The response of performance tested purebred Simmental heifers to various superovulatory treatments with ovine FSH was examined in two experiments. The heifers were 12 months old at embryo recovery, had average live weights of 468·4 kg (experiment 1) and 493·2 kg (experiment 2), and were fat (body condition score approx.4·0 to 4·5 units) at embryo recovery. In experiment 1, the effect of administering a total of 9·0 or 10·8 mg ovine FSH (Ovagen) administered as eight equal doses twice daily over 4 days was evaluated. In experiment 2, a total of 9·0 mg ovine FSH was administered either in equal doses in a level pattern or in declining doses twice daily over 4 days.

The response to the low, compared with the high, dose of ovine FSH in experiment 1 was 8·8 v. 10·5 ovulations (corpora lutea); 7·7 v. 7·7 totalova plus embryos recovered; 6·0 v. 4·1 viable embryos; 4·4 v. 3·1 grade 1 embryos (P > 0·05); and 1·7 v. 4·1 non-fertile ova(F < 0·01). In experiment 2, the response to the same total dose of ovine FSH administered in a level compared to a declining pattern was 8·5 v. 10·7 ovulations; 5·6 v. 9·6 total ova plus embryos; 3·1 v. 5·6 viable embryos; 2·5 v. 3·8 grade 1 embryos; and 1·7 v. 2·2 non-fertile ova. It was concluded that, although the differences between the treatments in the yields of viable and grade 1 embryos were not significantly different, there are practical and economic advantages to using a low rather than a high level of gonadotropin and there are no marked disadvantages in these areas to administering ovine FSH in a declining rather than a level pattern of doses.

Sixteen first lactation dairy cows were used in a 2 × 2 × 2 × 2 factorial design experiment. Two silages, an extensively fermented inoculant-treated silage or a restricted fermented, mixed aliphatic carboxylic acid-treated silage were offered with two concentrate types (starch- or fibre-based) and supplementary lactic acid (LA, 0·4 kg/day) or soya oil (SO, 0·41 kg/day). Concentrates containing 180 g crude protein per kg were offered at 6 kg/day. Silage dry-matter intake tended to be higher (P = 0·07) with restricted fermented silage compared with the inoculant silage. Milk fat or protein concentrations were not significantly affected (P > 0·05) by silage fermentation type. LA inclusion had no significant effect (P > 0·05) on animal performance. SO inclusion significantly increased (P < 0-05) milk yield (+ 0·8 kg/day), decreased milk fat concentration and yield (40·2, 32·9 g/kg and 779, 667 g/dayfor - and + SO respectively, P< 0·001) and decreased milk protein concentration (-0·81 g/kg, P < 0·01). A significant concentrate × soya-oil interaction (P<0·01) suggested a greater reduction in milk fat concentration with the SO, starch compared with the SO, fibre combination. Modified acid-detergent fibre (P < 0·01) and neutraldetergent fibre (P < 0·001) apparent digestibility coefficients were significantly lower with starch- compared with fibre-based concentrates. Results suggest that milk production responses to changes in concentrate composition were not influenced by the extent of restriction of the silage fermentation process.

The aim of the present study was to investigate the effect of feeding strategy on the performance of oral stereotypies, such as tongue-rolling and bar-biting, and other behaviours in lactating dairy cows. Thirty–seven cows of the Swedish Red and Wliite breed were randomly assigned into three treatments with different feeding strategies. Cows in treatment (AL) were given food ad libitum during the whole experimental period, which lasted from weeks 3 to 26 post partum. The second group (AL–R) was given food ad libitum during weeks 3 to 14 post partum, thereafter they were given food at a restricted level. The third group (R) was given food at a restricted level during the whole experiment period. All cows were offered a total mixed ration consisting of 650 g concentrate and 350 g forage per kg twice a day and their individual daily food intakes were registered. Behavioural recordings were made for 4 h on a fixed day every 2nd week, where each individual cow was observed every 2nd minute.

