Thirty-six piglets were used to investigate the effect of six concentrations of dietary protein ranging from 155 to 235 g/kg, and corresponding dietary lysine concentrations from 10·1 to 15·4 g/kg, on the performance of pigs weaned at 28 days of age and growing between 7·5 and 20 kg live weight. Voluntary food intake was not significantly affected by dietary protein, and growth rate increased with increase in dietary protein and lysine up to 167 and 10·9 g/kg respectively (0·75 g lysine per MJ digestible energy (DE)). Food: gain ratio improved significantly with each increase in dietary protein and lysine up to 177 and 11·6 g/kg (0·79 g lysine per MJ DE) respectively.

Selection for the reduction of carcase fat and the promotion of lean tissue growth has resulted in the production of faster growing, genetically lean breeding females. These animals often have very limited body fat reserves to utilise at times of high nutrient demand, such as during lactation. It is possible that reproductive performance and longevity may be improved as a consequence of alteration of the body composition of the breeding female by nutritional means.

The experiment was designed to investigate the consequences for genetically lean animals of restricting lean tissue growth and promoting fat deposition in the period prior to a maiden service and in gestation using a low protein diet, and minimising fat loss in lactation using a nutrient dense diet (Treatment E) in comparison with feeding a conventional single diet (Treatment C). Two hundred and forty purebred Large White and Landrace gilts were allocated to one of these two nutritional regimes at 6 months of age on the basis of breed, liveweight and backfat. Animals remained on treatment for three parities and growth and performance parameters were monitored.

A 2 × 2 factorial feeding experiment was conducted to examine the effects of varying the maturity level of the grass used to prepare silage and the nature of concentrate starch source and their interactions on dry matter intake (DMI), diet digestibility, energy corrected milk (ECM) production and milk composition in dairy cows. Twenty-eight multiparous Swedish Red dairy cows, 133 ± 45 days in milk (DIM), with an average milk yield of 30 ± 4 kg/day and a live weight of 624 ± 69 kg were blocked by DIM and randomly assigned to seven replicated balanced 4 × 4 Latin squares with four 21-day experimental periods. The experimental diets consisted of four total mixed rations (TMR) consisting of early-cut grass silage (EGS) supplemented with either barley- or maize-based concentrate and late-cut grass silage (LGS) supplemented with either barley- or maize-based concentrate. All TMR contained identical proportions of forage (51%) and concentrate (49%). Total tract digestibility was estimated by determining indigestible NDF (iNDF) concentrations in feeds and faeces and using iNDF as an internal marker. The feeds’ ruminal degradation parameters were determined using both in situ (nylon bag) and in vitro (gas production (GP)) techniques. Cows offered diets containing EGS had greater (P < 0.001) daily dry matter (DM) intakes, ECM yields and total tract digestibilities for DM and organic matter (OM), but these were not affected by the nature of the concentrate starch source. No interaction between the maturity of the silage and the nature of the concentrate starch source was observed for DMI, diet digestibility or ECM yield. Both grass silages and concentrates had similar rates of ruminal degradation of NDF when measured in situ. The in situ DM (P < 0.001) and starch (P = 0.001) degradation rates of barley-based concentrate were greater than those for maize-based concentrate. In vitro OM GP rates and extents were similar for both concentrate feeds. The results showed that diets containing EGS offered better animal performance and diet digestibility than diets containing LGS. The concentrate starch source did not affect animal performance, but total NDF digestibility was better with diet containing barley- than maize-based concentrate.

The majority of sows in the United Kingdom farrow in commercial ‘crates', irrespective of the housing system in which they were kept during gestation. Consumer demand is influencing current thinking on intensive husbandry systems and this, together with approaching legislation concerning the ban on stalls and tethers, is forcing the UK pig industry to move further towards group housing for gestating sows. More research needs to be carried out to assess the effects that the close confinement afforded by farrowing crates, have on sows which have previously gestated in an open environment. The objective of this study was to determine whether the housing conditions of gestating sows had effects on their responses to farrowing conditions.

The study was carried out on twenty - two Large White X Landrace sows ranging from 3rd to 6th parity. Eleven sows housed in stalls, and eleven sows loose-housed in a large group were each observed over two farrowings; once in an open pen and once in a conventional crate, giving eleven farrowings observed in each of four treatments. Five days before the predicted farrowing date, the sows were removed from the dry sow house, weighed, washed and moved to the farrowing house. Here they were recorded, using timelapse video, from entry until farrowing had occurred. Production figures were also noted. The number of posture changes were recorded, and the average duration and total duration per posture type calculated in three separate 24 hour periods.These periods were;1) the first 24 hours in the farrowing house,2) the period between 72-48 hours before farrowing.and 3) the 24 hours preceding farrowing. Not all sows farrowed on the fifth day after entry into the farrowing house, and where Period 1 overlapped with Period 2, the Period 2 results were omitted from the analysis. The postures recorded were; Standing, Sitting/Kneeling, Lying on Udder and Lying with Udder Exposed.

