The effect of three different growth rates from 15 to 40 kg live weight on some offal components of lambs was studied. The treatments were: high (H) ad-libitum feed intake, low (L) restricted feed intake and high-maintenance-high (HMH) ad-libitum feed intake from 15 to 25 kg followed by a 50-day period of weight stasis, which was followed by ad-libitum feeding. In each treatment, two animals were killed at 25, 30 and 35 kg and three animals at 40 kg. Analyses of covariance were used to compare linear regression equations representing results from each treatment using the logarithmic transformation of the allometric equation, y = axb.

Differences between treatments were found for the weight of certain non-alimentary tract offals including the liver (H, HMH > L), kidney (H, HMH > L), skin (H, HMH > L) and hind-hooves (H < HMH, L). The slope of the regression for the heart, liver, kidney, and the combined trachea and lungs was greater in the HMH, than in the H, treatment. These differences in slope were attributed to a decrease in weight of each component in the HMH animals during weight stasis except for the lungs and trachea, where the greater slope was due to an increased weight of this component in the HMH animals killed at 40 kg.

Fat-trimmed weights of the omasum, abomasum, small intestine and large intestine were greater in both the H and HMH animals than the L animals. The weights both of the rumen-reticulum and total alimentary tract (TAT) were less at 25 kg in HMH animals than in either H or L animals although, overall, the weight of TAT was greater in the H and HMH treatments than in the L treatment. A comparison of data for the H and HMH treatments showed that weight stasis decreased the weight of all separate parts of the alimentary tract, particularly the rumen-reticulum and the small intestine.

Chemical analyses (water, N × 6·25 and ether extract) were conducted on four alimentary tract components, namely the combined rumen-reticulum and omasum (RRO) abomasum, small intestine and large intestine. The results of these analyses showed that composition was similar in the three treatments despite treatment effects on the weight of some parts of the tract.

Chemical data were pooled across treatments to compare composition of the different alimentary tract components. This analysis showed that chemical composition was different both for all parts of the tract and for all chemical components with two exceptions. There was no difference between the RRO and small intestine for either water or ether extract.

Common regression equations are presented for each component of the alimentary tract relating the weights of three chemical components to tissue weight. Water and protein content were more closely related to tissue weight than was ether extract. It is suggested that both water and protein content may show a sufficiently close relationship to tissue weight whereby they may be predicted from a knowledge of the latter, particularly the RRO and small intestine.

There were no differences between treatments in the weights of fat trimmed from the alimentary tract despite treatment effects on either the weight of some parts of the tract or other offals.

Apart from a greater weight of digesta in the small intestine in the H animals than in L animals relatively minor differences between treatments were found in the amounts of digesta in different parts of the tract.

An anatomical study compared the effects of sex and a twofold nutritional difference in growth rate between 20 and 100 kg live weight, on 63 entire males, castrated male and female Large White × Landrace pigs. While the effect of growth rate was significant for overall fat deposition in the carcasses of all three sexes, it was greatest for the entire male. In contrast, sex and nutritional effects on the distribution of fat and on the proportion and distribution of muscle and bone were small.

The fertility of a stock of red deer kept under farming conditions on hill land over a period of 7 years has been assessed. The stock consisted of five cohorts of hinds born in successive years from 1971 to 1975. The fertility of hinds was related to their body weight by the general relationship P = 1 – exp(– 0·085(W– 52)) where Pis the probability that a hind will calve and W is her weight in kg at the time of the rut. When body weight was taken into account in this way, age had no effect on hind fertility. Fertility was, however, poor in one year following a rut which occurred in bad weather. Separation of calves from hinds at the time of the rut had no effect on fertility, and under the farm conditions there was no increase in fertility of hinds which had been barren the previous year above that expected from their body weight. Date of calving was slightly skewed, but 63 % of all calves were born in the first 20 days of June. Smaller hinds calved later; 1 kg body weight increased date of calving by about 0·3 days. Evidence of stag infertility was obtained and it was shown that one stag could effectively mate with 28 hinds such that they mostly calved within a 20-day period. It was possible to run 60 hinds with three stags and obtain calving rates which were similar to those for the hind population as a whole. There were no differences in fertility between matched groups of hinds exposed to one or two stags. The results are compared with those obtained by observation of wild stocks in Scotland.

