Fetuin A (also known as α2-Heremans–Schmid glycoprotein) is a protein primarily expressed by the liver and secreted into the blood. Previous studies have suggested that plasma concentrations of fetuin A are elevated with impaired growth rate in swine. The present study was designed to examine the relationship of porcine fetuin A with growth rate in the pig and to also elucidate the regulation of fetuin A expression by examining the hormonal and cytokine regulation of fetuin A mRNA abundance in hepatocytes prepared from suckling piglets. Quantitative real-time PCR assay was used to quantify the number of fetuin A mRNA molecules/molecule cyclophilin mRNA. Total RNA was isolated from liver of three different groups of pigs to assess changes in mRNA abundance of fetuin A: normal piglets at day 1, day 7 day 21 or 6 months of age (n=6 for each age); runt and control piglets at day 1 of age (n=4); slow growing and normal growing piglets at 21 days of age (n=8). Following birth, fetuin A gene expression increased from day 1 and 7 of age (P<0.05), and then declined at 21 days of age (P<0.05), with a much greater decline to 6 months of age (P<0.01). Fetuin A mRNA abundance was higher in runt pigs v. their normal birth weight littermates (P<0.05). Similarly, fetuin A gene expression was higher in livers of pigs that were born at a normal weight but that grew much slower than littermates with the same birth weight (P<0.05). Hepatocytes were isolated from preweaned piglets and maintained in serum-free monolayer culture for up to 72 h to permit examination of the influences of hormones, cytokines and redox modifiers on fetuin A mRNA abundance. Fetuin A gene expression was enhanced by glucagon, T3 and resveratrol (P<0.05). Growth hormone, cytokines (interleukin6, tumor necrosis factor-α) and antioxidants (N-acetylcysteine, quercertin) reduced fetuin A mRNA abundance (P<0.05). A role for fetuin A in postnatal development is suggested by the differences in fetuin A mRNA abundance between runt piglets or slow growing piglets and their normal growing sized littermates. The hepatocyte experiments suggest multiple hormones and cytokines may contribute to the regulation of fetuin A during early growth of the pig.

Records ivere collected on Romanov (R), Finnsheep (F), and Booroola Merino (B); first cross; and backcrosses of these breeds with a new synthetic breed of Dorset, Leicester and Suffolk (DLS). The data covered the period from the birth of ewes to weaning of their progeny. The heaviest lambs at birth were the B backcross and R first and backcrosses (4·1 to 4·0 kg) and the lightest were pure R (3·0 kg). The fastest pre-weaning average daily gain was that ofR crosses. R purebreds were more fertile (109%, P < 0·01) than F (81%) and B (62%). They were also more prolific at birth and at weaning (2·44, 2·13) than F (2·04, 1·71, P < 0·01) and B (2·36, 2·09, P > 0·05) purebreds, respectively. Similarly, first-cross R ewes were more prolific than first-crosses of F and B (1·99 v. 2·86 and 1·70), also backcross R ewes were more prolific than backcrosses ofF and B (1·63 v. 1·45 and 1·42, P > 0·05), respectively. R first-cross ewes had heavier litters (6·31 and 26·1 kg) than B (5·17 and 20·3 kg, P>0·01) and F (5·52 and 24·4 kg) at birth and at day 50. The lambs born to DLS ewes were the heaviest at birth and at day 50 compared with those from prolific ewes. Fleece weight in B and its crosses was significantly higher than in R. Crosses showed generally positive heterotic effect in weights, prolificacy and wool production compared with pure breeds. In two data sets, additive direct effect ofR was higher than that ofF at birth (by 0·11 and 0·10 kg) and at day 50 (by 0·57 and 0 kg) but was similar at day 100 and day 365. The additive direct effect of both R and F was non-significantly different to that of B at birth in both data sets, but in only one data set was it higher (P < 0·001) at day 50 (by 2·29 and 1·72 kg), at day 100 (by 5·24 and 5·30 kg) and at day 365 (by 8·7 and 8·4 kg, respectively). Maternal direct effects ofR was higher (P < 0·05) than F in lamb weights at day 1 and 50, and higher than B in lamb weight at day 50. Individual heterosis between both R and F and DLS were -3·7 and -3·6% in weight at birth, 1·46 and 2·09% in weight at day 50 respectively. The corresponding maternal heterosis were, -2·9, -5·2, 1·46 and -0·02%.

