bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical and haematological changes associated with short periods of work in draught oxen
Authors: Pearson R. Anne , Archibald R. F.
Published: September 2010

Blood samples were taken from three Brahman × Friesian cattle while they walked for 1 h daily on a treadmill pulling 20 or 25 kg weights suspended in a cage. Heart rate and energy expenditure during work were closely correlated. The work had no significant effect on blood levels of red cells, haemoglobin, packed cell volume, total protein, albumin, glycerol, urea, Mg, Ca, Na, K and chloride. White blood cells, glucose, lactate, free fatty acids, P-hydroxybutyrate and inorganic phosphate were affected by work although the changes were shortlived and values had returned to resting levels 75 min after work finished. The changes were similar in each animal and indicated work done by draught cattle is largely at a submaximal level. Apart from lactate no blood parameters were identified that could be usefully used to compare performance.
The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning
Authors: Newton J. E. , Orr R. J.
Published: September 2010

The intake of silage, concentrates and grazed herbage, and the performance of 16 Masham ewes carrying and suckling either single or twin lambs, was measured during the last 7 weeks of pregnancy, during lactation and after weaning.

There was no difference in intake between ewes with singles or twins in pregnancy, lactation or after weaning. The metabolizable energy intakes, from silage and concentrates, of the ewes with singles and twins were 101 and 100 MJ per head per day in weeks 7 and 6 pre partum, 21·4 and 19·9 MJ in weeks 3 and 2 pre partum, and 24·4 and 23·8MJ in the 1st week of lactation. The intakes from grass and concentrates were 32·3 and 338MJ in weeks 5 and 6 of lactation for the ewes with singles and twins respectively, and 13·8 and 15 2M J from grass alone after weaning. There was no effect of ewe live weight on intake and, although the ewes with singles were producing less milk than those with twins, their intakes were similar.

The same ewes consistently ate the most feed. The overall coefficient of concordance was 05 6 and the coefficients for mid- and late-pregnancy, late pregnancy and early lactation, and early- and mid-lactation were 0·57, 0·62 and 0·66 respectively. The ewes with twins that consistently ate the most lost less weight in pregnancy, produced similar litter weights and suckled lambs that grew faster. Their levels of intake and production were high: the growth rate from 0 to 6 weeks of age of the twin lambs suckling the large-eaters was 721 g/day compared with 631 g/day for those suckling the small-eaters. During lactation the ewes with singles appeared t o consume more metabolizable energy than their maintenance, milk yield and live-weight gain requirements justified, whereas the group of smaller-eating ewes with twins put on more weight than expected from their intakes.
Gastro-intestinal re-entrant cannulae for studies of digestion in sheep
Authors: Ash R. W.
Published: September 2010

The design and manufacture of plastic cannulae are described and the chief hazards associated with cannulated re-entrant fistulae in sheep are discussed.
Effect of soaking the meal ration of growing pigs in water or skim milk
Authors: Barber R. S. , Braude R. , Mitchell K. G.
Published: September 2010

1. Thirty-two individually-fed pigs were used to determine the effects of soaking their daily meal ration in either water or in liquid skim milk and water for approximately 24 hr. before feeding. The experimental period continued from about 10 weeks of age to bacon weight.

2. Neither soaking procedure had any significant effect on the rate of growth, efficiency of food utilisation, dressing percentage, carcass length, backfat thickness or commercial grading results of the pigs.

3. The growth rate and efficiency of food utilisation of the pigs given meal plus skim milk were significantly better than for those given the all meal diet. The dressing percentage of the former was also significantly higher than the latter, but there were no significant differences between the two groups in carcass length or backfat thickness.

4. Possible reasons for the difference in performance of the all meal and meal plus skim milk-fed pigs are discussed.
Effects of variations in energy and protein intake on digestibility, nitrogen balance and carcass composition in British Friesian castrate male cattle
Authors: Griffiths T. W.
Published: September 2010

Twenty-seven castrate male cattle were used in two nutritional balance and slaughter experiments to measure the effects of increasing levels of dietary protein (9 to 15% in the dry matter) at two levels of feeding (approximately 16 and 22 MJ metabolizable energy (ME)/100 kg live weight (LW) per day) on digestibility, nitrogen (N) balance and carcass growth and composition over the LW range 130 to 390 kg.

The higher level of feeding increased LW gain and carcass gain (CG) but higher protein intake increased LW gain and CG only at the higher feeding level as a result of its favourable effect on digestibility. N balance tended to overestimate carcass N retention at higher levels of protein intake.

