bluuebunny/crossref_metadata_2025 huggingface dataset:
Cereal grains in complete diets for dairy cows: a comparison of rolled barley, wheat and oats and of three methods of processing oats
Authors: Moran J. B.
Published: September 2010

Two experiments are described in which dairy cows in early lactation were individually offered ad libitum complete diets containing firstly rolled barley, wheat or oats comprising proportionately 0·6 of the total dry matter (DM) and seeondly, whole oats, rolled oats or whole oats soaked in sodium hydroxide comprising proportionately 0·5 of the total DM. Organic-matter (OM) digestibility was measured using chromium III oxide as an external faecal marker and production of milk, milk fat and milk protein were monitored. Rumen digestion rates of each grain type were measured in sacco using non-lactating cows.

In the first experiment, voluntary DM intakes did not differ between diets, OM digestibilities were, in decreasing order, wheat > barley > oats, and faecal starch concentrations were, in decreasing order, barley > wheat > oats. Cows given oats produced the most milk and milk fat while cows given wheat produced the most milk protein. Digested OM was used most efficiently by cows given oats and their greater productivity was attributed partly to higher levels of dietary fibre and lipid.

In the second experiment, cows fed alkali-treated oats had higher (though non-significant) DM intakes and produced the most milk, milk fat and milk protein. Excretion rates of whole grain from cows given treated or untreated whole oats did not differ, but grain weight loss in transit through the gut was higher with the alkali-treated grain. Food intakes and yields of milk and milk solids were similar in cows given either whole untreated or coarsely rolled oats.
Inter-breed relationship of maintenance efficiency to milk yield in cattle
Authors: Taylor C. S. , Thiessen R. B. , Murray J.
Published: September 2010

As part of a multibreed cattle project for studying genetic variation between breeds, four adult females from each of five breeds of cattle were kept for up to 2 years in a non-pregnant, non-lactating state on each of four feeding levels. The breeds, which were Hereford, Aberdeen Angus, Dexter, British Friesian and Jersey, provided a wide range of genetic potential for body size and milk yield. The feeding levels were arranged to make the weight of lipid in the whole body about 0·05, 0·15, 0·25 and 0·35 times body weight. After an animal had been assigned to a fixed daily intake, its body weight and condition score were monitored over a period varying from 6 to 18 months until an equilibrium body weight and body composition had been established.

For standard adult body weight, Akg, and for an equilibrium body weight, Wkg, and an associated metabolizable energy intake, f/MJ, the maintenance efficiency of a breed adjusted for breed size was defined as Em = W/fA0·21. The ‘lactability’ of a breed, that is, its genetic potential lactation yield, Ykg, adjusted for breed size, was defined as Y = Y/A. The between-breed regression of Em on Y had a coefficient of -0·043 (s.e. 0·007). There was, thus, a highly significant dairy-beef gradient in the equilibrium maintenance efficiency of these non-pregnant, non-lactating adult females.

An expected value for the equilibrium maintenance requirement, of a breed or individual as a function of its lactability was estimated to be:

which implies that the maintenance requirement of dairy breeds is about 0·2 times greater than that of beef breeds, a result which was strongly supported by a literature survey, although mean estimates from feeding trials and fasting trials were anomalous.

Combining this result for milk yield with published results on growth rate, leads to the hypothesis that the greater the maximum gross efficiency of a breed for meat or milk production, the less efficiently it maintains itself, not because of any difference in fasting metabolism, but because of a reduced efficiency of food utilization for maintenance.
Amino acid requirements of growing pigs. 7. The response of pigs from 25 to 55 kg live weight to dietary ideal protein
Authors: Yen H. T. , Cole D. J. A. , Lewis D.
Published: September 2010

One hundred and twenty pigs were used in a 3 × 8 factorial design. The factors were sex, 40 trios of littermate boars, castrated males and gilts, and dietary lysine, eight concentrations from 7×5 to 14×5 g/kg diet with 1 g/kg diet intervals of lysine with corresponding crude protein (CP) concentrations from 114 to 226 g/kg diet. Increases in dietary lysine were associated with concomitant increases in the other essential amino acids so as to provide an ideal protein. All diets had similar digestible energy values (13·65 MJ/kg). Pigs were fed once daily on a restricted scale from 25 to 55 kg live weight. For growth and carcass characteristics there was a range of linear response followed by a plateau. The inflexion points of dietary lysine for growth characteristics were at 11·1, 10·2 and 10·9 g/kg diet (171, 157 and 168 g CP per kg diet) together with daily intakes of 18·0, 16·7 and 17·6 g (daily intake of 277, 257 and 271 g CP) for boars, castrated males and gilts respectively. The equivalent points for carcass characteristics were 10·4, 9·7 and 10·1 g/kg (160, 149 and 156 g CP per kg diet) with daily intakes of 16·9, 15·9 and 16·4 g lysine (daily intakes of 260, 245 and 252 g CP). Blood urea data gave good support for these observations.
A note on the factors affecting pre-weaning growth in Beetal and Black Bengal kids and their crosses
Authors: Malik C. P. , Kanaujia A. S. , Pander B. L.
Published: September 2010

