Genetic and phenotypic parameters for body condition score (BCS), days to first service (DFS), non-return rate (NRR), somatic cell score (SCS), and 305-day milk, fat and protein yields were estimated, using 38930 multiple lactation records of cows across 1830 herds. The cows were daughters of '243 different sires. Single- and multi-trait repeatability animal models were used to estimate parameters based on restricted maximum likelihood methodology. Fixed effects in the model varied depending on the individual trait. Further, genetic relationships between 27 (linear and descriptive) type traits and functional traits (fertility and SCS) were estimated by regressing daughter type records on their sire's estimated breeding values for functional traits, using the same data set. Estimated regression coefficients were then subsequently used to derive approximate genetic correlations between type and functional traits (DFS, NRR and SCS). Body condition score had a moderate heritability (h2) of 0-26 and fertility traits had a low h2 (0-12 for DFS and 0-06 for NRR). Heritability of SCS and milk production traits was 0-14 and around 0-30, respectively. Ratio of permanent environmental variance to phenotypic variance was higher than h2 for all traits considered and ranged from 0-09 for NRR to 0-45 for milk yield. Body condition score had a favourable genetic correlation (rg) with SCS, but it was not strong (-0-08). Milk production was genetically antagonistic with fertility (rg: range 0-12 to 0-27 with DFS and -0-12 to -0-24 with NRR), with BCS (-0-39 to -0-50), and with SCS (0-10 to 0-15) showing that selecting for milk production alone would lead to decline in genetic merit for these functional traits. Body condition score had favourable genetic correlations with fertility traits (-0-35 with DFS and 0-04 with NRR) suggesting that BCS could be considered in a fertility index. Several type traits (especially 'udder' traits) had a favourable genetic relationship with fertility traits and SCS whereas dairy character had an unfavourable genetic relationship. Results of this study on genetic and phenotypic correlations among several functional, type and production traits could be used to design improved selection indexes for dairy producers.

Myofibre composition in longissimus dorsi (LD) muscle of Erhualian (EHL) and Large White (LW) pigs was investigated by determining the ratios of mRNA abundances of four myosin heavy chain (MyHC) isoforms (MyHC I, MyHC 2a, MyHC 2x and MyHC 2b) using multiplex RT-PCR. The relationship between expression of growth hormone receptor (GHR) and peroxisome proliferator-activated receptor α coactivator-lα (PGC-lα) mRNAs and changes ofmyofibre type composition during postnatal growth from 3 to 180 days of age were analysed. At 3 days of age, proportions of MyHC I, 2a and 2x fibres were high while only a few MyHC 2b fibres were differentiated. Dramatic changes were observed from day 3 to day 20 with significantly decreased MyHC I, 2a and 2x fibres but abrupt increases in MyHC 2b fibres in both breeds of pigs. Breed difference was exhibited only from day 90, with higher MyHC 2b but less MyHC I and 2a expression in LW pigs. Developmental pattern of GHR mRNA expression in LD muscle coincided with that of MyHC 2b, with LW pigs expressing higher abundance of GHR mRNA. PGC-lα mRNA expression followed distinct patterns in the two breeds of pigs, a higher level of PGC-lα mRNA being expressed in LD muscle of EHL pigs, the breed that possessed more oxidative fibres (MyHC I and MyHC 2a).

Castrated and entire Boer bucks (no. = 60) in groups of between three and five animals were slaughtered at 5,15, 30, 45, 60, 75, 90 and 105 kg live weight (5- and 15-kg animals were not castrated). Ultimate pH, muscle colour (subjective and objective measurement), subcutaneous fat colour, total pigment concentration, shear force values and eating quality were investigated. The ultimate pH o/longissimus muscle increased from 5-7 to 6-2 (P < 0-05) as animals were slaughtered at heavier weights. Slaughter weight had an influence on chromameter muscle colour (L*, a*, b* values) and subjective muscle colour scores recorded using a nine-point colour scale (P < 0-05) for both entire and castrated bucks. Muscle redness (a* values) and subjective muscle colour scores increased gradually in older animals while muscle lightness and yellowness (L* and b* values) decreased. Subcutaneous fat colour became more yellow at heavier slaughter weights (P < 0-05). Shear force values were affected (P < 0-05) by slaughter weight but not by castration of bucks. All eating quality scores were influenced by slaughter weight but not by castration, and flavour, as predicted by eating quality scores, was the most important attribute that contributed to overall acceptability of the goat meat.