The higher level of feeding increased the separable fat and total fat in the carcass. Increased protein intake had no effect on the lean meat content but increased the percentage protein in the edible portion of the carcass. LW gain, CG and carcass energy deposition were related to ME intake only but N balance and carcass protein gain were related to both ME and digestible crude protein intake.
The effect of reduction in daylength, level of feeding and age on the reproduction of young female sheep mated at an induced ovulation
Authors: Al-Wahab R. M. H. , Bryant M. J.
Published: September 2010

Fifty-six young female Suffolk × (Cadzow Improver × Scottish Blackface) sheep were used in a 2 × 2 × 2 factorial experiment investigating: (i) change in daylength (constant C v. reduced R), (ii) level of feeding (to appetite, H, v. 75% of that allowance, L), and (iii) age at hormone treatment (20 v. 28 weeks). At the appropriate age, the sheep were treated with a progestagen (MAP) and 750 i.u. PMS, inseminated, and slaughtered 26 days later. In a second experiment, change in daylength and level of feeding only were investigated. Hormone treatment took place at 20 weeks of age. In both years, all sheep showed oestrous behaviour and ovulated. A greater number of sheep yielded embryos on C than on R treatments (P<0·05 in Year 2), but no effect of feed level or age was found. Of those sheep not yielding embryos, a greater number on R than on C treatments showed a second ovulation at 20 weeks but not at 28 weeks.
A note on sexual development of Icelandic rams
Authors: Dýrmundsson Ó. R.
Published: September 2010

The results of studies into penial, scrotal and testicular development of Icelandic male lambs indicate relatively early attainment of physiological puberty. This stage of sexual maturity is generally reached by 4 months of age, with marked variation in both puberal age and body weight. Testicular and epididymal weights were more closely associated with body and carcass weights than with age of the lamb. It is a common practice to use Icelandic male lambs for breeding at 7 months of age.
Energy cost of eating in cattle given diets of different form
Authors: Adam I. , Young B. A. , Nicol A. M. , Degen A. A.
Published: September 2010

1. Energy costs of eating were determined from the increased rates of oxygen uptake by five steers aged 18 to 20 months and weighing 298 to 407 kg.

2. Five diets were tested: pelleted concentrate (500 g barley grain per kg, 400 g lucerne meal per kg, 90 g soya bean meal per kg, and 10 g NaCl, trace mineral and vitamin supplement per kg); pelleted lucerne; lucerne hay; chopped-grass hay (700 g brome per kg, 300 g fescue per kg); and chopped fresh turnips. The dry-matter concentration of the pellets and hays was approximately 900 g per kg while the turnips contained only 140 g per kg.

3. The rates of ingestion differed markedly between diets during the (15 to 50 min) twice-daily (morning and evening) feeding periods. On a dry-matter basis, the pellets were consumed most rapidly at a rate of 130 to 138 g per min, while the hays were consumed at approximately 38 g per min and the turnips at 30 g per min.

4. The energy costs per min spent eating were similar for all rations (27·6 to 35·6 J/ kg live weight). However, because of different rates of ingestion, the energy costs per kg DM ingested were different: 222 to 238 J/kg live weight for the pelleted foods, 1029 J/kg live weight for the hays and 1427 J/kg live weight for the turnips.

5. The energy cost of eating is more a function of time spent eating than a function of the amount of food ingested. Thus, rate of ingestion and duration of the meal are key factors in determining the energy cost of eating in cattle.
Variation in rectal temperature of cattle in a tropical environment and its relation to growth rate
Authors: Turner H. G.
Published: September 2010

Rectal temperatures of cattle grazed near the tropic of Capricorn in central Queensland were studied. The cattle were of Bos indicus, B. taurus and crossbred lines, and were represented by over 200 growing heifers in each of 2 years and some supplementary groups.

Rectal temperatures were loge normally distributed when they were expressed as deviations from a basal temperature of 38°C. They were significantly repeatable, but were more highly repeatable when herd mean temperature was above 39·5°C. The heritability estimate was 0·33 (P < 0·01).

The mean phenotypic regression of growth rate on rectal temperature, within breed groups, was 0·04 (s.e. 0·006) kg/day per °C (r = 0·3, P < 0·01) over the entire growth period from birth to 18 months of age but greater during warmer seasons. The estimated genetic correlation was insignificant in one group of heifers but −0·86 (s.e. 0·17) in the other.

The evidence of favourable and possible unfavourable responses to selection of cattle for low rectal temperature in warm environments is discussed.
A note on the effect of mixed or segregated penning of boars and gilts over the live-weight range 20 to 80 kg on performance, carcass characteristics and behaviour
Authors: Smith W. C. , Pearson G. , Holmes R. J.
Published: September 2010

In a study involving 32 boars and 32 gilts penned in either single-sex or mixed-sex groups of eight over the live-weight range 20 to 80 kg, the system of penning did not influence performance or carcass measurements, and with boars had only slight effects on the colour and ultimate pH of the m. longissimus. Sensory panel evaluation of heated backfat from fresh and cured carcasses of boars showed a similar and low sex odour level for single- and mixed-sex groups. System of penning did not influence the extent and duration of agonistic behaviour nor the incidence of mountings.
The rôle of the breed of dam and of the breed of lamb in determining the copper status of the lamb. 1. Under a dietary regime low in copper
Authors: Wiener G. , Wilmut I. , Woolliams Carol , Woolliams J. A. , Field A. C.
Published: September 2010

The relative importance of the breed of lamb and the breed of dam in determining the copper status of the lamb until 24 weeks of age was investigated by transferring embryos within and reciprocally between Scottish Blackface and Welsh Mountain ewes. A diet low in Cu (2·4 mg/kg dry matter (DM) was fed both to the ewes from mating onward and subsequently to their lambs.

At birth, lambs with Welsh dams had greater concentrations of Cu in their livers than lambs with Blackface dams. This difference, although reduced, still remained at 9 weeks of age (weaning), when lambs with Welsh dams also had greater concentrations of Cu in plasma.

