In extensive pastoral systems, where mating cannot be controlled, the breeding strategies of intermingling owner flocks interact. We present a method to evaluate a breeding programme in extensive reindeer (Rangifer tarandus) management which can also be applied to other pastoral production systems. Our main objective was to evaluate the method by applying sensitivity analyses. The method included a gene flow model with maternal effects. The potential response Rp was defined as the response that could be achieved in a closed nucleus with a given selection procedure. The value of Rp was derived from the gene flow from dams to daughters, selection differentials, and the realized difference between subpopulations. We studied a population structure having two subpopulations, only one of which had been subjected to selection. Random mating between subpopulations and a common male pool were assumed. A reference case was defined using reindeer data from the literature. After 9 years of continued selection among progeny the estimate of Rp was 7·0 times higher than the realized subpopulation difference. We analysed deviations of Rp from the reference case caused by different female age structures between subpopulations. We also analysed the sensitivity of maternal effects. The method proved insensitive to differences in female age structure between subpopulations but was sensitive to the relative contribution of maternal effects to progeny performance.

The contribution of the leucine/valine substitution at amino acid position 127 in the bovine growth hormone (GH) protein to variation in carcass traits was studied. The data included 109 Polish Friesian bulls slaughtered at 15 months of age. The traits measured were carcass gain, weights of meat, bones, intermuscular and subcutaneous fat in the carcass and meat, bones and fat in valuable cuts (fore and best ribs, sirloin, round of beef and shoulder). The bulls’ GH genotype was determined using the PCR-RFLP technique. The frequencies of leucine (Leu) and valine (Val) alleles were 0·64 and 0·36, respectively. The GH concentration was determined in serial blood plasma samples collected every 15 min starting from 15 min before to 135 min after intravenous administration of 0·15 µg thyrotropin releasing hormone (TRH) per kg live weight. Response GH variables were: baseline (the mean of samples collected at –15 and 0 min), peak (the sample taken at 15 min post injection of TRH) and disappearance rate (calculated as peak minus the sample at 60 min, divided by time interval 45 min). Mixed animal models were used for the statistical analysis. Differences were found between the Leu/Leu and the Val/Val genotypes for carcass gain and weight of meat in the carcass (P ≤ 0·05). Moreover, differences in the size of the GH peak between the two homozygotes approached significance (P ≤ 0·10). The effect of GH genotype accounted for a moderate part of the phenotypic variance in the carcass traits, corresponding to a reduction in the residual variance of ≤ 5·25% when included in the model, whereas the corresponding value for the effect of GH genotype on the variation in GH release was lower, ≤ 1·77%. In conclusion, the Leu/Val polymorphism seems to be associated with carcass traits in dairy bulls, although the effect was relatively small when compared with the effects of season and background genome.

Estimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.

Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).

This investigation was designed to evaluate the effects of the dietary inclusion of vegetable oil and its composition on fatty acid composition and lipid oxidation in pig muscle. Pigs were given the following diets from 50 kg to slaughter (90 kg): a control diet with no added fat (NF) or diets containing 20 g/kg of sunflower (SUN), olive (OL) or sunflower + linseed (SUN + LIN) oils. Meat from pigs given the SUN + LIN diet showed the highest thiobarbituric acid reactive substances (TBARS) from day 3 of refrigerated storage to the end of the experiment (P < 0·05). The OL group showed the lowest TBARS after 9 days of storage (P < 0·05). Pigs on NF showed intermediate values that were generally closer to those recorded for pigs given the SUN + LIN than the OL diet. By day 9, there was no statistical difference between the NF and the SUN + LIN group. The SUN group also showed intermediate TBARS throughout storage, with no statistical differences compared with the NF group. After 9 days of storage the lowest CIELAB a* value, corresponded to the SUN + LIN group and the highest to the OL group. These results indicate similar behaviour to that of lipid oxidation. Meat samples from pigs given the diet not enriched with fat showed greater drip loss than those given the remaining diets (P < 0·05) while there was no significant effect of dietary fat source on water-holding capacity. The inclusion of oils rich in linoleic fatty acids in pig diets modifies muscle fatty acid composition but susceptibility to lipid oxidation does not appear to be increased with respect to that occurring in pigs given diets with no added fat.

