1. Observations were made at 2 years of age on 25 freemartins and their castrated brothers. Three of the freemartins belonged to a set of 4-egg quadruplets. For comparison there were 93 normal pregnant twin and single-born heifers and 14 males twin to males.

2. Twelve body measurements on each animal were taken. Averages for each character for 25 single-born Ayrshire heifers and for 10 single-born Friesian heifers were used as standards for comparison with the various groups of twins of like and unlike sex, triplets, and quadruplets.

3. Normal twin heifers were slightly smaller in all respects than the standard. Freemartins were also smaller but more so. The quadruplet freemartins were smaller still, but at 2 years they had the live-weight of normal heifers only 1½ years old. Twin males, whether from like or unlike-sexed pairs, were on average slightly smaller than the standard.

4. Percentage deviations of each group mean from standard varied systematically when characters were listed in a pre-determined order based on earliness of maturing. This relation has been summarised for each group by the regression of the percentage deviation on order of maturity, the order beginning with head width, and ending with the widths of hooks, pins, and chest. Each available group differed significantly from the chosen standard in conformation in such a way that the later a character appeared in the order, the less it exceeded, or the more it fell short of the standard.

5. As judged by the size of these regression coefficients, males twin to males showed the greatest difference in conformation from normal single-born females. Males twin to freemartins showed a slightly smaller difference. Freemartins were intermediate but closer to males. Fertile twin females and single-born females differed very little. These relations held at both 2 years of age and a live-weight of 650 lb. (1½ to 1½ years).

6. The quadruplet freemartins were anomalous in having the linear dimensions of immature normal instead of freemartin females of the same weight as if their early maturing body characters had been permanently retarded during slow growth before and after birth.

The aim of this study was to estimate the parameters of the lactation curve of dairy cows in Scotland so as to improve the prediction of milk yield. The data used for deriving the parameters were ‘milk test’ yield values recorded by the Scottish Milk Records Association during a 2-year period. The data were grouped, according to lactation number, breed and area of Scotland, into 27 groups. The data pertaining to each group were then averaged so as to produce by regression analysis a curve for each calving week, lactation number and area. Areas and breeds were found to affect the shape of the lactation curves.

A study of the intake potential of a range of well-preserved silages offered to lambs over several years showed that, of the many parameters considered, those with the greatest positive effect on DM intake were sugars in the grass as ensiled, residual sugars and protein nitrogen in the silage, with ethanol concentration in the silage having a negative effect (Henderson, Anderson and Phillips, 1984). In the experiments reported here ADD-F (85 per cent formic acid) from BP Chemicals International was applied to ryegrass at a rate sufficient to conserve much of the sugar (WSC) in the silage by inhibiting the growth of the micro-organisms on the grass. The initial lowering of the pH should also inhibit the activity of the plant enzymes, conserve protein nitrogen (PN) in the silage and prevent extensive deamination.

In 1986 first-cut perennial ryegrass, and in 1987 Italian/perennial ryegrass, was ensiled direct-cut, untreated or treated with 5 1 ADD-F/t grass in 100t capacity clamp silos. The grass was cut with a mower and lifted with a precision-chop forage harvester. The acid was pumped onto the grass through a dribble bar sited over the pick-up drum.

Heat production, energy and nitrogen balances of artificially reared piglets from specific pathogen free sows, housed in a respiratory chamber, were measured over five successive periods of 7 days each from 4 to 39 days of age. The experiment was carried out at an environmental temperature decreasing from 33 to 27°C. The mean weight increased from 1·5 (at day 4) to 11·9 kg (at day 39). Daily rate of gain increased from about 100 g in periods 1 and 2 to 502 g per piglet in the fifth period.

Daily protein deposition, as measured via nitrogen balance, increased from 17 to 96 g; fat deposition increased from about 0 to 100 g. Body composition at the start and end was determined by a comparative slaughter technique. Protein and fat content had a high correlation coefficient with body weight (R2 = 0·69 and 0·89, respectively). At birth these values were much lower, 0·24 and 0·01 for protein and fat, respectively.

Nitrogen balance compared with slaughter technique led to an overestimation for protein deposition of proportionately 0·07. Fat gain measured from slaughter was proportionately 0·08 lower than that calculated from energy balance.

Ratio of gain estimated from protein and fat gain with the balance technique relative to that measured ranged between 0·93 to 1·15 in various periods.

