The fatty acid composition of the depot fats of lambs reared for 4–5 months under gnotobiotio conditions have been determined and an estimate made of the endogenous synthesis of stearic acid.

In an uninoculated gnotobiotic lamb no hydrogenation of dietary lipids occurred in the rumen and this was reflected in the virtual absence of trans acids in depot lipids. In this animal the stearic acid content of perirenal depot fat accounted for 16% of the total fatty acids which was similar to the value found in newborn lambs (17%). Inoculation of the rumen of two gnotobiotic lambs with seven species of bacteria resulted in the establishment of partial hydrogenation processes in the rumen. Various trans isomers of octadecenoic acids were produced in these lambs from the dietary fatty acids but no stearic acid was formed.

These findings are compared with the fatty acid composition of depot fats of other herbivorous and omnivorous animals.

Digestibility trials were carried out to study the digestibility of Rhodes grass fed alone and in mixed concentrate diets. Twelve Awassi rams were used to examine the seasonal effect on the digestibility of Rhodes grass harvested at 21-day intervals.

A consistent increase in the content of crude protein up to the 6th harvest was observed, being accompanied by an increase in crude protein digestibility and voluntary feed intake.

In the second experiment Rhodes grass and concentrate mixed diets were examined. Sixteen Awassi rams were allocated to four diets which included 16, 32, 52 and 100% Rhodes grass. Dry-matter digestibility was found significantly different between the all-grass diet and the rest. The digestibility of crude fibre in the whole diet decreased significantly with the increase in concentrate content. The digestibility of crude fibre of Rhodes origin was calculated. It appears that the detrimental effect of concentrate on the digestibility of crude fibre of Rhodes grass origin is limited. This finding is supported by the high C2/C3 ratios in rumen liquor which were maintained up to 68% concentrate in the diet.

This study indicates that Rhodes grass may serve as a highly efficient roughage component in dairy rations.

Resistance in Rossol and Nematex is separately conditioned by single genes. The genes are incompletely dominant and non-allelic. It was not possible to distinguish between homozygous and heterozygous resistant plants in segregating families.

Dissection data for 753 steer carcasses from 17 breed-type x feeding system groups were used to examine the prediction of lean content in the side (half carcass) from the lean content of standardized wholesale joints. Different prediction equations were examined and the joints compared both in terms of predictive precision and the stability of their prediction equations between groups.

The relative precision of the joints for predicting weight of lean in the side depended on whether or not the prediction equation included joint weight. With side weight and weight of lean in joint as independent variates, there was little difference between most joints in precision, and the smaller joints, shin and leg (hind shin) appeared to be best because they are convenient and easy to dissect. The addition of joint weight to the equation improved considerably the precision of all the joints except the shin and leg. The coast and top piece gave the most precise predictions with the trivariate equation (residual standard deviations about the common regression line computed ignoring groups, RSD overall, were 1·44 and 1·48 kg respectively) and the fore rib probably offered the best compromise between cost and precision (RSD overall = 1·82 kg).

The stability of prediction equations between groups was influenced in a similar way by the inclusion of joint weight as an independent variate. The joints which gave the most precise predictions tended to have the most stable equations. The average biases between the actual group means and the means predicted using the trivariate equation computed ignoring groups were ± 0·46, ± 0·49 and ± 0·76 kg for the top piece, coast and fore rib respectively.

In a glasshouse experiment, sulphur was applied to 22 soils as 35S-labelled gypsum. Estimates of available sulphur using different extractants were correlated with yield responses and sulphur uptakes by oats. The largest correlation coefficients were obtained with ‘A’ values and sulphur soluble in 0·5 M-NaHC03, 1% NaCl after heating and ammonium acetate–acetic acid. Critical levels of available sulphur obtained by relating these four methods to yield responses were 24·0, 22·0, 11·0 and 10·5 mgS/kg soil respectively.

One hundred and fifty-nine Corriedale x Dorset Horn lambs were slaughtered at 32 kg live weight at ages varying from 98 to 303 days. The youngest lambs were from ewes on a pasture with high herbage availability and had not been weaned; the next youngest were from the same group of ewes but had been weaned at 6 or 12 weeks of age. Older lambs had been weaned at 6, 12 or 29 weeks from ewes on a pasture with low herbage availability. The weaned lambs grazed either a phalaris or a lucerne pasture.