This study investigated the effects of flock, sex and leg shape scores (assessed in the live animal) on the carcass yield, conformation and composition of purebred Texel lambs. Two flocks were managed in a common environment. The first (Lean Index flock) had a 6-year history of selection for lean tissue growth rate using an index of live weight and ultrasonic muscle and fat depths measured at 20 weeks of age. The second (Conformation flock) had recently been established by mating rams of extreme conformation selected from the UK Texel population with ewes in the Lean Index flock. Lambs were evaluated at a mean age of 139 days at the end of an 11-week performance test in which they were reared indoors on a concentrate diet. Prior to slaughter, the lambs were assessed for conformation of the hind leg (leg shape score). Mean live weights and ultrasonic fat depths did not differ significantly between flocks or leg shape scores but ultrasonic muscle depths were highest in the high leg shape score (27·9, 27·7 and 30·1 mm in low, medium and high scores, s.e.d. 0·55). At constant slaughter weight, the lean weight in the side was 0·4 kg higher in the Conformation flock and 0·3 kg higher in lambs of high v. low leg shape score (P < 0·001) with no significant differences in other tissue weights. Consequently, lean: bone ratio and lean proportions in both the live weight and carcass were higher in the Conformation flock and in lambs of high leg shape score. Lambs of high leg shape score had better carcass conformation scores (14·1, 12·9 and 11·9, for high, medium and low scores respectively, s.e.d. 0·30), shorter side length and higher values for all muscularity traits. Lean tissue distribution in major joints and individual muscles did not differ between flocks but the mean proportion of total lean in the higher priced cuts was higher (553·1 v. 543·9 g/kg, s.e.d. 3·26) for lambs of high v. low leg shape score. Males were 6·5 kg heavier than females at scanning (P < 0·001), had lower ultrasonic fat depths (2·8 v. 3·2 mm; P < 0·01) but did not differ in ultrasonic muscle depths. At equal slaughter age, males produced 1 kg more lean tissue and had a higher proportion of lean in the side than females (665·2 v. 638·9 g/kg) but did not differ in lean proportion in the live weight, carcass conformation and muscularity scores. Females carried a higher proportion of total lean in the higher priced cuts (555·6 v. 541·8 g/kg; P < 0·01) and in some individual muscles. It was concluded that there is important variation within the Texel breed in lean yield at constant live weight and that this is likely associated with differences between strain and conformation type.

A feeding trial was conducted to determine the dietary choline requirement of juvenile grass shrimp, Penaeus monodon. Purified basal diets were formulated using vitamin-free casein (containing 370 mg choline per kg) as the protein source. Graded levels (0, 300, 600, 1000, 2000, 4000, 7000, and 10 000 mg choline per kg diet) of choline chloride were added to the basal diet, resulting in eight dietary treatments in the experiment. Each diet was given to three replicate groups of shrimp initially averaging 1·18 (s.d. 0·01) g for 8 weeks. Weight gain was highest in shrimp given the diets supplemented with 7000 and 4000 mg choline per kg diet, followed by the groups given 2000 mg/kg, then 1000 and 600 mg/kg, and finally 300 mg/kg and the unsupplemented control group (P < 0·05). Shrimp given diets supplemented with 7000 and 4000 mg choline per kg diet had significantly higher food efficiency and survival than those given diet with 300 mg choline per kg or the control diet. Higher body crude protein and choline concentrations were recorded in shrimp given diets supplemented with 4000 and 7000 mg choline per kg diet than shrimp given diets with ≤600 mg choline/kg and ≤2000 mg choline per kg, respectively. Analysis by polynomial regression of weight gain and body choline concentration for P. monodon gave a maximum at about 6000 mg/kg. Taking into account the choline concentration of the unsupplemented basal diet, the optimal dietary choline requirement for growing P. monodon is about 6200 mg/kg.

