Lamb live weight is one of the key drivers of profitability on sheep farms. Previous studies in Ireland have estimated genetic parameters for live weight and carcass composition traits using a multi-breed population rather than on an individual breed basis. The objective of the present study was to undertake genetic analyses of three lamb live weight and two carcass composition traits pertaining to purebred Texel, Suffolk and Charollais lambs born in the Republic of Ireland between 2010 and 2017, inclusive. Traits (with lamb age range in parenthesis) considered in the analyses were: pre-weaning weight (20 to 65 days), weaning weight (66 to 120 days), post-weaning weight (121 to 180 days), muscle depth (121 to 180 days) and fat depth (121 to 180 days). After data edits, 137 402 records from 50 372 lambs across 416 flocks were analysed. Variance components were derived using animal linear mixed models separately for each breed. Fixed effects included for all traits were contemporary group, age at first lambing of the dam, parity of the dam, a gender by age of the lamb interaction and a birth type by rearing type of the lamb interaction. Random effects investigated in the pre-weaning and weaning weight analyses included animal direct additive genetic, dam maternal genetic, litter common environment, dam permanent environment and residual variances. The model of analysis for post-weaning, muscle and fat depth included an animal direct additive genetic and litter common environment effect only. Significant direct additive genetic variation existed in all cases. Direct heritability for pre-weaning weight ranged from 0.14 to 0.30 across the three breeds. Weaning weight had a direct heritability ranging from 0.17 to 0.27 and post-weaning weight had a direct heritability ranging from 0.15 to 0.27. Muscle and fat depth heritability estimates ranged from 0.21 to 0.31 and 0.15 to 0.20, respectively. Positive direct correlations were evident for all traits. Results revealed ample genetic variation among animals for the studied traits and significant differences between breeds to suggest that genetic evaluations could be conducted on a per-breed basis.

1. A series of calorimetric experiments was conducted with sheep which had fleeces ranging in thickness from 0·1 cm. to 12 cm. at environmental temperatures between 8 and 32° C. Heat production, heat loss by radiation, by convection and conduction, by vaporisation of water and due to warming food and water to body temperature were measured together with losses of energy in faeces, in urine and as methane.

2. The effects of a rise in environmental temperature on digestion of the food and on the loss of energy in urine or as methane resulted in a slight rise in the metabolisable energy of the ration by 6 Cal./° C.

3. Environmental temperature had a marked effect on heat production, particularly when the fleece was short. The critical temperature (i.e. the environmental temperature at which heat production was minimal) of the closely-clipped sheep varied from 24° C. at a high level of feeding to 38°C. at a sub-maintenance level of feeding. These critical temperatures are similar to that of naked, resting man but much higher than that of the pig when fed similarly.

4. As the fleece grew the critical temperature fell. Thus, on a maintenance level of feeding, a sheep with a fleece of 0·1 cm. had a critical temperature of 32° C.; when the fleece had grown to 2·5 cm. the critical temperature was 13° C. while with a 12 cm. fleece the critical temperature was 0° C.

5. Below the critical temperature heat losses increase more rapidly in sheep with light fleeces. Thus a heavy fleece not only depresses the critical temperature but also reduces the rate of increase of heat loss with falling temperature under sub-critical conditions.

6. At environmental temperatures well below the critical, the heat losses of the sheep per unit surface were identical. Under such conditions, when the whole of the metabolisable energy of the food is used to keep the animal warm, the criterion of ration adequacy is a high content of meta-bolisable energy in small bulk.

7. At environmental temperatures above 32° C. the heat production on a constant ration increased, the rise being greatest with the highest level of feeding. Consequently the net energy value of the food declined at these high environmental temperatures.

8. The calorimetric experiments were supplemented by two comparative feeding trials in which the effects of normal outdoor environmental conditions on the body weight of groups of Cheviot and Blackface sheep were measured. Control groups were kept indoors in heated pens.

9. During the mild winter of 1956-7 the out-wintered Blackface wethers i n full fleece did not loose any more weight than those fed the same rations indoors.