The economic value of the goat depends upon its growth and reproductive and productive efficiency. The growth determines the meat producing ability up to a marketable age i.e. 6 months. Rapid growth during the pre-weaning period minimizes the cost of rearing, thus providing more profit to the farmer. The present investigation reports the effect of genetic groups, years and season of birth, sex of kid, type of birth and dam's weight at kidding on pre-weaning growth traits, and the extent of the genetic variability and covariability among these traits.
The energy value to sheep of saturated and unsaturated fat fed singly or in combination
Authors: Wainman F. W. , Dewey P. J. S.
Published: September 2010

Four diets containing either 0 or 50 g fat per kg were prepared from a basal mix of barley, sugar-beet pulp, soya-bean meal and molasses. The fats used were tallow (saturated), soya-acid oil (unsaturated), or a 45:5 mixture of both fats. The diets were given with chopped dried grass to adult wether sheep in the ratio 4:1 of diet to dried grass. Measurements of heat production of the sheep were made in closed-circuit respiration chambers and from the data the efficiencies of utilization of energy for maintenance (km) and production (kf) were calculated for each diet, together with the metabolizable energy (ME) values for the fats.

Values for bothkmandkfwere not significantly different between diets, the means were 0·81 and 0·61 respectively. The ME values (MJ/kg DM) of the fats were for tallow 36·2, for soya-acid oil 36·6 and for the tallow/soya mixture 31·6; these values were not significantly different.

No evidence of any synergistic effect caused by the addition of an unsaturated fat to a saturated fat was seen in this experiment.
A note on the effect of cannulation of the terminal ileum of the growing pig on the apparent ileal digestibility of amino acids in ground barley
Authors: Moughan P. J. , Smith W. C.
Published: September 2010

Ileal digesta are often sampled from the pig through either re-entrant or simple T-piece cannulas. There is conflicting evidence, however, concerning the effects of cannulation on nutrient digestion and absorption. In several studies with the pig, cannulation has not influenced overall protein digestibility (Furuya, Takahashi and Omori, 1974; Sauer, Stothers and Parker, 1977; Taverner, 1979; Huisman, Weerden, Leeuwen, Hof and Sauer, 1984) or energy metabolism (Close, Heavens, Stephens and Sambrook, 1984) while in other studies (Laplace and Borgida, 1976; Sauer, Aherne and Thacker, 1979) there have been indications of adverse effects of cannulation on nutrient digestibility. Livingstone and McWilliam (1985) showed an effect of simple ileal cannulation on pig growth which may have been due to decreased nutrient digestibility or utilization.
Milk production in early lactation dairy cows given grass silagead libitum: Influence of concentrate energy source, crude protein content and level of concentrate allowance
Authors: Sloan B. K. , Rowlinson P. , Armstrong D. G.
Published: September 2010

There is increasing interest in how the raw material make-up of concentrates can influence the milk performance of dairy cows. Thus, over two consecutive winters, 54 dairy cows were used to investigate the effects on dry matter (DM) intake, milk yield and its composition of feeding concentrates of diverse energy source (LNDF — 131 g neutral-detergent fibre per kg DM, 492 g starch plus sugars per kg DM; HNDF — 244 g neutral-detergent fibre per kg DM, 293 g starch plus sugar per kg DM) at two formulated crude protein (CP) levels (157v.187 g/kg DM) and three levels of concentrate allowance (9, 11, 13 kg DM). The concentrates were formulated to be of equivalent metabolizable energy concentration (MJ/kg DM) and were offered with silagead libitumfor a 10-week period (weeks 4 to 13 of lactation).

Silage intakes were variable but not significantly influenced by concentrate energy source or formulated CP level, except in the 1st year where animals consuming the high CP concentrate ate more silage. Silage DM intake decreased as concentrate allowance was increased with the substitution rate (kg silage DM per kg concentrate DM) increasing as concentrate allowance was increased.

Increasing the concentrate allowance effected the expected increases in milk yield. Concentrate energy source did not influence milk yield but the higher CP levels effected a 2-kg increase in milk yield. Feeding of LNDF concentrates depressed milk fat concentration and its yield, the depression being accentuated with each increase in concentrate allowance. The depression in milk fat concentration was negatively correlated with the forage: concentrate ratio of the diet consumed. Furthermore, dietary NDF proportion was shown to account for greater than half of the variation in milk fat concentration. In contrast to the observations made for milk fat, feeding the LNDF concentrates effected an increase in milk protein concentration but only at the lower CP level of the concentrate.
Evaluation of British Friesian, Canadian Holstein and beef breed × British Friesian steers slaughtered over a commercial range of fatness from 16-month and 24-month beef production systems 2. Carcass characteristics, and rate and efficiency of lean gain
Authors: Kempster A. J. , Cook G. L. , Southgate J. R.
Published: September 2010

Carcass characteristics, and the rate and efficiency of lean gain of purebred British Friesian and Canadian Holstein steers and of crossbred steers out of British Friesian dams by Charolais, Hereford, Limousin, Lincoln Red, Simmental, South Devon and Sussex sires were examined in two beef production systems. One was similar to the commercial 18-month grass/cereal system (16-month) and the other to a commercial 2-year system (24-month). The cattle were serially slaughtered at three pre-determined fatness levels, estimated by the Scanogram ultrasonic machine. The trial extended over 4 years and involved a total of 650 cattle, 398 of which had their left sides separated into tissues. Breeds were compared at equal carcass subcutaneous fat proportion determined by visual carcass assessment (SFe). Data for the two production systems were analysed separately.