In order to assess the extent of genotype by environment interactions (G×E) and environmental sensitivity in sheep farm systems, environmental factors must be identified and quantified, after which the relationship with the traits(s) of interest can be investigated. The objectives of this study were to develop a farm environment (FE) scale, using a canonical correlation analysis, which could then be used in linear reaction norm models. Fine-scale farm survey data, collected from a sample of 39 Texel flocks across the United Kingdom, was combined with information available at the national level. The farm survey data included information on flock size and concentrate feed use. National data included flock performance averages for 21-week-old weight (21WT), ultrasound back-fat (UFD) and muscle (UMD) depths, as well as regional climatic data. The FE scale developed was then combined with 181 555 (21WT), 175 399 (UMD) and 175 279 (UFD) records from lambs born between 1990 and 2011, on 494 different Texel flocks, to predict reaction norms for sires used within the population. A range of sire sensitivities estimated across the FE scale confirmed the presence of genetic variability as both ‘plastic’ and ‘robust’ genotypes were observed. Variations in heritability estimates were also observed indicating that the rate genetic progress was dependent on the environment. Overall, the techniques and approaches used in this study have proven to be useful in defining sheep FEs. The results observed for 21WT, UMD and UFD, using the reaction norm models, indicate that in order to improve genetic gain and flock efficiency, future genetic evaluations would benefit by accounting for the G×E observed.

Two lines of pigs that had been selected for five generations for lean tissue growth rate (LTGR) on a high (HP) or low (LP) protein diet were evaluated on a commercial diet (165 g crude protein per kg diet). The growth characteristics of 534 animals were measured, and carcass data were obtained on 405 animals. Differences between lines were tested for significance taking genetic drift into account. The animals from the HP-line grew faster both before and during the test and were 6·5 days younger at slaughter than the LP-line pigs. The HP-line pigs had a higher lean content (587 v. 558 g/kg) and a thinner backfat layer (17·8 v. 22·7 mm) than the LP-line. LTGR was higher in the HP-line (374 v. 347 g/day). No significant differences between lines were found in meat quality or in the incidence of osteochondrosis in elbow or knee. The realized differences between lines confirm that selection for LTGR on a high protein diet was more effective in improving both leanness and growth rate compared with selection for LTGR on a low protein diet.

Three pelleted diets based on rolled barley, whole oats and ground oats respectively were offered ad libitum to mature wethers and growing lambs. With wethers, intakes on the whole oat diet were significantly greater than on the barley diet but digestible dry-matter intakes were not significantly different. On average, growing lambs ate significantly greater quantities of the ground oat diet and whereas digestible dry-matter intakes on the ground oat and barley diets were not significantly different, both were higher than on the whole oat diet. Examined at successive live weights, intakes on the whole oat diet were, at 15 kg, initially lower than on the barley diet but were ultimately higher at 60 kg, when there were no significant treatment differences in digestible drymatter intakes.

In three successive years cows from an Aberdeen Angus cross Shorthorn herd were mated to pedigree Charolais, British Friesian and Hereford bulls. A comparison of the progeny of the three breeds of sire under controlled conditions was therefore possible using a random selection of dams for mating, and identical rearing of the calves. Results for live-weight gain of the suckled progeny were analysed and showed superiority of the Charolais breed over the other two when used in this form of beef cattle production.

For birth weights and daily live-weight gains, particularly during the grazing period, the Charolais cross progeny showed superiority over the other two. There was a consistent although not always statistically significant tendency for these differences between the breed crosses to occur in the male calves only, the females showing little difference between breeds. The data also showed highly significant relationships between gestation period and birth weight, both within and between breed crosses.