During the complete experimental period, 27 out of the 37 cows showed stereotypies; 13 cows in group R, 10 in group AL–R and four in the AL group. The proportions of cows showing stereotypies were not independent of feeding treatment within the respective periods (P < 0·01). The stereotypy levels, counted as the mean frequency of recordings per treatment period, increased significantly between period 1 (lactation weeks 3 to 14) and period 2 (weeks 17 to 26) in group AL–R (P < 0·01) and in group R(P < 0·01), but not in the AL group. In period 2 the R cows had significantly higher stereotypy levels than the cows in the AL–R group (P < 0·01). Group R decreased the time spent eating between the periods (P < 0·001), with the same tendency in group AL–R. The AL group had longer eating time in period 2 than the AL–R (P < 0–001) and the R (P < 0·001) cows. The AL cows had a higher frequency of rumination than the other treatments in period 2 (P < 0·01). Both the AL–R and the R cows increased their activity levels between the periods (P < 0·001 for both). There were also differences between treatments in period 2, where the AL cows were less active than the AL–R (P < 0·05) and the R cows (P < 0·01).

It is concluded that oral stereotypies in dairy cows are highly affected by feeding strategy, where restrictive feeding of a mixed food induces significant increases of stereotypies. The results of this investigation clearly indicate that restricted feeding of a diet with high levels of concentrate has a negative effect on the well being of lactating cows.

To examine the effects of increasing the crude protein (CP) content of concentrates at either equal concentrate intake (increasing CP intake) or at reducing concentrate intake (equal CP intake), 44 multiparous Holstein-Friesian cows were allocated to one of five treatments for weeks 4 to 18 of lactation. The treatments were 6 kg dry matter (DM) per day of concentrates containing nominally 200, 300 or 400 g CP per kg DM or 9 or 3 kg DM per day of concentrates containing 200 or 600 g CP per kg DM respectively. In addition 23 first-calf cows (heifers) were offered 5 kg DM per day of concentrates containing 200, 300 or 400 g CP per kg DM. All the animals were offered first-cut perennial ryegrass silage ad libitum. Increasing the concentrate CP content at equal intake caused only small and non-significant increases in silage intake by both heifers and cows. It significantly increased yields of milk and milk protein for both groups but whereas the cows responded to both increments of CP, the heifers only responded to the first. The concentrations of total protein, true protein, casein and non-protein nitrogen (NPN) in milk were significantly increased but the concentration of whey protein remained unchanged. Increasing CP concentration while the concentrate ration was reduced enhanced silage intake but had no significant effect on yields of milk or milk solids. The concentrations of total protein, true protein (non-significant), casein and NPN all increased but whey protein was unchanged. Overall the concentrations of casein and NPN were linearly related to the dietary CP concentration. With both concentrate strategies the proportion of true protein in total milk protein decreased and the proportion of NPN increased with increasing dietary CP concentration but the changes, though highly significant, were relatively small. It is concluded that the strategy of reducing the concentrate ration while maintaining concentrate CP intake causes only small reductions in milk solids production but it is dependent for success on supplies of high-quality grass silage to substitute for the concentrates.

This study examined whether a prolonged anoestrus had any long-term effect on subsequent fertility of cows and estimated the relationship between repletion and resumption of reproductive activity. Twelve low body-condition, non-milking, non-cycling (depletion state) F1 crossbred dairy cows (Friesian × Boron and Simmental × Boran) were stratified to two diets (H: natural grass hay offered ad libitum and mineral lick +3 kg concentrate, and H + P: H + 7 h/day natural pasture grazing) according to parity, body weight, body condition score and calving intervals. Daily dry-matter intake was similar between cows on the two diets, but total intake of nitrogen was proportionately about 0·10 greater for cows with access to pasture. The calculated metabolizable energy intake was more than twice the estimated maintenance requirement for cows on both diets. Live weights increased from depletion to ovulation, to oestrus and to conception, but were not significantly different between cows on both diets. Body condition score increased from depletion time to first oestrus and to repletion and was greater for H + P than for H cows at first oestrus and at conception. After an average of 45 days of repletion, cows were already ovulating with no significant differences between cows on either diet. Days to onset of oestrus were 83 and 44 days for diet H and H + P, respectively. Time to conception was similar between coivs on both diets. Conception occurred when cows on H and H + P diets had recovered proportionately 0·51 and 0·58 of their live-weight and 0·84 and 1·27 of their body condition loss, respectively. Interval to repletion weight was 178 and 139 days for cows on the H and H + P diet, respectively. Cows subjected to an exceptionally long depletion period were able to resume ovarian cyclic activity and to conceive in less than 3 months when given twice maintenance requirements. These results have important management implication for on-farm situations in the tropics where fluctuations of food availability and quality occur.

