The effects of level of supplemental carbohydrate from turnips and level of rumen degradable nitrogen on bacterial cellulolysis, food intake, live-weight gain and diet digestibility were examined with 36 300-kg Friesian steers allocated, in a randomized-block design, to one of six dietary treatments: (i) sodium hydroxide treated straw plus a supplement of urea (30 g urea per kg straw dry matter (DM)) (uO); (ii) uO plus turnips (23·5 g DM per kg M0·75); (Hi) uO plus a high level of turnips (47 g DM per kg M0·75); (iv) (v) and (vi), the same three diets, but with additional urea (60 g urea per kg straw DM). In two separate experiments each lasting for 56 days, the turnip allowance was given in either two feeds, or one feed per day and the straw was given to appetite. Rumen fluid was obtained by stomach tube from all steers before feeding (07·30 h) and after feeding (11.00 h) on days 10 and 24 of each experiment.

Weight gains for all groups given straw plus turnips were high (> 0·90 kg/day). Increasing the quantity of turnips gave significantly increased DM intakes and weight gains but then turnips substituted for straw, and the proportion of straw consumed decreased from 0·8 to 0·6 of the dietary DM (P < 0·01) There were no significant interactions between frequency of feeding of turnips and level of urea on the variables food intake and weight gain. Fibre digestibility was not depressed by the addition of turnips to the diet. Rumen fluid pH decreased after the steers ate turnips but tended to remain above 6·7. There were no large changes in the total number of viable cellulolytic bacteria as a result of either addition of urea or turnips to the diet; counts remained in the order of 107 per ml. Steers consumed large quantities of sodium hydroxide treated straw; turnips were therefore only a small proportion of the overall DM intake with relatively little effect on bacterial cellulolysis.

The responses in traits measured at the start of the mating period and at farrowing were examined after seven generations of divergent selection for daily food intake (DFI), lean food conversion (LFC), lean growth rate (LGA) on ad-\ibitum feeding and lean growth on scale feeding (LGS). Weight and backfat depth at mating were measured on 330 gilts and 74 boars, which were selected on the basis of performance test traits. Farrowing information was available on 259 gilts. At the start of the mating period, gilts selected for high DFI, LGA or LGS had similar live weights (135, 137 and 137 (s.e.d. 4·5) kg) but different backfat depths (20·3, 14·0 and 11·3 (s.e.d. 1·3) mm) while the corresponding low lines had different live weights (129, 117 and 124 kg), but similar backfat depths (17·5, 17·8 and 17·8 mm). Gilts selected for high LFC had lower mean live weight and backfat depth (114 kg and 10·7 mm) than gilts in the other selection lines. Conception rates of gilts selected for low DFI or high LGS were similar (0·62 and 0·64, s.e.d. 0·12) and lower than for the alternative selection strategies (0-78), but the low DFI gilts were significantly older at farrowing than gilts selected for high LGS (424 v. 408 (s.e.d. 5·5) days). Responses in live weight, backfat depth, age at mating and particular reproduction traits were selection strategy dependent, such that identification of relationships between growth and reproduction traits will require measurement of additional growth traits at an earlier age than in the current study

Malic enzyme 1 plays a fundamental role in lipid metabolism because it yields a significant amount of the NADPH necessary for fatty acid biosynthesis. In ruminants, however, its contribution to this biochemical process seems to be less relevant than in other livestock species. In this study, we have partially sequenced the goat ME1 gene with the aim of identifying polymorphic sites. Structural analysis of the goat ME1 amino acid partial sequence evidenced the existence of two dinucleotide-binding motifs, located at positions 158 to 163 (GLGDLG) and 301 to 306 (GAGEAA), and three amino acid residues (E245, D246 and D269) involved in the binding of Mn2+ and strongly conserved among mammalian species. Moreover, multiple sequence alignment allowed us to identify four single nucleotide polymorphisms at exons 5 (c.483C > T), 6 (c.667G > A), 9 (c.927C > T) and 11 (c.1200G > A). The effects of ME1 genotype on milk production and composition traits were investigated in a Murciano–Granadina goat population. None of the associations found reached statistical significance after applying Benjamini–Hochberg correction. At most, associations with uncorrected P-values below 0.01 were observed for C16:0, C18:1n-9t and total conjugated linoleic acids. These negative results reinforce the notion that ME1 plays an ancillary role in ruminant lipogenesis.

