Although ostriches are herbivores, their diets in commercial farming in Israel consist mainly of concentrates. The objective of this study was to evaluate an alternative for fattening ostriches aged 10 to 30 weeks, which combines pasture with concentrate feeding. Chicks were allotted to three treatments. Diet of group C40 consisted of concentrate only, provided at 40 g/kg body mass (mb). Groups CG20 and CG30 received concentrate at 20 and 30 g/ kg mb, respectively, and grazed 4 to 6 h/day on lush green alfalfa (Medicago sativa), sown barley (Hordeum vulgare), natural pasture or sulla (Hedysarum coronarium). During the last 10 weeks of experiment, groups CG20 and CG30 were merged into one group, managed as CG20 and grazed natural pasture, sulla, alfalfa, or vetch (Vicia sativa). Ostriches from group CG20 and CG30 consumed 390 (s.e.30) g and 260 (s.e. 20) g DM per day at pasture, i.e. 0·46 and 0·28 of their total daily intake, respectively. Pasture intake for CG20 was higher (P < 0·05) than for CG30. Intake of pasture (both grazing treatments combined) was twice as much as on natural pasture or alfalfa as on barley. These results were consistent with the ostriches’ preference for forbs rather than grasses in the natural pasture. The mean organic matter digestibility was 0·84 (s.e. 0·01), ostriches gained at 347 (s.e. 13) g/day, and the food conversion ratio was 3·05 (s.e. 0·16), with no effect of group. Also, grazing did not affect the dressing rate (0·47, s.e. 0·015) or the size and mass of the different parts of the gastro-intestinal tract, with the exception of the glandular and muscular stomachs, which were proportionately 0·4 (P < 0·05) heavier in grazing birds. Lower (P < 0·05) fat content (33·8 v. 26·5 g/kg) but not tenderness, of a selected muscle (fibularis longus) was found for grazing birds. This study suggests that, in young ostriches, grazing lush green pasture may reduce concentrate intake by proportionately 0·4, without altering growth performance or carcass yield and quality.

The present experiment was undertaken to investigate adaptations to insulin action on metabolism during lactation by using plasma concentrations of β hydroxybutyrate (β OH) free fatty acids (FFA) and lactate (L) as indicators. The study included three groups each of four goats. One group was used at 12 to 31 days post partum (early lactation), one group at 98 to 143 days post partum (mid lactation) and one group at 1 year post partum (dry period). For a given physiological state, each goat was examined four times to study the effect of insulin infused for 2·5 h at two rates, medium (0·36 nmol/min) followed by high (1·79 nmol/min) in two protocols: under normal aminoacidaemia in study 1 followed by hyperaminoacidaemia in study 2. Appropriate amino acid infusions were used to blunt insulin-induced hypoaminoacidaemia under eukaliaemic and euglycaemic clamp conditions or to create hyperaminoacidaemia and maintain this state under insulin treatment. In the basal state βOH (P < 0·05), mid lactation) and FFA (P < 0·05 early lactation) were higher during lactation than in the dry period. Plasma L was unmodified. Insulin infusion always resulted in a decrease in βOH levels (P < 0·05). In both studies, the change in βOH concentration as a function of changes in plasma insulin (an index of insulin sensitivity) was greater during early lactation than in the dry period (P < 0·05); this was also the case of mid lactation in study 1. Insulin infusion decreased plasma FFA during early lactation and in the dry period in study 1 (P < 0·05), and there was a trend for insulin sensitivity to be greater during early lactation. In both studies insulin infusion did not affect plasma L in lactating goats whereas plasma L was increased in dry animals (P < 0·05). The results demonstrate that during early lactation, compared with the dry period, there is an increased ability of insulin to lower βOH and FFA concentrations. These effects were not altered by increasing plasma amino acid concentrations during insulin infusion.