10. During the more severe winter of 1957-8, Cheviot, in-lamb ewes kept on a maintenance diet gained 2·3 lb.; those kept outside on the same ration lost 3·3 lb. With Blackface, in·lamb ewes the difference between the two groups was 0·3 lb. in favour of the indoor group.

11. The food utilisation of sheep is affected considerably by environmental conditions. With little fleece the critical temperature is high and even when in full fleece an effect of cold can be demonstrated under practical conditions.

Genetic influences on body weights, taken at three-monthly intervals from birth to two years, were measured in the progeny of Angus, Boran and Red Poll bulls mated to Ankole, Boran and local Zebu cows. At two years old, progeny of Angus and Red Poll sires were 9% heavier than progeny of Boran sires. Progeny of Boran dams were 15% heavier than progeny of Zebu dams and 8% heavier than progeny of Ankole dams at two years. Differential performance by progeny of Ankole dams in different years suggested that genetic × environment interaction might be of some importance, and indicated the necessity of testing breed types over several years. Low and variable heritability estimates of weight-for-age up to two years old, and significant hybrid vigour effects on weight, indicated that in this environment, exploitation of hybrid vigour could be of great importance. Repeatability estimates for calf pre-weaning weights averaged 0·42.

Data from 675 litters were used to study the effects of type of service, number of services, parity, year, season, breed of sire, sire, type of dam (purebred or crossbred), breed of dam, dam, breed of sire × type of dam and breed of sire × breed of dam on litter size (live births), number of males, number of females, sex ratio (percentage of males) and length of gestation. Yorkshire, Landrace and Lacombe breeds and their crosses were represented. Artificial insemination significantly reduced litter size and the number of females and increased sex ratio. Parity had a significant effect on all traits except sex ratio. Lacombe-sired litters were approximately one-half pig smaller than Yorkshire- and Landrace-sired litters. Landrace-sired litters had gestations of one-third day shorter than Yorkshires. On average, crossbred dams farrowed 0·65 more pigs per litter than pure-bred dams. Litters from Yorkshire dams, however, were more than one pig larger than Landrace and Lacombes, and did not differ significantly from crossbred dams. Gestation length of Lacombe sows was 1·34 days shorter than Yorkshires. Repeatabilities of litter size, number of males, number of females, sex ratio and gestation length were 0·15, 0·08, 0·06, 0·05 and 0·32 respectively.

Faecal egg counts, haematocrits, erythrocyte potassium contents and serum iron concentrations were determined in 1005, 3- to 5-month-old Merino lambs infected with a single dose of 11 000 Haemonchus contortus larvae. Live-weight gain and wool growth also were recorded. Lambs were infected in six different groups over a 3-year period. When infections were terminated after 5 weeks, faecal egg counts in the six infected groups had reached a peak of 5170 to 20 339 eggs per g (average 12 909), haematocrits had declined to between 196 and 309 ml/1 (average 233), erythrocyte potassium contents had risen to between 16·7 and 37·5 mequiv. per 1 (average 31·5) and serum iron concentrations, in some cases following an erratic course, had dropped to between 0·512 and 1·546 mg/1 (average 0·946).

Of the three haematological parameters, haematocrit correlated best with faecal egg count (r = 0·7 in four of six infected groups). However, in two groups with low faecal egg counts this correlation was much lower (r = 0·3). Erythrocyte potassium concentration and serum iron concentration significantly correlated with variability of haematocrit not accounted for by faecal egg count, suggesting that both erythropoiesis and iron availability influence the degree of anaemia.

The effect of H. contortus infection on productivity of lambs was best predicted by haematocrits: for each further 0·01 proportional decrease in haematocrit, a 0·03 reduction of live-weight gain over a 9-week post-infection period, a 0·007 reduction in clean wool growth and a 0·004 reduction in fibre diameter over a 4- to 9-week period were observed. Some evidence was obtained indicating a tolerance level of anaemia at approximately 280 ml/1 packed cell volume.

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.