Sire breed differences were not detected in the regression on SFe for most characteristics (P > 0·05). Sire breeds differed in killing out and visual conformation score in both production systems (P < 0·001): Charolais and Limousin crosses had the highest values and purebred Canadian Holsteins the lowest. The overall range between sire breeds was 30 g carcass weight per kg live weight and five points on a 15-point conformation scale.

Breeds with the higher conformation scores generally had higher carcass lean proportions and higher lean: bone ratios. Canadian Holsteins had a 20 g/kg lower carcass lean proportion than the British Friesians (P < 0·05).

Breed crosses with larger adult body size tended to have higher lean tissue growth rates: the difference between mean values for Charolais crosses and Hereford crosses was 49 g/day (16-month) and 38 g/day (24-month). The lean tissue growth rates of the British Friesians and especially the Canadian Holsteins were low in relation to their adult body size.

Limousin and Charolais crosses had the highest efficiency of lean gain (g lean per kg digestible organic matter intake). These and the other crosses were significantly more efficient than the purebred Canadian Holsteins (P < 0·05). The overall range between breeds was 20 g/kg.
The effect of sward height and active immunization against androstenedione on reproductive performance of ewes of two Welsh breeds in different body conditions
Authors: Gunn R. G. , Rhind S. M. , Maxwell T. J. , Sim D. A. , Jones J. R. , James M. E.
Published: September 2010

In a 2 × 2 × 2 × 2 factorial experiment, the effects on reproductive performance of active immunization against androstenedione and of two sward heights in two periods, August to October (period 1) and October to November (period 2), were investigated in 144 Beulah Speckled-face and 146 Brecknock Cheviot ewes. Sward heights of either 5 to 6 cm (2200 kg dry matter (DM) per ha) (high) or 2 to 3 cm (650 kg DM per ha) (low) were achieved by adjustment of stocking rate during period 1. Two groups of ewes were balanced for body condition score across breed and sward height and the ewes of one group were actively immunized against androstenedione by injection with Fecundin® at 8 and 5 weeks before mating at the second synchronized oestrus after progestagen pessary withdrawal. Ewes were reallocated to the high (at 15 ewes per ha) and low (at 20 ewes per ha) swards at the start of period 2 by breed and immunization treatment, balanced for live weight, body condition score and sward height in period 1. After mating in mid November, all ewes were run at 19 ewes per ha on the residual pasture of the high sward until slaughtered either at return to service or at 4 weeks after first mating when corpora lutea and embryos were counted.

There were no effects or interactions due to sward height in period 1 on the reproductive responses to sward height in period 2. Ovulation and potential lambing rates were greater in the Beulah breed than in the Cheviot, and on the high sward than on the low in period 2. Ovulation rates were higher in immunized ewes than in control ewes but the effects of immunization and sward height on potential lambing rate were not independent. Potential lambing rates were higher in immunized ewes than in control ewes at the low sward height but not at the high sward height.

Adjustment of stocking rate during period 1 served to increase the range in ewe body condition at the start of period 2 in mid October. Reproductive response to body condition at this time differed between the breeds, the relationship being strongly positive in the more prolific Beulah control ewes but less so in the less prolific Cheviot control ewes. The response to immunization in both breeds was relatively greater at lower levels of body condition, thereby reducing the effect of body condition in immunized ewes.

The use of Fecundin® is therefore unlikely to produce much advantage when pre-mating nutrition or body condition are high but there may be some advantage in using it when nutritional resources are limited in the autumn, particularly in ewes in poorer body condition.
Utilization ofdl- andl-tryptophan in young pigs
Authors: Schutte J. B. , van Weerden E. J. , Koch F.
Published: September 2010

Two trials involving young pigs (total numbers 288 and 400, respectively) were performed to compare the biological activity of Dl- and L-tryptophan under restricted (trial 1) andad libitum(trial 2) feeding conditions. In trial 1, three additions of Dl-tryptophan (0·3, 0·6 and 0·9 g/kg) and two additions of L-tryptophan (0·3 and 0·6 g/kg) to a basal diet containing 0·9 g natural tryptophan per kg were tested. In trial 2, the treatments were additions of 0·4, 0·8 and 1·2 g Dl- or L-tryptophan per kg to a basal diet having 1·3 g natural tryptophan per kg. Both trials were of 6 weeks duration. In trial 1, almost equal performance was achieved with both tryptophan sources at a dietary level of 0·3 g/kg, whereas at a level of 0·6 g/kg, Dl-tryptophan produced slightly better performance in weight gain, food intake and food conversion efficiency than did L-tryptophan. In trial 2, the supplemental level of 0·4 g L-tryptophan per kg produced weight gain and food intake results which were significantly superior to those of Dl-tryptophan. However, at supplemental levels of 0·8 and 1·2 g/kg, diets with Dl-tryptophan produced somewhat better performance than did L-tryptophan. Based on the results of trial 2, it was estimated that the pig's need for total tryptophan over the weight range of 10 to 35 kg is at least 2·3 g/kg in a diet having 10·3 MJ net energy per kg.
Some factors affecting the estimation of genetic parameters for cattle dystocia under a threshold model
Authors: Manfredi E. J. , Cristobal M. San , Foulley J. L.
Published: September 2010