Winter growth of young male red deer can be increased by exposure to 16 h of light (L) and 8 h of dark (D) per day (16L: 8D). This study tested the duration of photoperiod required for this growth response, determined if the time to reach slaughter weight can be reduced and monitored plasma IGF-1, prolactin and reproductive development. Fifty male calves were allocated to five equal groups. Four groups were housed indoors and for 33 weeks from the winter solstice (22 June, southern hemisphere) until 11 February were placed under either 16L: 8D (16L), 13·25L: 10·75D (13L), 10·751:13·25D (111) or 8L: 16D (8L) photoperiods. The fifth group of deer (OC) remained outside in a gravelled enclosure. All groups were given a pelleted diet ad libitum. Group food intake was recorded daily, individual live weight was measured weekly and testes diameter and blood samples taken at weekly or 2-week intervals.

Plasma prolactin concentrations in 16L increased within 4 weeks of treatment and were different (P < 0·001) between groups from 14 August to 4 September. IGF-1 increased in both 16L and 13L 4 weeks after treatments and then increased further in 16L above that of 13L (P < 0·01). All groups grew at the same rate for the first 7 weeks. 16L then gained more weight (P < 0·001) than the other groups over the next 19 weeks (50·7 kg v. 38·5 for 13L, 35·7 for 11L, 37·0 for 8L and 37·4 for OC; s.e.d. 3·76). Food intake was positively related to growth rate in a similar way among the inside groups (P < 0·001), however there was a higher energy requirement outdoors (P < 0·05). A target live weight for slaughter of 95 kg was reached 7 weeks earlier for 16L than the other groups (P < 0·01). Testes diameter of 16L was larger than in the other groups from 13 November until 24 December (P < 0·001). The growth oflSL slowed from 1 January while that of OC increased and the live weight ofOC was equal to 16L by the end of the experiment. OC also had the largest testes diameter from 5 February onwards (P < 0·01). The live-weight increase in OC was associated with increases in both prolactin and IGF-1 levels.

This study confirmed that 16L: 8D stimulates rapid growth of young male red deer during winter for sufficient time to achieve an earlier slaughter date. The live-weight advantage was lost by late summer however. The increased growth rate was mediated by food intake and associated with increases in IGF-1 and prolactin and earlier reproductive development. Photoperiods of 13 h of light per day or less did not stimulate growth and increases in IGF-1 and prolactin were of a lower amplitude than under 16L: 8D.

The use of barley for intensive beef production, as described by Preston, Aitken, Whitelaw, Macdearmid, MacLeod and Philip (1963) is now a well established practice, but one of the hazards of this feeding system is bloat. There is evidence that the risk of this condition is accentuated if the barley husk is broken down too finely as happens if the grain is ground (Preston, Macdearmid and MacLeod, 1963; Preston, 1964). It was therefore recommended that barley should be processed in a roller mill and that the moisture content should be at least 16% (Preston, 1963), for if the grain is drier than this it is difficult to prevent excessive shattering and destruction of the husk. Suitable containers, which can be sealed in order to ensure anaerobic conditions and so overcome the problem of storing damp grain (greater than 16% moisture) have additional advantages at harvest since they can be filled quickly and easily. The purpose of this experiment was to evaluate the nutritive value of barley stored under these conditions.

A total of 219 lambs of the Welsh Mountain (W) and Scottish Blackface (B) breeds, and six types of crossbred with varying proportions of the two breeds from a cyclical crossbreeding experiment, were slaughtered in six groups at fortnightly intervals from 6 to 8 months of age. Each group had balanced numbers of each genotype and each sex. Genotype differences and effects of heterosis were estimated. Fat grades were assessed by farm staff before slaughter and Meat and Livestock Commission fat and conformation scores and external linear hindquarter measurements of each carcass were recorded.

At the same age, W carcasses were lighter (W: B = 0·86, W = 11·7 kg, B = 13·4 kg) but were more mature and had more kidney fat (W: B = 1·73) and higher fat and conformation scores especially in the loin region, but relatively shorter, thinner legs. At the same degree of maturity (carcass weight/estimated mature carcass weight), the Welsh carcasses had more kidney fat but the difference in leg measurements was reduced, and the differences for fat and conformation scores disappeared. When compared at the same grade, the Welsh lambs were 2 kg lighter and had higher conformation scores suggesting comparative undergrading, especially by the farm assessors. Results for crossbred lambs were as predicted from their breed composition and there was no evidence of heterosis.