The growth of grass varies considerably from month to month. Where stock numbers are constant, as in a dairy herd, it is difficult to use grassland efficiently by grazing alone. But where grassland is used for meat production, livestock numbers may be subject to a considerable fluctuation, and with skilful adjustment of classes of stock this fluctuation can be made to approximate to the seasonal pattern of growth in the pasture.

The adjustment of stock numbers to the quantity of grass present is an art which is part of successful grazing management. Understocking will lead to an accumulation of pasture which will then have to be grazed at a more mature stage, while overstocking will result in a lower plane of nutrition for the animals. The efficiency of equating stocking intensity to the pasture available in a given period will be reflected in the progress of the individual animal (in terms of daily milk yield or live-weight gain) and in the output per acre of pasture.

Successful and timely rebreeding is of major importance to the economics of suckler cow enterprises. Research into the causes of reprodutive failure and extended calving intervals can be difficult, not least because of the need for experiments involving large numbers of animals if statistically significant treatment effects are to be demonstrated. Useful information however, can be obtained from the analysis of data derived from a number of relatively small-scale experiments, not necessarily on reproduction per se, but in which records of reproductive performance are available.

This paper deals with the analysis of data on the reproductive performance of beef cows used in a number of experiments on the effects of nutrition during pregnancy and lactation on components of production such as milk yield and composition, calf birth weight and early calf growth rate. The objective of the analysis was to identify the major factors affecting calving interval and to quantify the magnitude of the effects of these factors.

Insulin-like growth factor binding protein-5 (IGFBP-5) is a key molecule in mammary gland development, which facilitates the removal of mammary epithelial cells (MECs) by apoptosis that takes place during remodeling of the mammary gland during involution. IGFBP-5 binds with IGFs for their bioavailability. IGFBP-5 has been reported to perform pleiotropic roles such as cellular apoptosis, proliferation and differentiation. To understand the role of IGFBP-5 during lactation and clinical mastitis, expression profiling of IGFBP-5 at the protein level was performed in both indigenous cows (Bos indicus) and buffaloes (Bubalus bubalis) belonging to two different breeds – Sahiwal cows and Murrah buffaloes. Reverse-transcriptase PCR (RT-PCR) of IGFBP-5 mRNA confirmed its expression in milk somatic cells and MECs of Sahiwal cows. ELISA was performed for quantitative measurement of IGFBP-5 concentrations in milk during different days (0, 50, 100, 150, 200, 250 and 300) of lactation, during the involution period and in animals exhibiting short lactation and clinical mastitis. The highest concentration of IGFBP-5 in milk was observed during the involution period followed by colostrum, late and early lactation, respectively, in both cattle and buffaloes. No significant difference in the concentration of IGFBP-5 was observed during the first 150 days of lactation between cows and buffaloes. However, higher concentration of IGFBP-5 was observed in cows during late lactation (200 to 300 days) in comparison with buffaloes. To validate the ELISA data, quantitative real-time PCR was performed in MECs of Sahiwal cows. The relative mRNA abundance of IGFBP-5 was found to be significantly (P<0.05) higher on day 15 than between 50 and 150 days of lactation in case of Sahiwal cows. Highest mRNA expression of IGFBP-5 was observed around 300 days of lactation followed by 200 and 250 days (P<0.05), respectively. Murrah buffaloes showed low levels of IGFBP-5 protein in milk as compared with Sahiwal cows during lactation in ELISA. Animals having history of short lactation length (short lactating animals) showed higher levels of IGFBP-5 expression (at protein level) in comparison with normal lactating animals. We propose that higher level IGFBP-5 expression may have functional significance in lactation persistency. As a pro-apoptotic molecule, higher expression of IGFBP-5 was observed to be inversely related to lactation length and milk production.

Fleece characteristics of three distinct strains of Scottish Blackface sheep were studied by sampling eighteen ewes of the Lanark, Galloway and Lewis strains on three occasions in a single year. During the period of maximum growth the Lewis strain, which is largely of historical interest, differed significantly from the others in S/P ratio and mean weight, diameter and degree of medullation in fine and coarse fibres. The differences between the other two strains were small and although a considerable range in fleece characteristics was found, most of the whole fleeces would be classed as ‘medium’ wool.

All three strains showed a considerable reduction in follicle output during the winter and spring months when differences amongst them were minimised.