Eighteen F1 crossbred dairy cows (Friesian × Boran and Simmental × Boran) were allocated to one of three diet groups (H: natural pasture hay; H+3: natural pasture hay + 3 kg concentrate; and H+5: natural pasture hay + 5 kg concentrate) using a stratified random sampling procedure, with parity, milk production genotype, body weight and body condition score as blocking variables. Cows on each diet were then allocated to three draught forces (7, 11 and 15 kg draught force per 100 kg live weight) in a cross-over design to investigate relationships between work output, live-weight changes, dry-matter intake (DMI) and milk yield. Each cow worked for 36 days in early lactation (from calving to 90 days) and for a further 36 days in late lactation (from 250 to 340 days post partum). Work output was similar for cows on each of the three diets. Cows on the H diet consumed more hay than cows on H+3 and H−5 diets. Hay and total DMI, milk yield and milk fat were similar across draught forces and during working and resting days when the cows were not pregnant. Similar results were obtained when cows were from 82 to 172 days pregnant. Pregnancy did not affect the ability of cows to perform work at different intensities. During working days cows lost live weight both when pregnant and when non-pregnant. During rest days, non-pregnant cows on diets H, H+3 and H+5 compensated proportionately 0·12, 0·59 and 0·59, respectively, of the live weight lost during working days. Pregnant cows on diet H+3 and H+5 compensated proportionately 0·95 and 1·77 live weight, respectively. Lower total live-weight losses during the pregnant period could be attributed partly to relatively greater DMIs and lower milk production, but also to gestation. Prediction of live-weight change from total DMI above maintenance, milk yield and work output during periods of 6 working days was poor (R2 = 0·18). However, the same parameters explained adequately changes in live weight for supplemented and non-supplemented working cows (R2 = 0·38 and 0·79, respectively) during a period of 90 days.

In order to study the effect of day length and temperature on performance, data from 495 growing, non-castrated bulls of the Swedish Red and White breed were analysed. Groups of 11 bulls were housed in either an insulated building in pens having slatted floors or in an uninsulated building with pens having both a deep straw bed and a concrete floor. The majority of the bulls (330) were given a concentrate diet ad libitum, while the remainder (165) were given grass silage ad libitum supplemented with concentrate. Energy intake, live-weight gain, housing temperature, day length and change in day length were calculated as 14-day period means for the two housing systems. Regression analyses showed that live-weight gain was associated with increasing day length in bulls on both feeding treatments. For bulls given concentrate ad libitum, metabolizable energy intake was associated with increasing day length. The intake of heavier animals was more influenced by day length than that of those which were lighter. The seasonal influence on daily energy intake in bulls given silage did not show the same pattern as for bulls given concentrate ad libitum. The intake was highest in June and lowest in December for the bulls given concentrate but for the bulls given silage it was highest in August, September and October and lowest in March and April. This was due to the varying quality of the grass silage over the year. No effect or very little effect of temperature or housing system on energy intake or on weight gain was found.

Commercial application of multiple ovulation and embryo transfer (MOET) technology will be subject to practical constraints and economic rationalism. This study examines use of MOET in its most profitable arena: to breed stud rams which will disseminate genetic improvement widely through multiplier studs to commercial flocks. A deterministic prediction is used to evaluate schemes based on an open nucleus MOET group within a Merino parent stud, taking account of genetic merit and inbreeding. Selection is based on clean fleece weight with an assumed heritability of 0·4. Embryos are collected at a rate equivalent to 3·45 live lambs per donor. Benefits of MOET were calculated from the discounted expressions of rams sold, and compared with the costs incurred.

As the proportion of the flock born from MOET increases, the rate of genetic gain increases rapidly at first, but diminishing returns are observed. The costs ofMOET increase linearly with the number of lambs produced, so the optimum proportion ofMOET lambs is for practical purposes always less than 100%.

Some use of MOET was profitable provided the stud sells sufficient stud rams each year. Sensitivity tests found that other parameters had only a small impact on the optimum level ofMOET. In general however, changes which increased the rate of genetic gain (heritability, flock size) or increased its value (wool price, lower discount rate) increased the optimum number ofMOET lambs.