The sex and number of calves born to a breeding herd of red deer kept under farm conditions are analysed together with information on mortality and on growth rate of the calves until weaning in September–October. The results showed some anomalous deviations of the sex ratio from a 50:50 expectation. Birth weight was related to the weight of the hind at the time of the rut, and so too was the subsequent daily rate of gain of the calf. Stag calves weighed more than hind calves and there was no effect of age of hind on birth weight once weight of hind had been discounted. Mortality was divided into two components; perinatal mortality included stillbirths, deaths at parturition and during the first 24 h of life and an unidentified mortality representing failure to find a calf although the hind had calved. Postnatal mortality was defined to include all deaths from after 24 h of life to weaning. Mortality was related to the weight of the calf at birth, being 100 % for calves weighing less than 4·0 kg and declining to 5 % for calves weighing 6·0–7·0 kg. The data are discussed and the effect of size of hind at the time of the rut on her fertility, the time at which she calves, the birth weight and growth rate of her calf and its survival rate are combined to estimate the annual number of viable weaned calves and the total weight of calves produced by herds of hinds of different weights. An increase in hind weight of 50 % (from 60 to 90 kg) results in a doubling of the number of calves born and surviving to September and an increase in the weight of the calf crop by 160%. Reasons are given to suggest that total calf mortality could be reduced to 7 %.

Data are presented relating various stages of growth of field-grown bush tomatoes cv. Sleaford Abundance established from dry and pre-germinated seeds and from transplants to accumulated day-degrees. In general, Ontario units predicted the dates of 50% flowering, of the first harvest and the date when 37·5 t/ha of ripe fruit had been picked, more accurately than day-degrees above 10 °C or calendar days. The number of Ontario units from sowing to 50% flowering for dry and pre-germinated seeds were 956 ± 35 and 871 ± 85, respectively. The corresponding figures from sowing to first harvest were 1958 ± 59 and 1867 ± 85. For transplanted crops the number of Ontario units from planting to 50 % flowering and from planting to first harvest were 322 ± 62 and 1352 ± 133, respectively. For transplanted crops the number of Ontario units required to give a yield of ripe fruit of 37·5 t/ha (the minimum level currently necessary on economic grounds for tomatoes for processing) was 1937 ± 112. Using this figure in conjunction with long-term meteorological records it was estimated that crops established from transplants at East Mailing, Kent (latitude 51° N), would fail to give yields of ripe fruit of 37·5 t/ha by late September on only 1–6 occasions in 100 whereas at Wellesbourne, Warwickshire (52° N) and Warsop, Nottinghamshire (53° N) crops would fail to reach this yield on 13–53 occasions in 100. Crops established directly from seeds would fail to give this yield on more than 50 occasions in 100 at all three sites.

Potato cyst-nematode, Globodera rostochiensis, was controlled in a three-course rotation (potatoes-sugar beet-barley) by treating the soil with an effective nematicide before growing susceptible Pentland Crown potatoes, or by growing Maris Piper potatoes, resistant to the nematode. In moderately infested sandy loam, Maris Piper potatoes grew and yielded much better in soil treated with a nematicide than in untreated soil. Maris Piper outyielded Pentland Crown only in years with ample rain in August. Sugar beet and barley in some years yielded better after Pentland Crown than after Maris Piper potatoes. Yield loss in Pentland Crown due to potato cyst-nematode varied greatly in the same field. The nematode was controlled better by 5·6 kg oxamyl/ha, or by 448 or 672 kg dazomet/ha, than by 448 kg Telone/ha. Large soil populations of G. rostochiensis declined faster under sugar beet and barley than small soil populations did, suggesting action of a predator or pathogen.

Teff (Eragrostis tef) was cut at various stages of growth and divided into leaf, stem (including leaf sheath) and inflorescence. Cell walls were isolated from the leaf and stem fractions and their composition determined. Acetyl groups and individual sugars were determined by gas-liquid chromatography.

Recoveries of cell walls from the same fresh weight of leaves or stems were similar at each stage of growth, but increased with maturity.

Throughout the growing season the leaf cell walls differed in composition from those of the stem. At the start of growth the leaves had a lower content of xylose and acetyl groups but were otherwise similar to the stems. However, with increasing maturity and the production of a flowering stem the stem cell wall composition changed much more than that of the leaf cell walls, with a marked decrease in the content of arabinose and an increase in the content of lignin and acetyl. Over the same period the leaf cell walls showed a smaller increase in acetyl content and decrease in arabinose and uronic acid, but were otherwise unchanged.

Digestion of the cell walls with a fungal cellulase preparation showed that although the two cell wall types were equally degradable while the grass was in the vegetative state, the digestibility of the stem cell walls decreased well below that of the leaves with the onset of maturity and the production of a flowering stem. This was confirmed by in vivo incubations of the cell walls in nylon bags.