Data records from 556 beef heifers which included age at first oestrus (AFE) were used to test the null hypotheses: 1) daylength at birth is not a determinant of AFE in beef females; and 2) there is not an association between the day on which first oestrus occurred and the lunar phase.

The effect of daylength at birth was measured by forming a variable, X1 where X1 = sine (X1′ 360/365·25)°, and including it among the set of variables in a multiple linear regression equation with AFE as the dependent variable. The resultant estimated coefficient on X1 was -3·617 with a standard error of 21·32, and led to the conclusion that daylength at birth was not a factor which affected AFE in this group of beef heifers.

The lunar phase hypothesis was tested by forming the frequency distribution of the 556 observations of first oestrus over the 30-day lunar cycie. The chi-square test was applied with the theoretical (hypothesized) distribution being the uniform distribution. The value of the test statistic was such that the null hypothesis would not be rejected even with an a value approaching 0·50. Additionally, coefficients of autocorrelation calculated for lag phases of 7, 14 and 21 days were quite small. Thus it was concluded that the occurrence of first oestrus was uniformly distributed over the lunar cycle.

There were no differences in toughness, juiciness, intensity of flavour and incidence of taints between samples of meat from wether lambs and cattle which had been treated with oestrogens and similar meat samples from untreated controls.

During feeding trials prior to slaughter both the cattle and sheep which had been given oestrogens gained in live-weight significantly faster than their respective controls.

A total of 142 pigs, born at four different times of the year, were slaughtered between 1 and 9 months of age to study the effects of season of birth and sex on heart weight and body weight in the equatorial climate of southern Nigeria.

Analysis of loge heart or body weight showed that season of birth influenced heart and body growth (P < 0·001). The differences occurred largely during the phase of rapid growth, with smaller differences at weaning and at 9 months. Pigs born during the high-rainfall period (May to September) showed stunted body and heart growth during the subsequent dry and warmer seasons. Those born during the dry seasons (November to March), but which passed their rapid-growth phase through the rainy, cooler seasons, were attaining market weights and adult heart weights earlier in life. However, all pigs with early growth reductions recovered, at least partially, later in life. The males had larger hearts at later ages than the females although the differences were not significant (P > 0·05). Allometric regression analyses for heart and body weight showed no seasonal effects but there was a small but significant sex effect (P < 0·001). The males had a smaller intercept and a larger slope when log, heart weight was fitted to log, body weight.

Pigs reared in this equatorial climate appeared to have higher heart weights relative to body weights than those reared in temperate regions. The highest recorded proportional value of 0·0032 is outside the range of 0·0023 to 00028 recorded in temperate regions. This suggests a probable physiological adaptation to increased work load on the heart under warm tropical conditions.

An 8-h photoperiod, compared with 12-, 16- or 23-h photoperiods, has been shown to reduce the incidence of injurious pecking and leg problems in intact male turkeys but to result in lower body weights, slower sexual development and less efficient food conversion. The effect of 8 h of illumination given as a solid photoperiod, as eight 1-h periods equally spread through the 24 h or concentrated into a 12-h part of the day on the performance of BUT 8 intact male turkeys was investigated.

Fragmentation of the daily illumination increased body weight, improved food conversion efficiency but did not significantly affect food intake. Increased sexual displaying and significantly better food conversion between 16 and 20 weeks by the two intermittently illuminated groups strongly suggested that both regimens were interpreted as stimulatory daylengths. Generally, losses due to mortality and culling were higher in both fragmented groups, while injurious pecking was higher in 8(1L: ID) birds before 5 weeks and in birds given a 12-h ‘subjective day’ after 5 weeks than in 8-h controls. Culling due to leg problems was significantly higher in birds on the 8(1L:2D) regimen but the incidence of leg imperfections was minimal (< 0·037) in all groups. Both intermittent groups but the 8(1L: 2D) in particular, showed a reduced response to hand movement across the eyes compared with 8-h controls. The controls ate proportionately more food during their 16-h dark period than did the intermittent group during their 12-h ‘subjective night’, though both groups increased their ‘nocturnal’ feeding with age.