An experiment was carried out over successive years (1982 and 1983) to measure the extent to which live-weight advantage as a result of feeding in the dry season was maintained during the subsequent wet season at pasture. Two ages of Brahman steer (weaners and yearlings) were kept on three dry season treatments (molasses, sugar cane or grazing only) from January to May and then turned out to pasture as a single group until November. Although the molasses and sugar cane treatments produced significantly higher live-weight gains during the dry season the resultant weight advantage at turn-out was largely reduced during the wet season due to compensatory growth exhibited by previously restricted animals. Yearlings were less able to compensate than weaners.

Determining best practices for managing free farrowing systems is crucial for uptake. Cross-fostering, the exchange of piglets between litters, is routinely performed amongst crate-housed sows. However, cross-fostering can increase fighting amongst the litter and may be more challenging within free farrowing systems as sows have more freedom to respond to cross-fostered piglets. This study compared the effect of either cross-fostering (FOS), or a control of sham-fostering (CON), of four focal piglets per litter on Day 6 postpartum in crates (CRATE) and free farrowing pens (PEN). The post-treatment behavioural responses of sows were recorded (Day 6 = 60 min; Day 7 = 300 min; n = 48), as were the average daily gain (ADG; g/day), total weight gain (TWG; kg) and body lesion scores of focal piglets and their littermates throughout lactation (Day 6, Day 8, Day 11 and Day 26; n = 539) and the post-weaning period (Day 29, Day 32 and Day 60; n = 108). On Day 6, though post-reunion latency to nursing did not differ, latency to successful nursing was longer amongst FOS than CON litters (P < 0.001), more so amongst CRATE FOS than PEN FOS (P < 0.01). On Day 7, PEN FOS sows had fewer successful nursing bouts (P < 0.05) and exhibited decreased lateral (P < 0.01) and increased ventral lying frequencies (P < 0.01) compared to all other housing and treatment combinations. Focal piglet ADG was lower for FOS than CON in the CRATE during Day 6 to Day 8 (P < 0.01) and lower in the PEN during Day 6 to Day 8 (P < 0.001), Day 8 to Day 11 (P < 0.01) and Day 11 to Day 26 (P < 0.05). The TWG of pre-weaned focal piglets (Day 6 to Day 26) was higher amongst CON than FOS litters (P = 0.01). Post-weaning, piglet ADG was higher for PEN than CRATE during Day 26 to Day 29 (P < 0.01) and higher for FOS than CON during Day 26 to Day 29 (P < 0.05), Day 29 to Day 32 (P < 0.001) and Day 32 to Day 60 (P < 0.01); thus, TWG was higher for FOS than CON during the weaner (P = 0.001) and the combined lactation and weaner periods (P = 0.09). In conclusion, sow behaviour was disrupted by cross-fostering in the crates and pens and continued to be disturbed on the following day amongst penned sows. FOS piglets exhibited reduced ADG after cross-fostering, which extended throughout lactation in the pens. However, the increased post-weaning weight gain of FOS piglets meant that their TWG was higher than CON piglets, irrespective of the farrowing system used.

Increased plasma α-1 acid glycoprotein (AGP) is correlated with reduced growth rates in neonatal swine. The specific physiological mechanisms contributing to this relationship are unknown. This study was performed to determine if AGP can modify muscle metabolism by examining glucose oxidation and protein synthesis in the C2C12 muscle cell line. Cells were used for experiments 4 days post-fusion as myotubes. Myotubes were exposed to AGP for 24 h, with the last 4 h used to monitor 14C-glucose oxidation or to measure protein synthesis by incorporation of 3H-tyrosine. Treatment of C2C12 myotubes with mouse AGP (100 µg/ml) reduced glucose oxidation (P<0.01, n=3 trials), whereas bovine insulin (1 µM) stimulated glucose oxidation (P<0.05, n=3 trials). Treatment with AGP in combination with insulin reduced 14C-glucose oxidation (P<0.05, n=3 trials), similar to the effect of AGP alone. Glucose transport, as measured by 3H-deoxyglucose uptake, was increased by 38% with 1 µM insulin (P<0.05, n=3 trials), whereas AGP alone increased glucose uptake by 36% (P<0.05, n=3 trials). The combination of insulin and AGP in the medium resulted in an 88% increase in glucose uptake (P<0.01, n=3 trials). Protein synthesis was measured by 3H-tyrosine incorporation into C2C12 myotubes. Insulin stimulated a 18% increase in 3H-tyrosine incorporation (P<0.05, n=6 trials). The incorporation of 3H-tyrosine into myotubes was reduced by 20% with AGP incubation (P<0.01, n=6 trials), like the 20% decrease in 3H-tyrosine incorporation in response to the combination of AGP and insulin (P<0.01, n=6 trials). Protein breakdown, as measured by the release of 3H-tyrosine from C2C12 myotubes, was reduced 27% by insulin (P<0.01, n=6 trials). Treatment with AGP had no effect on protein breakdown (P>0.05, n=6 trials), whereas incubation with both AGP and insulin reduced 3H-tyrosine release by 15% (P<0.01, n=6 trials). First, these data indicate that the acute phase protein AGP can interact with the skeletal muscle to reduce glucose oxidation, but this is not the result of an effect on glucose transport. Second, AGP can specifically reduce protein synthesis. Lastly, AGP can inhibit insulin-stimulated glucose oxidation, protein synthesis and breakdown.