By 24 weeks of age, Welsh lambs, irrespective of their dams' breed, had greater concentrations of Cu in both liver and plasma than Blackface lambs, although the average Cu concentration in the liver was below 10 mg/kg DM in both breeds.

Results are also given for concentrations of Cu in kidney, brain and milk.

The experiment suggests the importance of maternal breed in determining the susceptibility, both of the foetus and of the young lamb to problems associated with Cu deficiency.
The rôle of the breed of dam and of the breed of lamb in determining the copper status of the lamb. 2. Under a dietary regime moderately high in copper
Authors: Wiener G. , Wilmut I. , Woolliams Carol , Woolliams J. A. , Field A. C.
Published: September 2010

The relative importance of the breed of dam and the breed of lamb in determining the copper status of the lamb was investigated by transferring embryos reciprocally between Scottish Blackface and Welsh Mountain ewes. A diet moderately high in Cu (8 mg/kg dry matter (DM)) was fed both to the ewes from mating onward and subsequently to their lambs.

At birth, 9 and 24 weeks of age the concentration of Cu in the liver of lambs was the same for the two maternal breeds but within breed groups there was correspondence between full sibs when they were born to the same dam.

By 9 weeks and at 24 weeks of age Welsh lambs, irrespective of their dam's breed, had greater concentrations of Cu in liver than Blackface lambs. The average concentration at 9 weeks was 190 and 130 mg/kg DM respectively for the two breeds of lamb.

Results are also given for concentrations of Cu in plasma, kidney, brain, milk and faeces.

The results differ from those found in the previous paper under a regime of low dietary Cu where the maternal breed affected concentration of Cu in the liver of lambs up to 9 weeks of age.
The allometric relationship between carcass muscle and carcass bone in Scottish Blackface sheep
Authors: Jackson T. H.
Published: September 2010

Thirty-seven Blackface wether sheep, ranging from birth to eighteen months of age, were used to derive the allometric relationship between carcass muscle and carcass bone.

The equation

log10 muscle (g) = 1·36 log10 bone (g)—0·804

fitted the data well. (r = 0·995, b = 1·36±0·05, Sy.x = 0·0595.)

The deviations from this equation had a coefficient of variation of 14% indicating that other factors may influence the relationship of muscle to bone.

It is suggested that the variable

log10M—1·36 log10 5 + 0·804

is independent of differences due to different stages of natural development and can be used to examine the effects of different treatments on the muscle: bone ratio. The constant applies to sheep only.
The effect of pattern of daily feeding of pregnant sows on apparent digestibility
Authors: Frape D. L. , Hocken R. W.
Published: September 2010

Three trials with pregnant sows tied in stalls have been conducted to measure the effects on ration digestibility: (a) of a pelleted compound given once or twice per day, (b) of half the daily ration fed as barley at a separate time from the pelleted concentrate and (c) when the order during the day in which the barley and concentrate were fed was reversed.

Giving pelleted complete rations twice as opposed to once per day led to slight improvements in the apparent digestibility of dietary dry matter, grpss energy, crude fibre and phosphorus. When half the daily ration was given as crushed barley in the morning the apparent digestibility of phosphorus was slightly higher than it was when barley was given in the afternoon. Nevertheless the apparent digestibility of dry matter and crude protein was greater for the complete mixture given twice per day. All these effects were statistically significant.
Responses of British Friesian steers with or without implants of oestradiol-17β to undegradable dietary protein
Authors: Newbold J. R. , Garnsworthy P. C. , Buttery P. J. , Cole D. J. A. , Haresign W.
Published: September 2010

The ability of the protein nutrition scheme proposed by the Agricultural Research Council (ARC, 1980, 1984) to predict responses to protein supply was examined in two experiments. In experiment 1, groups of nine British Friesian steers implanted with oestradiol-17β and nine non-implanted steers were fed from 133 to 300 kg live weight on each of four all-concentrate diets (metabolizable energy (ME) = 12 MJ/kg dry matter (DM)) containing ratios of soya-bean meal and formaldehyde-treated soya-bean meal such that undegradable protein (UDP) concentration was 19, 25, 32 or 42 g/kg DM. Rumen degradable protein (RDP) concentration was relatively constant (111 to 116 g/kg DM). Implantation did not affect DM intake (DMI, g/kg M0·75). Both live-weight gain (LWG) and food conversion efficiency (FCE) (LWG/DMI) were greater (P < 0·05) for the implanted cattle (LWG = 1·41 (s.e. 0·04) kg/day; FCE = 0·24 (s.e. 0·02)) than for the non-implanted cattle (LWG = 1·23 (s.e. 0·05) kg/day; FCE = 0·22 (s.e. 0·02)). There were no dietary effects on either DMI or FCE. In the non-implanted steers, UDP did not affect LWG but, for the implanted steers, there were positive, linear responses in LWG to both UDP concentration (P = 0·048) and UDP intake (P = 0·026). In experiment 2, groups of eight implanted steers were fed from 132 to 300 kg live weight on each of six diets (ME = 12 MJ/kg DM, soya-bean meal and formaldehyde-treated soya-bean meal as chief protein sources) supplying 17, 26, 34, 39, 54 and 82 g UDP per kg DM and concentrations of RDP up to 1·5 times ARC recommendations. There was no effect of UDP on either DMI or FCE but positive, linear responses in LWG to both UDP concentration (P = 0·019) and UDP intake (P = 0·010). In both experiments, mean DMI exceeded that predicted by ARC (1980) (P < 0·05). LWG predicted by the ME system and the ARC protein scheme was not significantly different from observed LWG for non-implanted steers, but was an underestimate of observed LWG for implanted steers (P = 0·002 in experiment 1, P < 0·001 in experiment 2). Observed responses in LWG to UDP concentration were also poorly predicted (regressions of observed on predicted LWG: experiment 1, r2 = 0·12, residual s.d. = 0·126; experiment 2, r2 = 0·004, residual s.d. = 0·119). It was concluded that oestradiol-17p has significant effects on responses in LWG to UDP, which are not predicted by the current ARC (1980, 1984) protein nutrition scheme.
Milk production from diets of silage and dried forage. 3. Effect of formalin-treated ryegrass silage of high digestibility givenad libitumwith and without urea
Authors: Tayler J. C. , Aston K. , Daley S. R.
Published: September 2010