The objectives of this study were to compare the in situ ruminal degradation of CP and amino acids (AAs) of dried distillers’ grains with solubles (DDGS), and to estimate intestinal digestibility (ID) of undegradable crude protein (UDP) with the in vitro pepsin–pancreatin solubility of CP (PPS), using either DDGS samples (DDGS-s) or DDGS residues (DDGS-r) obtained after 16 h ruminal incubation. Thirteen samples originating from wheat, corn, barley and blends were studied. Lysine and methionine content of DDGS-s varied from 1.4 to 4.0 and 1.3 to 2.0 g/16 g N, respectively. The milk protein score (MPS) of DDGS-s was low and ranged from 0.36 to 0.51, and lysine and isoleucine were estimated to be the most limiting AAs in DDGS-s and DDGS-r. DDGS-r contained slightly more essential AAs (EAAs) than did the DDGS-s. Rumen degradation after 16 h varied from 44% to 94% for CP, from 39% to 90% for lysine and from 35% to 92% for methionine. Linear regressions showed that the ruminal degradation of individual AAs can be predicted from CP degradation. The PPS of DDGS-s was higher than that of DDGS-r and it varied from 70% to 89% and from 47% to 81%, respectively. There was no significant correlation between the PPS of DDGS-s and PPS of DDGS-r (R2=0.31). The estimated intestinally absorbable dietary protein (IADP) averaged 21%. Moderate correlation was found between the crude fibre (CF) content and PPS of DDGS-r (R2=0.43). This study suggests an overestimation of the contribution of UDP of DDGS to digestible protein supply in the duodenum in some currently used protein evaluation systems. More research is required and recommended to assess the intestinal digestibility of AAs from DDGS.

The distribution of lean tissue between eight standard joints was examined in 956 crossbred lambs slaughtered at constant live weights of either 35 or 40 kg. The sire breeds used were the Dorset Down, Ile-de-France, Oldenburg, Oxford, Suffolk and Texel. Sire breed did not have a significant effect on the proportion of total carcass lean found in the higher-priced joints but did show significant differences in the proportion of total carcass lean found in individual joints, with a maximum difference of 7·7 g total lean per kg joint being recorded. Similarly, small but significant effects due to ewe age (1 to 3 years), rearing type (single, twin, triplet), sex (male castrate, female) and weight of total lean were reported for the proportion of total carcass lean found in different joints.

Heritability estimates ranged from 0·07 (s.e. 008) to 0·65 (s.e. 0·16) for the proportion of total lean in the best-end neck and higher-priced joints respectively. Phenotypic standard deviations of 5·8g/kg and 17·9g/kg were reported for the proportion of total lean found in the best-end neck and the higher-priced joints respectively. The genetic correlations between the proportion of total lean in each of the higher-priced joints and the proportion of total lean in the higher-priced joints combined were positive. A genetic correlation of 017 (s.e. 0·20) was found for the relationship between average daily gain from birth to slaughter and the proportion of total lean in the higher-priced joints.

Both growth and immune capacity are important traits in animal breeding. The animal quantitative trait loci (QTL) database is a valuable resource and can be used for interpreting the genetic mechanisms that underlie growth and immune traits. However, QTL intervals often involve too many candidate genes to find the true causal genes. Therefore, the aim of this study was to provide an effective annotation pipeline that can make full use of the information of Gene Ontology terms annotation, linkage gene blocks and pathways to further identify pleiotropic genes and gene sets in the overlapping intervals of growth-related and immunity-related QTLs. In total, 55 non-redundant QTL overlapping intervals were identified, 1893 growth-related genes and 713 immunity-related genes were further classified into overlapping intervals and 405 pleiotropic genes shared by the two gene sets were determined. In addition, 19 pleiotropic gene linkage blocks and 67 pathways related to immunity and growth traits were discovered. A total of 343 growth-related genes and 144 immunity-related genes involved in pleiotropic pathways were also identified, respectively. We also sequenced and genotyped 284 individuals from Chinese Meishan pigs and European pigs and mapped the single nucleotide polymorphisms (SNPs) to the pleiotropic genes and gene sets that we identified. A total of 971 high-confidence SNPs were mapped to the pleiotropic genes and gene sets that we identified, and among them 743 SNPs were statistically significant in allele frequency between Meishan and European pigs. This study explores the relationship between growth and immunity traits from the view of QTL overlapping intervals and can be generalized to explore the relationships between other traits.