Commercial application of multiple ovulation and embryo transfer (MOET) technology will be subject to practical constraints and economic rationalism. This study examines use of MOET in its most profitable arena: to breed stud rams which will disseminate genetic improvement widely through multiplier studs to commercial flocks. A deterministic prediction is used to evaluate schemes based on an open nucleus MOET group within a Merino parent stud, taking account of genetic merit and inbreeding. Selection is based on clean fleece weight with an assumed heritability of 0·4. Embryos are collected at a rate equivalent to 3·45 live lambs per donor. Benefits of MOET were calculated from the discounted expressions of rams sold, and compared with the costs incurred.

As the proportion of the flock born from MOET increases, the rate of genetic gain increases rapidly at first, but diminishing returns are observed. The costs ofMOET increase linearly with the number of lambs produced, so the optimum proportion ofMOET lambs is for practical purposes always less than 100%.

Some use of MOET was profitable provided the stud sells sufficient stud rams each year. Sensitivity tests found that other parameters had only a small impact on the optimum level ofMOET. In general however, changes which increased the rate of genetic gain (heritability, flock size) or increased its value (wool price, lower discount rate) increased the optimum number ofMOET lambs.

The results should provide guidelines to optimum investment in MOET for the wool industry. An across flock genetic evaluation scheme is probably necessary to motivate this investment.

The Romney sheep group breeding scheme was initiated in 1979. Twelve pedigree breeders formed a Nucleus flock (N), at Wye College, each contributing ten “elite” ewes identified as prolific. The minimum entry requirement was that each ewe should have given at least twins at the previous lambing. The elite ewes were then performance tested in a common environment and those failing to give a multiple litter were replaced by other candidates from the flock of origin. The performance test was discontinued in 1982 when N was closed. Male and female replacements were chosen from the N-bred progeny. Replacements were selected on the basis of dam and sire's dam prolificacy record (live lambs born/ewe joined LLB/EJ)); ten ram lambs were chosen each year and thirty to forty ewe lambs. Ram lambs were used once as sires. Selection was for prolificacy with independent culling levels for tendency to prolapse, udder shape and breed type. A control flock (C) was set-up in 1982 by sampling at random within flock and age the twelve scheme member's flocks. Fifty pregnant ewes were assembled prior to the 1982 lambing. N and C were managed together apart from mating. No selection was applied to C.

Marker-assisted gene pyramiding provides a promising way to develop new animal breeds or lines, in which genes responsible for certain favorable characters identified in different breeds or lines are incorporated. In consideration of features of animal populations, we proposed five schemes for pyramiding three genes, denoted Scheme A–E, and five schemes for pyramiding four genes, denoted Scheme F–J. These schemes are representative of the possible alternatives. We also provided an algorithm to compute the population sizes needed in each generation. We compared these schemes with respect to the total population size and the number of generations required under different situations. The results show that there is no scheme that is optimal in all cases. Among the schemes for pyramiding three genes from three lines (L1, L2 and L3), Scheme D (a three-way cross between the three lines are first performed, followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) has a significant advantage over the other schemes when the recombination rate between adjacent genes ranges from 0.1 to 0.4, while Scheme A (a two-way cross between L1 and L2 and a subsequent intercross are performed, followed by a cross with L3 and a subsequent intercross to obtain the desired genotype) is optimal when recombination rate is 0.5. Among schemes for pyramiding four genes from four lines (L1, L2, L3 and L4), Scheme I (seperately, a two-way cross between L1 and L2 (L3 and L4) followed by a backcross to L1 (L3) and a subsequent intercross are performed, then the offspring from the two sides are crossed and followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) is optimal when the recombination rate ranges from 0.1 to 0.4, while Scheme F (cross and subsequent intercross between the four lines are performed successively) is the optimal when the recombination rate is 0.5. We also disscuss how the animals’ reproductive capacity, the probabilities of obtaining the desired genotypes and genetic distance between adjacent genes would affect the design of an optimal scheme.