The fatty acid composition of longissimus thoracis (LT) muscle and adipose tissues (subcutaneous and intermuscular fat) from castrated and entire male Boer goat bucks was investigated. Sixty Boer bucks in groups of between three and five animals were slaughtered at 5, 15, 30, 45, 60, 75, 90 and 105 kg live weight (5 and 15 kg animals were not castrated). The fatty acid composition of LT muscle from castrated and entire Boers was significantly affected by slaughter weight. The fatty acid content ofLT muscle and subcutaneous and intermuscular fat from both castrated and entire Boer bucks was primarily composed of oleic acid followed by palmitic and stearic acid. Both oleic and palmitic acid increased with slaughter weight whereas stearic acid decreased. LT muscle from castrated Boer bucks contained higher amounts of desirable fatty acids. In contrast to slaughter weight, castration of Boer bucks resulted in only minor changes in fatty acid composition of adipose tissues. It can be concluded that slaughter weight plays a role in changing the fatty acid composition ofLT muscle and adipose tissues from Boer bucks.

Twenty-eight New Zealand White X Californian doe rabbits weighing 3791±141 g were surgically fitted with a glass T-cannula at ileum level. Animals were given ad libitum access to either a casein-based diet (C) or a protein-free diet (PF). The only difference in the ingredient composition of the diets was the substitution of 160g/kg of maize starch by casein in the C diet. Animals were randomly allotted to each experimental diet. Seven rabbits per diet were not allowed to practice caecotrophy. The C diet resulted in higher food dry matter (DM) intake (DMI) (111-5 v. 51-5 g/day), food nitrogen intake (3-12 v. 0-20 g/day), ileal flow of DM (56-0 v. 23-8 g/day) and ileal flow of nitrogen (0-72 v. 0-24 g/day) but lower soft faeces DMI (21-7 v. 41-4 g/day) than the PF diet. A linear relationship between ileal endogenous nitrogen flow and total DMI was found for animals given the C but not for the PF diet. The ingestion ofC diet led to a higher (proportionately 0-41, on average), endogenous ileal amino acid flow than PF diet for all amino acids except for glycine. The ileal flow of glycine was proportionately 0-25 higher in animals given the PF diet than in animals given the C diet. The C diet resulted in higher content of nitrogen, threonine and proline in soft faeces than the PF diet. In contrast, the ingestion of the PF diet led to a higher content of lysine and methionine in soft faeces than the C diet. Within the C diet, animals practising caecotrophy showed higher ileal flow of DM (73-4 v. 56-0 g/day) and phenylalanine (0-834 v. 0-677 g/kg DMI) than animals not practising it. Caecotrophy led to a higher endogenous proportion of some of the most important limiting essential amino acids in rabbits, such as arginine, lysine, phenylalanine and threonine. In rabbits, the use of PF diets has limited practical application in the estimation of nitrogen endogenous losses as the low food DMI and the high soft faecesDMI leads to abnormal food: soft faeces intake ratio. Moreover, due to the important effect of caecotrophy on the amino acid composition of endogenous losses, it is important to correct the total amino acid content of the ileal chyme by the undigested amino acid residue coming from the soft faeces intake. This correction could be made, without the methodological complexity implied, by fitting animals with a wooden collar and thereby avoiding caecotrophy as in the present trial.