In three experiments with 60, 72 and 72 housed Greyface (Border Leicester × Scottish Blackface) and Suffolk × Greyface lambs on silage-based diets, a range of barley and fish-meal supplementation levels was compared. In experiment 1, six barley levels ranging from 0 to 625 glday were offered to lambs on flail-harvested and precision-chopped silages. In each of experiments 2 and 3, three levels of barley, 200, 400 and 600 g/day, were factorially arranged with four levels of fish meal, 0, 40, 80 and 120 g/day. The daily intake of flail-harvested silage was proportionately 0·76 of that of precision-chopped silage but because of a slower rate of gain the total requirement of silage dry matter (DM) per kg carcass gain was greater with flail-harvested than with precision-chopped silage. On average, over all barley supplemented diets in experiment 1, the requirement per kg carcass gain was 9·2 kg silage DM and 4·9 kg barley DM, with flail-harvested silage, compared with 8·2 kg silage DM and 3·4 kg barley DM with precision-chopped silage. Increasing barley supplementation in experiment 1 from 125 to 625 gl day reduced the silage DM requirement for carcass gain by 4·7 kg/kg increase in barley DM given. The corresponding figure over the range 200 to 600 g barley in experiments 2 and 3 was 2·6 kg silage DM per kg increase in barley DM given. The reduction in silage requirement with increasing barley was generally greater at low than at high levels of barley supplementation within the ranges examined. On silage-based diets optimum barley supplementation level was estimated to be in the region of 500 g/day.

Increasing fish-meal supplementation from 0 to 40 g/day, in experiments 2 and 3, reduced the requirement per kg carcass gain by 2·78 kg silage DM and 1·25 kg barley DM for an increase of 0·40 kg in input of fish meal DM. A further increase from 40 to 80 g/day fish meal reduced the silage DM requirement per kg carcass gain by 1·44 kg and the barley DM requirement by 0·50 kg, for an increase in input of 0·26 kg fish meal DM. A further increase to 120 g/day fish meal resulted in increases in both the silage and barley requirement per kg carcass gain. The optimum level of fish-meal supplementation was between 40 and 80 g/day and was not affected by the level of barley given.

There was evidence of an increase in carcass fat at the higher levels of gain achieved through increasing barley supplementation, but no evidence of increase in carcass fat at the higher levels of gain achieved through fish-meal supplementation.

Thirty-two Blackface female mature sheep weighing 45 kg on average were blocked by weight and randomly allocated 60 days before slaughter to be untreated controls (C) or subcutaneously implanted with 20 (TA1), 40 (TA2) or 60 (TA3) mg trenbolone acetate (TBA). Samples of blood were collected throughout the study and post-mortem samples of selected body tissues were analysed residues.

Concentrations in blood of 17β-hydroxy-trenbolone (TBOH) peaked within 1 to 2 weeks of implantation and declined thereafter. Concentrations in blood of oestradiol-17β (OE) were elevated and generally increased with increasing dose levels of TBA. The highest concentrations of solvent extractable residues (TBOH for group TA3) ranged from 613 ng/kg in kidney to 130 ng/kg for rib muscle. Trenbolone-17β- glucuronide was detected in liver and kidney at maximum concentrations of 157 ng/kg and 94 ng/kg respectively. Implantation with TBA had no effect on concentrations of OE in any of the post-mortem tissues examined.

Dried molassed sugar-beet pulp in Great Britain has for many years contained about 400 g molasses per kg dry matter (DM). Whilst this high concentration of molasses might help to maximize palatability, in many places outside Great Britain considerably lower amounts of molasses (100 to 300 g/kg) are normally added to sugar beet. The relative costs depend on year-to-year fluctuations.