Following a pilot study, the aim of this study was to test the hypothesis whether occurrence of massaging the anogenital region of a calf by a non-maternal hind is a reliable indicator of adoption. The investigation was conducted between 28 May (1st day of calving) and 2 September (abrupt weaning of all calves) on a red deer farm at Vimperk, Czech Republic. Fifty hinds and their calves were observed but only complete data sets of sucking bouts were considered for evaluation. Massaging occurred mostly during the 1st month of the calf’s life. All filial calves were massaged repeatedly. Other calves received ano-genital massage at least twice (termed adopted), on a single occasion or not at all (termed non-filial). Filial and adopted calves behaved in a similar way but differently from non-filial calves. They sucked in an antiparallel standing position so that the hind could lick their ano-genital region more often than the non-filial calves. This occurred even when two calves were involved in the bout. When two calves were involved in the sucking bout, non-filial calves sucked from behind, between the hind’s hind legs. This position occurred more frequently with non-filial than among the filial and adopted calves. It was therefore concluded, that repeated allonursing accompanied with massaging of the ano-genital region of the sucking calf by the hind can be considered a signal of adoption. Hinds usually adopted calves older than their own progeny. The adopted calves were on average 2·5 days old. This suggests that it is most likely the calf’s activity which leads to bonding. No reciprocity was found in allosucking and/or allonursing. The fact that non-filial calves commonly initiated allosucking from a non-maternal hind during the day when she gave birth appeared crucial for establishing bonding which subsequently led to adoption. Hinds may be bonded with several calves including their own. Therefore, bonding with a non-filial calf did not principally mean failure in looking after their own progeny as shown in other studies.

It is generally presumed that allosucking brings benefits to the allosucking infants. Nevertheless, the data supporting such a presumption are rare. The aim of the study was to determine whether allosucking has any impact on growth rates of the allosucking calves. Fifty pregnant hinds were observed between 28 May (1st day of calving) and 2 September (abrupt weaning of all calves) on a red deer farm at Vimperk, South Bohemia, the Czech Republic. Of the 50 calves born the growth curve was calculated for 39 calves. During their 1st month of life these calves were observed in 1015 sucking bouts. In 690 cases the calves sucked from maternal hinds and in 325 cases non-maternal hinds. Only 25·64% of calves sucked exclusively from maternal hinds. The prevailing type of sucking behaviour was a combination of sucking from maternal hinds and allosucking (74·36%). Calves sucking from maternal and non-maternal hinds showed 1·6-fold higher sucking frequency than did calves feeding from maternal hinds only. Our results indicate that to some extend allonursing behaviour of the hind may affect their calves’ feeding behaviour. The more non-filial calves the maternal hind nursed, the higher frequency of the sucking by their calves occurred. The groups of calves did not differ in birth weight. With increasing age, the relative body weight increased faster in calves sucking maternal hinds only than in calves sucking maternal and non-maternal hinds. This gain in body weight was not essentially influenced by the fact whether or not the calf’s maternal hind nursed non-filial or exclusively filial calves. However, at weaning (99 days), the lowest body weight occurred in allosucking calves whose maternal hinds were allonursing. The results suggest that allosucking does not mean an extra profit to the allosucker. Instead, in our subjects, allosucking was rather attributed to compensation of nutritional requirements based on a combination of various factors, such as discrete differences in body weight at birth and also later and allonursing of the maternal hind.