A selection of the hemicellulose-utilizing rumen bacteria isolated by Henning (1979) were partially characterized. These and a number of other cellulolytic organisms were incubated in vitro with teff (Eragrostis tef) cell walls, and the extent of solubilization and utilization by the bacteria of individual cell wall sugars was determined. Results were compared with the action of the bacteria on isolated xylan and cellulose.

The cellulolytic rumen bacteria solubilized more of both cellulosic and hemicellulosic sugars in the cell wall than the non-cellulolytic organisms. Bacteria which were unable to solubilize isolated cellulose could also degrade very little of the cell wall cellulose, and this appeared to limit the amount of cell wall hemicellulose which could be attacked.

There was no direct relationship between the extent of degradation of isolated xylan and solubilization of cell wall hemicellulose, but those xylanolytic organisms which produced freely diffusible enzymes (as evidenced by production of clearings in 3 % xylan-agar) were more effective in attacking the cell wall than those which did not.

Examination of thin sections in the electron microscope showed no relationship between attachment of bacteria to the cell walls and ability to degrade them.

The aims of this work were to determine the feasibility of using the incorporation of radio-labelled thymidine into fat cell DNA in vivo as an index of cell division in the adipose tissue of young pigs, and to distinguish between the processes of new cell synthesis and the ‘filling’ of existing ‘empty’ cells.

Five Large White pigs were given tritiated thymidine as follows: two animals were injected at 2 days of age, two at 9 days of age and one at 40 days of age. The animals were killed at different times after the injection and adipose tissue was removed from various sites. The tissue was separated, using collagenase, into ‘fat cell’ and ‘stromal cell’ fractions. The specific (radio)activity of DNA isolated from each fraction was measured.

Fat cell synthesis occurred rapidly in pigs aged between 2 and 40 days of age. It appeared that by 40 days of age the rate of synthesis declined in backfat such that the filling of pre-existing empty fat cells became a more important contributor to the increased mass of adipose tissue than the filling of newly synthesized cells.

The performance of Suffolk cross-bred ewe lambs produced either by Suffolk crossbred ewes, 70–90% Suffolk (HS), or by Ossimi ewes, 35–45% Suffolk (LS), was investigated. Forty-three ewe lambs from both groups were available, and were given two different levels of feeding.

The LS ewe lambs showed, insignificantly, better growth performance than the HS group, and breed group differences increased with age. They also reached puberty earlier (305·4 v. 334·6 days for the HS ewe lambs). Using the HS breeding rams rather than the imported Suffolk ones, for improving lamb production from the local sheep flocks, is recommended.

The LS ewe lambs started their first breeding season 18 days earlier, and ended 34 days later, than the HS ewe lambs. Both cross-bred groups showed clear anoestrous periods of 225·4 and 202·2 days, respectively. The onset of their second breeding season was similar, on average 29 August. These figures are close to those of the purebred Suffolk ewes, and far away from the nonseasonal local parents.

A study was carried out during three successive years from 1970 to 1972 on different wool types. Breed groups involved were Merino (M), coarse-wool Barki sheep and five of their crosses. Traits studied were greasy-fleece weight, clean-fleece weight, kemp score and means of staple length and fibre diameter in the whole fleece.

The heaviest greasy fleeces were produced by ¾ followed by ⅝ M. Total average greasy fleece weight of the crosses was 3·43 kg. There was a general trend of increase in greasy fleece weight with increasing Merino proportion.

The total average percentage clean yield of the crosses was 42·2, and ½ M and ¾ M produced the heaviest clean fleeces. The total average clean fleece weight of the crosses was 1·44 kg. Skirting the fleeces caused a reduction in the within-fleece variability of staple length and diameter. Percentages reduction for staple length were 10·3, 9·6 and 14·6 and those for fibre diameter were 2·4, 5·0 and 9·5 in Barki, crosses and Merino respectively.

Barki had the coarsest diameter and the whole fleece of ¾ M showed the finest mean diameter of the crosses. The within-staple variability in distribution of fibre diameter was high in Barki and throughout the crosses. The average percentage medullated fibres was highest in Barki and decreased throughout the series of crosses. The ¼ M had the highest frequency medullated fibres of the crosses.

The longest mean staple in the crosses was produced by ¼ M. The within-fleece variability in staple length was generally low. In the crosses, the variability assumed slightly higher values than those of the parental breeds.

Kemp production was mainly contributed from the dorsal line, particularly from the back and hip.

As regards some wool and mutton characteristics, ⅝ M might be considered the most suitable cross-bred type.