The objects of this investigation were to discover the amount of current inbreeding, the extent of any genetic divergence between the beef and dairy types, and whether the breed was dominated by an élite group of herds as for example, in the British Friesian (Robertson, 1953). An extensive investigation by Sewall Wright (1923a), (1923b) and McPhee and Wright (1925), (1926) established that there was at that time little current inbreeding and that genetic divergence between Dairy and Beef Shorthorns was negligible. This work adds to and corroborates their findings and throws some light on breed structure.

The sampling technique in this investigation is based upon Wright (1925). If consisted of noting the number, parents, grandparents and great-grandparents of a randomly selected sample of 128 females registered in Coates’ Herd Book, Vol. 94, 1948. Simple random lines were traced back from each great-grandparent as far as 1900, a toss of a coin deciding whether to record a sire or a dam. The information contained in Coates’ Herd Book made it a simple matter to record in addition the mate of the randomly selected ancestor, thus providing 16 random lines behind the eight great-grandparents.

The histological characteristics of the skin of docked and undocked fat-tailed sheep were studied at 15-day intervals between birth and 90 days of age, then every 30 days until 180 days and every 3 months until 1 year of age. Data presented in this paper were recorded at birth, 30, 60, 120,180 and 360 days of age. The fleece characteristics were studied at 1·0,1·5 and 2·0 years of age.

The skin structure was similar in docked and undocked Rahmani sheep and did not differ from that of other breeds of sheep.

The effect of docking was significant at most ages of the study on internal diameter of primary follicles and on the external and internal diameters of secondary and on average diameters of wool follicles (P < 0·05). The effect of docking was highly significant on each of staple length and wool diameter.

Body weight and gain data from eight studies conducted with weaner pigs to determine the relationship between stocking density and performance were used to evaluate the effect of various stocking densities on several factors which measure variation within pens. The initial weight of the pigs ranged from 5·7 to 8·3 kg and final weight ranged from 17·7 to 32·1 kg. There were 244 pens of pigs with floor space ranging from 0·11 to 0·28 m2 per pig. Average daily gain and body weight were depressed as stocking density increased. Natural logarithms of variance, coefficients of variation and ranges of average daily gains and body weights were not increased by stocking density. Body weights and daily gains appeared equally effective in measuring variance of weaner pigs housed at various densities. These results indicate that increasing stocking density within the range of densities tested does not cause a greater variation in body-weight gains.

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

The intricate pattern of distribution of the Devon breeds of sheep can be broadly related to variations in natural conditions. Some ebb and flow in the popularity of breeds is to be expected as a result of changing economic circumstances. Pre-war, there was wide scale crossing with the Dorset Down and South Down rams to obtain earlier maturity. Since the war, the ploughing-out and the new marketing arrangements for fat-stock have brought a revival of interest in the pure-breeds, but as in other parts of Britain, the change over to dairying, especially in West and Mid-Devon, has been accompanied by a permanent reduction in sheep flocks.

The growth of male red deer slows during the first winter of life before increasing again during spring. This study aimed to determine if this period of slow growth could be minimized using artificial photoperiods during autumn and winter (10 April (week 1) to 11 September (week 23), southern hemisphere). Four groups of deer (no. = 10) were housed indoors as follows. Two groups were placed on a winter solstice photoperiod (8·5 light (L): 15·5 dark (D)) and given either a natural increase in photoperiod to 11·25L: 12·75D (WSN) or held on 8·5L: 15·5D for 7 weeks followed by an abrupt increase to 11·25L: 12·75D (WSH). One group was exposed to a summer solstice photoperiod of 16L: 8D (SS) and one group exposed to a natural photoperiodic pattern (IC). A fifth group of deer (no. = 10) was maintained outside on a gravelled enclosure under natural changes in photoperiod (OC). All groups were given a diet containing 160 g protein per kg and 11·0 MJ metabolizable energy per kg dry matter (DM) ad libitum. All animals were weighed weekly and group food intake recorded daily. Metatarsal length was measured at weeks 3,17 and 22 from the start of treatments.

The major differences occurred between SS and the other groups. After a period of slower growth (weeks 1 to 5, SS = 88 g/day v. 168 g/day other groups, s.e.d. 31·2, P < 0·05), SS grew more rapidly from week 10 (P < 0·01). As a result, SS was heaviest from week 17 (P < 0·05) until the end of the experiment (P < 0·01). The mean growth rate of SS animals from weeks 10 to 23 was 346 g/day compared with 173 g/day (s.e.d. 15·3; P < 0·001) for the other groups. Over the whole experiment, SS animals gained 42·3 kg live weight, compared with 31·1 kg for WSN, 26·6 kg for WSH, 25·1 kg for OC and 23·7 kg for IC (s.e.d. 2·08 kg P < 0·01). The DM intake of SS from week 9 until the end of the experiment averaged 2·04 kg DM per head per day compared with 1·48 (s.e. 0·041) kg DM per head per day for the mean of the other groups. Metatarsal length increased more in SS than the other groups (P < 0·001) between weeks 3 and 17 and was longest in SS at weeks 17 and 22 (P < 0·01). Exposure to a 16L: 8D photoperiod during winter advanced the rapid growth of red deer calves normally associated with spring and summer. This response may be used to advance slaughter dates for venison production.