The results should provide guidelines to optimum investment in MOET for the wool industry. An across flock genetic evaluation scheme is probably necessary to motivate this investment.

This experiment involved a commercial evaluation of carcasses of extensively reared crossbred lambs. These were sired by Suffolk rams from either a selection line or a control line of a Scottish Agricultural College (SAC) selection experiment, in which selection wasfor lean growth, or by Suffolk ‘reference sires’ from an industry co-operative breeding scheme (SSRS). The lambs were slaughtered at a target live weight of 42 kg between June and October 1992. In total, 421 lamb carcasses were included in the evaluation, 173 from six selection-line rams, 193 from six control-line rams and 55from three SSRS rams. Each of the carcasses was visually appraised for estimated subcutaneous fat proportion and for conformation of the shoulder, loin and leg, as well as being classified using conventional Meat and Livestock Commission (MLC) scales for fat and conformation. Animals were slaughtered at an average age of 139·5 (s.d. 25·6) days and achieved an average cold carcass weight of 20·04 (s.d. 0·96) kg. Carcasses had an average estimated subcutaneous fat proportion of 122·3 (s.d. 22·4) g/kg — equivalent to MLC fat class 3L to 3H. Overall conformation scores, on a 15-point scale, averaged 8·63 (s.d. 1·80) points. Carcasses were cut into joints according to a leading supermarket specification. The weights of pairs of shoulder, flank, loin and leg joints were obtained for each carcass, as well as weights of bone and fat removed during jointing. Saleable meat weights and proportions averaged 15·31 (s.d. 0·76) kg and 765·9 (s.d. 10·0) g/kg respectively. At a constant carcass weight, the SAC selection-line progeny were significantly younger (-11 days), had a significantly higher carcass value (+£1·50), a significantly lower estimated subcutaneous fat proportion (-13 g/kg), and a significantly higher weight of saleable meat (+0·1 kg) and higher proportion ofsaleable meat (+4 glkg) than control-line progeny, but had lower conformation scores. SSRS progeny had similar growth and fatness to selection-line lambs, but had poorer conformation, and significantly more bone in the carcass than either of the SAC lines. When comparisons were made at a constant estimated subcutaneous fat proportion, all differences in conformation between SAC lines disappeared. However, SSRS progeny remained poorer in conformation. The SSRS rams werefrom afoundation generation of the scheme, and were not expected to be markedly superior for carcass characteristics. Carcass weight was byfar the most important predictor of weight of saleable meat, or leg and loin joint weights. Conformation and estimated fat proportion made only marginal improvements, if any, to the precision of prediction, with fat proportion being the more important of the two predictors.

Stochastic simulation was used to compare selection response and rate of inbreeding in four nucleus breeding systems and a sire referencing scheme for sheep: an open nucleus system (ONS), an open nucleus system with sequential selection of the nucleus (ONS-S), a sire referencing scheme (SRS) and a dispersed open nucleus system (DONS). Selection was based on best linear unbiased prediction of breeding values for a single trait measurable on all individuals prior to selection. Selection in a population of 1200 ewes equally divided into 10 flocks was simulated over a 15-year period. The mean rate of genetic gain was proportionately about 0-15 higher in ONS-S and DONS compared with ONS and SRS. The rate of inbreeding in SRS was considerably lower and in ONS-S, considerably higher, than in the other systems. The level of prolificacy in the population did not influence the relative ranking of the breeding systems but may have implications for their optimal structure.