The nylon bag technique was used to determine the effects of offering to steers an allowance of turnips in a diet based on straw on the degradation of dry matter and acid-detergent fibre of the straw. Rumen-cannulated steers were offered basal diets of (a) sodium hydroxide (NaOH)-treated straw ad libitum, (b) NaOH-treated straw plus turnips (50 g dry matter per kg W0·73) offered once daily or (c) turnips ad libitum. Samples of straw, treated with NaOH, anhydrous ammonia (NH3,) or untreated straw were incubated in nylon bags in the rumen along with each of the basal diets. Additionally molasses (66 g dry matter per kg W0·75) was infused into the rumen of the steers offered the NaOH-treated straw. Dry matter and fibre losses of straw from nylon bags were in the order NaOH-treated > NH3,-treated > untreated; there was no interaction (P > 0·05) between method of straw treatment and effect of basal diet on 40-h or 72-h dry matter or fibre degradability. Supplementation of the basal straw diet with either turnips or molasses depressed (P < 0·01) degradability of both dry matter and fibre of the incubated straw at 40 and 72 h, molasses infusion producing a greater depression (P < 0·05) than offering turnips. There was a fall in rumen fluid pH shortly after steers consumed their turnip allowance or molasses was infused into the rumen, minimum pH values were 6·09 ± 0·241 and 5·75 ± 0·205 respectively. The pH of rumen fluid and degradability of dry matter and fibre of barley straw were depressed by the presence of carbohydrates in turnips and molasses. A reduction in the activity of cellulolytic bacteria may have been the cause of the depression in straw degradability.

The timing in which supplements are provided in grazing systems can affect dry matter (DM) intake and productive performance. The objective of this study was to evaluate the effect of timing of corn silage supplementation on ingestive behaviour, DM intake, milk yield and composition in grazing dairy cows. In total, 33 Holstein dairy cows in a randomized block design grazed on a second-year mixed grass–legume pasture from 0900 to 1500 h and received 2.7 kg of a commercial supplement at each milking. Paddock sizes were adjusted to provide a daily herbage allowance of 15 kg DM/cow determined at ground level. The three treatments imposed each provided 3.8 kg DM/day of corn silage offered in a single meal at 0800 h (Treatment AM), equally distributed in two meals 0800 and 1700 h (Treatment AM-PM) or a single meal at 1700 h (Treatment PM). The experiment was carried out during the late autumn and early winter period, with 1 week of adaptation and 6 weeks of measurements. There were no differences between treatments in milk yield, but 4% fat-corrected milk yield tended to be greater in AM-PM than in AM cows, which did not differ from PM (23.7, 25.3 and 24.6±0.84 kg/day for AM, AM-PM and PM, respectively). Fat percentage and yield were greater for AM-PM than for AM cows and intermediate for PM cows (3.89 v. 3.66±0.072% and 1.00 v. 0.92±0.035 kg/day, respectively). Offering corn silage in two meals had an effect on herbage DM intake which was greater for AM-PM than AM cows and was intermediate in PM cows (8.5, 11.0 and 10.3±0.68 kg/day for AM, AM-PM and PM, respectively). During the 6-h period at pasture, the overall proportion of observations on which cows were grazing tended to be different between treatments and a clear grazing pattern along the grazing session (1-h observation period) was identified. During the time at pasture, the proportion of observations during which cows ruminated was positively correlated with the DM intake of corn silage immediately before turn out to pasture. The treatment effects on herbage DM intake did not sufficiently explain differences in productive performance. This suggests that the timing of the corn silage supplementation affected rumen kinetics and likewise the appearance of hunger and satiety signals as indicated by observed changes in temporal patterns of grazing and ruminating activities.