A total of 148 dairy cows in their first lactation and with a mean calving date of 6 December were used in a 4–year experiment. The experiment was designed to examine the effect of level and distribution of concentrate given during the winter period in addition to grass silage (ad libitum) and hay (4 kg/day) on total lactation performance. Each year the same five treatments were compared: three levels of concentrate supply during the winter period (H, M and L), and, for levels M and L, two different allocation patterns (standard (S) or flat rate (F)). Concentrate allocation was individually pre-determined according to expected milk production. During summer, all animals grazed together as a single group. During the experimental period (weeks 4 to 18 of lactation), concentrate and roughage intakes were 6·3, 5·0 and 3·6 kg dry matter (DM) per day and 9.;5, 9·6 and 10·0 kg DM per day in group HS, MS and LS respectively. Milk yield and protein concentration of group HS were higher than that of group MS (+1·3 kg I day and +1·0 g/kg) or LS (+3·0 kg/day and +1·7 g/kg). During winter, live-weight changes were +4, -26 and -39 kg for group HS, MS and LS respectively. Over the 40 weeks of lactation, the differences in milk production and concentrate supply were 193 kg and 196 kg DM between groups HS and MS, and 518 kg and 413 kg DM between groups HS and LS. There was no significant difference between groups S and F.

Six male lambs from each of Najdi, Azvassi and Hejazi breeds of sheep were given the same diet and serially slaughtered at 3, 6, 9 and 12 months of age. Slaughter and growth data including estimates of body maturity were collected. Allometeric growth coefficients were obtained for body components and breed differences in the proportions of the components at the same degree of body maturity or groivth rate were computed.

The live weight of lambs slaughtered at 6, 9 and 12 months of age differed between the breeds. Awassi lambs were less mature than Najdi or Hejazi lambs at slaughter. Hejazi lambs grew (relative to their mature size) faster than lambs of the other two breeds. The allometric regression coefficients of body components were similar1 in the breeds except those of the head, skin and genital organs.

Body composition of the breeds was reasonably similar at the same degree of body maturity or growth rate except skin and feet proportions were higher in Awassi and Najdi lambs, respectively, than in the other two breeds. Thus the three breeds conform to the scaling rules relating growth characteristics to mature size.

In a Welsh Mountain flock of 104 ewes, 51 had their tails tied aside for the duration of one oestrus. Tail-tying significantly increased the conception rate at this oestrus. It also significantly increased the mean litter size of ewes superovulated with 1000IU PMSG from 1·70 to 2·33. It is suggested that the most likely reason for this increase in the number of multiple births was an increased number of ejaculations per oestrus. Perinatal mortality was high in lambs from multiple births. The effect of PMSG and tail-tying was to increase the lambing percentage from 77 to 120.

The experiment compared the performance of pigs from 11 to 56 days of age when given diets based on maize which had been rolled, or ground through coarse, medium or fine screens, or which were made with maize which had been ground through a medium screen and which were then pelleted or pelleted and crumbled. All diets were given ad libitum.

From 11 days to weaning at 28 days, little feed was eaten and there were no significant effects of the treatments. From 29 to 35 days, daily gain and feed conversion were best on the fine, medium and pelleted diets. From 36 to 56 days, pellets and crumble gave the best performance. There were no significant differences between treatments in the incidence of scouring.

In order to avoid excess feed consumption during the force-feeding period in foie gras production, a dose-response experiment with seven feed consumption levels (450, 540, 630, 720, 810, 900, 990 g/day per bird) was conducted to evaluate the effects of feed consumption levels on growth performance and carcass composition of male Mule ducks from 91 to 102 days of age. One-day-old Mule ducklings (sterile and artificial hybrid of male Albatre Muscovy duck and female Pekin duck were fed a two-phase commercial diets for ad libitum intake from hatching to 91 days of age, followed by graded feeding levels of a corn diet by force-feeding from 91 to 102 days of age. Fifty-six 91-day-old male Mule ducks with similar BW were randomly assigned to seven treatments, with eight birds per treatment. Birds were housed in individual pens. At 102 days of age, final BW was measured and BW gain and feed conversion ratio of ducks from each treatment were calculated from day 91 to 102, and then all ducks were slaughtered to evaluate the yields of skin with subcutaneous fat, abdominal fat, breast meat (including pectoralis major and pectoralis minor), leg meat (including thigh and drum stick), and liver. Significant differences in BW gain, total liver weight and liver relative weight were observed among the treatments (P<0.001). According to the broken-line regression analysis, the optimal feed consumption levels of male Mule ducks from 91 to 102 days of age for maximum BW gain, total liver weight and liver relative weight were 217, 227 and 216 g feed/kg BW0.75·per day, respectively.