The results suggest that at the same estimated carcass fatness, the Blackface has the potential to produce a heavier carcass but is later maturing, taking approx. 12 days longer to reach this degree of fatness.

Masham ewes carrying single, twin or triplet foetuses were offered a ration of concentrates which increased from 200 to 650 g per ewe per day over the last 7 weeks of pregnancy in 2 years. Silage was offered ad libitum and the voluntary intake of each ewe was measured. In the first year, 30 ewes were offered a poorly-preserved, wet silage (A) which had a low digestibility, followed by a better-preserved silage (B) which had a higher digestibility and dry-matter concentration. There was an increase in silage intake when the change was made from A to B. In the following year, 32 ewes were offered silage (C) which was well preserved, similar in digestibility to B but with a lower dry-matter concentration. The ewes ate more silage organic matter (g/kg live weight) with C than A (12·77 v. 9·34) in weeks 15 to 17 of pregnancy but more of B than C (13·76 v. 10·38) in weeks 19 to 20. Ewes carrying single lambs ate more silage and had a slower rate of decrease in silage intake when the concentrate ration was increased as pregnancy progressed. As litter size increased there-was either greater loss or smaller gain in body condition score.

Crossbreeding of desert goat does with the temperate Saanen x Toggenburg buck was found to result in a significant increase in the daily live-weight gain and the empty body weight of their progeny slaughtered at about 30 kg live weight when compared with purebred desert goat kids (P < 0·001). Food intake did not differ between the two types of kids, but live-weight food conversion efficiency was significantly superior in crossbred kids (P < 0·05).

Carcass weight and killing-out proportion tended to be greater in the crossbred kids reflecting lower weights of head, skin, internal organs and gut fill. Breed types did not differ in the weights of individual wholesale cuts. Carcass dissection revealed significantly higher muscle proportion (P < 0·05), significantly lower fat proportion (P < 0·01) and higher muscle: bone ratio in the crossbred kids.

The value of several live animal measurements for predicting carcass lean content was assessed on 97 Hereford bulls. The bulls were from a series of performance tests extending over a period of 4 years. The measurements made were live weight, ‘Weighband’ estimate of live weight, skin-fold thickness at the 13th rib, anal-fold thickness and Danscanner and Scanogram ultrasonic fat area. All measurements, except anal-fold thickness, showed satisfactory repeatability from one day to the next (0·45 to 1·00). Ultrasonic measurements showed the highest correlations with carcass lean content (0·22 to 0·66; corresponding residual s.d.'s, 13·87 and 26·46 g/kg). The most precise prediction of lean content was achieved with live weight and ultrasonic measurements in a multiple regression. The precision achieved and best anatomical sites for ultrasonic measurement varied with the group of bulls (highest R2 values 0·61 to 0·77; corresponding residual s.d. 's, 25·75 and 22·47 g/kg). The Scanogram machine produced more repeatable results than the Danscanner. When compared on the same animals Scanogram measurements gave slightly more precise prediction of carcass lean content than Danscanner measurements. Over all groups of bulls the two machines produced results of similar accuracy. Accounting for precision of estimating carcass lean content, response to selection for leanness was estimated to be 0·0034 to 0·0049 of the mean per annum for bulls of about 400 or 500 days of age.