The intake and the digestibility of herbage, and the effect of level of supplementary concentrate food, were measured in late spring and late summer in two studies, each with eight multiparous, pregnant sows. In the spring study sows were nose rung to prevent rooting but only four nose-rung sows were available for the summer study; the remaining four were unrung. In both cases, sows had access to a plentiful (>2·5 t organic matter (OM) per ha) ryegrass/clover sward in a paddock of 1922 m2. After a week of adaptation to the herbage in the experimental paddock, sows were offered 1·5 or 3·0 kg/day concentrate for consecutive 2-week periods in a change-over experimental design with four sows on each treatment in each period. Samples of herbage were also taken to measure the sward density, chemical composition and n-alkane content. Herbage intake and digestibility estimates were calculated using the n-alkanes technique, with the marker dosed on small food pellets. In the spring study, the herbage intake ranged from 0·9 to 1·8 kg OM per day in the first period (herbage neutral-detergent fibre(NDF) content 439 (s.e.41·6) g/kg OM) and 0·2 to 1·4 kg in the second (475 (s.e.29·3) g NDF per kg OM). The intake was affected by the level of concentrate only in the second period. The results obtained during the summer study with the rung and unrung sows showed an intake between 0·9 and 2·4 kg OM per day in the first period (524 (s.e. 16·0) g NDF per kg OM) and between 1·3 and 4·8 kg in the second (526 (s.e. 21·8) g NDF per kg OM). A high intake estimation for certain unrung individuals appeared to reflect their frenzied feeding behaviour and possible loss of some marker pellets. There were no differences between level of concentrate treatments in either period. Digestibility of the diet was affected by the intake of herbage and the level of fibre consumed (P < 0·01). These herbage intakes equated to proportionately 0·50 (s.e. 0·05) and 0·66 (s.e. 0·1) (or 0·49 (s.e. 0·07) excluding problem sows) of the maintenance energy requirement in each season. Faeces of unrung sows indicated a high ingestion of soil or stones by some individuals: one of the sows produced a bulked faeces sample containing 450 g/kg fresh weight of stones, whilst another sow had a faecal ash content of 937 g/kg DM. The results indicate that the intake of nutrients from herbage by grazing sows is highly variable between seasons and individuals.

Ileal apparent digestibility of amino acids (AA) in a cassava root meal and soya-bean meal diet without and with an inclusion (150 g/kg) of sun-dried cassava leaves, ensiled cassava leaves, leucaena leaves and groundnut foliage was studied in a change-over experiment (5 ✕ 5) with post-valve T-caecum cannulated growing pigs.

The ileal apparent digestibility of dietary crude protein (CP) and AA were unaffected by the inclusion of groundnut foliage (P > 0·05). In contrast, when sun-dried and ensiled cassava leaves, and leucaena leaves were included in the diet the ileal apparent digestibility of dietary CP and AA were significantly reduced (P < 0·05).

The estimated ileal apparent digestibilities of essential and non-essential AA in groundnut foliage were higher (P < 0·05) than those of the other leaf products and there were no differences among cassava leaves and leucaena leaves (P > 0·05). On average ileal apparent digestibility of essential AA was 0·71 in groundnut meal and 0·56 in cassava and leucaena leaves.

It was concluded that, under tropical conditions, groundnut foliage has the potential to improve the dietary protein and AA supply and to replace partially soya-bean meal, in low fibre diets for growing pigs. Further, when conventional protein-rich foods are not available, cassava and leucaena leaves may also have the potential to improve the protein and AA supply for pigs.

Performance in pigs is greatly reduced during periods of heat stress through a reduction in voluntary food intake (VFI). However, little information is available as to what extent growth in piglets is affected by high temperature. The objective of this study was therefore to quantify the change in VFI as affected by environmental temperature. Piglets, initially 15·5 (s.e. 1·9) kg body weight (BW), were individually housed and exposed over a period of 17 days to either 19, 21, 23, 25, 27, 29, 31, 33, or 35ºC. Animals had ad libitum access to a starter diet and water. VFI was measured daily whereas BW was determined twice weekly. Over the 17 days, daily VFI and BW gain were proportionately 0·48 and 0·51 lower at 35ºC than at 19ºC. Due to the reduced VFI at high temperatures, the average BW during the experiment was greater at low temperatures than at high temperatures. Consequently, part of the difference in VFI is directly due to temperature and part may be explained by cascading, indirect effects (i.e. the increased BW). To account for this, VFI was expressed as a power function of BW (VFI = aBWb). It was assumed that environmental temperature affected the scalar (a) through a quadratic or a ‘plateau-linear decline’ function of temperature. The VFI appeared relatively constant between 19 and 25ºC (0·096 (kg/day)/(kg BW0·83)) and decreased thereafter. Between 25 and 35ºC, VFI decreased on average by proportionately 0·28 in a 20-kg pig.