Genetic parameters for dystocia in the Main-Anjou breed were estimated. Data consisted of 28 178 birth records collected between 1978 and 1989 in 995 herds, with 161, 71 and 12 415 sires, maternal grandsires and dams, respectively, represented. Original scores (1 through 5) were collapsed in order to set two dystocia definitions: dystocia 1 (scores 1+2v.3+4+5) and dystocia 2 (scores 1v.2+3+4+5). Four models were proposed for genetic parameter estimation: (1) fixed effects plus sire effects; (2) model 1 plus maternal grandsire effect; (3) model 2 plus dam within maternal grandsire effects; (4) same as model 3 but a random effect ‘herds’ replaced a fixed effect ‘regions’. Two methods of fitting models were applied: marginal maximum likelihood and the ‘tilde-hat’ approach. Estimates of genetic parameters by the two methods were similar. Models ignoring maternal effects overestimated the heritability of direct effects especially in the case of dystocia 2. Dystocia definition was responsible for the greatest difference among estimated genetic parameters. Possible reasons for this are discussed. When analysing large data sets, it is recommended judiciously to collapse dystocia categories and to apply approximate statistical procedures to complete models including maternal effects.
The digestion and utilization of amino acids of heat-treated fish meal by growing/finishing pigs
Authors: Wiseman J. , Jagger S. , Cole D. J. A. , Haresign W.
Published: September 2010

A batch offish meal was (a) untreated, (b) heated to 130°C and (c) heated to 160°C under controlled conditions.

In trial 1, these materials were incorporated into a diet based on barley meal (278·7 g/kg), wheat starch (412·5 g/kg), maize meal (245·3 g/kg) and tallow (33·5 g/kg) at a rate of inclusion of 100 g/kg. Diets contained a vitamin/mineral pre-mix together with the inert marker titanium dioxide and were given to four pigs fitted with simple T-piece Heal cannulas over four time periods each of which lasted for 6 days and which allowed the determination of faecal and Heal apparent digestibilities of nitrogen and amino acids. The results indicated that over-heating fish meal results in a reduction in both Heal and faecal apparent digestibility although, as there was no effect of treatment on the quantity of nitrogen absorbed from the large intestine, the two measurements were directly related. Heal and faecal apparent digestibilities for individual amino acids were not the same as data for nitrogen and, accordingly, the latter cannot be used to predict the two former.

In trial 2, the three fish meal samples were included in diets formulated on the basis of total, faecal and Heal apparent digestible amino acids. The nine diets were given to pigs over the live-weight range 27·5 to 52·5 kg. Giving diets formulated on the basis of both faecal and Heal apparent digestible amino acids resulted in improved performance compared with giving diets based on total amino acids when the diets containing fish meal heated to 160°C, but performance achieved with diets containing untreated fish meal was still higher.

Heal apparent digestible amino acids from heat-treated fish meal are not completely available to the pig, and it is suggested that care needs to be taken in equating digestibility with subsequent availability. There appears to be no advantage of using Heal rather than faecal, apparent digestible amino acid values in texms of accuracy of diet formulation.
A note on the effects of high levels of dietary calcium, phosphorus and sodium on nutrient utilization by sheep offered a roughage-based diet
Authors: van Houtert M. F. J. , Leng R. A.
Published: September 2010

Castrated male sheep were offered a roughage without (control sheep, no. = 8) or with calcium, phosphorus and sodium (CaPNa sheep, no. = 8; Ca, P and Na intake 34, 10 and 17 g/day per sheep respectively, given twice daily as drench). Food intake and live-weight change were unaffected. Water intake and urine excretion were higher whereas dry-matter apparent digestibility, nitrogen retention and wool growth were lower in the CaPNa sheep. The excretion of allantoin in urine indicated no differences in microbial protein absorption from the gut. There were small differences in the proportions of volatile fatty acids, numbers of protozoa and mineral concentrations in rumen fluid between the sheep in the two groups. Retentions of Ca, P and Na were higher in the CaPNa sheep, whereas retention of potassium was lower.
A note on the rate of passage of digesta in pigs ileo-rectostomized or fitted with an ileal T-cannula
Authors: Leterme P. , Pirard L. , Théwis A. , François E.
Published: September 2010

A comparison was made between the rate of passage of digesta through the digestive tract of pigs with an ileo-rectal anastomosis (IRA) or an Heal T-cannula according to the single marker dose method by using polyethylene glycol (PEG) as liquid marker, Cr2O3 as solid phase marker and Yb2O3-mordantedcell walls as fibre marker. The rate of passage was slightly faster with IRA than with cannulated pigs.
Production responses of lambs immunized against somatostatin
Authors: Zainur A. S. , Hoskinson R. M. , Kellaway R. C.
Published: September 2010

The production responses of crossbred lambs [Poll Dorset (♂ × (Border Leicester ♂ × Merino ♀)] immunized against somatostatin (sornatotropin release inhibiting factor; SRIF) and whose mothers were also given anti-somatostatin vaccination was investigated in this study. There were no significant differences between immunized and control lambs in term of live-weight gain, food intake, food conversion efficiency, digestibility, eating pattern, wool growth and carcass composition. The concentration of growth hormone in plasma of immune lambs was not significantly elevated, even though the lambs had a generally increasing anti-SRIF antibody titre during the experiment. The findings suggest that although the lambs were successfully immunized against SRIF, homeorhetic mechanisms maintained growth hormone and productivity traits within normal levels.
Effects of management options on creep feeding by piglets
Authors: Appleby M. C. , Pajor E. A. , Fraser D.
Published: September 2010

