 and 1986, were analysed. Pedigree information and records on live weight at birth, at weaning, 105 days of age and at first and subsequent matings was recorded. There were flock-year differences for all traits studied (P < 0·01) and birth type was important for all traits except post-weaning growth rate. Dam lactation number had no significant effect on birth weight and pre-weaning growth rate, but it significantly affected all subsequent weights and post-weaning growth rate. Estimated heritabilities increased with age and ranged from 0·13 (s.e. 0·14) (birth weight) to 0·30 (s.e. 0·15) (mature weight). Genetic correlations were generally positive between weights and growth traits. Phenotypic correlations were positive and followed the pattern of the genetic correlations. The results suggest that selection for 105-day weight will result in increased mature weight.
A note on conception rates and litter sizes following the intrauterine insemination of ewes at an induced oestrus during seasonal anoestrus
Authors: Aitken R. P. , Wallace J. M. , Robinson J. J.
Published: September 2010

Priming with a progestagen-impregnated vaginal pessary followed by an injection of 750 i.u. pregnant mare serum gonadotropin at pessary withdrawal was used to induce oestrus and ovulation during anoestrus (13 June, latitude 57°N) in 58 Border Leicester × Scottish Blackface ewes that had lambed previously in late March/early April. At 54 to 58 h after pessary withdrawal the uterus of each ewe was viewed by laparoscopy and 50 × 106 viable sperm deposited into each uterine horn. Mean ovulation rate was 2·9 (s.d. 0·12; range 1 to 5). Plasma progesterone concentrations remained >1·5 μg/l in 54 (93%) of the ewes until at least day 21 after insemination implying a high fertilization rate. After allowing for three ewes that were observed to abort between 39 and 55 days after insemination and another three, carrying nine normally developed lambs, that died between 102 and 136 days of gestation, 40 of the remaining 48 ewes (i.e. 69% of the original 58) produced 76 viable lambs in early November. These conception and lambing rates obtained following the intrauterine insemination of 100× 106 viable sperm per ewe are more than double those obtained following natural mating or conventional cervical insemination with four times the number of viable sperm and imply that intrauterine insemination may enhance lamb production from ewes induced to breed during seasonal anoestrus.
Correlated responses to selection for cow fertility in a tropical beef herd
Authors: Mackinnon M. J. , Hetzel D. J. S. , Corbet N. J. , Bryan R. P. , Dixon R.
Published: September 2010

Correlated responses to selection in a tropical beef herd for high (H) and low (L) estimated breeding value for pregnancy rate were measured over three calf crops. The H line calves were proportionately 0·04 lighter at weaning but during the ensuing dry season they lost less weight than L line animals, so that between the ages of 12 and 18 months there were no significant line differences in live weight. It was concluded that selection for cow fertility had not directly altered the progeny's growth rate. Tick resistance and heat tolerance also did not differ between the lines. However, resistance to worms was lower (P < 0·05) in the H line indicating genetic antagonism between cow fertility and worm resistance. Scrotal circumference and scrotal circumference adjusted for live weight were significantly higher in H line bulls between 9 and 18 months of age. Pregnancy rates of heifers in the H line were 0·12 higher than in the L line despite similar average live weights at mating. It is suggested that accelerated sexual maturity in both heifers and bulls has occurred as a result of selection for lifelong cow fertility.
Prediction of the voluntary intake of grass silages by beef cattle. 1. Linear regression analyses
Authors: Rook A. J. , Gill M.
Published: September 2010

Data on individually recorded silage dry-matter intake (SDMI), concentrate dry-matter intake (CDMI) and live weight of steers and data on silage composition including toluene dry matter (TDM), pH, total nitrogen (N), ammonia nitrogen (NH3-N), volatile fatty acids (VFAs), digestible organic matter in the dry matter (DOMD) and neutral-detergent fibre (NDF) obtained from experiments conducted at three sites were used to obtain simple and multiple linear regressions of SDMI on other variables.