An evaluation of the response to selection for prolificacy within a nucleus sheep flock of a commercial group-breeding scheme is presented. In 1979, the Romney Group Breeders formed a nucleus flock of 120 prolific ewes chosen from 12 contributing flocks. A control flock was established in 1982 from the same source. The analysis was conducted on the trait of litter size. Selection differentials are presented for each year of birth progeny group in both flocks. Expected selection response was calculated from selection differentials and was found to have an average value of 1·5% of parent mean litter size per year. Using least squares procedures the litter size performance of control and nucleus ewes of 2, 3 and 4 years of age was corrected for environmental effects. Realized response was estimated from the differences between corrected litter size means of control and nucleus flocks. Response in litter size was found to be significant within years and within ewe age groups (P < 0·05).

Mastitis is a major source of culling and economic loss in the dairy herd. To date in England and Wales the main monitor of mastitis both within a herd and nationally is provided by monthly herd milk cell counts. The main thrust of mastitis control programmes has been to improve management practices such as dry cow treatment and milk machine testing. Interest has also been shown in the use of milk cell count as an indirect means of selecting for resistance to mastitis infection. Wood and Booth (1983) indicated that the cell count at the third monthly recording had the highest correlation with lactation mean cell count. The objective of this study was to estimate the herilability of somatic cell count, taken at the third recording after calving in the heifer lactation and to examine the association between cell count and production traits.

Profitable beef production in stickler herds depends upon each cow within the herd producing a heavy, well-grown calf every year. The weight of the weaned calf has a large effect on the producer's income. The pedigree beef breeder therefore needs to select female lines within his herd which produce calves above the herd average weight at weaning.

Water balance, electrolyte and acid-base status of a group of five South African Mutton Merino wethers given chopped lucerne hay ad libitum was determined before and after ileorectal anastomosis. In general, the sheep recovered rapidly from surgery, resuming, within 10 days, a level of dry matter intake only slightly less than pre-operative levels (1323 (s.e. 147) and 1419 (s.e. 196) g/day respectively, P > 0·05). A new water balance was established at about the same time, when sheep with an ileorectal anastomosis drank about 2500 ml/day more water, while losing about 2400 ml/day more water in the faeces and about 365 ml/day less water in the urine than did the control sheep. Most of the electrolyte and acid-base parameters tested were not significantly affected by the anastomosis but the concentrations of oxygen and potassium in the blood of sheep with an anastomosis were significantly lower (P < 0·001), while those of chloride (P < 0·001) and bicarbonate (P < 0·05) were significantly higher, than before surgery. These observations, together with normal blood pH values, suggest that bypassing the large intestine caused a compensated metabolic alkalosis.

Energy balance was determined on the five sheep with an ileorectal anastomosis as well as five control animals in an indirect, open-circuit calorimeter. Despite a significantly lower (P < 0·05) loss of nitrogen and energy via the urine (due to a lower output of urine) in sheep with an ileorectal anastomosis, total heat loss, whether absolute or relative to energy intake, did not differ from control values and therefore indicated that basal metabolic rate was not significantly affected.

From post-mortem examinations, anastomoses appear to have induced a marked atrophy of the bypassed caecum and colon, whilst the mass of the large intestine was significantly less than in control animals, despite the significant enlargement of the rectum. On the other hand, the small intestine appeared unaffected, either macroscopically or histologically.

The most significant physiological changes that occurred on bypassing the large intestine were related to loss of water reabsorbtion. However, good adaptation to the increased turn-over of water was evident, providing free access to water and a salt lick was allowed.