Genotype × environment and genotype × sex interactions were investigated using lines of Scottish Blackface sheep that had been divergently selected under intensive husbandry conditions for predicted carcass lean proportion, and offspring of rams from these selection lines which were reared under extensive hill conditions. Traits considered were live weight and ultrasonic fat and muscle depth. These were measured at 20 weeks of age on the intensively reared lambs and at 17 weeks of age on the extensively reared animals. Heritabilities for the two environments were 0-39 and 0-20 for fat depth, 0-36 and 0-25 for muscle depth and 0-23 and 0-12 for live weight. Genetic correlations between the environments were 0-54 (s.e. 0-17), 0-90 (s.e. 0-14) and 0-11 (s.e. 0-43) for fat depth, muscle depth and live weight, respectively. The extensive environment may be subdivided according to whether the lambs are reared on improved pasture or on the hill side. The genetic correlations (with s.e.s where estimable) between performance in these two environments were 0-70 (s.e. 0-33), 0-71 (s.e. 0-23) and 1-00 for fat depth, muscle depth and live weight. Genetic correlations between male and female performance under extensive conditions were 0-84 (s.e. 0-28), 0-99 (s.e. 0-14) and 1-00 for fat depth, muscle depth and live weight. T-or fat depth, the genetic correlations of the intensively reared lambs (males only) with extensively reared females and males were 0-37 (s.e. 0-22) and 0-67 (s.e. 0-17), respectively.

Plasma concentrations of growth hormone (GH) are elevated in sheep during undernutrition. The present study attempted to determine whether this increased secretion mediated nutritional effects on reproduction or wool growth, using sheep immunized against growth hormone-releasing hormone and given a low-quality, sub-maintenance diet. Immunization reduced plasma concentrations of GH at all times measured (P < 0·01), through reduced pulse frequency, reduced pulse amplitude, and reduced baseline concentrations. Plasma insulin-like growth factor-1 (1GF-1) was also reduced in the immunized sheep (P < 0·01). Despite this, rates of live-weight loss and wool growth were similar in immunized and control ewes. Plasma concentrations ofLH and FSH were also similar in immunized and control ewes, both during the late luteal phase and after ovariectomy and supplementation with oestradiol and progesterone. Numbers of ovarian follicles and corpora lutea were also unaffected by immunization. It is concluded that high endogenous concentrations of GH in sheep given food below maintenance are necessary to maintain plasma IGF-1, but do not affect the concentration of gonadotropins or ovarian follicular growth. Furthermore, rates of live-weight loss and the depression in wool growth in such animals were also independent of concentrations ofGH or IGF-1.

The rôle of growth hormone (GH) in normal growth is well established, but its rôle during recovery after live-weight loss in adults is less defined. This study examined the interaction of endogenous GH with energy or protein supplements during re-feeding of ewes in low body condition. Control ewes and ewes immunized against growth hormone-releasing hormone were housed in individual pens and given food below maintenance for 107 days, before re-feeding was initiated by supplementing half of each group with either fish meal or barley for 28 days (P1), after which the supplements were switched for a further 28 days (P2). Following supplementation, the ewes grazed abundant green pasture for 92 days before slaughter. Immunization reduced plasma concentrations of GH, insulin, insulin-like growth factor 1 (IGF-1) and prolactin. Production responses to the two food supplements were similar in the control and immunized ewes, but when grazed at pasture immunized ewes gained live weight more slowly (P = 0·06), grew less wool (P<0·01), and had heavier fat depots, but lighter carcass, skin and liver weights at slaughter. The sequence of re-feeding treatments affected subsequent wool production in both control and immunized ewes. During P2, and for 52 days after supplementation ceased, ewes supplemented with fish meal then barley (F/B) produced less wool (P < 0·05) than those supplemented with barley followed by fish meal (B/F). At slaughter, the F/B ewes had lighter omental and kidney fat depots than the B/F ewes (P < 0·05). It is concluded that during live-weight regain, endogenous GH initially affected fat deposition, which in turn affected food intake and wool growth. Furthermore, provision of supplements with a high protein to energy ratio to sheep in low body condition, followed by supplements with a low protein to energy ratio, caused a prolonged suppression of wool growth. This effect was not mediated by endogenous GH.

The effects of spineless cactus (Opuntia ficus indica var. inermis) supply on digestion of wheat straw was studied n rumen cannulated sheep. In addition to urea (10 g) and mineral and vitamin mixture (30 g), the animals — received wheat straw alone or supplemented with graded levels of spineless cactus (150, 300, 450 or 600 g dry natter (DM) per head per day). The diets were studied in five successive 25-day periods from February to June 992 in Tunisia. "Water consumption, food intake, digestibility, diurnal variations of ruminal fermentation (pH, mmonia nitrogen, volatile fatty acids, protozoal concentrations in rumen fluid) and cellulolytic activity in the umen were measured.