Four trials were carried out to determine the effect of feeding a supplement to stirks 6–9 months of age when turned out to grass. In two trials there was no response and in two there was a response to supplementary feeding.

No response was obtained in five trials when supplements were fed to store and fattening cattle. The feeding of undecorticated cotton cake did not have any apparent effect either on rate of live-weight gain or on scouring.

It is concluded that while the feeding of a supplement to young animals can bejustified when maximum live-weight gain is required, feeding of supplements to older cattle cannot be recommended so long as the animals are grazing good swards.

This study analyzes key factors influencing water productivity in cattle rearing, particularly in contexts characterized by water scarcity. This was done through year-round monitoring of on-farm practices within five smallholder farms located in the Saïss area (northern Morocco). The on-farm monitoring protocol consisted of characterizing: (i) volumes of water used for fodder production and distinguished by source (rainfall, surface irrigation and groundwater), (ii) virtual water contained in off-farm feed resources, (iii) total forage biomass production, (iv) dietary rations fed to lactating cows and their calves and (v) milk output and live weight gain. Findings reveal a mean water footprint of 1.62±0.81 and 8.44±1.09 m3/kg of milk and of live weight gain, respectively. Groundwater represented only 13.1% and 2.2% of the total water used to get milk and live weight gain, respectively, while rainfall represented 53.0% and 48.1% of the total water for milk and live weight gain, respectively. The remaining water volumes used came from surface irrigation water (7.4% for milk and 4.0% for live weight gain) and from virtual water (26.5% for milk and 44.7% for live weight gain). The results also revealed a relatively small gross margin per m3 of water used by the herd, not exceeding an average value of US $ 0.05, when considering both milk and live weight. Given the large variability in farm performances, which affect water productivity in cattle rearing throughout the production process, we highlight the potential for introducing a series of interventions that are aimed at saving water, while concurrently improving efficiency in milk production and live weight gain. These interventions should target the chain of production functions that are implemented throughout the process of water productivity in cattle rearing. Moreover, these interventions are of particular importance given our findings that livestock production depends largely upon rainfall, rather than groundwater, in an area afflicted with sustained droughts, overexploitation of groundwater resources and growing water scarcity.

For 25 weeks starting at week 3 post partum autumn-calving dairy cows were offered either a flat rate of concentrates in which all cows received the same daily amount throughout the experiment (F), or a variable rate based on their individual milk yield at 2 weeks post partum, and which was reduced at weeks 10, 15 and 20 of the experiment (V). Two mean amounts of concentrates were compared, 11 kg/day (11) and 7 kg/day (7) and grass silage was available ad libitum. For treatments 11F, 11V, 7F and 7V respectively, mean milk yields were 26·2, 24·5, 21·5 and 21·3 kg/day, mean live-weight changes were +0·18, +0·07, -0·09 and -0·05 kg/day, and mean silage dry-matter intakes were 8·0, 7·1, 9·4 and 9·0 kg/day. Differences between systems of allocation were not significant, but differences between amounts of concentrates offered were significant. Due to the greater milk yield and milk fat concentration of the F system of allocation, milk fat yield was significantly greater than for the V system. The substitution rate of concentrates for silage dry matter was significantly greater during the first 10 weeks of the experiment than during the succeeding 15 weeks. In the residual period (3 weeks indoors and 14 weeks grazing), there were no significant effects on performance. The mean 305-day milk yields for 11F, 11V, 7F and 7V respectively were 6957, 6388, 5862 and 5901 kg.

In order to contribute to the improvement of the national greenhouse gas emission inventory, this work aimed at estimating a country-specific enteric methane (CH4) emission factor for the Italian Mediterranean buffalo. For this purpose, national agriculture statistics, and information on animal production and farming conditions were analysed, and the emission factor was estimated using the Tier 2 model of the Intergovernmental Panel on Climate Change. Country-specific CH4 emission factors for buffalo cows (630 kg body weight, BW) and other buffalo (313 kg BW) categories were estimated for the period 1990–2004. In 2004, the estimated enteric CH4 emission factor for the buffalo cows was 73 kg/head per year, whereas that for other buffalo categories it was 56 kg/head per year. Research in order to determine specific CH4 conversion rates at the predominant production system is suggested.

