Four experiments with 133 piglets of between 21 and 55 days of age were used to examine, by slaughter and chemical analysis, the composition of the body of young pigs. Following removal from the sow, the lipid content of the empty body decreased from about 15 to 7·6%, and in the subsequent 4 weeks had recovered only slightly to between 7·7 and 10·9%; with the exception of pigs with a particularly high intake of energy whose 42-day lipid content had increased to 13·2%. Where Y3 was the lipid gain, X1 the digestible energy intake (MJ) and X2 the ratio of digestible energy to digestible crude protein (g), over all experiments Y3 = 7·83X1 + 4945X2−1260. There was little change in the protein content of pigs consequent upon the effects of either removal from the sow, pig age, diet type or nutrient intake. Over all experiments and slaughter weights; P = 0·164W−100, where P was the protein content of the body (g) and W the empty body weight (g). The efficiencies of conversion of digestible energy to energy gain in body protein and lipid were 0·36 and 0·33 respectively, associated with a constant (daily maintenance) term of 0·462 MJ ME/kg LW0·75. The low value for lipid is as would be expected for animals catabolizing lipid within the experimental period.

A field experiment testing the effects of potassium and magnesium sulphates applied from 1960 to 1967 and sodium chloride applied in 1966 and 1967 on a range of crops (Bolton & Penny, 1968) was sown with ryegrass in 1967. Only basal N and P was given to all plots until 1971 when basal K was also applied. The experiment terminated in autumn 1974.

Grass yields were increased by K residues for 3·5 years but overall yields became small due to K deficiency. After giving basal K, residual K no longer increased yields but did slightly increase % K in the grass until the end of the experiment. Some residual K from the 1960–7 dressings was found in the sandy loam soil after the final harvest.

Magnesium fertilizer residues slightly increased grass yields in the 1967–70 period but not later. However, % Mg in the grass dry matter was increased by the residues for the whole 7·5 year period. Exchangeable Mg was also increased in soil sampled after the final harvest, especially in the 23–46 cm subsoil.

Sodium fertilizer residues increased grass yields until the basal K was applied, especially on plots without added K. Significant increases in % Na in the grass and Na uptakes were detectable in all years, i.e. up to 7·5 years after the last Na application. This finding is contrary to most accepted views on the longevity of Na fertilizer effects and could be important in areas where sodium deficiencies in cattle and sheep occur.

Increases in % Cl in the grass from the sodium chloride were only detectable in the first two cuts in the year following the final application.

Silages were made from lucerne using either a flail or a precision-chop harvester without additive, with 8 1 formaldehyde (35% w/w/)/t or with 1·5, 3·0 or 6·01 formic acid (85% w/w)/t. The silages were deep frozen and later offered to young sheep with and without intraperitoneal injections of DL-methionine. Fresh lucerne, cut with both machines from the same crop, was deep frozen and offered to sheep with and without methionine injections in a separate experiment.

The untreated silages were characterized by extensive protein degradation, high contents of ammonia and acetic acid and low contents of lactic acid. Formaldehyde markedly reduced protein degradation and carbohydrate fermentation in the silo and caused a large reduction in nitrogen digestibility; these effects were of greater magnitude with precision-chopped than with flail-harvested silage. Voluntary intake and nitrogen retention were increased by formaldehyde application.

Increased rate of addition of formic acid reduced the overall extent of carbohydrate fermentation, decreased the proportion of fermentation products Which could be attributed to clostridial activity, and decreased protein degradation, though not by the same extent as did formaldehyde. With the precision-chop harvester, formic acid addition increased both voluntary intake and nitrogen retention. Intakes were low on the three flail-harvested silages made with formic acid, as these were heavily contaminated with soil. However, the additive improved nitrogen utilization and within this group of treatments intake increased with increasing rate of formic acid application. The increases in nitrogen retention with additive treatment resulted from increases in the quantity of nitrogen truly retained per unit of nitrogen intake as well as from increases in intake.

Methionine supplementation had no effect on voluntary intake, but caused a small and consistent improvement in nitrogen utilization except with the soil-contaminated silages. There was no effect of methionine supplementation on utilization of nitrogen in the fresh lucerne.

Voluntary intake, apparent biological value and nitrogen retention all decreased linearly with increasing protein degradation and formation of acetic acid and ammonia. Separate regression equations were calculated for the prediction of organic-matter intake for silages made with the two types of harvester. These were parallel, but with intakes from the precision-chopped silages higher by ca. 20 g D.M./kg W0·75 per day. Precision chopping produced a similar advantage with the fresh lucerne. Data from silages made by the two harvesting methods fitted the same regressions for nitrogen retention, which decreased by 0·3 g/day for each 1% increase in ammonia-N (% total N). It was deduced that to produce silage with high nutritive value it is particularly important that the degradation of amino acids by proteolytic clostridia is prevented; restriction of the degradation in the silo of true protein to amino acids is apparently less important.

Lucerne was made into ten silages using either a flail or a precision-chop harvester with application of formaldehyde or a range of rates of formic acid during harvesting. Amino-acid analyses were done on the silages and on samples taken from the herbage at ensiling.

In excess of 70% of aspartic acid, serine, glutamic acid, tyrosine, threonine, lysine, histidine and arginine were destroyed in untreated silages when a flail harvester was used and in excess of 50% when a precision-chop harvester was used. Glycine, leucine, iso-leucine, valine and methionine showed little change, with net losses or increases of up to 10%, whilst proline, cystine + cysteine and phenylalanine were intermediate between these two categories. Net synthesis of alanine and α and γ amino-butyric acids occurred in the untreated silages. Increasing rates of formic acid addition, and the use of the precision-chop harvester, reduced the loss of the amino acids which were extensively degraded in the untreated silages and minimized the increases in alanine and α and γ amino-butyric acids. Formaldehyde treatment also reduced amino-acid degradation, apart from apparently high losses of lysine, histidine and tyrosine. It was concluded, however, that these losses arose through problems of estimation in formaldehyde-treated silages following HCl hydrolysis.