Effects of creep food presentation on feeding behaviour and intake were studied with eight litters of eight to 10 Yorkshire × Landrace piglets in the 3rd and 4th weeks after birth, before weaning at 4 weeks of age. In each week, four treatments were applied, each for 24 h: a single two-space feeder unchanged from the previous day; a clean feeder with fresh food supplied at 09.00 h; a clean feeder with fresh food supplied at three times during the day; and three feeders (six feeding spaces) providing increased access to food throughout the day. There were no significant differences between the first three treatments in time spent at the feeder (recorded by video over 24 h) or food intake of piglets. However, the fourth treatment increased average intake in week 3 to 2·1 times the average of the other treatments, and in week four to 1·4 times. In week 3, most piglets spent more time at the feeder when access was increased, while in week 4 the effect was restricted to piglets which ate very little. This suggested that imitative learning was important in the initiation of feeding. Analysis of both litter means and within-Utter variation showed that piglets which ate more solid food before weaning gained more weight in the 2 weeks after weaning. However, this correlation was confounded by correlations of both measures with birth weight and other variables. Causal links between creep feeding and post-weaning weight gain remain to be demonstrated.
A note on the use of mate selection in closed MOET breeding schemes
Authors: Toro M. , Silió L. , Pérez-Enciso M.
Published: September 2010

Simulation results of closed MOET schemes have evidenced several problems issuing from selection in small populations using family information and diverse modifications of the original schemes have been proposed. Mate selection, based on linear programming techniques, includes most of the desirable properties of other methods and offers additional advantages. Some applications of this technique to improve the results of dairy cattle MOET schemes with hierarchical and factorial mating systems have been analysed in this note by computer simulation. Other applications of the method are also discussed.
Prediction of the yields of milk constituents in dairy cows offered silagead libitumand concentrates at a flat rate
Authors: Rook A. J. , Sutton J. D. , France J.
Published: September 2010

Individually recorded milk yields, yields and concentrations of milk components, food intakes and live weights of multiparous dairy cows given silagead libitumand concentrates at a flat rate in weeks 4 to 13 of lactation and data for silage and concentrate composition from experiments conducted at four sites, were used to obtain simple correlations and multiple linear regressions of yields and concentrations of milk constituents on other variables.

Simple correlations between yields and concentrations and other variables were low. Yield terms were most highly correlated with intake terms. Milk fat concentration was most highly correlated with silage fibre concentration. Milk protein concentration was most highly correlated with digestible energy intake. The best multiple regression models including time effects accounted proportionately for 0·35 of the variation in fat yield, 0·51 in protein yield, 0·55 in lactose yield, 0·39 in total milk yield, 0·19 in fat concentration, 043 in protein concentration and 0·19 in lactose concentration. Most of these models included terms for silage intake and cow live weight which are not generally available on farms. More practical models including fewer independent variates were therefore produced. These models accounted proportionately for 0·33 of the variation in fat yield, 048 in protein yield, 0·50 in lactose yield, 0·32 in total milk yield, 0·19 in fat concentration, 0·40 in protein concentration and 0·17 in lactose concentration.
Heterogeneity of variance and dairy cattle breeding
Authors: Visscher P. M. , Hill W. G.
Published: September 2010

The effects of heterogeneity among herds in phenotypic variance (σ2p) and in heritability (h2) on the accuracy of evaluation of dairy sires and cows are discussed with reference to estimates from field data. It is argued that heterogeneity of σ2P can be accounted for by using a (Bayesian) regression procedure. While the same procedure could be used to correct for heterogeneity of h2, in most practical situations the sampling errors of the h2 estimates for individual herds are likely to be so large that regressed estimates of h2 will differ little from each other, so constant values can be assumed.
Intake, digestion, gastro-intestinal transit time and nitrogen balance in working oxen: studies in Costa Rica and Nepal
Authors: Pearson R. A. , Lawrence P. R.
Published: September 2010

Experiments were carried out in Nepal and Costa Rica to compare voluntary dry-matter intake (DMI) by oxen of diets based on poor quality hay (Costa Rica) and rice straw (Nepal) supplemented with different levels of concentrate foods when the animals were working and not working. Values for the apparent digestibility of the diets, rates of passage of solid and liquid phases ofdigesta and nitrogen balance are also reported.

Amounts of work calculated to raise daily energy expenditure to 1·3 to 1·6 × maintenance were associated with the following effects. (1) A depression of proportionately 0·11 and 0·14 in the DMI of oxen given a diet based on rice straw plus 18 and 27 g/kg live weight of concentrate respectively during work. No depression of DMI was seen with the hay diets which had slightly higher metabolizable energy but less nitrogen than the rice straw diets. (2) An increase in intake in the weeks following work on both the hay and rice straw diets. (3) Variable effects on apparent digestibility of food probably related more to the changes in DMI. (4) A tendency for gastro-intestinal mean retention time to be increased in working weeks particularly on the more fibrous diets.
Comparison of Friesian, Canadian Hereford × Friesian and Simmental × Friesian steers for growth and carcass composition
Authors: Keane M. G. , O'Ferrall G. J. More
Published: September 2010

One hundred and twenty spring-born steers comprised of 40 Friesians (FR), 40 Canadian Hereford × Friesians (HF) and 40 Simmental × Friesians (SM) were reared together from shortly after birth to slaughter after a mean period of 740 days. During the finishing winter there was a 3 (breed types) × 2 (3 and 6 kg supplementary concentrates per head daily with grass silage ad libitum) × 2 (222- and 225-day finishing periods) factorial arrangement of treatments. One side from each of 96 carcasses (eight per treatment) was completely separated into bone, muscle, intermuscular fat and subcutaneous fat and a 10th rib sample of m. longissimus was chemically analysed.