To identify the separate and combined effects of energy and crude protein (CP) from concentrates on responses to concentrate feeding, 42 multiparous Friesian cows were given fixed amounts of concentrates with primary growth grass silage (194 g CP per kg dry matter (DM)) ad libitum for weeks 4 to 22 of lactation. A basal treatment of 3 kg DM per day of a standard concentrate (197 g CP per kg DM) was compared with 6 kg DM per day of the same concentrate (doubling energy and CP intake), 6 kg DM per day of a low-protein concentrate (106 g CP per kg DM) (doubling energy intake alone), or 3 kg/day of a high-protein concentrate (383 g CP per kg DM) (doubling CP intake alone). Results are presented in terms of main effects as interactions were not significant except for energy apparent digestibility. Silage intake was reduced by energy but increased by CP; in consequence extra energy from concentrates increased digestible energy (DE) intake but reduced CP intake and concentration whereas extra CP from concentrates increased not only DE intake but also CP intake and concentration. The ratio of the responses to CP compared with the responses to energy were 1·7 for milk yield, 0·9 for fat yield, 3·2 for protein yield and 1·4 for lactose yield. Energy reduced milk protein concentration and tended to increase milk fat concentration whereas CP had the opposite effect. The efficiency of converting food nitrogen to milk nitrogen was unaffected by extra CP but was increased, from 0·195 to 0·229, by extra energy. The poor response in milk protein yield and the reduction in its concentration with extra energy reflected the lower CP intake due to the reduced silage consumption. The experiment emphasizes the importance of concentrate CP supply in stimulating silage intake and yields of all milk constituents for diets containing fairly small amounts of concentrates.

A long-term experiment was designed to study the effect of feeding different sources of crude fibre during pregnancy on the reproductive performance of sows. The four treatments imposed during pregnancy were: C, a control compound diet; CS, the same control diet with additional chopped straw (0·2 kg/day); CM, the same control diet in which 0·25 kg was replaced daily by 1·5 kg maize silage; and CFR, a compound diet with a higher crude fibre content. In total 567 sows were used. On the treatments C, CM, CS and CFR the number of sows was 147, 142, 147 and 133 respectively. The sows remained on the experiment for five successive parities on a treatment or until the moment of culling. Feeding levels were about 32 MJ digestible energy (DE) per day during the first months of pregnancy and about 40 MJ DE per day in the last month of pregnancy. During lactation the feeding level ranged between 75 and 90 MJ DE per day.

In sows giving birth to five litters, the effect of parity was calculated irrespective of the treatments. The optimum litter size was observed in the fourth litter and the percentage of successful services within 10 days post weaning stabilized after the third parity. The live weight of the sows increased gradually up to the fifth parity.

Compared with the sows on the control treatment the proportional changes in consumption of the sows on the other treatments were: 0·45 more crude fibre, up to 0·02 more digestible energy and up to 0·06 less digestible protein.

There were only slight differences in reproductive performance. The mean number of weaned piglets per sow per year were 19·7, 19·3, 20·1 and 20·2, respectively for the treatments C, CM, CS and CFR. Higher piglet birth weights were observed for sows on the CM treatment and a higher proportion of the culled sows had leg disorders. On the CS treatment a higher number of weaned piglets per litter was observed and this was due to the higher number of piglets born and lower piglet mortality during lactation. The sows on this treatment tended to have more difficulty in becoming pregnant after the third and fourth parities. The sows on the CFR treatment had the highest body weights and had a higher number of litters per year mainly due to lower numbers returning to service and less nonproductive days. The results from this experiment gave no clear evidence that either the inclusion of roughage or a higher crude fibre content in the diet improved reproductive performance.