It is suggested that the most probable precursors for alanine and α and γ aminobutyric acids were respectively aspartic acid, threonine and glutamic acid. Voluntary intake and the utilization of silage nitrogen by young sheep were related to the net changes in amino acids involved in decarboxylation reactions, the best measures of this being the interconversions involving the formation of alanine and α and γ aminobutyric acids. Deamination reactions appeared to be of much less importance in limiting silage nutritive value than those involving decarboxylation.

Mature cyclic ewes were treated intravaginally with sponges impregnated with 30 mg SC-9880 (G. D. Searle) or intramuscularly with 100 μg Cloprostenol (I.C.I. 80, 996) and examined subsequently for oestrus, ovulation and fertilization. At 70 h after the end of treatment, 90% of ewes treated with SC-9880 and 45% of those treated with Cloprostenol had ovulated. Of ewes yielding eggs at 100 h a significantly higher proportion of SC-9880 treated sheep showed evidence of fertilization (69% v. 7%).

Gibberellic acid (GA3); monophenols, salicylic acid (SA) and β-naphthol (β-N); diphenols, catechol (CT) and resorcinol (Res); and polyphenols, chlorogenic acid (CA) and tannic acid (TA) hastened the emergence of ears and increased the numbers of branches and ears, number of seeds, seed weight and the 1000-seed weight in cheena millet (Panicum miliaceum L.). The results show that the action of phenolic compounds is not related to their structural configuration as is considered by some workers.

Seven experiments carried out over 3 years investigated the effects of the date of defoliation of the seed crop and the storage temperature of the seed on subsequent sprout growth.

The time of defoliation of the seed crop had a small, variable effect on the number of sprouts but with all varieties in every year, early defoliation gave the greatest total sprout length. The effect of later defoliation on sprout length varied according to the variety and the year. Most of the variation in total sprout length per tuber appeared to be attributable to differences in the date of dormancy break of the seed tuber.

Storage throughout the winter at 15 °C gave fewer sprouts but a greater total sprout length per tuber than storage at 9 °C. A linear relationship between total sprout length per tuber and accumulated day degrees above 0 °C from dormancy break accounted for most of the variation in sprout length occurring in Désirée, Pentland Crown and Majestic as a result of storage at 9 °C and 15 °C for different periods of time.

Six experiments carried out over 3 years investigated the effects of the date of defoliation of the seed potato crop and the storage temperature of the seed on the growth of the subsequent ware crop.

Defoliation of the seed crop in July tended to reduce foliage dry weight particularly at later harvests, and in two experiments in 1974 affected the tuber yield. In one of these experiments defoliation in July resulted in a lower yield than from defoliation in August, while in the other experiment it significantly reduced the bulking rate of the ware crop and gave a lower yield of King Edward at the final harvest. Storage of the seed tubers at low temperature (2–3 °C) tended to increase the amount of foliage produced but only in two out of six experiments was there any effect of storage temperature on yield; in both storage at low temperature gave the lowest yield.

There was a significant relationship between the effect of storage temperature on tuber yield and its effect on the time to emergence of 50% of the plants. It is suggested that in these experiments a combination of late planting and weather conditions before emergence reduced the effect of storage temperature on the time to 50% crop emergence and therefore reduced its effect on tuber yield.

In 1973 when there was a large effect of storage temperature on yield, there was a significant relationship between the tuber yield of the ware crop and the physiological age of the seed measured as accumulated day degrees above 0 °C from dormancy break to planting.

Studies of ewe behaviour are not only necessary to facilitate management procedures but also to ensure high productivity. Indeed, information on the ewe behaviour during parturition would help in reducing ewe and lamb wastage, but there is little information available. This paper gives information on the diurnal variation in lambing and time taken for placenta expulsion in Awassi ewes.

In the winter-rainfall areas of southern Australia cattle and sheep grazing dry pastures in late summer and early autumn commonly lose weight because of a decline in the availability and nutritive value of the dry herbage (McLaughlin, 1973). Early-weaned calves and young lambs are affected more severely than older animals probably because of their low feed intake and their high requirements for energy and protein (Preston & Willis, 1970).

It has been shown (Gordon, 1975) that certain progestagens administered intravaginally can be highly effective in the control of oestrus, ovulation and fertility in ewes. Prostaglandin (PGF2α) when infused into the uterine vein ipsilateral to the ovary containing the corpus luteum has been shown to result in luetolysis and a return to oestrus in a high proportion of ewes (Hearnshaw, Restall & Gleeson, 1973). Synthetic analogues of PGF2α have also been shown to have a marked luteolytic effect in ewes (Baird & Scaramuzzi, 1975). Variable fertility has been reported following the use of prostaglandin or its analogue for oestrous synchronization (Jennings, 1975; Haresign, 1976; Fairnie, Cumming & Martin, 1976; Lightfoot, Croker & Marshall, 1976; Trounson, Willadsen & Moor, 1976). Low fertilization has been reported after the use of a prostaglandin analogue and artificial insemination at a predetermined time in ewes (Boland, Gordon & Kelleher, 1978). The purpose of the present experiment was to extend these observations, using a ram in natural service after employing a double prostaglandin injection regime or an intravaginal progestagen treatment for the control of oestrus in cyclic sheep.