A total of 1088 females of 14 breed groups (Angus and Hereford purebreds, and 12 first-cross groups) were evaluated over two locations for lifetime survival, numbers of calvings, numbers of calves weaned and cow lifetime records of calf survival. These traits are known to be related to a cow's lifetime productivity. The animals were part of the Ruakura Beef Breed Evaluation, designed to compare the growth and carcasses of steers, and the reproductive and maternal performance of females of different breed groups. Data were from 4 birth years of females and 11 breed-groups at location 1, and from 5 and 10 respectively at location 2, with seven breed-groups common to both locations. Females were first mated as yearlings. Culling at ages 2·5 to 4·5 years was based mainly on females that were non-pregnant on two occasions, whereas in subsequent years any non-pregnant female was culled. At location 1, there was a maximum possible number of mating years of 22 for females in the 1st birth year, declining to a maximum of 9 for those in the 4th birth year; for each age group at location 2 there was a maximum of 9 mating years. The average cow survival (number of mating years) was 7·26 (s.d. 3·02) at location 1 and 5·81 (s.d. 2·31) at location 2, with a coefficient of variation similar at both locations and averaging 0·41. The performances from the poorest to the best breed groups had a 1·5-fold range for number of mating years and a 1·8-fold range for number of calvings and number of calves weaned. The heritability of number of mating years (no. = 150 sire groups) was 0·13 (s.e. 0·08), number ofcalvings 0·11 (s.e. 0·08), number of calves weaned 0·15 (s.e. 0·08), and calf survival as a cow trait 0·027 (s.e. 0·018). This last heritability increased to 0·093 if adjustment was made to the underlying liability scale. There was no significant effect of breed of cow on number of mating years, nor on number of calves weaned per 100 calvings at either location, whilst the effect was significant for number ofcalvings and for number of calves weaned per cow (P < 0·10). The wide breed variation pointed to opportunities for selection among breeds, whilst the low heritabilities suggested that within-breed selection will be slow unless early indicator traits can be found.

An intensive sheep production system using flocks of 100 Scottish Halfbred (SHB), 100 Welsh Speckleface (WSF) and 100 Finn Blackface (FBF) ewes maintained by 8, 4 and 6 ha grassland respectively for a 5-year period, was investigated to establish the consequences of high flock prolificacy and the measures taken to achieve it, including PMS administration. Mating occurred in late October/November at ewe: ram ratios of 25 or 33: 1. Ewes were housed in winter and fed silage, with supplementary cereals in late pregnancy. Lambs in excess of 2 (SHB) and 1 (WSF and FBF) per ewe were artificially reared and fattened indoors; ewes and lambs at grass were rotationally grazed (with forward creep grazing by the lambs). Prolificacy in the SHB breed was 225 lambs born per 100 ewes mated for untreated ewes and 237 for hormone-treated ewes; 119 and 155 respectively for WSF ewes; and 255 for FBF ewes (all untreated). Lambs sold per 100 ewes mated were: for SHB, 200 and 177; WSF, 102 and 107; FBF, 201.

Good ewe condition and heavy live weights at mating were associated with appetite problems on silage in late pregnancy; PMS injection with a failure to secure conception rates above 80% at the critical oestrus and a markedly lower prolificacy for ewes conceiving at later oestruses; mating in the middle of the breeding season and March/April lambing with slow lamb growth rates on grass in July and August. Hormone-induced high prolificacy was associated with a greater proportion of large multiple litters than natural high prolificacy, and consequent smaller lamb birth weights and more perinatal mortality. There was a significant negative regression relating fleece weight with litter size. The results suggest the existence of an optimal level of prolificacy for the system employed.

This study investigated the potential use of blood metabolite and hormone concentrations as genetic markers for milk fat production and their possible interactions with sex and age. Two groups of calves, one from the Massey University high breeding index (HBI) line of dairy cattle (seven males, eight females) and the other from the low breeding index (LBI) line (four males, 11 females), were studied at 3·5 months and 7 months of age. The average breeding indices (BI) of the calves based on ancestry BI were 138 (s.d. 4·4) and 111 (s.d. 2·3) respectively. Serial blood sampling regimens were conducted in relation to feeding (chaffed lucerne hay at 1·3 times maintenance energy requirement), during an intravenous urea load (120 mg/kg live weight) and during fasting (63 h) and refeeding. Urea spaces and fractional decay constants at each age were estimated by a single compartment distribution model based on plasma urea concentrations following the intravenous urea load.