Carcass weights per day of age and carcass weights were 404, 433 and 449 (s.e. 4·6) g and 301, 320 and 330 (s.e. 3·4) kg for FR, HF and SM, respectively. Corresponding proportions of carcass muscle were 602, 577 and 628 (s.e. 4·8) g/kg. FR and HF had similar proportions of their total muscle in the hindquarter, whereas SM had more of their muscle in the hindquarter. M. longissimus lipid concentrations for FR, HF and SM were 36, 39 and 26 (s.e. 1·96) g/kg. Increasing supplementary concentrate level from 3 to 6 kg/day increased side weight by 7 kg, of which proportionately 0·48 was fat. Extending the finishing period from 121 to 225 days increased side weight by 22 kg of which proportionately 0·45 was fat. Both the higher concentrate level and the longer finishing period reduced carcass muscle and bone proportions, and increased carcass fat proportion. Allometric regression coefficients for side muscle, bone and fat weights on side weight were 0·75, 0·51 and 2·13, respectively. It was calculated that FR, HF and SM would have similar carcass fat proportions at approximate carcass weights of 320, 290 and 380 kg, respectively.
Chemical composition, intake, apparent digestibility and nylon-bag disappearance of leaf and stem fractions from straw of four barley genotypes
Authors: Herbert F. , Thomson E. F.
Published: September 2010

Four experiments examined the chemical composition, intake, dry matter (DDM) and organic matter (DOM) apparent digestibilities and rates of disappearance from nylon bags of hand-separated leaf and stem fractions of straw from four genotypes of barley: Arabi Abiad, Beecher, C63 and ER/Apam. In experiment 1, 900 g leaf from each genotype was offered to three or four wethers together with 200 g soya-bean meal (SBM), and in experiment 2 the leaf from the same four genotypes was offered ad libitum with 200 g SBM. In experiment 3, 500 g stem from Arabi Abiad and Beecher was offered with 100 g SBM to six wethers in two groups. Experiment 4 measured the rate and extent of disappearance of the leaf and stem fractions from nylon bags incubated in the rumen of wethers. The genotypes had widely contrasting morphological characteristics. Stems contained about half as much ash and crude protein as leaves and differences within fractions were small. The leaf and stem fractions of the two-rowed barleys Abiad and Apam contained less modified acid-detergent fibre than the six-rowed Beecher and C63 genotypes.

When leaf was offered with SBM, both restrictedly and ad libitum, the DDM and DOM of this fraction were similar between genotypes (P > 0·05) and in experiment 2 the intake of leaf was also similar between genotypes (P > 0·05). The apparent digestibility of stem differed significantly between Arabi Abiad and Beecher in experiment 3 (P < 0·05). Significant differences were apparent between genotypes in the extent and rate of disappearance of leaf and stem from nylon bags after 48 h incubation in the rumen.
The effect of virginiamycin on sow and litter performance
Authors: Kyriakis S. C. , Vassilopoulos V. , Demade I. , Kissels W. , Polizopoulou Z. , Milner C. K.
Published: September 2010

The present paper discusses the results of a trial study, which was carried out to demonstrate the potential beneficial effects of virginiamycin (VM) on sow and litter performance. VM was added to the sow food at the levels of 0, 20 and 40 mg/kg, for a period of two breeding cycles, covering pregnancy and lactation. VM supplementation of the sow food improved sow performance by: (i) decreasing sow weight loss from farrowing to weaning (first period: 8·78 v. 3·54 v. 2·88 kg, P < 0·05; second period: 8·98 v. 3·93 v. 2·32 kg, P < 0·05), (ii) decreasing the duration of the reproductive cycle (first period: 154·5 v. 152·2 v. 151·2 days, P < 0·05; second period: 153·8 v. 151·5 v. 250·6 days, P < 0·05) and (in) increasing milk fat content (second period: 63·7 v. 81·3 v. 83·3 g/kg, P<0·05). Litter performance was also improved in terms of: (i) litter size at weaning (first period: 8·16 v. 8·88 v. 9·18, P < 0·05; second period: 8·98 v. 9·30 v. 9·76, P < 0·05), (ii) body weight at weaning (first period: 5·78 v. 6·29 v. 6·56 kg, P < 0·05; second period: 5·88 v. 6·38 v. 6·60 kg, P < 0·05), (Hi) average daily gain (first period: 172 v. 189 v. 197 g, P < 0·05; second period: 178 v. 292 v. 198 g, P < 0·05) and (iv) food conversion ratio (first period: 0·356 v. 0·331 v. 0·324, P < 0·05; second period: 0·363 v. 0·334 v. 0·325, P < 0·05). These beneficial effects of VM were more pronounced at the higher of the two inclusion levels.
Relationships among post-calving anoestrous interval, oestrous cycles, conception rates and calving date in Angus and Hereford × Friesian cows calving in six successive years
Authors: Pleasants A. B. , McCall D. G.
Published: September 2010

The records of 1397 cows calving in the spring were collected in the years 1979 to 1984. They were from 638 Angus and 759 Hereford × Friesian cows, and were used to examine the dependencies of post-partum anoestrous interval (ppai), length of oestrous cycle after calving, and conception rate to each oestrus after calving.