A total of 48 sub-adult hares and adult reproducing farmed hares were used to characterize carcass and meat traits according to the age and gender of animals. With respect to carcass traits, when age increased, the carcass weight significantly increased (2022 to 3391 g; P<0.001), but dressing out percentages did not change. The dissectible fat (1.3% to 2.2%; P<0.05) and Longissimus lumborum (LL) proportions (13.5% to 14.5%; P<0.001) and muscle-to-bone ratio of hind legs (5.11 to 6.23; P<0.001) increased, whereas the hind leg proportions decreased (37.3% to 36.3%; P=0.01). As for the meat quality, the pH of hind leg (5.74 to 5.83; P<0.001) and LL (5.53 to 5.69; P<0.001) increased with age, while the L* index decreased in both cuts (42.9 to 34.4 in hind leg; 45.1 to 40.3 in LL; P<0.001). The redness index increased at the hind leg (4.07 to 5.76; P<0.001), while it decreased at LL (3.03 to 1.46; P<0.001). In the case of the hind leg, meat thawing losses decreased (1.58% to 1.02%), and shear force increased (2.97 to 4.02 kg/g). In the case of LL, thawing losses decreased (8.79% to 4.91%; P<0.001) in the adult hares compared with the sub-adult ones. Meat water and protein contents decreased in the hind leg and LL of the adult hares compared with the sub-adult ones, whereas ether extract increased in a restricted range in LL only (0.92% to 1.11%; P<0.001). In the case of the hind leg, the rate of the saturated fatty acids (SFA) decreased (41.0% to 26.7%), and the rate of the polyunsaturated fatty acids (PUFA) increased (34.0% to 45.3%) (P<0.001). In the case of LL, SFA (38.6% to 42.9%) and monounsaturated fatty acids (19.4% to 27.2%) increased, whereas PUFA decreased (42.0% to 30.1%) when the age increased (P<0.001). Gender affected only the slaughter results and carcass traits. In conclusion, farmed hares have favourable slaughter results (high dressing percentage), carcass traits (high hind legs and loins rates), and meat nutritional value (high-protein, low-fat meat). This fact would offer additional commercial opportunities, in addition to restocking, to hare farmers.

The metabolic state of pregnant mammals influences the offspring’s development and risk of metabolic disease in postnatal life. The metabolic state in a lactating dairy cow differs immensely from that in a non-lactating heifer around the time of conception, but consequences for their calves are poorly understood. The hypothesis of this study was that differences in metabolic state between non-lactating heifers and lactating cows during early pregnancy would affect insulin-dependent glucose metabolism and development in their neonatal calves. Using a mixed linear model, concentrations of glucose, IGF-I and non-esterified fatty acids (NEFAs) were compared between 13 non-lactating heifers and 16 high-yielding dairy cows in repeated blood samples obtained during the 1st month after successful insemination. Calves born from these dams were weighed and measured at birth, and subjected to intravenous glucose and insulin challenges between 7 and 14 days of age. Eight estimators of insulin-dependent glucose metabolism were determined: glucose and insulin peak concentration, area under the curve and elimination rate after glucose challenge, glucose reduction rate after insulin challenge, and quantitative insulin sensitivity check index. Effects of dam parity and calf sex on the metabolic and developmental traits were analysed in a two-way ANOVA. Compared with heifers, cows displayed lower glucose and IGF-I and higher NEFA concentrations during the 1st month after conception. However, these differences did not affect developmental traits and glucose homeostasis in their calves: birth weight, withers height, heart girth, and responses to glucose and insulin challenges in the calves were unaffected by their dam’s parity. In conclusion, differences in the metabolic state of heifers and cows during early gestation under field conditions could not be related to their offspring’s development and glucose homeostasis.

1. Eight-one British Friesian and 44 Jersey steers was slaughtered at 1. 12, 24, 48 or 72 weeks of age. Those aged 24 weeks and over were reared on a standard complete diet offered ad libitum, and individual food intakes were recorded until slaughter when carcasses were dissected on an anatomical basis.

2. From 1 to 72 weeks British Friesians were on average 50% heavier than Jerseys and consumed 47% more food. Total lean tissue (L) increased 11-fold to 137 + 6·4 kg in the British Friesians and 16-fold to 84 ± 4·7 kg in the Jersey. L as a percentage of live weight rose to 32% ±0·6 in the British Friesians and to 29% ±0·8 in the Jerseys. Breeds did not differ significantly in average efficiency of growth of lean tissue in any period.