A 10-week feeding trial was conducted to re-evaluate the level of dietary vitamin E (DL- α-tocopheryl acetate) that was adequate for juvenile tilapia Oreochromis niloticus ✕ O. aureus given diets containing two dietary lipid concentrations. Purified diets with eight levels of vitamin E (0, 25, 50, 75, 100, 150, 200, 400 mg/kg diet) at either 50 or 120 g lipid per kg were each given to three replicate groups of tilapia (mean weight: 0·69 (s.e.0·02) g) reared in a closed, recirculating system. Food efficiency and protein deposition were significantly (P < 0·05) higher in fish given 50 mg vitamin E per kg diet and 75 mg/kg diet in the 50 and 120 g lipid per kg groups respectively, compared with fish given the unsupplemented control diet. Mortality of fish was not affected by dietary treatment. Weight gain and liver microsomal ascorbic acid-stimulated lipid peroxidation data analysed by broken-line regression indicated that the optimum dietary vitamin E requirements in juvenile tilapia are 42 to 44 mg vitamin E per kg and 60 to 66 mg vitamin E per kg in 50 and 120 g lipid per kg diets, respectively.

During a 2-year study from January 1997 to December 1999, the visual characteristics of the cervical mucous discharge of cows and heifers in oestrus and their relations to conception rate were studied in a large dairy herd of Holstein-Friesian cows. Cows were divided into two groups based on mucous discharge being of normal or abnormal appearance and the group with abnormal discharge was further divided into the following classes: cervical mucus with urine (CMU), cervical mucus with microbes (CMM), cervical mucus with blood (CMB) and a group with no cervical mucus (NCM). From 6169 cases of cows in oestrus, 82·2% had normal discharge, and the remaining 17·8% had abnormal discharge classifications (6·1% CMU, 5·1% CMM, 0·5% CMB and 6·1% NCM). Conception rate after artificial insemination (AI) in the normal group (38·3%) was significantly higher than that of the abnormal group (27·9%), (P < 0·05). When the conception rate of the normal group was compared with each one of the abnormal classifications, it was significantly different from that of CMU (26·5%), CMM (22·6%) and CMB (21·8%), (P < 0·05), but not from that of NCM (34·4%), (P > 0·05). From 1734 cases of heifers in oestrus, only 6% had abnormal discharges, and the conception rates of the normal and abnormal groups were not significantly different (P > 0·05).

We conclude that AI of cows in oestrus discharging cervical mucus that is contaminated with urine, microbes or blood produces conception rates significantly lower than those of cows discharging a normal and clear mucus. Absence of a cervical mucous discharge at the time of AI of cows does not imply a low conception rate. In the case of heifers, appearance of cervical mucus had no effect on the conception rate after AI.

The objective of the present study was to evaluate the efficacy of a prostaglandin F2α (PGF2α) and progesterone (P4) treatment in initiating oestrus and ovulation post partum (PP) in Holstein-Friesian cows. Using four herds, the treatment protocol consisted of a single intra-muscular injection of PGF2α (Estrumate) between days 12 to 14 PP followed 48 h later by progesterone treatment via intra-vaginal CIDR insertion for a period of 7 days. Milk samples for progesterone determination were collected three times weekly from 7 to 65 days PP. The ovarian activity and reproductive performance of treated (T, no. = 153) animals and untreated control cows (C, no. = 315) were compared. Treatment was effective (P < 0·001) in reducing the mean interval to PP commencement of luteal activity from 29·62 (s.e. 0·82) days to 22·09 (s.e. 0·70) days. The mean interval to first PP oestrus in the T animals was significantly reduced (P < 0·001) from 55·62 (s.e. 1·58) days to 44·91 (s.e. 1·44) days and the incidence of silent ovulation in cycles between days 21 to 65 PP was reduced (P < 0·001) from 56·28% to 42·27%. In two herds under one management regime and with a similar block-calving pattern (no. = 280 animals), the treatment protocol was beneficial to the overall reproductive performance as there was a significant shortening in the mean interval to first PP service (75·82 (s.e. 1·93) v. 80·86 (s.e. 1·32) days) and in the interval to PP conception (83·07 (s.e. 2·49) v. 88·90 (s.e. 1·95) days), both P < 0·05.