1. Young cattle were fed on four types of wafer containing chopped or coarsely-milled dried grass, with or without 50% of barley.

2. At slaughter, the alimentary tract of each animal was removed and the contents of each part were weighed and sampled to determine the extent and site of digestion. Chromic oxide was used as an indigestible marker.

3. The form in which the grass was processed had no effect on any of the parameters measured.

4. The dry-matter content of the digesta in all parts of the alimentary tract was significantly higher when barley was included in the wafers. The inclusion of barley decreased the proportion of acetic acid and increased the proportion of butyric acid in the rumen liquor. The proportions of propionic and valeric acids were unaffected. Barley also appeared to reduce the proportion of digestible dry matter which disappeared in the forestomachs (31·44%) compared with that when grass was given alone (42·59%).

5. With grass alone about 70% of the apparently digestible cellulose disappeared from the forestomachs, but the technique used did not allow a good estimation of these proportions when mixed diets were given. The retention time of dry matter in the forestomachs was not affected by the diet but the inclusion of barley in the wafers increased the retention time of cellulose in the forestomachs.

6. Of 1·6·1·9 kg of starch ingested in mixed diets, 92-96% was apparently digested in the forestomachs, and only 80-130 g per day escaped rumen fermentation. The intake of starch on diets of grass alone was negligible and almost all the soluble sugars were digested in the forestomachs.

7. More N was recovered at the omasum than was ingested, but the different diets had no effect on the site of digestion of N.

1. A field investigation to estimate the mean weight and chest girth of unserved Friesian, Ayrshire and Dairy Shorthorn heifers of between 3 and 24 months of age was carried out.

2. Data from 1,620 Friesians, 725 Ayrshires and 455 Dairy Shorthorns in the North of England were obtained, with a mobile weighbridge and a. spring-loaded steel tape in the winter 1958–59.

3. It was found that on average the Friesians were heavier and had a greater chest girth than the Ayrshires and Dairy Shorthorns, which did not differ significantly.

4. These heifers were apparently reared on planes of nutrition which, judged by conventional feeding standards, may be described as ‘low’.

5. After eliminating the linear effect of age by covariance analysis, highly significant differences between herds and between sires in weight and chest girth were found.

6. The investigation demonstrated the feasibility and value of collecting field data on body size.

Scrapie, a transmissible spongiform encephalopathy (TSE) or prion disease, is a fatal, neurodegenerative disease in sheep and goats. This disease has been known in Europe for more than 250 years. Susceptibility to scrapie is associated with polymorphisms in the sheep prion protein gene (PrP) gene. In sheep, polymorphism in the PrP gene has been identified at a number of codons, and polymorphisms at codons 136, 154 and 171 have reported linkage with susceptibility to scrapie. Polymorphisms at the PrP locus were studied in 413 animals representing three native sheep breeds (Imroz, Chios and Kıvırcık) in Turkey. Genomic DNA was obtained from blood, and genotypes were screened using PCR and direct DNA sequencing. We report 17 genotypes derived from seven different alleles. The most frequent genotype in the Kıvırcık sheep is ARQ/ARQ, whereas the ARR/ARQ genotype is predominant in the Chios and Imroz breeds. In general, the ARQ haplotype was the predominant haplotype. ARQ haplotype was also predominant in the Kıvırcık and Chios sheep breeds, whereas the Imroz sheep predominantly had the ARR haplotype. The susceptibility-associated VRQ haplotype was found in 2.38%, 0.35% and 0.81% of the Imroz, Kıvırcık and Chios sheep, respectively. Moreover, seven additional polymorphisms have been detected at codons G127S, G127V, H143R, G145S, Y172D, N174Y and Q189L. Among these polymorphisms, the N174Y allele is a novel polymorphism, and the G145S allele is a novel allele for a known polymorphic locus.