1. Young adult and adult lactating British Friesian female cattle (heifers and cows) were individually fedad libitumon perennial ryegrass silage (F) made with an additive of formic acid (3·41 of 85% acid/t fresh grass) or on a silage (FF) made from the same crop with an additive of 9·01/t of a mixture of equal volumes of formic acid and formalin (35% w/w solution of formaldehyde). Silage F was supplemented with a concentrate containing 50% dried grass and 50% barley at a low (L) or high (H) level of feeding; silage FF was supplemented with the same concentrate at the lower level only, either with urea at 2·0% of the silage DM (FFLU) or without urea (FFL).

2. Silage F had a lower pH (P< 0·001) and contained more lactic, acetic and total fermentation acids (P><0·001). The DOMDin vivoof the diet was lower (by up to 3 units) for treatment FFL than for the other treatments (P<0·05 in weeks 17 and 18).

3. Over weeks 4 to 18 of lactation the mean dry-matter intakes (DMI) of silage on treatments FL and FFL were similar, but silage DMI was 12 to 13% greater on treatment FFLU than on FL or FFL (P<0·05). Digestible OM intake was greater with FFLU than with FFL (P<0·01) and with FL (P<0·05).

4. Milk yields did not differ significantly between treatments and metabolic blood profiles were normal.
Approximating invariant densities of metastable systems
Authors: GONZÁLEZ-TOKMAN CECILIA , HUNT BRIAN R. , WRIGHT PAUL
Published: September 2010

We consider a piecewise smooth expanding map on an interval which has two invariant subsets of positive Lebesgue measure and exactly two ergodic absolutely continuous invariant probability measures (ACIMs). When this system is perturbed slightly to make the invariant sets merge, we describe how the unique ACIM of the perturbed map can be approximated by a convex combination of the two initial ergodic ACIMs. The result is generalized to the case of finitely many invariant components.
The techniques and technical problems associated with the processing of naturally and artificially dried forage
Authors: Shepperson G. , Marchant W. T. B. , Wilkins R. J. , Raymond W. F.
Published: September 2010

The principal objective to date in packaging dried forages into wafers, cobs or pellets has been to improve handling and storage. Over 80% of the dried forage produced in the UK is still used as a component in pig and poultry rations, for which a milled and pelleted product is the most suitable. However there is evidence that the different forms of package are not of the same nutritive value to ruminants. With the increasing interest in the use of dried forages for ruminant feeding it is important to examine packaging in these dual rôles, as both mechanical and nutritional treatments.
When technology speaks language: an evaluation of course management systems used in a language learning context
Authors: Yu Wen-Kai , Sun Yu-Chih , Chang Yu-Jung
Published: September 2010

In light of the growing popularity of the use of computer management systems (CMSs) in higher education today, this study critically evaluates CMS adoption through a content-specific lens. By employing a mixed-method approach, the study examines college teachers’ and students’ experiences and perceptions of CMS adoption for language learning and teaching purposes. The findings show that despite the users’ perceived advantages of using CMSs in language courses, the systems’ lack of content-area specificity undermines many of the potential benefits. The study calls for better-rounded professional training to assist language teachers in integrating CMS functions strategically into their disciplinary pedagogy and incorporating multimedia language resources selectively to maximize the benefit of CMSs. Furthermore, the findings demonstrate the importance of developing content-specific CMSs with functions tailored toward pedagogical needs in different contexts.
Effects of artificial photoperiods on sexual behaviour and sperm output in the rabbit
Authors: Theau-Clément M. , Michel N. , Esparbié J. , Bolet G.
Published: September 2010