One hundred 1-day-old Ven Cobb chicks were used to study the effect of supplementation with 0-2 mg chromium (Cr) per kg diet from potassium chromate (T1), chromium chloride (T2) and chromium-yeast complex (T3). The control group (C) received no supplemental chromium. Each experimental group consisted of five replicates of five birds each and the supplementation was continued for 35 days. The weekly live-weight gain, food conversion ratio and the live-weight gain: food intake ratio were unaffected by the treatments. Metabolizability of the organic nutrients increased in the Cr supplemented groups compared with the C group and significantly higher values were observed in the T3 group indicating beneficial effects of Cr-yeast complex. Intake of the trace elements (copper, zinc, iron and manganese) fulfilled the requirements specified for broiler chickens. Retention of all these trace elements was higher (P < 0-001 for Cu, Zn and Fe, P <0-01 for Mn) in all the Cr supplemented groups compared with that in the C group. Furthermore, in the T3 group the retention of copper, zinc, iron and manganese was higher (P < 0001) than that in the T1 and T2 groups. Two birds were slaughtered from each replicate at the end of 21 and 35 days of feeding to observe Cr in the liver; this was higher (P < 0-01) after 35 days feeding only. Despite supplementation, liver Cr was lower (P < 0-01) in T1 T2 and T3 groups. Cr concentration in the plasma was higher (P < 0-05) in the T3 and T3 groups than that in the C group although its concentration did not change with the age of the birds. Higher (P < 0-01) plasma concentrations of copper were observed in the T1 T2 and T3 groups titan those in the C group. The differences between the Cr supplemented groups in this respect were not significant, however. Liver copper was higher (P < 0-001) in C while liver iron was the lowest (P < 0-05) in that group. The concentrations of copper, iron (P < 0-01) and zinc in the liver (P < 0-05) were higher after 35 than after 21 days while those of manganese were not affected by slaughter age. Protein accretion in the meat tended to be increased in the Cr supplemented groups while deposition of fat in the meat was lower but these differences were not significant (P > 0-05). Other meat quality parameters including sensory evaluation scores improved due to Cr supplementation and Cr-yeast complex was found to have exerted significantly greater effects on these parameters. It was concluded that the supplementation of 0-2mg Cr per kg food dry matter would improve the performance of broiler chickens in terms of metabolizability of organic nutrients, retention of trace elements and meat quality.

An experiment was performed to assess the metabolic adaptation and hormonal regulation in young female rabbits during long-term food restriction and subsequent compensatory growth during rearing. Feeding level was either ad libitum (AL, no. = 52) or restricted (R, no. = 52). From 6 to 12 weeks of age, food intake ofR was kept at a constant level. This resulted in an increase in relative restriction as compared with AL to 0-54of AL intake at 12 weeks of age (restriction period). Thereafter food intake gradually increased to 0-95 of AL at 17 weeks of age (recovery period). During the last 5 days before insemination at 17-5 weeks of age, all animals were fed to appetite. Blood samples were taken weekly from 6 to 17 weeks of age from 11 animals in each group. Growth rate of R was reduced during the restricted period (29 (s.d. 2) v. 44 (s.d. 5) g/day for R and AL, respectively; P 0-05), but was higher in the recovery period (30 (s.d. 3) v. 27 (s.d. 4) g/day, respectively; P<0-05). At first insemination, AL rabbits were heavier than R (4202 (s.d. 388) v. 3798 (s.d. 220) g, respectively; P < 0-001). During the restricted period, plasma glucose was constantly lower (P < 0-05) in R. Insulin levels paralleled those of glucose, being lower (P < 0-05) in R than in AL. Restriction reduced (P < 0-05) circulating corticosterone and tri-iodothyronine (T3) levels in R. Leptin, non-esterified fatty acids, and plasma urea nitrogen levels were similar for AL and R during food restriction, whereas triglycerides were similar until 10 weeks of age, after which the levels were lower in R. During the recovery period, the food intake of the R but not AL rabbits increased. Insulin was the only hormone in R rabbits that had returned to levels found in AL rabbits by the 2nd week of the recovery period. Glucose, T3, and corticosterone levels returned to levels found in AL rabbits between 3 to 4 weeks after refeeding. Non-esterified fatty acids, triglycerides, and leptin were higher (P < 0-05) in AL rabbits from 13 weeks of age onwards. The pattern of changes in the endocrine status during food restriction and compensatory growth in rabbits do conform with those from other species, although some specific changes may vary depending on the severity of food restriction and its duration.