Lambs that grazed lucerne had a greater dressing percentage and a heavier carcass. Over all lambs, ultimate pH of the m. semimenxbranosus ranged from 5·4 to 6·0 and Warner-Bratzler shear values increased twofold from lowest to highest pH. Minimum ambient temperatures during the nights before the slaughter days ranged from 13 to – 1°C; ultimate pH increased by 0·25 units with decreasing temperature over the range, equivalent to an increase in shear value of 26%. Shear values adjusted for pH differences increased from about 3·4 kg/cm2 at 130 days of age to about 7·5 kg/cm2 at 300 days.

Visual attractiveness of 13th rib chops increased with increasing area of the m. longissimus dorsi. Attractiveness was least at intermediate dominant wavelength (redness) of this muscle, but was not related to its reflectance. Optimum fat depth was about 2·4 mm. In general, chops from younger lambs were more attractive than those from older lambs.

Total cell wall, in vitro digested cell wall and fermentation-gas production were determined in the separated tops and stubble of five tropical and two temperate grass species grown under controlled temperatures and humidities. As the day/night temperatures increased from 18/10 to 25/17 °C the total cell wall and in vitro digested cell wall increased. With a further increase to 32/24 °C the total cell wall increased, but not the in vitro digested cell wall. In vitro digested cell-wall values were also calculated from a previously derived relationship between in vitro digested cell wall and total cell wall. The differences between observed and calculated values increased (negatively) with increasing growth temperature suggesting that the in vitro digested cell wall was depressed with increasing growth temperatures, but the extent of this depression was small.

In vitro gas production from the fermentation of plant tops or stubble in buffered rumen fluid for 24 h was significantly affected by growth temperature and humidity, apparently because of changes in chemical composition induced by the treatments. The volume of gas produced between 24 and 48 h fermentation times was appreciably lower from stubble than from plant tops and this was thought to be due to a higher resistance of part of the cell wall of stubble to digestion by rumen bacteria. Gas production in this period was slightly lower in the tops of grasses grown at the lower temperatures, but this could have been an indirect effect from an associated decrease in the total cell wall.

Heat-tolerance tests and observations on coat shedding were made on Santa Gertrudis and Hereford heifers of similar age in the warm humid climate of Fiji.

Coat shedding (which is influenced by day length) was normal in the locally bred, smooth-coated Santa Gertrudis whose heat-tolerance was good. However, the Herefords, which had come from New Zealand and had very woolly coats failed to shed properly and suffered serious heat stress.

Clipping and the use of a close-fitting jute rug demonstrated the specially high heatretaining properties of a thick natural coat of cattle hair; also the special need to select animals of low coat score for the very humid tropics.

Two gene markers were observed among cowpea breeding lines in Ibadan, Nigeria. One is the swollen stem base which is due to a larger quantity of phloem parenchyma in the bottom part of the stem below the first primary leaf than in the normal stem. It is inherited as a simple dominant trait and the symbol Sw is suggested. The other is the hastate-leaf which is expressed as extremely narrow trifoliate compared with the normal. It is inherited as a simple dominant trait and the symbol Ha is suggested. Dominance may not be complete in both cases as variable expressions of the marker genes were observed in F2. The effects of the marker genes on yield and other characters are currently being investigated.

In group and individual feeding experiments of 98 days duration, a total of 96 Large White x Landrace 9-week-old pigs were fed diets (containing 0–09 mg selenium/kg) based on 85% of barley (containing 3 mg δ-α-tocopherol/kg), which had been stored aerobically for 1 year, with 0 (basal), 10, 20, 40, 80 or 160 mg/kg of synthetic δ-α-tocopherol added. In both experiments the tocopherol supplementation significantly improved growth rates over those obtained from the basal diet. Serum creatine phosphokinase and aspartate aminotransferase activities were not significantly affected.