Male rabbits aged from 4 to 4·5 months were subjected to a 8L: 16D photoperiod for 4 weeks and were then split into two groups. One group of13 males was maintained at 8L: 16D (group 8). The other included 16 males and was submitted to 16L: 8D (group 16). Two successive ejaculates zvere collected and analysed once a week for 6 months. Animals from group 8 were sexually more active and ejaculated significantly larger volumes of semen than those from group 16. Performance of males from group 16 was better for all other measurements, whether these were qualitative (motility, percentage of live spermatozoa) or quantitative. Averages for the total number of spermatozoa and number of live spermatozoa per ejaculate were significantly greater in males submitted to 16L: 8D (509 and 408 v. 452 and 344 × 106 spermatozoa, respectively). However the testes of rabbits in group 8 had a significantly greater volume than those in group 16 (22·3 v. 17·4 cm3, P < 0·001). After the animals were slaughtered when 11 months of age, the volume and weight of the testes and the testis and epidydimis reserves did not differ significantly between groups. Under our experimental conditions, the sperm output of bucks exposed to 16 h of daylength was greater than that of bucks exposed to 8 h of daylength but in vivo and post-mortem measurements did not reflect this difference.
Nutrient apparent digestibility and the performance of growing fattening pigs as affected by incremental additions of fat to starch or non-starch polysaccharides
Authors: Bakker G. C. M. , Jongbloed R. , Verstegen M. W. A. , Jongbloed A. W. , Bosch M. W.
Published: September 2010

In a factorial design, animal fat was added incrementally (0, 35, 70 and 105 g/kg) to maize starch (M) or to two sources of fermentable carbohydrates (260 g purified cellulose (C) per kg or 270 g soya-bean hulls (S) per kg). The 12 experimental diets were formulated by replacing maize starch in the control diet with fat, cellulose and soya-bean hulls of equivalent estimated net energy. Ninety-six castrated males were given these diets according to net energy. Apparent digestibilities of crude protein, crude lipid, crude fibre and nitrogen-free extract were measured and were compared with those expected from the separate ingredients. Net energy conversion ratio (nECR) was also measured. Results showed that in the C and the S diets prediction of the apparent digestibility of nutrients was worse than in the M diets (significant effect of source of carbohydrate). Prediction of apparent digestibility of crude protein and crude lipid improved as the added fat increased (significant effect of amount of fat), except in the C and S diets where for digestible crude lipid the 70 g added fat per kg gave the worst prediction (significant effect of the interaction). The net energy calculated from the experimental data on apparent digestibility was proportionately between 0·83 and 0·98 of that calculated from the expected data. The pigs on the C and S treatments showed a significant lower nECR when calculated from the expected apparent digestibility coefficients, but not when calculated from those which were measured. At the highest fat addition, the nECR was poorest. It is concluded that the amounts of digestible components in compound foods cannot always be obtained from those in the separate ingredients.
Effects of food level on performance and behaviour of sows in a dynamic group-housing system with electronic feeding
Authors: Spoolder H. A. M. , Burbidge J. A. , Edwards S. A. , Lawrence A. B. , Simmins P. H.
Published: September 2010

Evidence from studies of group-housed sows in unbedded systems indicates that hunger may be a cause of increased aggression between animals. The present study aimed to investigate the effects of food level on performance, aggression and skin damage in a deep-straw system. Sixteen groups offive gilts were introduced over 8 months to one of two dynamic groups in a deep-straw yard (2·35 m2per sow) receiving different food levels from an electronic sow-feeding system: high (H: 3·0 kg and 38 MJ/day) and low (L: 1·6 kg and 20 MJ/day). Seventy second-parity sows were returned to the same treatments in the same subgroups. The behaviour of the animals was recorded throughout both pregnancies using a time sampling technique. Severity of skin damage was recorded as a number from 0 to 4 for each of nine areas, the average of which being the ‘damage score’. The total number of animals in each dynamic group was maintained at around 30, through the use of additional sows. As expected, H sows were heavier than L sows but no effect offood treatment was found on litter size or performance. L sows were more active (Lv.H; standing: 41v.31% of total observation time respectively, F114 = 7·65,P< 0·05) and showed more straw manipulation than H sows (Lv.H: 17v.10% respectively, F 3 34 = 18·4,P< 0·001). No differences between treatments were found either in number of aggressive interactions (Lv.H: 3·6v.3·8 interactions per sow per observation day, F, u = 0·82, P > 0·05), or in damage score (Lv.H: 0·24v.0·28; Flu = 0·27; P > 0·05).

However, introduction of new animals did influence aggression, with sows being more involved in aggressive interactions on the day they were introduced, than on other sow's introduction days and on no introduction days (Tukey,P< 0·05). Average skin lesions per experimental sow were also higher in the days immediately following introduction. It can be concluded that in a sequential feeding system with plentiful straw, aggression is not influenced by the level offeeding. In these systems, the major factor giving rise to aggression is the introduction of new sows to the resident group.
Predicting changes in food energy requirements due to genetic changes in growth and body composition of growing ruminants
Authors: Amer P. , Emmans G. C.
Published: September 2010

Incorporation of food intake into breeding objectives for ruminants is often difficult because the relevant genetic parameters are unavailable. A non-statistical approach to estimating the genetic relationships between food costs and genetic changes in growth and body composition traits was therefore developed.

Equations which predict additional food requirements associated with genetic changes in growth and body composition traits are derived from an interspecies growth model. In the growth model, a genotype is mainly described according to its expected mature weights of protein, lipid and a composition trait of interest in the empty body under non-limiting conditions. Other model parameters describe the expected growth of the animal in a specific environment.