Endogenous flows of nitrogen and amino acids at the terminal ileum of broilers (6 weeks old), layers (70 weeks old) and adult roosters (70 weeks old) were determined using the peptide alimentation method. The ileal endogenous output of nitrogen and total amino acids in broilers, layers and roosters, expressed as mg/kg dry matter intake, were similar (F > 0-05). Endogenous flows were similar (F > 0-05) for nine of the 17 amino acids analysed, but the flows of serine, glutamic acid, proline, alanine, isoleucine, tyrosine, arginine and methionine differed (P < 0-05) among the classes of chickens. The amino acid profile of endogenous protein, expressed asg/100 g crude protein, did not differ (F > 0-05) between the three classes of chickens, except for serine, glutamic acid, proline and isoleucine. The concentrations of proline were higher (F < 0-05) in broilers, compared with the other two groups. The concentrations of glutamic acid in layers were lower (F < 0-05) than the other two groups. The concentrations of serine and isoleucine were higher (F < 0-05) in roosters than the other two groups. In all three groups, the most abundant amino acid in the ileal endogenous protein was glutamic acid, followed by aspartic acid, proline, serine, glycine and threonine. The present study provides estimates for endogenous amino acid flow at the terminal ileum in broilers, layers and adult roosters under normal physiological conditions.

The effects of season in a tropical climate and parity on lactation performance of 106 Large White sows over several reproductive cycles (301 lactations in total) were studied in Guadeloupe (French West Indies, 16°N latitude, 61°W longitude) between January 1999 and March 2003. Two seasons were determined a posteriori from climatic parameters recorded continuously in a station close to the experimental unit. During the warm season, ambient temperature and relative humidity averaged 23-5°C and 0-831, respectively. In the hot season, the corresponding values were 26-0°C and 0-834, respectively. Over the 28-day lactation period, average daily food intake (ADFI) was lower (P < 0-001) and live-weight (LW) loss was higher (P < 0-05) during the hot season than during the warm season (3-9 v. 4-7 kg/day and 17 v. 12 kg, respectively). Growth rate and mean LW of piglets at weaning were lower (P < 0-05) during the hot season (203 v. 220 g/day and 7-0 v. 7-5 kg, respectively). However, the weaning-to-oestrus interval was not affected by season (5-4 days on average). The effect of season on ad libitum ADFI was less accentuated for primiparous than for multiparous sows (warm-hot 360 v. 2002 g/day). Irrespective of the season, ADFI was lower (P < 0-01) and piglet growth rate tended to be lower (P < 0-2) in primiparous than in multiparous sows (4-0 v. 4-4 kg/day and 205 v. 215 g/day, respectively). Moreover, the percentage of sows that returned to oestrus later than 5 days after weaning was higher in primiparous than in multiparous sows (25 v. 2%, P < 0-001). This study confirmed the negative effects of the hot season on performance of lactating sows raised in a humid tropical climate; the effects of season are dependent on parity number.

The effect of including purified jack bean lectin (concanavalin A) in the diet of grower pigs on endogenous ileal nitrogen (N) and amino acid (AA) losses, and apparent and true ileal AA digestibility was investigated in a study with four growing pigs (average initial live weight (LW) 25 kg) fitted with simple T-cannulae at the terminal ileum. Both the homo-arginine (HA) method and peptide-alimentation method were used to estimate endogenous gut AA losses. The animals were offered four diets :(1) an enzymatically hydrolysed casein (EHC) containing diet, (2) an EHC containing diet supplemented with 266 mg/kg jack bean lectin, (3) a normal casein (NC) containing diet, and (4) a NC containing diet supplemented with 266 mg/kg lectin. For the estimation of ileal endogenous AA flows in pigs given NC diets, a subsample ofNC was guanidinated to convert lysine to HA. The experiment was conducted using a 4X4 Latin-square design. In each experimental period, pigs were adjusted to the experimental diets for 5 days. On day 6, ileal digesta was collected continuously for 24 hfor determination of apparent ileal digestibility. At 08:30 h of day 8 the HA NC diets were offered to pigs on NC treatments and ileal digesta were again collected for 24 h from all pigs. There were no interactive effects of casein type and added dietary lectin on apparent and true ileal AA digestibility and endogenous ileal AA flows (P > 0-05). The addition of lectin to the diet did not influence (P > 0-05) the apparent ileal digestibility of dry matter (DM), crude protein (CP) and AA. Casein type did not affect ileal DM digestibility (P > 0-05). Pigs given the NC-based diets had higher (P < 0-05) apparent ileal AA digestibility than pigs given the EHC-based diets. Addition of lectin to the diet did not influence (P > 0-05) endogenous ileal CP and AA flows. Endogenous ileal AA losses were generally higher (P < 0-05) in pigs given EHC diets than in pigs given NC diets. Neither casein type nor diet lectin level influenced (P > 0-05) the true ileal digestibility ofCP and AA; values ranged for most AA between 0-98 and 1-00. These data suggest that including purified jack bean lectin at the level of 266 mg/kg in a casein-based diet did not influence the ileal endogenous CP and AAflow, nor the apparent and the true ileal digestibility ofCP and AA, in growing pigs between 25 and 50 kg LW. Compared with the HA method, the peptide-alimentation method yielded higher estimates of ileal endogenous CP and AA acid losses in pigs given casein-based diets, although these two methods yielded similar estimates of true ileal AA and CP digestibility.