Plasma concentrations of urea, creatinine and non-esterified fatty acids (NEFA) were not significantly different between the lines in any of the periods examined and at either age. In contrast, plasma concentrations of glucose and insulin were greater in the HBI calves than in the LBI calves although these differences were restricted mainly to the period immediately after feeding. Urea space at 7 months of age was also greater in the HBI animals than in the LBI animals. Plasma concentrations of all hormones and metabolites except insulin were significantly influenced by sex and/or age.

The study does not confirm previous findings that genetic merit for dairying is expressed in terms of plasma levels of urea and NEFA, particularly those during a fast. However, the results of the present study are consistent with previous observations of differences in glucose and insulin metabolism between the tivo Massey University genetic merit lines. These traits may therefore have potential as genetic markers for milk fat production.

Studies of the social behaviour of a hill flock of sheep confirmed the existence of home range groups with each group having a definable territory. The groupings were not broken by a period of individual penning of the sheep.

1. Forty British Friesian and 33 Ayrshire male calves were reared on one of three treatments differing in frequency and method of feedingwhole milk and milk substitute.

2. The calves were introduced to their treatments on arrival. The Ayrshire calves were offered whole milk for 24 days as two feeds of up to 1·42 litres warm milk each (2W), or one feed of up to 2·84 litres warm milk (1W) daily, or cold milk ad libitum (AC). Thereafter they received milk substitute on one of the following regimes which were applied to the Friesian calves from arrival. The regimes were 454 g milk-substitute powder reconstituted at the rate of 158 g per litre warm water (approximately blood temperature) given in two feeds of 227 g per day (2W) or one feed of 454 g per day (1W), and milk-substitute powder reconstituted with cold water at the rate of 100 g per litre offered ad libitum (AC).

3. Calves on treatment AC had higher live-weight gains and consumed more whole milk, milk substitute and less concentrates than those on other treatments. These differences were significant. There were differences in drinking behaviour on treatment AC between Friesian and Ayrshire calves which may have been due to differences in age at the start of the experiment. Solid food intake was affected by both level and pattern of liquid milk consumption. The practical and financial implications of treatment AC are discussed.

Twenty-eight lactating cows were used in an experiment of changeover design with four periods to evaluate concentrates containing 0, 16, 32, 49, 65, 81 and 97% dried grass. The dry matter of the dried grass was 63% digestible. The concentrates also contained barley, together with groundnut meal to equalize their protein content at approximately 16-5% of dry matter. All animals had grass silage ad libitum and all concentrates were given at the rate of 0·4 kg/kg milk. Milk yield, milk composition and liveweight change were not affected by including dried grass in the concentrate. No significant effect of concentrate on silage intake was obtained. Ration digestibility and nitrogen utilization were measured with four animals per treatment. The digestibility of dry matter, organic matter and nitrogen was not reduced by increasing the proportion of dried grass in the concentrate. The efficiency of utilization of apparently digested nitrogen for total productive purposes (body retention and milk nitrogen) was also not affected by the proportion of dried grass.

1. The effects of 0·9 to 1·0 kg molassed sugar beet pulp cubes, supplemented with minerals and vitamins and with either 0, 3·0 and 7·8% urea, on the voluntary intake of oat straw (either 2·0 or 3·0% crude protein) were measured in two experiments with 250 to 300 kg British Friesian steers.

2. Straw intake was increased by a maximum of about 20% when a total of about 165 g crude protein was supplied by the urea-containing sugar beet products.

3. In one digestibility trial conducted with 385 kg steers, the inclusion in sugar beet pulp of urea equivalent to 89 g and 169 g crude protein/day comparably and significantly increased the digestibility of dry matter and crude fibre.

Five hundred and ten Danish Red male calves slaughtered for the production of veal at live weights of approximately 200 kg were used to estimate carcass composition.