An example is shown for beef cattle in the United Kingdom, where increases in carcass weight by 1 kg and carcass subcutaneous fat proportion by 0·01 result in increases in food costs by £0·97 and £7·34 respectively for a production system where animals are given an intensive silage/concentrate diet, are slaughtered at 305 kg and have a commercial fat grade 4L. A strong dependence of the results on the type of production system, especially the degree of maturity in protein at slaughter, is demonstrated.

The model is easily adapted to other breeds and ruminant species. The approach is recommended for incorporating food intake into breeding objectives for ruminants in situations where reliable estimates of the necessary genetic parameters for a more conventional specification of the breeding objective are unavailable.
Effects of a maximum permissible journey time (31 h) on physiological responses of fleeced and shorn sheep to transport, with observations on behaviour during a short (1 h) rest-stop
Authors: Parrott R. F. , Hall S. J. G. , Lloyd D. M. , Goode J. A. , Broom D. M.
Published: September 2010

Concern for the welfare of export lambs during long-distance road transport has prompted much research and a recommended change in procedure. The latter envisages an absolute maximum journey time of 31 h and includes a rest-stop (minimum duration 1 h) for feeding and watering. In the present experiment, the physiological and behavioural responses to this new protocol have been investigated in fleeced and shorn lambs (no. = 10 per group) provided with venous catheters and heart rate monitors. The two groups were loaded on a vehicle into separate adjacent pens and driven for 14 h; then unloaded into a lairage, where their behaviour was recorded. After 1 h they were reloaded and driven for a further 15·5 h, finally arriving at a slaughterhouse where carcass condition was evaluated. Blood samples collected at 30- or 60-min intervals by experimenters travelling with the animals were analysed to determine haematocrit, plasma osmolality, plasma concentrations of glucose, creatinine phosphokinase (CPK), and the stress-responsive hormones, cortisol, prolactin, adrenaline and noradrenaline. The results showed that haematocrit increased after loading although the general trend during transport, as with osmolality, was a decline (P< 0·05). No significant changes in plasma glucose were detected but CPK increased in fleeced lambs after loading (P< 0·05). Cortisol release was stimulated by loading, especially in fleeced sheep (P< 0·001) but returned to home pen values within 6 h; heart rates changed in a similar manner. Transport did not markedly affect prolactin release although concentrations were consistently greater in fleeced sheep (P< 0·001). Noradrenaline, however, tended to be higher in shorn animals (P< 0·05). In lairage, both groups readily consumed hay, and especially concentrates, but the shorn lambs spent more time eating (P< 0·001). None of the shorn sheep, and only a few fleeced animals, drank water. There was no evidence for differences in weight loss between the two groups during the experiment and carcass quality at slaughter was within the normal expected range. The implications of these, and other related studies, for future transport policy are discussed, with particular reference to rest-stop duration and handling procedures.
Developing breeding objectives for beef cattle production 2. Biological and economic values of growth and carcass traits in Japan
Authors: Hirooka H. , Groen A. F. , Hillers J.
Published: September 2010

A deterministic bio-economic model simulating beef production during the life cycle of a cow and her offspring was used to estimate biological and economic values of daily gain, marbling score, birth weight, weaning weight and mature weight for three production systems (cow-calf, feedlot and integrated) and alternative production circumstances in Japan. Biological efficiency (live-weight basis and lean-weight basis) and economic efficiency (returns over costs) were regarded as breeding objectives. Alternatives included reducing the maximum number of reproductive cycles, marketing by constant slaughter weight (BASE), constant age or constant carcass fat content, lighter slaughter weight and doubling food prices. Biological efficiency on a live-weight basis for the cow-calf system was most influenced by increasing weaning weight; for the feedlot and integrated system, increasing daily gain had the largest influence. For biological efficiency of lean production, increasing daily gain and mature weight had the largest influence in the feedlot and integrated systems, respectively. For economic efficiency, increasing weaning weight was most beneficial in the cow-calf system and increasing marbling score was most beneficial in the feedlot and integrated systems. Economic values of daily gain and weaning weight decreased markedly with increasing genetic levels of these traits. Marketing by age decreased the biological values of daily gain but increased the economic value of daily gain. Marketing at a constant carcass fat content decreased biological values of mature weight but increased the economic value of mature weight. Decreasing slaughter weight provided negative economic values of daily gain and weaning weight. Economic values were reduced when food prices were doubled.
Effects on maternal and foetal traits of feeding supplement to grazing pregnant ewes
Authors: Frutos P. , Buratovich O. , Giràldez F. J. , Mantecòn A. R. , Wright I. A.
Published: September 2010

Thirty single-bearing Merino ewes were used to examine the effect of feeding supplement, from 91 to 140 days of gestation, on changes in chemical composition of the ewes, on the relationships with live weight and body condition score and on the foetus. Ewes grazed a perennial ryegrass pasture and were offered either no supplement or 500 g per head per day of a concentrate supplement from days 30 to 90 and (or) from days 91 to 140 of pregnancy. Maternal carcass and non-carcass components, uterine wall, foetus and placenta plus cotyledons were chemically analysed. Live weight (LW) and body condition score (BCS) on day 140 were both affected by supplementation during late pregnancy, mobilization of protein and fat being lower in animals receiving supplement. BCS accounted for more variation than LW in the carcass fat depot. Because this depot was the most important source of energy from days 91 to 140 of gestation, this suggests that BCS is a useful estimator of mobilization of maternal fat reserves during this stage of pregnancy. The ability to mobilize reserves and protect foetal growth by Merino ewes in southern Europe, where large fluctuations in grass growth rate exposes them to considerable undernutrition as pregnancy proceeds, was confirmed in this experiment. However, when the nutritional regime is extreme, supplementary feeding to the ewes is recommended, in order to make the whole system economically profitable.
Comparison of laparoscopic and transcervical insemination with frozen semen in Sarda dairy ewes
Authors: Cappai P. , Sanna S. R. , Branca A. , Fraghì A. , Bomboi G.
Published: September 2010