Spineless cactus had high contents of ash (260 g/kg DM) and water (926 g/kg fresh weight) and low neutral-detergent fibre content (185 g NDF per kg DM). Crude protein (CP) content of spineless cactus was 2-5 times reater than that of wheat straw (58 v. 23 g/kg DM, respectively). Drinking water consumption was substantially educed (P < 0·001) as the level of spineless cactus increased. When spineless cactus supply exceeded 300 g DM peray, sheep consumed practically no drinking water. The voluntary intake of straw increased significantly with vineless cactus level. Total diet apparent digesibilities of DM, organic matter and CP tended to increase with mneless cactus supply. Such increase was significant only with the 450 and 600 g levels of cactus. NDF and acidetergent-fibre apparent digestibilities were not affected by spineless cactus supply. Addition of spineless cactus up i 300 g DM significantly increased ruminal ammonia nitrogen (P< 0·001) but there was no additional effect with irther supplementation. When sheep were supplemented with spineless cactus, total rumen volatile fatty acid icreased and acetate: propionate ratio decreased significantly. Moreover, spineless cactus supply increased total wtozoa number and reduced significantly rumen cellulolytic activity measured as DM and NDF disappearance of heat straw from incubated nylon bags.

The eyes of eighteen female sheep (Ovis aries) were refracted and details of inter ocular distance, pupil size, shape and fundus presence recorded. The sheep eyes generally possessed very low hyperopia with little astigmatism, such physiological optics being expected to produce a well focused retinal image for objects in the middle and long distance. No evidence was found for accommodation, which would have produced a well focused ocular image for near objects. A further 10 sheep had their monocular and binocular visual fields measured. The estimated visual field suggests the existence of at least binocular vision, if not the presence of stereopsis. Given the lack of accommodation and a wide inter-ocular distance, it is likely that some degree of stereopsis exists in the animal's middle and long distance vision, but is absent in near vision. These findings support those taken from the animal's neurophysiology and observations of its visually guided behaviour.

Ultrasound imaging is widely used in animal breeding to provide in vivo estimates of the carcass composition of candidates for selection. Although the technique is less accurate than more recent medical imaging methods, such as X-ray computed tomography and magnetic resonance imaging, it is relatively cheap and mobile. Therefore large numbers of animals can be measured. Most current ultrasound scanners require some degree of manual interpretation of images, which is time consuming and liable to vary both between and within individuals. Hence, this study investigated the automatic interpretation of ultrasound scans from sheep. A computer algorithm is proposed for identifying tissue boundaries. Estimates of tissue depth are shown to be comparable with those obtained by manual interpretation, for images of 72 sheep scanned twice at the position of the 13th thoracic vertebra. The root-mean-square errors of subcutaneous fat depth and m. longissimus muscle depth ivere 0·7 mm and 1·7 mm, respectively.

The development and moulting of the birth and first adult coat of two genotypes of cashmere-bearing goats, a highyielding Siberian (S) and low-yielding Icelandic × Scottish feral (IF), were examined. Samples of fibre from the neck, mid side, belly and rear-leg areas and of mid-side skin were obtained monthly from five male and five female kids of each genotype from birth to 13 months of age. Guard hair and undercoat length, secondary/primary (S/P) skin follicle ratio and the proportion of skin follicles containing a non-growing fibre with a brush end were recorded. S/P ratio reached an asymptote between 4 and 5 months of age and was higher fP < 0·01) in S (10·7) than in IF (6·7) kids. In both genotypes peaks of brush formation in primary follicles occurred between 2 and 4 months and again between 8 and 11 months of age. In contrast to primary follicles, secondary follicles had only a single peak of brush formation occurring at 10 and 8 months of age for S and IF kids respectively. Guard hair moulted from the birthcoat, but there was no loss of undercoat prior to 12 months of age and harvesting of cashmere prior to this time is unnecessary.

The secondary follicles of S kids had a longer growing period and fibre length increased at a greater rate than that of IF kids, resulting in more than a two-fold difference in the maximum undercoat length. Assessments to estimate the final weight and proportion of cashmere, made prior to completion of growth of the fleece, are likely to underestimate these parameters for high-yielding goats in comparison with their low-yielding counterparts. However, it is unlikely to alter the ranking, and hence the selection, of animals for retention in the breeding herd.