Two hundred Landrace × Large White sows were used to evaluate the influence of mating to Landrace or hybrid boars, at different intervals and with different frequencies, on subsequent reproductive performance. Sows were allocated at random to either a mating on each of the first 2 days of oestrus (double mating), two matings on the 1st day and one on the 2nd, one on the 1st day and two on the 2nd or single matings on each of the first 3 days of oestrus. All triple mating systems increased number of piglets born and born alive, with mating on 3 consecutive days significantly influencing these parameters compared with double mating (P < 0·05). Number of piglets weaned and mean piglet weaning weight were not affected significantly by treatment. Breed of boar used did not influence significantly any of the factors measured.

Seventeen non-lactating dairy-bred suckler cows (LF; Limousin×Holstein-Friesian) and 17 non-lactating beef composite breed suckler cows (ST; Stabiliser) were used to study enteric methane emissions and energy and nitrogen (N) utilization from grass silage diets. Cows were housed in cubicle accommodation for 17 days, and then moved to individual tie-stalls for an 8-day digestibility balance including a 2-day adaption followed by immediate transfer to an indirect, open-circuit, respiration calorimeters for 3 days with gaseous exchange recorded over the last two of these days. Grass silage was offered ad libitum once daily at 0900 h throughout the study. There were no significant differences (P>0.05) between the genotypes for energy intakes, energy outputs or energy use efficiency, or for methane emission rates (methane emissions per unit of dry matter intake or energy intake), or for N metabolism characteristics (N intake or N output in faeces or urine). Accordingly, the data for both cow genotypes were pooled and used to develop relationships between inputs and outputs. Regression of energy retention against ME intake (r2=0.52; P<0.001) indicated values for net energy requirements for maintenance of 0.386, 0.392 and 0.375 MJ/kg0.75 for LF+ST, LF and ST respectively. Methane energy output was 0.066 of gross energy intake when the intercept was omitted from the linear equation (r2=0.59; P<0.001). There were positive linear relationships between N intake and N outputs in manure, and manure N accounted for 0.923 of the N intake. The present results provide approaches to predict maintenance energy requirement, methane emission and manure N output for suckler cows and further information is required to evaluate their application in a wide range of suckler production systems.

Although the farrowing process has an impact on postnatal piglet survivability and growth performance, information on factors that influence the farrowing process under field conditions is rare. The objective of the study was to determine factors influencing the duration of farrowing and birth intervals in Large White×Landrace crossbred sows. Data were collected from the Pig Industry Board, Acturus, Zimbabwe. The durations of farrowing were log transformed to normalize them, while birth intervals remained skewed after the transformation. As a result, Friedman's test was used to analyse for factors affecting birth intervals. The mean duration of farrowing was 217 min. Number of piglets born alive (NBA), average birth weight and the presence or absence of stillbirths influenced ( P<0·05) the duration of farrowing. The total number of piglets born (NBT) and order of piglets significantly influenced birth intervals ( P<0·05). There was wide variation in birth intervals, with the within-litter coefficient of variation ranging from 50 to 140 percent. The relationship between birth interval and order of birth was: Y=0·1011x2−1·771x+37·917 ( P<0·05). Relative birth order, expressed as a proportion of the total number of piglets born, also showed a significant quadratic relationship with birth interval: Y=0·0021x2−0·121x+23·952 ( P<0·05). The study found that relative birth order, NBA and NBT play an important rôle in influencing birth intervals and duration of farrowing, while parity and piglet weight do not. Logarithmic transformation failed to normalise data on birth intervals, highlighting their highly skewed nature.