Ninety twin-bearing ewes were given food individually and allocated to five (no. = 18) treatments in order to determine the effects of supplementing their diet in late pregnancy with mineral-block components on colostrum production, lamb serum immunoglobulin G (IgG) concentration and colostral IgG absorption. Ewes were offered grass silage ad libitum, supplemented with 400 to 500 g per ewe per day of concentrates from day 99 of gestation, in addition to receiving one of the following supplements: C, (control) no supplement; B, mineral block; ML, liquid molasses; MN, granular minerals; ML + MN, liquid molasses and granular minerals. The experiment commenced on day 99 of gestation. Ewes were milked at lh, 10 h and 18 h post lambing and all lambs were fed measured quantities of colostrum, proportionate to birth weight, via stomach tube. Treatment had no effect (P > 0-05) on colostrum yield at lh, 10 h or 18 h post partum or on total colostrum yield to 18 h post partum. Ewes offered molasses (ML) or molasses plus minerals (ML + MN) had a lower colostral IgG concentration at lh post lambing than the control ewes (C) (P < 0-05). Ewes offered molasses (ML) also had a lower colostral IgG concentration than the control (C) at 10 h post partum (P < 0-05). Treatment had no effect on total IgG yield to 18 h post partum. When ewes were supplemented with minerals in any combination, with or without molasses (B, MN, ML + MN) it resulted in lambs having an impaired ability to absorb colostral IgG. Lambs from treatments B, MN and ML + MN had significantly poorer efficiency of colostral IgG absorption than lambs born to control ewes (C) or molasses (ML) supplemented ewes (P < 0-001). This in turn resulted in the progeny of mineral supplemented ewes (B, MN or ML + MN) having lower serum IgG concentration at 24 h post partum than either the control (C) or the molasses treatments (ML) (P < 0-001). When ewes were supplemented with molasses only (ML) lamb serum IgG content at 24 h was lower than in lambs born to control (C) ewes (P < 0-05) but this was as a result of a lower intake of colostral IgG (P < 0-05) and not a result of reduced IgG absorption efficiency. In conclusion, the data show that when ewe mineral intake is high in late pregnancy, as was the case in the current experiment, lamb serum IgG concentration and colostral IgG absorption efficiency are reduced. Further work is required to determine which component of the mineral formulation is responsible for this reduced IgG absorption efficiency and the mechanism through which this impaired efficiency operates.