Poor feed intake of conventional dry diets in the immediate post-weaning period can be a major factor limiting potential growth rate in the young pig. Feeding systems based on the automatic dispensing of liquid milk -substitute have been developed over the last 10-15 years but they have not achieved widespread usage within the U.K. industry for various reasons. Several studies have shown, however, the potential benefit of offering liquid or slurry diets over this critical period around weaning (eg. English, Maclean and MacPherson 1988; Anon 1991). Deprez et a] (1987) also demonstrated its beneficial effects on the morphology of the small intestine post-weaning. The present study examined the use of an experimental automated feeder (‘Autofeeder’, patent applied for) which could dispense a conventional pelleted starter diet plus water (1:1 ratio) 6, 8, 12 or 24 times throughout the day in varying quantities. It was compared against a conventional dry hopper (control) with ad libitum feeding.

In three trials conducted in 3 successive years, Africander, Brahman, Tswana, Tuli and crossbred cattle were injected intramuscularly with 500 jug of cloprostenol on two occasions 11 days apart to synchronize oestrus. The cattle were inseminated 72 and 96 h after the second injection. Controls of the same breeds were exposed to natural service for a period of 22 days. In all trials the conception rate to natural service was significantly higher (P < 0·01).

Conception rates to both breeding methods were highest in Tuli and crossbred cattle and lowest in the Africander and Brahman. Non-lactating cows showed higher fertility than suckling cows and maiden heifers.

Vasectomized bulls used in one trial were shown to be useful in the selection of breeding cows suitable for oestrus synchronization. Further studies are justified to maximize the benefits of a potentially valuable method of breeding beef cattle in ranching conditions.

Complete diets each containing (1) 0%, (2) 20%, (3) 40%, (4) 60% high-quality, (5) 20% and (6) 40% low-quality dried grass were given ad libitum to 48 British Friesian calves.

The performance of the animals was studied over the stages of growth from 50 to 100 kg and 150 to 200 kg live weight. At each stage of growth the live-weight gain was similar on all treatments while the daily intake of dry matter was significantly affected by the treatments. Over the stage of growth from 50 to 100 kg live weight the intake of metabolizable energy was greatest on treatment 2 and lowest on treatment 4. The conversion ratio of metabolizable energy decreased with increasing levels and with both qualities of dried grass over the weight range 50 to 100 kg.

When the calves reached 100 kg live weight, digestibility and N balance studies were carried out. The metabolizable energy (ME) expressed as a percentage of the gross energy decreased with increasing levels and with the lower quality of dried grass. Nitrogen retention was not significantly affected by treatment differences.

The relationships of the voluntary intake of dry matter, ME intake and the conversion ratio of ME with the ME expressed as a percentage of gross energy over the lower live-weight range are also presented.

The data sets consisted of field performance data from 54 848 purebred and 16 175 crossbred animals (Czech data set, CZ) and 16 610 purebred and 9 228 crossbred animals (Slovak data set, SK). Animals from the following breeds were included: Duroc, Hampshire, Piétrain, sire line of Large White (CZ) or Yorkshire (SK), Czech Meat pig (CZ) or Slovak Meat pig (SK), Belgian Landrace (SK). Two-trait animal models were calculated for average daily gain from birth to the end of the field test (ADG) and lean meat content (LM, only in CZ) or backfat thickness (BF, only in SK). The models included additive breed and breed heterotic effects. Piétrain was the breed with the highest LM and the lowest BF. The additive genetic breed effect was about 1·5% LM (CZ) in comparison with Large White or −0·4 mm BF (SK) in comparison to Yorkshire. The sire line of Large White (CZ) or the Yorkshire breed (SK) clearly exceeded all the remaining sire breeds in ADG (on average by 30 to 50 g/day). There was a clear tendency to negative heterosis in LM in all crossbred combinations (CZ). In BF, heterotic effects between −0·2 mm and +0·3 mm were estimated, mostly not being significant (SK). The estimates of the heterotic effects for ADG were positive throughout. Higher values up to 40 g/day (7%) were observed in the Czech data set. Though heterotic breed effects are of some importance especially for ADG, their inclusion in the equations for breeding value estimation will have only a minor impact on the predicted breeding values.