It is known that pigs can acquire flavour preferences by brief social interactions with conspecifics that previously consumed a flavoured solid feed. However, there is no information about whether a flavoured solution could support flavour preferences through social transmission. Ninety-six pigs (49 days old) were housed in 12 pens (8 pigs/pen). Four animals per pen were randomly selected to act as observers and four as demonstrators. Demonstrator animals were temporarily moved to an empty pen where a protein solution was offered (porcine digestive peptides (PDPs), 4% weight/volume) with the addition of 0.075% aniseed (six pens) or garlic (six pens) powdered artificial flavours for 30 min. Afterwards, demonstrators were returned to interact with observer animals for 30 min. A choice test (30 min) between aniseed and garlic PDP was performed for each observer group after the interaction. Observers showed a higher intake of solutions previously consumed by their demonstrator conspecifics (648 v. 468 ml; SEM 61.36, P < 0.05). As with flavoured solid feeds, protein solutions containing artificial flavours can create preferences in pigs for those flavours through social transmission from conspecifics.

In a recent study carried out over three years, on a commercial Cheshire dairy herd, 86% of animals were found to be lame at some time. This level of disease is considerably higher than has been reported, (Rowlands, Russell and Williams, 1983; Dohoo, Martin, Meek and Sandals, 1983) and may have important economic implications.

Lameness has been associated with reduced 305 day yields (Rowlands and Lucey, 1986), lower than average lifetime yield (Cobo Abreu, Martin, Wiiloughby and Stone, 1979), lower yields in early lactation (Enevoldson and Grohn, 1991), and a reduction in percentage milk protein (Bigras-Poulin, Meek and Martin, 1990).

Cassava is increasingly available in the United Kingdom for use in compound feeds. The trial reported here was a 2 × 4 factorial and compared dairy cow compound feeds containing nil or 400 g of cassava per kg, and crude protein levels of 100, 120, 140 and 160 g/kg, given in conjunction with grass silage.

Forty-eight Friesian cows were used in a change-over design with four periods each of 4 weeks. The trial, therefore, compared six blocks of four cows on each of the non-cassava and cassava treatments, with each cow in a block receiving a different protein level. Compound feeds without cassava had a mean barley content of 600g/kg whereas feeds with cassava had a mean barley content of 103g/kg.

There were no significant differences in milk yield (21 14 and 22·27 kg/day) or milk fat level (41·4 and 40·4g/kg milk) on the non-cassava and cassava treatments respectively (P ≤ 0·05). Differences in solids-not-fat concentration were also not significant.

Average intakes of silage were similar on each type of diet. Daily intakes of the compound feed per cow varied from 6·95kg on the non-cassava treatment to 7·08kg on the cassava treatment. This difference in compound intake was not significant. The results indicated that compound feed containing 400 g of cassava per kg perform as well as cereal-based feeds and, therefore, cassava can be considered as a satisfactory replacement for cereals up to a level of 400 g/kg in compound feeds for dairy cows.

Twin Scottish Half bred × Suffolk lambs born to well-nourished ewes suffered no ill effects, in terms of growth rate or serum immunoglobulin levels, when deprived of colostrum for periods of up to 9 h after birth provided they received adequate colostrum after the deprivation period was completed.

Poor ewe nutrition during the last 8 weeks of pregnancy, when combined with 9-h periods of colostrum deprivation, adversely affected serum immunoglobulin levels and appeared to increase mortality.

Broilers select an adequate diet when they are given a cycle of 8h free access to whole grain wheat followed by 8h access to a pelleted balancer feed (Foote and Rose 1991). This study had 3 feeding trials. Their objectives were to investigate whether the sequential feeding regimen allowed dietary self-selection by broilers and to compare the productive performance of the broilers with other feeding regimens.

The first trial used 144 broilers in 24 cages. Three balancer feeds were formulated by removing part of the wheat component of a complete feed formulation. Either 35%, 50% or 65% of the wheat was removed from the original formulation. A fourth sequential feeding treatment used the 50% balancer but with another sample of whole wheat as the alternate feed.

The performance of groups of Holstein-Friesian, Dutch-Friesian and Friesian × Africander heifers in the coastal belt of Mozambique was compared over a 3-year period. The three groups of heifers were kept together under a reasonable level of management and feeding, and measurements were made of age at first calving, milk yield, days i n production, milkability, udder wearability, mastitis incidence, calving difficulties, reproductive efficiency, disease incidence, parasitic resistance and mortality.

The highest milk production was obtained with the Holstein-Friesians followed by the Dutch-Friesians. Last came the Friesian × Africander which also showed older age at first calving, poorer milkability, fewer days in production and more udder wear. No significant differences were found in calving difficulties, disease incidence, parasitic resistance, mastitis incidence and mortality. The fertility level was relatively low in all groups.

The results corroborate reports made by several workers that acclimatized European breeds can produce milk efficiently in the not-too-harsh areas of the tropics and sub-tropics if they are properly managed and fed. The main problem seems to be the relatively low fertility rates that are common in these areas regardless of breed.