To investigate the effect of red clover formononetin concentration on lamb growth rate and carcass characteristics, 20 lambs (10 ewe lambs and 10 wethers) were grazed on each of three forages : red clover with a high formononetin concentration (HF), red clover with a low formononetin concentration (LF) and a control perennial ryegrass. Animals were finished at condition score 3L, at which point half of all animals were slaughtered immediately, while the other half of the animals were moved to a common ryegrass plot for 3 weeks as a 'withdrawal' period. Mean formononetin concentrations were 0-0, 4-7 and 3-3 g/kg dry matter (DM) for grass, HF and LF swards respectively. The clover swards had higher crude protein concentrations and lower fibre and water-soluble carbohydrate concentrations than the control ryegrass sward. Lambs grazing the HF clover gained 40 g/day live weight more (P < 0-1) than lambs on the other two forages without an increase in forage DM intake as estimated using the nalkane technique. There was no difference in the empty body weight, killing-out proportion, carcass fat class or condition score between animals finished on any of the three forages. Following the 3-week withdrawal period on ryegrass, there were significant residual effects of previous grazed forage on carcass weight, with HF lambs producing heavier carcasses than other lambs. Plasma concentrations of growth hormone and insulin-like growth factor-1 were highest in lambs grazing the HF clover, and suggest a physiological mechanism for the increased growth rates of these animals. There were no differences in the equol contents of the meat of lambs finished on the clover, compared with animals finished on grass, suggesting that there would be no implications for human health following consumption of meat produced from lambs grazing red clover, even with a relatively high concentration of formo'nonetin.

This paper addresses the problem of assigning economic weights to heritable genetic traits of dairy cows while taking all implicit natural resource values into consideration. To do so, a deterministic bio-economic model of a dairy farm enterprise driven by input probabilities of oestrous detection and conception rates that act through the calving interval is constructed. The model further accounts for biologically limiting factors of both livestock and land within a neo-classical economics framework of profit maximization. Departing from the more customary approach of obtaining gross margins to calculate levels of return in the agricultural sector, we employ a natural resource economics methodology where returns are set against an economic point of reference specified as the value of natural assets' productivity and terminal assets' resale value. Introducing the impact of farming intensity on soil fertility enables us to obtain long-run variations in natural asset values as affected by tillage intensity. Results show that economic weights are not constant over the range of changes in genetic improvements due to the non-linearity of the system induced by diminishing marginal product of inputs and finite carrying capacity of resources employed. These values, while invariant to area farmed, are however subject to variations in resource quality and therefore will reflect the sensitivity of long-term sustainability of the system to managerial decisions on intensity of operation. Results further demonstrated that achieving optimum levels of output while precluding the impact of intensity on land productivity can seriously reduce the time horizon over which sustainability can be maintained. Inclusion of the implicit costs of land use on the other hand tended to suggest optimum levels of output below those identified when only considering accounting data.

This study was designed to obtain information on predicting intake and digestibility from near infrared reflectance spectroscopy (NIRS) scans of faeces in dairy cows given different diets and levels of intake. Comparisons were made between using NIRS to predict alkanes in faeces and direct calibration of NIRS for intake and digestibility. Faecal samples were obtained from 91 cows in five experiments where dry-matter intake (DMI) had been measured for individual cows. All samples were scanned by NIRS and concentrations of alkanes C32, C33 and C36 were determined in 32 samples. DMI (mean 19-4, s.d. 5-06 kg/day) was estimated with standard errors of 0-36 and 0-44 kg/day from C32 and C36 alkanes determined by gas chromatography, and with standard errors of 1-17 and 1-42 kg/day when DMI was estimated from C32 and C36 alkanes predicted by NIRS. When DMI was predicted directly by NIRS, the standard error of prediction was 0-48 kg/day (R2 = 0-97). Prediction of dry matter digestibility by NIRS was not accurate (standard error of cross validation = 0-032; R2= 0-68), probably because of the limited variation in digestibility values within the data set. It is concluded that using NIRS to predict alkane concentrations of faeces does not give accurate estimates of DMI but direct prediction of DMI by NIRS gives estimates with similar accuracy to estimates derived from the traditional alkane technique.

Grass silage constitutes a major proportion of the food offered to high producing dairy cows in the western regions of the European Union. In order to achieve optimal milk yield and quality from high genetic merit dairy cows, it is common practice to offer concentrates in addition to grass silage at feeding. The aim of the current study was to combine two existing empirical models in order to allow prediction of the response in milk production to offering varying ratios of grass silage and concentrates to high genetic merit dairy cows, allowing for the fact that grass silage quality can vary. Results have demonstrated that it is possible to predict, with reasonable precision, the milk production response to various combinations of grass silage and concentrates in the diet. This will facilitate investigation of production and economic responses of offering increased levels of concentrates in the diet on milk yield, milk quality and milk value.