Live weight accounted for a high proportion of the variation in intake but this effect could generally be removed by scaling intake by live weight raised to the power of 0·75 (M0·75). CDMI was the most important factor affecting scaled intake in mixed diets. TDM, NH,-N and VFAs all had important effects on SDMI. The relationship of SDMI with TDM was curvilinear suggesting that there is little to be gained in intake terms from wilting to TDM above 250 g/kg. The effect of NH3-N appeared to be related more to its correlation with VFAs than with any other nitrogenous constituent while the VFAs appeared to have a direct effect on SDMI. The effects of N and pH on SDMI were generally small. DOMD and NDF had relatively little effect on SDMI. Significant differences in intercepts between sites were found for most relationships although common slopes were often found.
Consumer responses to fresh meat and meat products from barrows and boars with different levels of boar taint
Authors: Diestre A. , Oliver M. A. , Gispert M. , Arpa I. , Arnau J.
Published: September 2010

In a consumer trial the assessments of 874 cooks and 5034 family members were analysed. Forty-one boar and 40 barrow carcasses were selected in a commercial abattoir so that the two sexes were similar in carcass weight, fat thickness and muscle pH. A boar sample including a higher proportion of tainted carcasses was selected. It was divided into three boar taint-level subgroups according to their 5a-androst- 16-ene-3-one (androstenone) concentration in fat (Jig androstenone per g fat) as follows: L < 0·5 (no. = 17), M 0·5 to 1·0 (no. = 13) and H > 1·0 (no. = 11). From each carcass, loin/rib chops were prepared and cooked hams, brine-cured bellies and Spanish dry-cured hams were processed. An analysis of variance was used to estimate the effects of sex and boar taint levels. Cooks (P < 0·05) and family members (P < 0·01) reported a higher level of odour for boar chops. A higher level of unfavourable responses to odour and flavour were found in the H taint-level subgroup. Also, the H taint-level group produced the highest proportion of negative judgements on overall acceptability in comparison with normal purchases. The response of cooks to odour from brine-cured bellies was significantly affected by sex (boar and barrow). For bellies, odour, overall acceptability and comparison with normal purchases were significantly affected by the boar taint-level subgroups (P < 005). The treatments had no significant effect on any quality question related to boar taint in cooked ham. However, boar taint level significantly affected the assessments of flavour and overall acceptability from Spanish dry-cured ham (P < 0·01). A higher proportion of negative responses was found in the H taint-level subgroup. The trial indicates that boar meat can produce an unfavourable response from consumers for fresh meat (chops) or products needing heating prior to consumption (brine-cured bellies). However, in cooked products with hot processing and cold consumption (cooked ham) no negative effect from using boar meat was observed. To produce Spanish dry-cured ham, androstenone quantification should be carried out to avoid consumer dissatisfaction.
The herbage intake and performance of autumn-calving beef cows and their calves when grazing continuously at two sward heights
Authors: Wright I. A. , Whyte T. K. , Osoro K.
Published: September 2010

Thirty-nine Hereford × Friesian autumn-calving cows (mean calving date 17 September) and their Charolais-cross calves were used in a 2 × 2 × 2 factorial experiment to assess the effects of feeding level in winter and sward height in summer on intake and performance. Mean estimated metabolizable energy intakes during winter (30 October to 6 May) were 63 (L) or 92 (H) MJ/day. Two sward heights, 4·8 (SI) or 7·6 (Tl) cm, were imposed from turn-out to weaning on 3 July, and a further two sward heights, 4·7 (S2) or 8·0 (T2) cm, from weaning to housing on 1 October. At turn-out the H cows were 17 kg heavier (P > 0·05) than the L cows and their calves were 30 kg heavier (P < 0·01). Cow herbage intakes were significantly higher on the Tl and T2 treatments compared with the SI and S2 treatments as were live-weight changes: 0·94 v. –0·01 kg/day (P < 0·001) for Tl and SI treatments and 0·96 v. –0·18 kg/day (P < 0·001) for T2 and S2 treatments respectively. Calves on the Tl treatment had higher live-weight gains than those on the SI treatment (1·40 v. 0·63 kg/day; P < 0·001). After weaning the SI cows had significantly higher herbage organic matter intakes than the Tl cows (P < 0·05) and had significantly higher live-weight gains (0·51 v. 0·28 kg/day; P < 0·05). Calving difficulty and calf birth weight were not affected by any of the treatments. The results demonstrate that both previous and current level of nutrition have an effect on cow performance. When cows are turned out to pasture at body condition scores of 2·25 to 2·5, the sward heights recommended for spring-calving cows are equally appropriate for autumn-calving cows.
Ovarian follicle populations, steroidogenicity and micromorphology at 5 and 9 weeks post partum in beef cows in two levels of body condition
Authors: Prado R. , Rhind S. M. , Wright I. A. , Russel A. J. F. , McMillen S. R. , Smith A. J. , McNeilly A. S.
Published: September 2010