Regression coefficients expressing the relationships between live weight and carcass components indicated that weight at 6 months of age consisted mostly of muscle development in the breast and hindquarters.

Variation in all of the more important growth and carcass attributes was very small, which suggested that selection responses would be difficult to obtain.

There was no apparent correlation between growth rate and the muscle, fat and bone components of the carcass. The best single indicator of the muscle content of the carcass was the muscle content of the pistol cut (r = 0·79), which itself involved complicated dissection procedures. The longissimus dorsi area provided relatively little information, and none of the body measurements, apart from the leg circumference, were strongly related to carcass composition.

The predictive value of many combinations of traits was examined. The best of them accounted for 90% of the variation in muscle content, but when the pistol cut was excluded, none of the multiple correlation coefficients exceeded 0·8.

Variation in scrotal wool cover influenced the percentage of abnormal cells in the semen of rams exposed in the hot room. The percentage of abnormal cells was highest in the rams with maximum wool cover on their scrota, intermediate in those with scrota completely devoid of wool cover and minimum in those with intermediate (2 to 3 cm) scrotal wool cover.

Advancing maturity of forage maize is associated with increases in the proportion of dry matter (DM) and starch and decreases in the proportions of structural carbohydrates in the ensiled crop. Three maize silages (286 (low, L), 329 (medium, M) and 379 (high, H) g DM per kg fresh weight) plus a concentrate formulated to give isonitrogenous intakes were offered to Holstein-Friesian steers fitted with a cannula in the dorsal sac of the rumen and a ‘T’ piece cannula in the proximal duodenum in an experiment with a cross-over design that allowed four collection periods. Nutrient flow to the duodenum was estimated using chromium-EDTA. Steers consumed approximately 0·6 kg DM per day less of diet L compared with the other two diets (P=0·026), resulting in less DM being digested (P=0·005) but digestibility did not differ between diets. Similar results were obtained for organic matter. There were no differences between diets in the intake or digestibility of neutral-detergent fibre. Intake, duodenal flow and faecal output of starch were greater for steers offered diets M and H compared with those given diet L (P<0·05). In all diets rumen digestion contributed to over 90% of total digestion of starch, although rumen digestibility declined significantly with advancing maize maturity (P=0·002). Molar proportions of acetic acid were higher in diet H (P<0·05) whilst proportions of propionic acid and n-butyric acid were higher in diets M and L. There were no significant differences between diets in mean rumen pH or ammonia concentrations. Mean circulating concentrations of insulin were higher (P=0·009) in cattle given diets L and M compared with diet H. There were no differences between diets in the mean circulating concentration of growth hormone, or the frequency, amplitude and duration of growth hormone pulses, or the mean circulating concentrations of IGF-1. Changes in forage composition that accompany advancing maize maturity affect overall silage digestion and circulating concentrations of insulin.

Four experiments were conducted to study the performance of pigs weaned at 10 days on to diets containing different amounts of flaked maize.

Digestibilities of dry matter and energy of flaked maize were found to be 0·87 for pigs between 11 and 16 days of age.

Starter diets containing 0, 250 or 375 g flaked maize/kg, given from 10 to 35 days, resulted in growth rates of 254, 254 and 213 g/day respectively and the reduction with the high level of maize was significant (P< 0·001). Feed conversion ratio was unaffected by treatment and averaged 1·08.

When the starter diets were replaced at about 24 or 27 days by a cereal-based diet containing 200 g dried skim milk/kg there were no significant differences in performance between 10 days and 10 kg live weight due to starter diet, and growth rates were similar t o those obtained when the starter diets were given to 35 days. However, there was a consistent trend of lower food intakes, poorer feed conversion ratio and, consequently, poorer growth during the immediate post-weaning period on the starter diet containing 375 g flaked maize/kg.

Two experiments were carried out in which subcutaneous implants of thyroxine pellets were made into Soay sheep in autumn after the wool follicles had become inactive. This hormonal treatment failed to restore wool growth or to shorten the winter period of follicle inactivity.