Laparoscopic insemination with frozen-thawed semen is currently used for planned matings in the Sarda breeding programme. In order to find a fast and less intrusive artificial insemination (AI) method that could replace laparoscopic insemination, a field comparison of laparoscopic and transcervical techniques was carried out on 200 mature Sarda ewes. After AI, ewes were assigned to teaser and fertile rams for 2 months. Return rates and cumulative (AI + natural mating) lambing rates were recorded over three subsequent 23-day periods. Lambing rates to AI were significantly different (P < 0·01), and were 62% and 7% respectively for laparoscopic and transcervical AI. Cumulative lambing rates after two further 23-day periods of natural mating were no longer significantly different (P > 0·05) and reached 82% and 74% respectively. Ewes with body condition scores at AI higher than 2·75 showed better overall reproductive performance, but not higher pregnancy rate to AI. Plasma cortisol concentrations, sampled twice, before and after AI, were higher (P < 0·01) in the last sample, suggesting a stress response to insemination. Cortisol levels after AI were lower (P < 0·01) for ewes submitted to transcervical rather than laparoscopic insemination (P < 0·01). However, cortisol levels after AI were no greater than those recorded when ewes were restrained in a milking yoke different from that usually employed. Laparoscopic AI was confirmed as the most suitable technique for insemination offrozen semen in the Sarda breeding scheme.
Comparative digestibility and digesta flow kinetics in two breeds of sheep
Authors: Ranilla M. J. , López S. , Giráldez F. J. , Valdés C. , Carro M. D.
Published: September 2010

A study was conducted to compare apparent digestibility and digesta flow kinetics in the whole digestive tract in two breeds of sheep (Churra and Merino) offered alfalfa hay at about maintenance. Ten mature sheep (five Churra and five Merino) each fitted with a rumen cannula were used in the study. Apparent digestibility was determined by total faecal collection. Liquid (Co-EDTA) and solid (Cr-mordanted fibre) markers were used to estimate rumen volumes and digesta flows. There were no significant differences between Churra and Merino sheep either in dry-matter or fibre apparent digestibility (P > 0·05). Liquid and solid passage rates did not differ between breeds and the estimated total mean retention times were similar for both genotypes. The volume of liquid in the rumen was proportionately 0·14 greater in Churra than in Merino sheep, although the difference was not significant. Estimated saliva secretion was greater in Churra (11·6 (s.e. 0·77) I/day) than in Merino sheep (10·5 (s.e. 0·72) I/day) but the difference did not reach statistical significance. Solid contents of the rumen did not differ between breeds. Rumen particle density was lowest at 2 h after feeding and remained stable at other sampling times, with no significant differences between breeds. There were no significant differences between breeds in the urinary excretion of total purine derivatives but urinary excretion of allantoin and microbial nitrogen supply tended to be higher in Merino than in Churra sheep (P < 0·20). This was attributed to the smaller rumen pool size of Merino (8·0 (s.e. 0·62) kg) compared with Churra sheep (9·2 (s.e. 0·63) kg). The study indicated that there were no apparent breed differences between Churra and Merino sheep in digestibility and digesta passage when they were given a good-quality forage at a low level of intake.
Effect of the dietary fibre origin on the digestion and on the caecal fermentation pattern of the growing rabbit
Authors: Gidenne T. , Bellier R. , van Eys J.
Published: September 2010

The effect of the origin of dietary fibre on digestion and caecal fermentation in the rabbit was studied independently of variations in the level of the different cell wall constituents (cellulose, lignin, etc.). Relationships between microbial activity and the digestion of nutrients were also evaluated over a 4-week growth period. Three experimental diets were givenad libitumfrom, weaning (28 days) to three groups of nine New Zealand White rabbits, subjected to caecal cannulation at 35 days of age with in-vivo digesta sampling at 6, 7, 8, 9 weeks of age. The diets were similar in their content of neutral-detergent fibre (NDF) (320 g/kg dry matter) and in the respective proportions of cell wall constituents (hemicelluloses (NDF - acid-detergent fibre (ADF)) = 0·54, cellulose (ADF -acid-detergent lignin (ADL)) = 0·37, lignin (ADL) = 0·09), but they differed by their main fibre origin: lucerne meal = diet LM, sunflower meal = diet SM, wheat straw = diet WS.