With increasing Merino contribution in the crosses, the mean fibre diameter showed a decreasing trend, but a high within-staple variability was maintained throughout the crosses. Inter se mating, in most of the crosses, produced animals that showed relatively more uniformity between fleeces than either both or one of the crosses. Inter se mating of the different cross-bred types with selection of the desired uniformity in length and diameter would be recommended.

The effect of three different growth patterns from 15 to 40 kg live weight on the feed utilization of lambs was studied. The treatments were: high (H) ad-libitum feed intake, low (L) restricted feed intake and high-maintenance-high (HMH) ad-libitum feed intake from 15 to 25 kg followed by a 50-day period during which live weight was maintained constant, which in turn was followed by ad-libitum feeding. Animals were individually penned and fed a pelleted lucerne chaff-cereal grain mixture. Intakes of pellets were converted to digestible organic matter (DOM) using the results of in-vitro digestion studies. Two animals were killed at the start of the experiment (15 kg) and the remaining 27 animals (nine in each treatment) were killed at common live weights of 25, 30, 35 and 40 kg.

A marked reduction was observed during weight stasis at 25 kg in the amount of DOM required daily by the HMH animals to maintain live weight. Despite marked compensatory growth by the HMH animals which were rehabilitated after the period of weight stasis, DOM intakes were similar in both these HMH animals and a corresponding number of H animals over identical live-weight ranges.

Differences between treatments were found in DOM intake per unit live-weight gain (H < HMH < L), empty body-weight gain (H = HMH < L) and carcass weight gain (H < HMH = L) from 15 kg until slaughter. DOM intake was utilized more efficiently for gains of all these components by HMH animals during compensatory growth compared with H animals over the same live-weight ranges.

DOM intakes were related to energy gains in the carcass both for all animals in each treatment from 15 kg until slaughter, and for the H and HMH animals which were killed at 30, 35 and 40 kg from 25 kg. Comparisons of these data showed treatment differences in the efficiency of DOM conversion to carcass energy (H > HMH > L) and that DOM was utilized no more efficiently by HMH animals during compensatory growth than by H animals over identical live-weight ranges.

It is concluded that the increased efficiency of utilization of DOM for carcass gain during compensatory growth was due to changes in carcass composition during the period of weight stasis.

Three husbandry systems were used to promote differential live-weight gains in 603 Cyprus Fat-tailed, Chios and Awassi ewes. Ewes on the high level of feeding had heavier litters than those on the medium and low levels. Litter size was not affected by level of feeding during pregnancy. Milk production was highest (P < 0·01) for ewes on the high level. The milk production of Chios and Awassi ewes was similar on the high and low feeding levels, but Awassi ewes outyielded both other breeds on the medium level. Chios ewes had larger and heavier litters (P < 0·01) than both other breeds. The correlations between live weights during lactation and milk yield were low and negative indicating a tendency for body loss at high yields.

This study was carried out to investigate the effect of crossing the subtropical fat-tailed Ossimi (O) sheep with the Hampshire (H) on ewe and lamb performance. Data used involved 457 ewe records of Ossimi, Hampshire and four crosses, and 404 lamb records of Ossimi and five crosses.

Hampshire ewes performed less well than the local Ossimi ewes in various reproduction traits. They weaned 0·26 lamb/ewe run with the rams compared with 0·82 from the local ewes mated to Hampshire rams. The Hampshire ewes seemed to be anoestrous during the first part of the normal breeding season of the local ewes (May–July). Different Hampshire–Ossimi cross-bred groups showed better ewe reproduction performance than the purebred Hampshire ewes, but were inferior to the Ossimi. The first cross ewes were, generally, the best among all the cross-bred ewes and the reproduction performance declined with increasing percentage of Hampshire genes. When the first cross was interbred, ewe performance declined clearly in the F2. All cross-bred groups of ewes gave significantly heavier annual greasy-fleece weight than Ossimi ewes.

The only lamb performance trait that was improved by up-grading the Ossiroi sheep with the Hampshire breed was the first greasy-fleece weight, while lamb survival and weaning weight were clearly decreased with the advance of up-grading.

The recombined cross-bred groups ( and ⅝ Hampshire) proved to be the best cross-bred and showed considerable improvement in lamb performance traits over the local Ossimi sheep, except for lamb survival.

It is concluded that crossing Ossimi sheep with the Hampshire improved only fleece weight but not lamb production.

Groups of weaner pigs, and single animals, were observed in a temperature-controlled room isolated from external noise and light for periods of up to 4 weeks. Continuous records were made of motor activity, food intake and water consumption.