Two-year-old cows had longer ppai (P< 0·05) than older cows (76v.72 days), and Hereford × Friesian cows had shorter (P< 0·05) ppai than Angus cows (68v.72 days). Cows due to begin calving on 8 August (early calving) had longer (P< 0·01) ppai than cows due to begin calving on 19 September (71v.55 days).

The linear regression between ppai and calving date (−0·60) did not differ between years, nor between early and late calving. Non-parametric regressions showed that the dependence between ppai and calving date was linear between plus or minus 20 days of the mean ppai in both early- and late-calving herds. Outside these limits variability of ppai increased and there was no relationship with calving date.

The length of the first oestrous cycle after calving was 22 days in 2-year-old cows and 24 days in older cows. Second and third oestrous cycles after calving were 20 days for all breeds and age classes. There was a correlation of −0·41 between the ppai and the length of the first oestrous cycle after anoestrum. There was no significant deviation from normality of ppai or the succeeding post-partum oestrous cycle lengths.

The conception rate to the first oestrus after calving was significantly lower (P< 0·01) than for later oestrous periods. The conception rate to first post-partum oestrus showed dependence on the ppai, logit regressions showing a 0·005 to 0·01 proportional improvement in conception at first oestrus per day increase in ppai.

The significance of these results to the construction of mathematical models of reproduction in the beef cow is discussed.
Initial growth rates of Charolais cross and Hereford cross steer and heifer calves on two methods of rearing
Authors: Lowman B. G. , Scott N. A. , Hinks C. E. , Hunter E. A.
Published: September 2010

Over 3 years a total of 204 bucket-reared calves (from Holstein/Friesian dams) and 187 suckled calves (from Hereford × Friesian dams) were monitored during the first 9 or 6 months of life respectively. Within each rearing system there were approximately equal numbers of calves sired by Charolais and Hereford bulls and also about equal numbers of heifer and steer calves. All breeds and sexes within each rearing system were managed as a single group.

Differences in daily live-weight gain from arrival (January) for the bucket-reared calves and from birth (April) for the suckled calves through to the autumn were significantly different at 0·66 and 1·01 kg/day respectively (P < 0·001). By comparison, differences in growth rate between sex and breed within each rearing system were small. Hereford cross calves from both systems however carried significantly more condition in the autumn compared with Charolais crosses (P < 0·01).

The results suggest that when animals are reared on the same plane of nutrition and given similar management, differences in initial growth rate between early and late maturing breeds and sexes may be less than those perceived by commercial producers the views of whom are influenced by the fact that the types are often managed differently in practice.
Oestrous synchronization in ewes: the effect of combining a prostaglandin analogue with a 5-day progestagen treatment
Authors: Beck N. F. G. , Davies B. , Williams S. P.
Published: September 2010

An experiment was designed to determine whether combining a single injection of 125 μg prostaglandin F2α analogue (PGF) with a 5-day progestagen pessary treatment (PPT) would obviate the problem with refractory animals that occurs when randomly cycling ewes are synchronized with PGF alone. The efficacy of the combined treatment, in comparison with single and double dose PGF regimes, was also assessed.

A total of 210 ewes were used in this investigation conducted during the 1989 and 1990 breeding seasons. In both breeding seasons, 100% of the ewes treated with PGF combined with PPT were mated by fertile rams within a 3-day period, compared with 52·9% of ewes treated with a single injection PGF or 100% of ewes treated with two injections of PGF, 11-days apart. Returns to service for the three groups were 14·2%, 16·2% and 17·4%, respectively. There was no effect of treatment on lambing performance in 1989. However, in 1990 there were differences between groups in gestation length and birth weight, but these were attributable to enzootic abortion. The results demonstrate that PGF combined with PPT will produce levels of oestrous synchronization and fertility comparable with other methods.
Evaluation of pig genotypes 1. Theoretical aspects of measuring genetic parameters
Authors: Ferguson N. S. , Gous R. M.
Published: September 2010

Predicting the performance of animals is a general problem in animal production, the solution to the problem depending, in part, on being able to describe the animals adequately. Numerous approaches have been made to model the growth of pigs, with different methods being employed to describe the genotype. A simple approach is to describe the potential rate of growth of body protein using a Gompertz equation, and to predict the growth of the other chemical components of the body using allometry. These components are added to determine the body weight of the animal.

In this paper an experimental procedure is proposed that will predict values for the parameters of the Gompertz growth equation under non-limiting conditions. These parameters include the rate of maturing of the animal and the mature protein weight. The lipid-to-protein ratio at maturity is required to describe the allometry between protein and lipid. With these few parameter estimates the potential growth rate of animals can be described. It is then possible to use this information to predict the growth rate of animals under conditions constrained by the food or the environment.
Some attributes of very high-yielding British Friesian and Holstein dairy cows
Authors: Wood P. D. P. , Wilson P. N.
Published: September 2010

In 1979/80, 390 cows of black and white breeds produced more than 750 kg fat plus protein in a 305-day lactation, compared with a mean of 390 kg for all recorded black and white cows. The cows were distributed in 207 herds and were the daughters of 177 sires whose breeding values (with population means in brackets) were +220 kg milk ( + 100), +8 kg fat (+5) and +6 kg protein (+2). The farms on which they were kept were not markedly different from average holdings in England and Wales. Management was characterized by high labour input, with high intakes of diets containing a high energy and protein concentration, and care was taken to ensure that food was on offer at all times. Grassland management tended towards conservation by silage rather than hay. Calving intervals were slightly longer than average (393 days v. 386 days for all recorded cows of a similar age).