The aim was to examine statistically the changes among days in the numbers of follicles relative to the growth of large follicles to test the hypothesis that follicular development occurs in a wave-like fashion in anoestrous ewes. The relationships among the patterns of circulating concentrations of FSH, oestradiol and inhibin-A and the pattern of follicular growth as well as relationships among follicular fluid steroid and inhibin-A concentrations were also studied. The ovaries of 11 ewes were examined daily using transrectal ultrasonography for 14 days and blood samples were collected every 8 h for 9 days. Five ewes were ovariectomized on the last day of ultrasound scanning. One to three identified follicles (a cohort) emerged every 2 to 5 days (mean 2·9 (s.e. 0·2) days) in individual ewes. The numbers of 4 and 5 mm follicles were fewest (P < 0·05) before and greatest (P < 0·05) 1 day after cohort emergence. This change in the numbers of follicles indicates a wave-like pattern of follicular growth. FSH concentrations were greatest (P < 0·05) on the day before wave emergence and lowest (P < 0·05) on the day of wave emergence. Peripheral concentrations of oestradiol and inhibin-A did not fluctuate (P > 0·05) in association with the emergence of follicular waves. The follicles that were collected at ovariectomy originated from one of three different waves. Oestradiol and inhibin-A concentrations in follicular fluid and the oestradiol-to-progesterone ratio were not different among the largest follicles of successive waves, when follicles were collected at the same time, indicating that new waves of follicles developed before the demise of old waves.

In conclusion, waves of follicles emerged about every 3 days in anoestrous ewes (defined as significant changes in numbers of follicles) and were associated with fluctuations in FSH concentrations but not peripheral oestradiol or inhibin-A concentrations. New follicular waves also emerged in the presence of steroidogenically active (positive oestradiol-to-progesterone ratio), inhibin-A producing follicles from a previous wave suggesting that follicles do not exert functional dominance during the non-breeding season.

British hill sheep are required to give birth to and rear their lambs under harsh extensive conditions. The aim of this study was to investigate whether genetic selection for increased (LEAN) or decreased (FAT) carcass lean content in the Scottish Blackface breed over 7 years had affected the ability of ewes to rear lambs by altering the expression of maternal and neonatal lamb behaviours. The behaviour of 61 ewes (32 LEAN and 29 FAT) and their 119 lambs were recorded at parturition and over the first 8 weeks of life. Overall there were very few effects of selection on the behaviour of the ewes. LEAN ewes were significantly faster than FAT ewes to start grooming their lambs after birth and FAT ewes tended to withdraw more frequently from their lambs than LEAN ewes. There was, however, a highly significant effect of selection line on lamb behaviour. LEAN lambs were significantly quicker than FAT lambs to perform all righting movements (median latency to stand (mins): LEAN = 11·7, FAT = 23·4, P < 0·01), were more likely both to suck (percentage that sucked: LEAN = 81·0%, FAT = 57·1%, P < 0·05), and to play within the first 2 h of birth. The higher rate of sucking in LEAN lambs persisted over the first 3 days after birth (percent observations where lambs were sucking: LEAN = 7·8 (s.e. 0·8), FAT = 5·1 (s.e. 0·6), P < 0·05), when LEAN lambs were also significantly closer to their mothers than FAT lambs. Thereafter, there were no significant effects of ewe or lamb line on behaviours recorded up to 8 weeks after birth. Overall lamb mortality to 8 weeks was 19·3% and was not significantly affected by lamb line. However, lambs that were slow to perform early behaviours had a reduced survival to 8 weeks of age. These data suggest that, although ewe maternal behaviour has not been significantly affected by selection for lean growth, the activity of the neonatal lamb has been affected. Lamb activity was related to lamb survival, even in our indoor lambing conditions. It is likely that the speed with which newborn lambs stand and suck will be even more important for survival under extensive conditions.