Estimating the feed intake of grazing herbivores is critical for determining their nutrition, overall productivity and utilization of grassland resources. A 17-day indoor feeding experiment was conducted to evaluate the potential use of Medicago sativa as a natural supplement for estimating the total feed intake of sheep. A total of 16 sheep were randomly assigned to four diets (four sheep per diet) containing a known amount of M. sativa together with up to seven forages common to typical steppes. The diets were: diet 1, M. sativa + Leymus chinensis + Puccinellia distans; diet 2, species in diet 1 + Phragmites australis; diet 3, species in diet 2 + Chenopodium album + Elymus sibiricus; and diet 4, species in diet 3 + Artemisia scoparia + Artemisia tanacetifolia. After faecal marker concentrations were corrected by individual sheep recovery, treatment mean recovery or overall recovery, the proportions of M. sativa and other dietary forages were estimated from a combination of alkanes and long-chain alcohols using a least-square procedure. Total intake was the ratio of the known intake of M. sativa to its estimated dietary proportion. Each dietary component intake was obtained using total intake and the corresponding dietary proportions. The estimated values were compared with actual values to assess the estimation accuracy. The results showed that M. sativa exhibited a distinguishable marker pattern in comparison to the other dietary forage species. The accuracy of the dietary composition estimates was significantly (P < 0.001) affected by both diet diversity and the faecal recovery method. The proportion of M. sativa and total intake across all diets could be accurately estimated using the individual sheep or the treatment mean recovery methods. The largest differences between the estimated and observed total intake were 2.6 g and 19.2 g, respectively, representing only 0.4% and 2.6% of the total intake. However, they were significantly (P < 0.05) biased for most diets when using the overall recovery method. Due to the difficulty in obtaining individual sheep recovery under field conditions, treatment mean recovery is recommended. This study suggests that M. sativa, a natural roughage instead of a labelled concentrate, can be utilized as a dietary supplement to accurately estimate the total feed intake of sheep indoors and further indicates that it has potential to be used in steppe grassland of northern China, where the marker patterns of M. sativa differ markedly from commonly occurring plant species.

Thirty-two N'Dama bulls aged 3 to 4 years were used to study the interactions between work, trypanosomosis and nutrition. The bulls were randomly allocated to two treatments, working (W) and non-working (N). Half in each treatment were placed on an andropogon hay basal diet (B), the other half on a better quality groundnut hay diet (H). Five days a week, four pairs of animals in the BW group and and four pairs in the HW group pulled weighted sledges four times around a 2056-m track. Loads were set to ensure energy expenditure was equivalent to 1·4 times maintenance. After 4 weeks all 32 bulls were injected intradermally with 104 Trypanosoma congolense organisms. The trial continued for a further 8 weeks.

Trypanosome infection caused a significant (P < 0·001) decline in packed cell volume (PCV), and the anaemia was more severe (P < 0·05) in working animals; three pairs in the HW group and two pairs in the BW group were withdrawn because PCV fell below 17%. Diet had no effect on PCV or parasitaemia. Infection caused a decline in food intake (P < 0·001) but with significant interactions between diet and work. Intake patterns were similar in the BN and BW groups whilst the HW animals consumed significantly more groundnut hay compared with the HN group (P < 0·01). However, nutrition had no significant effect on lap times or the team's ability to work under trypanosomosis challenge. Post-infection, diet was the dominant factor determining weight change, HN and HW animals weighed significantly more than BN and BW animals (P < 0·01) and the interaction between period, diet and work demonstrated that BWhad the lowest weights in the latter stages of the trial (P < 0·05).

The results suggest that supplementation with better quality forages confers no benefit to an animal infected with trypanosomes. Nor can trypanotolerant cattle sustain long periods of work if subiected to a primary challenge of trypanosomes.

The effect of water restriction on rumen degradability and outflow rate of low quality veld hay and dry-matter apparent digestibility was investigated in four rumen cannulated Tuli × Friesian steers (mean weight 329 (s.d. 36·6) kg) given food at maintenance (metabolizable energy allowance (maintenance) (MJ) = 8·3 + 0·091 M). Two diets with 20: 80 (low, L) and 80:20 (high, H) roughage to concentrate ratios were used in combination with free access to water for 2·5 h once daily or once every 3rd day. A 4 × 4 Latin-square design with a 2 (diets) × 2 (watering frequencies) factorial arrangement of treatments was used.