3. From 24 to 72 weeks, an allometric relationship held between L and total food consumed postnatally, F. The two breeds had the same allometric coefficient of 0·61. Current efficiency, 0·61 L/F, was thus proportional to cumulated efficiency, L/F. Allowance was made for the prenatal input, Fo, required to produce the newborn calf. An optimum slaughter point at which overall efficiency, L/(F+F0), reached a maximum occurred in each breed when postnatal input was 58% higher than prenatal input (F = 1·58F0). When the breeds had equal maximum efficiency the British Friesian: Jersey ratios for prenatal input, total food consumed and total lean produced were all 2·6:1.

The effects on reproductive performance of different strategies of pasture management designed to conserve herbage in situ during the late growing season for use during the pre-mating and mating period were studied in three experiments over 3 years with Greyface ewes. Two experiments with 341 ewes compared set-stocking of pasture at 12 ewes per ha on two initial levels of herbage mass with a conservation strategy which left half of the area ungrazed and grazed the other half of the area at 24 ewes per ha from late August until mid October (2 weeks before the start of mating) after which the total area was grazed at 12 ewes per ha. In a third experiment with 124 ewes, the conservation strategy left a quarter of the area ungrazed and varied stocking rate to a minimum of 12 ewes per ha to maintain two initial levels of herbage mass on the other three-quarters of the area and then compared set-stocking at six ewes per ha on this area with set-stocking at 18 ewes per ha on the previously ungrazed quarter of the area during the pre-mating and mating period.

Initial levels of herbage mass were within the range of 2000 to 2100 kg dry matter (DM) per ha (7 cm sward height; high) and 1500 to 1700 kg DM per ha (4 to 5 cm; low). Mean herbage accumulation rates between August and October were estimated to be 25 and 44 kg DM per ha per day in the first two experiments. Initial live weight and body condition score also varied considerably between years and subsequent response was influenced by herbage growth rate. Where mean ewe body condition was within the score 2·75 to 3·00, range over the mating period and herbage mass on set-stocked areas was not higher than 2200 kg DM per ha (8 cm sward height) in the pre-mating period or not lower than 1300 kg DM per ha (3·5 cm) at about 3 weeks after mating, the strategy of management did not influence reproductive performance in terms of the number of lambs born. Within these limits, however, reproductive performance was positively related to herbage mass in late August (low = 1·60, high = 1·94).

When herbage mass fell below the 1300 kg DM per ha level before or during mating, reproductive performance was improved by a herbage-conservation strategy which maintained ewe body-condition score within the 2·75 to 3·00 range. When herbage mass and growth rate were high, reproductive performance was also improved by a herbage-conservation strategy which restricted the development of excessive body condition before mating by avoiding the increase in barrenness shown to derive from very high levels of body condition.

Energy metabolism during flushing of mink (Mustela vison) in relation to a control group was studied by means of combining pooled data from balance and respiration experiments carried out in 1993 (experiment I) and 1994 (experiment II) and some blood metabolites from experiment II. The experiments, which were divided into six 1-week balance periods, started on 7 February and continued until 22 March. Flushing was performed by restricted feeding in periods 2 and 3 and refeeding in periods 4 and 5. Each balance period included a 24-h measurement of heat production by means of indirect calorimetry in open-air circuit respiration chambers. In experiment II blood samples were taken at weekly intervals and analysed for total triiodothyronine, total thyroxine, free thyroxine, glucose, insulin and fructosamine. Generally, intake of digestible nutrients and energy metabolism measurements within the flushed group were strongly influenced by period (energy supply), whereas they remained stable in the control group and differences between treatment groups over the total experiment were non-significant. The fluctuation in energy status induced by flushing did not involve major changes in body weight. Blood metabolites reflected the food intake by being fairly stable in the control group and decreasing during restriction and increasing during refeeding in the flushed group (P < 0·05). As an effect of flushing the number of corpora lutea increased significantly (P < 0·05).