As a consequence of the similar fibre level, the dietary intake was similar among the diets. The NDF digestibility ivas 0·03 units lower for the diet SM, and led to a lower quantity of NDF degraded (3·7 g NDF per day per kg live weight) compared with LM and WS groups (5·0 g NDF per day per kg live weight). Significant variations in caecal volatile fatty acid (VFA) levels were observed between LM and WS, although the intake of nutrients was rather similar, therefore suggesting a direct effect of the botanical origin of fibre. Compared with LM and SM diets, a significantly lower caecal VFA level was found for the WS diet and was associated with a higher incidence of digestive disorders. In the WS diet, fibres that come from only one botanical origin (wheat straw and bran) may be unfavourable to caecal fermentation and to the health status. The ammonia level, the caecal pH and the proportions of the different VFAs were not affected by the diets.

The total VFA level showed a significant quadratic trend between 6 and 9 weeks of age, whereas the butyrate molar proportion showed a significant linear increase from 0·08 to almost 0·10. In parallel, the daily quantity of hemicellulose digested was positively correlated to the butyrate molar proportion (r = 0·884,P< 0·001), and negatively correlated to the caecal pH (r = -0·705, P = 0·022).
The influence of the stag on pubertal development in the red deer hind
Authors: Fisher M. W. , Meikle L. M. , Johnstone P. D.
Published: September 2010

The possible influence of social factors on the timing of puberty in the hind was investigated utilizing seasonally advanced (melatonin-treated) hinds and stags. Melatonin treatment of both sexes resulted in a significant advancement in the onset of pubertal ovarian activity (26 days, P < 0·001) and calving (27 days, P < 0·001) in the treated hinds and antler casting (25 days, P < 0·001) in the treated stags. Ovarian activity and calving were not influenced by melatonin treatment of the stags alone and similarly, antler casting was not affected by melatonin treatment of the hinds alone. However, a group of hinds without stags until after the onset of the breeding season, reached puberty later (5 days, P < 0·05) than hinds with stags, suggesting the presence of the male is important in determining the timing of puberty.
Effect of nutritional growth restriction on timing of reproductive development and plasma concentrations of insulin-like growth factor-1 and growth hormone in male red deer (Cervus elaphus) reared in constant photoperiod
Authors: Adam C. L. , Kyle C. E. , Young P. , Atkinson T.
Published: September 2010

The effect of nutritional growth restriction on reproductive development in red deer stags reared in constant photoperiod was investigated and the correlation between reproductive status and circulating concentrations of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) examined.

Stags were reared from birth in constant photoperiod (12 h light: 12 h dark). They were offered a ‘complete diet’ ad libitum until they reached 52-5 kg live weight (LW) and were then maintained at this LWby restricting daily food dry-matter intake (DMI)for either a long (LR, 26 to 51 weeks of age, no. = 5) or short (SR, 21 to 33 weeks, no. = 6) period before being returned to ad libitum feeding.

Relative to SR stags, antlers hardened later in LR stags (72·0 v. 57·5 weeks of age, P < 0·001); sustained elevations in plasma testosterone also began later (55·2 v. 38·5 weeks, P < 0·001) but at lower LW (54·0 v. 60·6 kg, P < 0·05). In both groups, the testosterone rise followed the return to ad libitum food by 4 to 5 weeks. Plasma IGF-1 was closely correlated with DMI (LR, r = 0·84, P < 0·001; SR, r = 0-93, P < 0·001) and with plasma testosterone (LR, r = 0·42, P < 0·001; SR, r = 0·38, P < 0·01). Also the increase in plasma IGF-1 preceded that of testosterone (by 2·8 (s.e. 0·94) weeks) and was associated with a transient plasma GH peak (P < 0·05) and elevated LH concentrations (SR, P < 0·01; LR, P < 0·05).

The timing of reproductive development in growth-restricted male red deer in constant photoperiod may therefore be more sensitive to DMI than LW, and changes in plasma IGF-1 concentrations are consistent with a putative permissive role in relaying this information.
Sources of genetic variation for milk production in a crossbred herd in the tropics
Authors: Mackinnon M. J. , Thorpe W. , Baker R. L.
Published: September 2010

Crossbreeding parameters and variance components were estimated for lactation and reproductive traits of crosses between the Sahiwal, Brown Swiss and Ayrshire breeds in a dairy herd in sub-humid coastal Kenya. An individual animal model urns fitted to the data with a fixed effect for 20 distinct breed crosses. The estimates of breed cross means were then regressed on average breed content, expected average heterozygosity and recombination loss to determine the additive breed contributions, and the contributions of dominance and epistasis to heterosis. It was estimated that the Sahiwal contributed about 1345 kg (proportionally 0·33) less milk per lactation than the Brown Swiss. The Ayrshire was intermediate. The large amount of heterosis from the crosses of the Sahiwal (Bos indicusj and Bos taurus breeds more than compensated for the lower additive value of the Sahiwal when used in a three-breed rotational cross or synthetic. Heterosis amotig Bos taurus breeds was negligible. Estimates of the maternal heterosis and recombination loss (epistasis) were not significant, although the latter were consistently large and positive. It was concluded that the heterosis between the zebu and European breeds was mainly due to dominance effects. Estimates of heritability for milk yield traits were low (around 0·09 to 0·13) compared with other studies, although estimates of repeatability (around 0·29 to 0·33) were similar to results from the literature, indicating that the accuracy of estimated breeding values in this crossbred herd was reduced because of the non-additive genetic effects. The genetic improvement of crossbred herds is discussed.