The degradation pattern of veld hay was not affected by the type of diet and the watering frequency. Although the effective degradabilities of hay in steers given the two diets were low (177 and 258 g/kg for L and H, respectively), they were significantly different (P < 0·05) from each other. However, watering frequency did not affect the effective degradability of hay (218 and 217 g/kg). While the low roughage diet had a higher rumen outflow rate for Crmordanted hay than the high roughage diet (0·047 per h and 0·031 per h), this was not statistically significant. The same outflow rate was obtained for the two watering frequencies (0·039 per h).

SAC Edinburgh has a long established breed improvement programme to increase the lean growth rate of Suffolk sheep. Studies commenced in 1989 to evaluate the extra genetic gain which could be achieved through the application of multiple ovulation-embryo transfer (MOET). Theoretical studies show that rates of genetic progress in sheep could be increased by 100% through use of MOET to increase selection intensity amongst females and reduce female generation intervals (Smith, 1986). However, to achieve these levels of improvement requires good embryo transfer rates (10 progeny per donor) at 6 to 8 months of age. Smith (1986) identified that current transfer rates fell well short of these required by his calculations. Given that minimally invasive techniques for the recovery and transfer of embryos by laparoscopy are available (McKelvey, Robinson and Aitken, 1985a), the main impediment to achievement of the embryo transfer rates required is the low and variable superovulatory response in donor ewes. Previous studies investigating superovulatory drugs to increase the ovulation rate of donor ewes in MOET programmes identified Ovagen (Immuno-Chemical Products), as the most potent product (Dingwall, Fernie, FitzSimons and McKelvey, 1991). This trial reports the use of Ovagen in a large scale MOET programme applied to Suffolk ewes.

Forty-four single- and twin-born New Zealand Corriedale two-tooth ewes and rams aged 14 months were fed individually, in pens, a pelleted ration adjusted to maintain body weight after allowing for wool growth. The sheep were fed for a 3-month settling period, followed by a 3-month experimental period, during which wool growth, fibre diameter, fibre length and net efficiency of wool growth were measured.

Since the wool-growth cycles of the two sexes were found to be out of phase, a valid comparison of the sex data was not possible. Such phase differences may be important in some experimental designs. Significant sex by birth status interactions were identified for all wool production parameters except fibre length, confirming that care must be taken in assigning correction factors during selection of rams and ewes. The general trend was for single-born ewes to produce more and coarser wool more efficiently than twin-born ewes, while the differences between single- and twin-born rams were much smaller. Single-born animals were heavier than twin-born (P<0·01).

Individual values for wool growth and net efficiency varied by a factor of three within sex groups, indicating a considerable scope for selection

Effects of time of supplementation on forage intake, nutrient apparent digestibility and rumen fermentation were studied with 12 mature castrated male sheep (wethers) offered grass hay from 16.30 h to 09.30 h and supplemented with a cereal-based concentrate given at either 09.30 or 16.00 h. Voluntary intake of hay organic matter (OM) was decreased by feeding the concentrate (P < 0·01). Offering concentrate at 09.30 h after hay was available, increased intake of hay and total OM compared with offering it at 16.00 h before hay was available (P < 0·05). Daily pattern of hay intake was not changed when concentrate was offered at 09.30 h compared with feeding hay alone, but concentrate given at 16.00 h resulted in a lower hay intake between 16.30 and 18.00 h. Sheep offered concentrate at 09.30 h had higher rumen ammonia levels than those offered concentrate at 16.00 h, but there were no differences in the apparent digestibility of the nutrients, rumen pH and molar proportions of the main volatile fatty acids. There were also no differences between groups in the blood plasma concentrations of 3-hydroxybutyrate (30HB), nonesterified fatty acids (NEFA) and glucose. It is concluded that feeding supplement after rather than before a period of intake of forage or a bout of grazing may offer a means of minimizing reduction of forage intake as a consequence of feeding concentrate.

Oats constitute a small and decreasing share of the cereals grown and utilized in the United Kingdom. Compared with the major cereals wheat and barley, oats are perceived to have a low nutritive value in terms of metabolisable energy (ME). Unlike other cereals, the husk remains attached to the oat kernel at harvesting, hence increasing the fibre or cell wall content of the grain.

The proportion of kernel to husk which largely determines the nutritive value of the oat grain is dependent on variety, environment and season.

Previous values for oats (MAFF 1986) were based on a study of 16 samples at the Rowett Research Institute (RRI 1976) in which most were spring sown varieties with low oil contents. The aim of this present work was to examine currently recommended winter varieties and also to study naked oats. These differ from traditional husked oats by having a thin, non-lignified husk from which the grain threshes free.