The influence of season and management system on the productivity of Friesian cows in a Mediterranean climate was assessed. Intakes of food and water and milk yields were measured in 154 cows over 2·5 years while intensively managed in yards giving access to shelter (free stalls) or that were fully exposed to solar radiation (open lots). Food quality was also monitored to permit estimates of the efficiency of utilization of metabolizable energy for milk production over fortnightly periods.

The highest milk yields and energetic efficiencies were recorded during spring. Energy intakes were highest but energetic efficiencies were lowest during winter. Cows consumed the least food during summer and autumn and drank the most water during summer. The only significant effect of management system was for water intake, which was higher in the open lots than in the free stalls. There was evidence of heat stress in summer and cold stress in winter, but there appeared to be little benefit with milk yields through the provision of shelter.

The use of the animal as a means of evaluating pasture is an obvious approach to the problem, since this is the form in which the practical man will ultimately measure the return from his grassland. If anything has to be sacrificed it is the sward and not the animal, a point too often overlooked in our grassland work generally. Though many grazing trials of an observational nature are to be found in the early agricultural literature, the earliest experimental work was most probably that of the late Sir William Somerville. When Professor of Agriculture at Newcastle in 1897, he commenced the world-famous experiment at Cockle Park Agricultural Experimental Station on pasture improvement. An effort was then made to measure the effect of various systems of manuring in terms of the live-weight increase of sheep grazing on the different plots. In this experiment on Tree Field the relative values of the different systems of manuring were measured by weighing the sheep before and after the experimental period. In the early years the plots were stocked with hoggs, but in order to get closer grazing lambs and ewes are now used and have shown greater increases per acre.

The primary objective of this study was to examine the effects of different inclusion rates of dietary triticale replacing corn grain in starter rations of dairy calves on feed intake, average daily gain (ADG), feed efficiency, skeletal growth, fecal score, and selected blood and ruminal parameters. In all, 30 4-day-old Holstein calves (15 female and 15 male) were blocked by gender and birth weight, and then randomly allotted to three treatment groups (n=10 calves/treatment) and received either a corn-based diet without triticale (T0), or a diet containing 16% (T16) or 32% (T32) triticale (25% and 50% corn replaced by triticale, respectively) for 10 weeks. Calves were weaned on day 43 of study and remained on the study until day 70. During post-weaning period, calves fed T32 had the lowest starter intake (1.78 kg/day; P=0.02). In contrast, ADG was not affected in pre-weaning and overall periods, but calves fed T32 had a lower ADG (P=0.04) as compared with calves fed T0 in post-weaning period. No dietary effect was detected for feed efficiency. Dietary treatment did not affect heart girth and body length; however, height at wither and hip at weaning increased in calves fed triticale compared with T0. No detectable effects were observed in serum glucose and β-hydroxybutyrate. No difference was detected in blood urea nitrogen on day 35 either but on day 50 and day 70 the greatest concentration was recorded for calves fed T16. Compared with the control, ruminal ammonia concentration was increased for calves fed T32 (4.34 v. 7.50 mmol/l) and T16 (4.01 v. 8.12 mmol/l) on day 35 and day 50. No difference was detected in ruminal pH on day 35 or day 50; however, calves fed T32 had the lowest pH (6.11) at 70 days. No significant effect was detected in days scoured, respiratory score and general appearance. Under our experimental conditions, it appears that triticale at 16% dry matter (i.e. replacing corn grain up to 25%) in the starter diet does not have adverse effects on the performance and intake of calves. Therefore, substituting corn partially with triticale in calf starter diets may prove beneficial in places where corn is less abundant or its price is prohibitive. The low number of calves per treatment however may have limited the statistical power to detect significant differences among treatments, possibly affecting the results, which should be interpreted with caution.

Modifications to laying cages suggested by previous trials at Edinburgh include provision of a perch, a nest box and a dust bath, and increased area and height compared to conventional cages; the effects of combining these features is now described. Medium-weight hybrids were housed as groups of 4 in 48 cages of 4 types:

• control cages (C);

• experimental cages with nest box lined with litter (L);

• experimental cages with nest box lined with artificial turf (A);

• experimental cages with nest box lined with plastic grid (P).

In sub-treatments A1 and P1, eggs were prevented from rolling away for the first 6 weeks of lay, by blocking the rollaway slot. In sub-treatments A2 and P2, eggs rolled away from the beginning of lay.