The effects of different types of energy or protein supplementation on performance of cows given grass silage-based diets were studied. The possibility of maintaining high energy intakes by using different grain sources, barley or maize, or by the use of the physical processing of the barley was investigated. In addition, the relative quality of rapeseed meal as a protein supplement compared with alternative protein supplements was examined. In experiment 1 16 Finnish Holstein-Friesian cows were used in a cyclic change-over design experiment with eight diets and four 21- day periods. The concentrate supplements comprised a 2 ✕ 2 ✕ 2 factorial arrangement of two grain sources (barley (B) and maize (M)) given either ground (T–) or steam-rolled (T+), each supplemented with either rapeseed expeller (R) or a mixture of maize gluten and soya-bean meal (GS). Grass silage was given ad libitum and concentrates at a rate of 11·2 kg DM per day. M supplements increased milk, milk protein and lactose output (P < 0·05) and decreased milk urea concentration (P < 0·01) compared with B supplements. Blood β-hydroxy-butyrate (BHB) and plasma urea concentrations were higher (P < 0·01) for B than M diets. R supplements increased silage intake, energy-corrected milk yield and milk protein output and concentration (P < 0·05) compared with GS supplements. Steam-rolled grain decreased food intake, blood BHB (P < 0·05) and plasma and milk urea concentrations (P < 0·001). Steam rolling improved organic matter digestibility (grain ✕ processing interaction, P < 0·05) with M but not with B supplements.

In experiment 2 four Finnish Holstein-Friesian cows fitted with rumen cannula were used in a balanced complete change-over design to evaluate ground or steam-rolled barley (T– v. T+) and two protein treatments (rapeseed expeller, R or a mixture of maize gluten/soya-bean meal/sugar beet solubles, GSS). Cows were given concentrates at 11·2 kg dry matter (DM) per day and offered grass silage ad libitum. There were no differences (P > 0·05) in food intake, digestibility or milk production and composition between treatments. Plasma urea concentrations (P < 0·01) and molar proportion of butyrate (P < 0·05) in rumen fluid were decreased with R compared with GSS supplements. The results showed that replacing B with M grain resulted in minor increases in milk production. Steam rolling of grain did not influence animal performance. Among the protein supplements R increased animal performance compared with GS supplement.

To examine the effects of manipulating the amount and ruminal degradability of starch on food intake, milk production and digestion in the rumen of lactating dairy cows, cracked wheat (CW) and sodium hydroxide-treated wheat (SW) were compared when offered with either immature (IM) or mature (MM) maize silage given in a 3: 1 dry matter (DM) ratio with grass silage. The total mixed ration (TMR) contained (kg/t DM basis) forage 600, wheat (CW or SW) 170, rapeseed meal 100, soya-bean meal 100, molasses/urea supplement 30 and minerals and vitamins were added at 20 kg/t diet DM. In experiments 1 and 2 respectively, 16 multiparous Holstein-Friesian cows and four similar cows with duodenal and ruminal cannulas were offered four diets (IMCW, IMSW, MMCW, MMSW) in 4 ✕ 4 Latin-square designs. In experiment 3, the in sacco degradability of CW and SW was measured in the rumen of three lactating fistulated cows. In experiment 1 total DM intake was 0·7 kg/day higher and milk yield was 0·5 kg/day higher with MM than IM silage but the increases were not significant and type of wheat had no effect. Milk fat content was reduced by MM silage (P < 0·05) but was unaffected by type of wheat. For milk protein content SW caused a non-significant increase with IM but a decrease (P < 0·05) with MM silage (interaction P < 0·05). There were no significant effects on yield of fat or protein. Neutral-detergent fibre digestibility in the rumen was unaffected by the treatments. Starch intake increased (P < 0·05) with MM silage when compared with IM silage and was accompanied by an increase (P < 0·01) in starch flow to the duodenum and in the amount (P < 0·001) digested in the rumen, although there was no significant change in rumen digestibility. Replacing CW with SW increased starch flow to the duodenum (P < 0·05) and reduced rumen digestibility (P < 0·05). Although the amount of total nitrogen (TN) digested in the rumen and rumen digestibility decreased (P < 0·01) with crop maturity, the flow of TN and non-ammonia nitrogen to the duodenum was unaffected. Total tract digestibility of DM was unaffected by treatments. Although the amount of starch digested in the total tract increased for MM compared with IM silage, reflecting the higher starch intake, total tract starch digestibility was unaffected by treatment and averaged 0·972. There were no main treatment effects on daily mean pH, concentration of ammonia or concentration or molar proportions of volatile fatty acids in the rumen. With SW, effective degradability (outflow rate of 0·08 per h) for both DM and starch was reduced when compared with CW. In conclusion the studies confirm that SW is more slowly fermented than CW and can increase the supply of starch to the duodenum. However the concept that increasing starch supply to the duodenum by a combination of MM silage and SW is likely to be beneficial to milk protein yield or concentration is not established under the present dietary regimen.