While crossing of specialized sire and dam breeds can be biologically efficient overall, a by-product is produced in the form of (crossbred) males of the dam line that are unwanted for breeding. In the UK sheep industry, most commercial females are first crosses between males of ‘longwool’ crossing sire breeds, predominantly the Bluefaced Leicester, and females of hill breeds. Genetic improvement of carcass quality in longwool breeds would benefit the surplus F1 males as well as filter through to the terminal sire cross lambs produced by the F1 ewes. As a first step, this paper aims to describe the growth and carcass characteristics of crossbred ‘Mule’ wether offspring of Bluefaced Leicester sires and Scottish Blackface and Hardy Speckled Face dams, and relate the crossbred performance to the ‘lean’ index and live conformation score of the sires and the breed of the dams. In each of 3 years, 1500 hill ewes divided over three sites were mated to 15 ram lambs, selected using an elliptical design to best represent the full spectrum of lean index (designed to improve muscle and decrease fat content while keeping live weight unchanged) and live conformation score present in the Penglas Bluefaced Leicester Group Breeding Scheme. Full growth and slaughter records were available on 2192 Mule wether lambs slaughtered after reaching finished condition, defined as the borderline between MLC fat class 2 and 3L. Measurements included live weight, ultrasonic muscle and fat depth, live conformation score, carcass hot and cold weight, MLC fat score (on the standard seven-point scale) and conformation score (EUROP and 15-point scale) and a visual estimation of subcutaneous fat cover. Nearly 800 carcasses were dissected; 20% had a full side and 80% a shoulder dissection. In part-dissected carcasses, shoulder dissection results were used to predict the fat and lean content of the other joints. Fat and lean percentages and absolute weights were then regressed on the lean index and the residual live conformation score of the sire. At the same finished condition, Scottish Blackface offspring were heavier, older, and had less fat and more lean based both on ultrasound and on carcass dissection measurements compared with Hardy Speckled Face offspring. The index score of the sire had a positive effect on the lean content and a negative effect on fat content of all joints. Conformation of the sire did not have a significant effect on any of the carcass composition measurements, but most conformation traits measured on the animal itself (live or on the carcass) were positively related to fat and negatively to lean content in the carcass. When taking into account differences in visually assessed subcutaneous fat percentage, the carcass conformation traits persisted only in having a positive effect on carcass fat content; none of the conformation traits had an effect on carcass lean content. The results show that selection of sires on lean index is an effective way to improve carcass composition in Mule wethers, but selection on conformation is ineffective.

Ruminal bacterial counts and in vivo digestibility were determined on four Mediterranean buffalo bulls and four Friesian bulls, all fistulated at the rumen, and given at maintenance level (50 g/kg M0·75 per day of dry matter) four different diets with the same crude protein content (N ✕ 6·25 = 140 g/kg dry matter) and with forage: concentrate ratios as follows: diet D12·5 = 0·875: 0·125; diet D25·0 = 0·75: 0·25; diet D37·5 = 0·625: 0·375; diet D50·0 = 0·5: 0·5. All the animals received the diets during four consecutive periods in a Latin-square design. Buffaloes had higher total microbial counts (10·78 v. 10·08 log10 cells per g dry rumen content, P < 0·01) as compared with cattle; differences in total ruminal bacterial counts among the diets were only observed within the buffalo species (diet D12·5 v. diets D25·0, D37·5, D50·0: 10·04 v. 10·92, 10·98, 11·17 log10 cells per g dry rumen content, P 0·01) and when comparing the two species for each diet, significantly higher values for bacterial counts in buffaloes were found for diets D25·0: 10·92 v. 10·28 (P 0·05), D37·5: 10·98 v. 10·08 (P 0·01) and D50·0: 11·17 v. 9·76 (P 0·01) log10 cells per g dry rumen content. Cattle showed significantly higher digestibility values for: organic matter (0·696 v. 0·676, P 0·05), neutral-detergent fibre (NDF; 0·548 v. 0·511, P 0·05) and cellulose (0·621 v. 0 · 509, P 0·01), while the crude protein digestibility (CPD) values were similar (0·667 and 0·671). Comparing the two species for each diet, cattle showed significantly higher digestibility values for organic matter in diet D50·0 only (0·714 v. 0·688, P 0·01), for NDF in diet D12·5 only (0·578 v. 0·531, P 0·05) and for cellulose in all diets (0·660 v. 0·546, 0·630 v. 0·525, 0·605 v. 0·505, 0·588 v. 0·460, P 0·01); in contrast buffaloes showed higher values of the CPD for diet D12·5 (0·662 v. 0·632, P 0·05).