The effect of body condition at calving on ovarian follicle characteristics during post-partum anoestrus was studied in 38 suckling Blue-Grey cows with mean body-condition scores of 2·80 (s.e. 0·05) (H) or 2·35 (s.e. 0·05) (L) at calving and fed so that they maintained live weight and body condition during lactation. Cows of each level of body condition were ovariectomized at either 5 or 9 weeks after calving and follicles ≥3 mm in diameter were dissected out and incubated in a medium (Medium 199) for 2 h. Follicle incubates were assayed for progesterone, testosterone and oestradiol. L cows had fewer follicles ≥3 mm in diameter than H cows (24·1 v. 44·9; P < 0·05) at 5 weeks post partum due to a lower number of small (3 to 4 mm) follicles (12·9 v. 30·6; P < 0·05). At 9 weeks there was no effect of body condition on mean numbers of follicles (38·1 v. 40·4; P > 0·05). The proportions of healthy, intermediate and atretic follicles in all cows were 0·35, 0·20 and 0·45 respectively; these proportions were not affected by body condition or time of ovariectomy. Body condition did not affect the overall mean capacity of the cultured follicles to produce oestradiol or progesterone in vitro but testosterone production was higher in follicles from H than L cows (6406 v. 5206 pg/h; P < 0·05). However, at 9 weeks post partum a greater proportion of H than L cows had a large (>8 mm), healthy, highly oestrogenic follicle (4/8 v. 1/7; P = 0·18).

At 9 weeks post partum, the four large, healthy, oestrogen-active follicles (those secreting >250 pg/h) from H cows were approximately 11-fold more oestrogenic than the single comparable follicle from L cows (7100 v. 635 pg/h; P > 0·05). There was little difference at week 5 post partum: 3288 and 2785 pg/h (P > 0·05) for H and L cows respectively. Oestrogen-active follicles from H cows were significantly more oestrogenic at 9 than 5 weeks post partum (5807 v. 3021 pg/h; P < 0·05). The results suggest that the body condition-related reduction in the number and steroidogenic capacity of large oestrogenic follicles in post-partum cows may be associated with a reduction in LH pulsatility.
The effect of winter and summer nutritional levels on the reproductive performance of beef heifers bred at 2 years of age
Authors: van Niekerk A. , Kernick R. , Lishman A. W.
Published: September 2010

Reproductive data of 139 Simmentaler heifers, previously subjected to different levels of winter and summer nutrition, over a 3-year period, were analysed. Pregnancy rates of 77% and 96% were achieved during the first and second seasons for the two groups of heifers, respectively. Winter and summer nutritional levels affected the number of heifers culled, but had little effect on conception. There were no significant differences in the weight at mating between the heifers that conceived and those that failed to conceive. Mean date of conception was within 30 days and 20 days of the commencement of the breeding season for the first and second season, respectively. Post-weaning nutrition played a relatively minor role in affecting the time of conception. Birth weights of the progeny were not affected by treatment. Calf birth weight was however, significantly (P < 0·05) correlated with the weight of the dam at mating. Sixty-three % of the heifers produced three calves in 3 years, 35% produced two calves in 3 years and only two heifers produced one calf in 3 years. The data supported the original hypothesis that the emphasis, when heifers are bred at 2 years of age, should be shifted away from a physiological base to one where management and grazing strategy are more important in rendering the enterprise economically viable.