In the presence of a cycle of 12 h light and 12 h dark at 25 °C groups of pigs were most active in the light and took most of their food towards the end of the light period. Single pigs also tended to be more active in the light, but the rhythms were less marked, and one animal was most active during the dark period.

In continuous light, rhythms of activity and ingestion tended to collapse after only a few days, particularly in pigs which were kept by themselves. When the ambient temperature was increased to 35 °C during 12 h light and decreased to 25 °C during 12 h dark, a group of pigs was most active in the dark.

A model study of light absorption by rectangular hedgerows with different row orientations was made.

The effect of row orientation on daily light absorption is greatest around 25° latitude. North–south orientation gives highest absorption for most of the year near the equator. At higher latitudes, up to 55°, absorption is highest with N–S orientation during the summer months and with E–W orientations for the rest of the year, but the magnitude of the difference between orientations decreases with increasing latitude. From 65° upwards, E–W orientation gives highest absorption all the year round, but the difference among orientations is minor. The effect of orientation will be smaller as cloudiness is greater.

The results of this study are wholly consistent with yield differences due to different orientations, reported in the literature.

Two semi-dwarf and two conventional height European spring wheat varieties were grown at different sowing dates and sowing rates in two dry years. Yield component analysis showed the varieties to fall into three groups. The conventional height varieties were dependent for grain yield on either a high number of ears or a large number of spikelets per ear whereas the semi-dwarfs were dependent on high spikelet fertility.

The semi-dwarfs were consistently higher yielding over a range of environmental conditions than the conventional height varieties. Maintenance of high yield was associated with high spikelet fertility and 1000-grain weight, characters determined late in development. It is suggested that the change to the semi-dwarf plant type has resulted in high yields with greater consistency over a range of environmental conditions particularly when dry.

Three ewes were intraduodenally infused with yeast RNA (15, 20 and 30 g/day) or control solutions for 3 days and the net changes in urinary allantoin excretion determined. Four mature wethers fitted with a re-entrant cannula in the proximal duodenum were fed two levels (0·66 and 1 × maintenance) of pelleted lucerne hay. Allantoin excretion was compared with total nucleic acid (NA) flow in the small intestine.

The average proportion of the recovery of the infused RNA-N dose as urinary allantoin–N amounted to 0·119 ± 0·0046. The values of the net increase of allantoin-N (Y, g/day) above control levels were highly significantly correlated (n = 12, r = 0·98) with amounts of RNA-N infused (X, g/day): y = 0·1185 (± 0·0086) X–0·004 (P < 0·001). The average ratio of urinary allantoin-N to NA-N passing the duodenum during 24 h was 0·173. A difference between the two conversion factors is discussed in relation to endogenous allantoin excretion and purine base composition of yeast and bacterial RNA.

Four genotypes of dry beans were compared at three planting dates during one season (April to June, 1976) and four planting dates during a second season (November 1976 to January 1977). Yield declined with delay in planting in both seasons but in the second season yields were lower at the first planting and declined less rapidly. Canadian Wonder was the most stable-yielding genotype and had highest mean yield though it may have been inferior to other genotypes at the two most favourable plantings. Its stability was attributed to drought escape and good field resistance to drought and disease. Mexican 142 was the least stable genotype. A black-seeded landrace yielded well in dry conditions in spite of its long duration.

The most important components determining planting date effects on yield were numbers of pods per plant and seeds per pod. Canadian Wonder had markedly more stable numbers of pods than any other genotype.

Cooler temperatures in July and August retarded crop development in the first season. For one planting of the second season, flowering was retarded by 7–10 days in all genotypes and this was apparently an effect of water shortage. No effect of water was apparent on the time taken from flowering to maturity.

In three pot experiments and one field trial, the apical portion of the main stem of two soya-bean varieties (cv. Hampton and cv. Bossier) were removed at 3 weeks or 5 weeks after sowing in order to evaluate the response of the plants to the loss of apical dominance.

The results showed that early loss of apical dominance in Hampton (an indeterminate variety) led to increased vegetative development but shorter plants, higher dry-matter accumulation and increased seed yield through the production of more and/or heavier pods. On the other hand, apical debudding of Bossier (a determinate variety) during the vegetative stage evoked no significant beneficial response and in the case of field debudding at 3 weeks after sowing, plant height was decreased and seed yield was significantly reduced.

The response of soya bean to the loss of apical dominance therefore seems to be a function of the stage of vegetative development when the loss occurs as well as the growth habit of the variety.