The digestibility of protein of mixed whole rumen bacterial cells and Streptococcus bovis were determined in Bos bubalis and goats. The bacterial cells were labelled either with 35S or 14C in vitro incubation and were injected in a single dose into the rumen after protecting by formaldehyde treatment. Faeces were collected for 6 consecutive days and radioactivity excreted in the faeces was measured. The digestibility of bacterial protein ranged from 81·7 to 96·8% in both the species.

In two experiments, 192 individually penned pigs were given diets containing 900 g barley/kg together with either 100 g dried microbial cells (DMC)/kg or 100 g white fish meal (WFM)/kg, and grown from 23 to 60 kg live weight. In Expt 1 rationing was by live weight and there was no difference between diets for feed used or live weight gained. In Expt 2, pigs were rationed by time and those fed diet DMC grew 15 g/day slower than those fed diet WFM, and their carcasses were of lower specific gravity.

Few problems have been reported with the use of the isotope dilution technique for measuring volatile fatty acid (VFA) production in the rumen of sheep. However, early studies carried out in this laboratory, using a standard technique (Leng & Leonard, 1965) showed serious limitations associated with losses of activity from the infusates. Subsequent inquiries suggested that other laboratories had experienced similar problems (J. D. Sutton, National Institute for Research in Dairying, Shinfield, and D. E. Beever, Grassland Research Institute, Hurley, personal communication). When solutions of [U-14C]Na acetate, [l·14C]Na propionate and [l·14C]Na butyrate obtained from the Radiochemical Centre, Amersham, were each diluted with deionized water to provide 0·5 μtCi μtmol/ml (hereafter designated 14Ac, 14Pr and 14Bu respectively) and left to stand at room temperature for 6 h, losses of activity of C, 15 and 3% respectively were found.

The quantity of seed ingested and excreted by penned cattle from offerings of freshly cut kikuyu grass (Pennisetum clandestinum cv. Whittet) was measured during the autumn at Grafton, N.S.W. A mean 101·6 g of whole seed was ingested per head per day, of which 22·9% was excreted. During 18 weeks, seedlings emerged from every dung pat formed from collected faeces. The number of seedlings represented 3·45% of the whole seed ingested. The loss of covering structures from the seed during passage through the alimentary tract apparently reduced the 21–day germinability.

Many authors have studied the follicle population in sheep and goats with a view to establishing a scientific basis for the breeding of sheep and goats with improved wool.

Pant & Kapri (1966) examined skin samples from five Gaddis, ten Angoras seven F1S, eight first back crosses to Angora, four second back crosses to Angora and eight goats produced by inter se mating of the second back crosses and recorded the S/P ratio as 0·019, 6·55, 5·58, 6·25, 8·30 and 6·78 in the six types respectively. Das, Mitra & Nayudamma (1963) mentioned that the percentage of coarse hairs was about 35 in Indian goats. According to CLRI (1963) the density of hairs in Calcutta Black Bengal goats varies between 9000 and 13000/in.2 of the skin surface area and coarse hairs constituted about 28% of the total hairs. Ryder (1966) mentioned that the S/P ratio in Australian goats ranged from less than 5/1 to 7/1. He also noted the S/P value in Scottish goats as 3/1–5/1 and that in female Toggen-burg goats as 2·5/1–3·9/1. Sar & Calhoun (1966) reported that in Common American goats, three to six secondary follicles were associated with the trio of primary hair follicles. According to Burns (1965) the S/P ratio of Nigerian goats was 4/1. Margolena (1966) reported that in Texas and South African Angora does the primary follicles comprised about 9–14% of the total number of follicles. The purpose of this present investigation is to provide basic information on the S/P follicle ratio in Bangladesh Black Bengal goats.

Data on the inheritance of a closed-flower type in Vicia faba and its effect on bee visits and out-crossing are presented.

Closed flower was recessive to normal flower and segregation in the F2 generation showed monofactorial inheritance. The flowers remained more or less closed, they lacked the typical scent and generally the bees avoided them.

Six per cent out-crossing was observed. It is suggested that if spontaneous self pollinating occurs the closed-flower habit could prevent out-crossing, and could be a valuable contribution to breeding an obligate autogamous Vicia faba.