A nutritional hypothesis for the occurrence of the periparturient relaxation of immunity (PPRI) to gastrointestinal nematodes was tested within the bounds of a nutrient partitioning framework. It was hypothesized that at times of a scarce supply of metabolizable protein (MP), an increase in MP supply or a reduction in MP demand (having singles instead of twins) should lower the extent of PPRI in sheep. Twenty-one single- and 21 twin-bearing and -rearing Finn-Dorset ewes, 2 to 7 years old, and repeatedly infected with Teladorsagia circumcincta, were given one of three pelleted foods (no. = 7). The foods were formulated to supply 0·8 (L), 1·0 (M) and 1·2 (H) times the MP requirements during lactation, and were offered ad libitum from d–21 to d35 (d0 is day of parturition). Faecal egg counts (FEC) were assessed twice weekly as an indicator for host resistance. Dry-matter intake (DMI) during late pregnancy was higher than expected, and MP supply did not limit performance at this stage. In accordance with the hypothesis, there were no indications of a breakdown of immunity to T. circumcincta during late pregnancy. DMI during lactation did not differ between the single- and twin-rearing ewes. Calculated milk production was lower for the L than for the M and H ewes, especially for the twin-rearing ewes. A temporarily elevated FEC was observed during the first few days in lactation, which was probably mainly due to changes in faecal output rather than to PPRI. The FEC returned to low, late pregnancy levels at d12 and remained low for the single- but not for the twin-rearing ewes (P < 0·001). Overall, the L ewes had higher FEC than the M and H ewes from d19 onwards; this effect was more pronounced for the twin- than for the single-rearing ewes. It was postulated that DMI achieved overcame MP scarcity and thus prevented breakdown in immunity in the single-rearing ewes. The data support the view that, at times of MP scarcity, an increase in MP supply and reduction in MP demand can lower the extent of the breakdown in immunity towards T. circumcincta.

The aim of this research was to study the effect of genotype on the fatty acid composition in adult ewes and 5-to 6-month-old lambs of two mutton breeds (Suffolk and Pannon Sheep) and Booroola Merino. Samples of subcutaneous fat were obtained by surgical biopsy around the tailhead. Fatty acid composition of the adipose fat was determined by gas chromatography. Significant differences (P < 0·05) were found in the fatty acid composition of the adipose tissue among the three breeds. Suffolk showed a lower (P < 0·05) proportion of C12: 0 and C14: 0 fatty acids than the other two breeds. Considering the total quantity of saturated (TSFA) and the total quantity of unsaturated (TUFA) fatty acids, Booroola Merino showed a significantly (P < 0·05) higher proportion of TSFA and lower proportion of TUFA in their adipose tissue than the mutton genotypes (Suffolk and Pannon Sheep). Higher proportions of C18: 0, C18: 3 and C20: 1 (P < 0·05) but lower proportions of C12: 0, C14: 0, C16: 0, C16: 1 and C18: 2 (P < 0·05) were found in the subcutaneous fat of adult ewes than in that of their female progeny. Sex differences were also observed in the study. The proportions of saturated fatty acids were higher (P < 0·05) in female lambs than in males of the same age. These results indicate that a genetic approach may be useful to improve fatty acid composition of carcass lipids in sheep. However, age and sex differences also have to be taken into consideration.