Fast-myosin in frozen histological sections of eight, 10, 11 and nine muscles of the upper forelimb, lower forelimb, upper hindlimb and lower hindlimb, respectively, of goats was quantified by an immunohistochemical micromethod based on the enzyme-linked immunosorbent assay. The structure of the muscles is well preserved during the immunohistochemical measurement. High fast-myosin levels (more than 201 mg/g total protein) were observed in the triceps brachii (lateral head), rectus femoris, vastus lateralis, semitendinosus, semimembranosus, gastrocnemius (lateral head) and long digital extensor muscles. In contrast, low fast-myosin levels (less than 50 mg/g) were found in the triceps brachii (medial head), superficial digital flexor, vastus intermedialis, and soleus muscles. Fast-myosin-positive fibres (type II or fast-twitch type) were distributed more in the superficial regions than in the deeper regions in the triceps brachii (lateral and long heads), biceps brachii, brachialis, biceps femoris, vastus lateralis, vastus medialis, semimembranosus and gastrocnemius (lateral and medial heads) muscles. In contrast, type IIfibres were distributed more in the deeper regions than in the superficial regions in the extensor carpi radialis, deep digital flexor, cranial tibial, deep digital flexor and superficial digital flexor muscles. When the results obtained by the immunohistochemical micromethod were compared with those obtained by biochemical techniques and by histomorphometrical analyses, high correlations were noted. This technique could be used in research projects to study the muscle characteristics that determine meat quality.

Effects of a two-diet system combined with ad libitum lactation feeding of sows on food consumption, sow live weight (LW), backfat depth, condition scoring, rebreeding interval, symptoms of agalactia and culling were studied on 60 sows followed for four parities. Feeding regimes were: CR, conventional i.e. restricted during gestation and lactation; SA, a simplified diet offered at a restricted level during gestation and a conventional diet ad libitum during lactation; CA, conventional during gestation and the same diet ad libitum during lactation. During lactation CR sows consumed 5·9 kg food daily (71 MJ metabolizable energy (ME)), whereas SA and CA sows consumed on average 7·0 kg (85 MJ ME), the difference being larger in multiparous than in primiparous sows and larger in the first than in later weeks of lactation. From the second farrowing onward sows on CR treatment were lighter and had thinner backfat and lower condition scores than sows on CA treatment, with sows on SA treatment in between, i.e. approaching the CR sows in the gestation periods and the CA sows in the lactation periods. At first service LW was 130 kg and backfat thickness 14 mm. During the fourth lactation LW averaged 190 kg in CR sows and around 220 kg for SA and CA sows, and backfat thickness was 11 mm in CR sows and around 16 mm in SA and CA sows. SA sows tended to rebreed earlier after weaning than did CR or CA sows. CA sows and in particular SA sows had higher incidences of agalactia symptoms and higher rectal temperatures post partum than CR sows. The culling rates did not differ between feeding regimes, although the predominant causes for culling did, being shoulder lesions and abscesses in thin CR sows and leg disorders in SA and CA sows. At the end of the experiment, however, more SA sows than others were retained in the experimental herd. It was concluded that the SA feeding regime was superior in terms of sow performance, despite an increased incidence of agalactia symptoms.

Sixty gilts were allotted to one of the following feeding regimes: CR, a conventional diet offered at a restricted level according to Swedish feeding standards; SA, a simplified gestation diet (mainly oats and barley) offered at a restricted level and a conventional diet offered ad libitum during lactation; CA, a conventional gestation diet offered at a restricted level and the same diet offered ad libitum during lactation. The sows were followed for four parities. Piglet birth weight was unaffected by sow feeding, but differences in piglet live weight were found from 3 weeks of age to the end of the experiment when the piglets were 9 weeks old. CA piglets were heavier than SA piglets at 3 and 9 weeks of age and heavier than both CR and SA piglets at weaning (35 ± 3 days). Litter size was unaffected by treatment as was piglet mortality, whereas the cause of death varied with treatment. Mortality due to trauma was higher among CA piglets than among others, while mortality due to weakness was higher among SA piglets than others and there was also a tendency for higher mortality due to diarrhoea among CR piglets. It was concluded that the CA feeding regime was superior with regards to piglet performance.