The most obvious characteristic of management was the close attention given to ways of persuading the animals to eat enough food to satisfy their nutritional requirements.
The influence of plane of feeding in early life on the fertility of gilts
Authors: Lodge G. A. , MacPherson R. M.
Published: September 2010

The results of a previous experiment suggested that a scale of feeding at about 60% of full-feed level from weaning onwards could result in a high incidence of infertility in gilts, but numbers were insufficient to confirm this. The present trial was carried out, therefore, with 18 Large White gilts per treatment fed to scales rising from either 1·4 lb. meal per day at 36 lb. live-weight to 5·0 lb. at 200 lb. live-weight, or from 1·9 lb. to 6·5 lb. over the same weight range. Average growth rate of the low-plane gilts was 76·5% of that of the medium-plane group but none of the low-plane gilts failed to conceive.
Intensive beef production 2. The effect of three, twelve or sixteen week weaning on the performance of Aberdeen-Angus crossbred cattle
Authors: Aitken J. N. , Preston T. R. , Whitelaw F. G. , MacDearmid A. , Charleson Euphemia P.
Published: September 2010

1. Some characteristics are described of 10 steer progeny of a Friesian bull which is known to have carried the factor for muscular hypertrophy.

2. On average these steers had a higher birth weight, lighter hide and liver, smaller feet and cannon bones, a lower percentage of fat and higher percentage of lean in the 10th rib joint, than the progeny of three other Friesian bulls reared at the same time and under the same conditions.

3. No one character was an adequate criterion for separating affected from normal progeny. It appears possible that the bull concerned was homozygous for the double muscling gene, and that all his progeny showed one or more symptoms of the condition.
Herd-by-cow interaction effects in dairy production records
Authors: Searle S. R.
Published: September 2010

Records of cows each milked in two different herds have been used to estimate a component of variance due to cows that is free of variation arising from cow-by-herd interaction effects. By making use of a prior estimate of within-herd repeatability the variance component due to cow-by-herd interaction effects was estimated, and found to represent 35% of the total within-herd variance of butterfat yields and 9% of that of butterfat percentage records.
Birthcoat shedding in Wiltshire horn lambs
Authors: Slee J.
Published: September 2010

Observations on 160 Wiltshire lambs showed that shedding of the birth-coat occurred as a seasonal (normally May–July) phenomenon between the ages of 2 and 5 months. Denudation was usually considerable but not always complete. The average extent of denudation in 3 successive lamb crops was 89 %, 74 % and 92 %. Shedding usually spread progressively across the body according to a consistent, bilaterally symmetrical pattern.

Shedding did not appear to be influenced by the sex of the lamb, birthcoat type (hairy or smooth), or by follicle density, ratio of secondary: primary follicles, or fibre diameter. However, a number of different causes of variation in shedding behaviour were found.

1. Lambs born at different times tended to synchronise in onset of shedding so that they were more alike in the dates when they shed than in the ages at which they did so. Very early and very late-born lambs showed least effective synchronisation. Early lambs were older but still earlier than normal in commencing to shed; late lambs shed when younger than normal and in an atypical fashion. It was concluded that the age of the lamb, and an unknown environmental stimulus both interacted to influence shedding.

2. There was a positive association between rate of gain in live-weight and earliness of shedding. Differences in level of nutrition seemed associated with differences in rate of shedding between individual lambs and also with overall differences in the average rates of shedding between years.

3. Genetic variation in shedding was suggested by twins being more alike than half-sibs in some aspects of shedding, particularly when differences in level of nutrition were discounted.

4. In Wiltshire foetuses the order and pattern of development of embryonic follicles in different body areas resembled closely the sequence and pattern of subsequent birthcoat shedding. A causal connection was postulated.

In discussion it was suggested that there was a seasonally fluctuating environmental factor (possibly daylength), which was capable of reacting upon the Wiltshire lamb between the months of March and July. A hypothesis was developed to explain how such a stimulus could react upon the pelage follicles to produce the observed patterns of birthcoat shedding.
Social behaviour of domestic animals. IV. Growing pigs
Authors: McBride G. , James J. W. , Hodgens N.
Published: September 2010

1. The normal pattern of social behaviour in growing Large White and Berkshire pigs is described. The pigs were observed from 8 to 16 weeks of age in pens of 6 to 10 pigs. Large Whites were more aggressive than Berkshires.

2. Social rank was found to be positively correlated with initial weight.

3. Initial weight and social rank both influenced growth; the relative effect of rank compared with that of initial weight was greater in the second month than in the first.

4. The contribution of social rank to the total variance in growth over the 2-month period was estimated at about 13%.

5. It is suggested that the use of individual housing in pig progeny test schemes may not be desirable because of the absence of social environmental effects.