It has been shown in a previous communication that the meal-replacement value of young grass in actual pig-feeding practice is considerably poorer than would be anticipated from a consideration of its content of ‘total digestible nutrients’ as determined by means of pig digestion trials. This is because the figure for ‘total digestible nutrients’ takes no account of the energy expended by the pig in consuming and masticating its food. Although this wastage of energy does not represent a serious loss in relation to the rate of live-weight increase in the case of ordinary pig meals fed in the form of a thick slop, it becomes of considerable significance when grass forms a major component of the diet, on account of the bulkiness of the grass and its unfavourable physical texture from the standpoint of consumption by pigs.

Data concerning a random sample of about 4% of the flocks in Yorkshire were collected in the form of answers to a questionnaire. The information required was given by 98% of the farmers in the sample.

The survey has shown the extent of losses associated with pregnancy and parturition in 1952–3 and the areas in which they were most severe; it has also given some indication of the factors that might be affecting losses of different kinds.

In addition to this information, the survey has provided statistics concerning feeding and husbandry and the relative importance of different breed types in Yorkshire.

Four experiments were conducted to examine the extent to which some sampling procedures may bias the estimation of the nutritive value of herbage consumed by cattle which have been fistulated at the oesophagus.

In one experiment the nitrogen, sulphur and calcium contents (g/100 g organic matter (OM)) and organic matter digestibilities (OMD %) of 15 herbage samples were determined and compared with those of extrusa collectedfrom Hereford cattle fistulated at the oesophagus. The extrusa samples were analysed both as total extrusa, which included saliva, and as extrusa which had been squeezed through muslin and the solid and liquid fractions separated. The herbage samples covered a wide range of nutritive values (0·78–4·92 g N/lOOg OM; 0·08–0·27 g S/100 g OM; 0·17–1·43 g Ca/100 g OM and 34·4–85·7% OMD).

It was concluded that satisfactory estimates of nitrogen, sulphur and calcium contents and digestibility of herbage prehended by cattle can be made from oesophageal fistula extrusa and that the precisions of the estimates will not be increased if extrusa are separated into solid and liquid fractions immediately following collection. Corrections are not necessary for estimates of herbage sulphur, calcium and digestibility made from total extrusa but may be necessary for nitrogen values in excess of 2·74 g N/100 g OM. If extrusa are squeezed it is necessary to apply correction factors for nitrogen and sulphur but not calcium or digestibility.

In the other experiments three factors were examined in relation to the nitrogen content and digestibility of extrusa. They were the effects of (i) previous grazing experience of the pasture (ii) fasting for 0, 3, 6 and 23 h prior to sample collection and (iii) collection of extrusa during the morning or afternoon.

It was concluded that the lack of previous grazing experience of apasture or the length of a pre-collection fast up to 23 h will not significantly bias the estimation of the nutritive value of extrusa, but that it is preferable to collect extrusa samples from cattle in the morning and that sampling on rainy days should be avoided.

The reproductive performance of breeding and cyclic Welsh Mountain (WM) and Border Leicester (BL) ewes was compared in two contrasting photoperiodic environments during January 1971–April 1972. Treatment 1 consisted of natural daylength changes at latitude 51° 43’ N. There was no difference between the two breeds in onset of the breeding season, percentage exhibiting oestrus or percentage lambing. The breeding season of BL ewes terminated earlier (mean date, 31 January) than that of WM ewes (mean date, 9 March). The WM ewes had 8–12 oestrous periods and the BL ewes 7–11 oestrous periods. In treatment 2 a simulated equatorial photoperiod (13 h light: 11 h dark) was applied from January 1971 but was inadvertently interrupted by a short period of continuous light in June 1971. All WM ewes exhibited oestrus compared with 37·5% of BL ewes. The failure to show oestrus in the majority of BL ewes contributed to the marked difference between breeds in the percentage of ewes lambing: 88·9% in WM compared with 11·1% in BL ewes. In the cyclic subgroup, the WM ewes had 3–10 oestrous periods and the BL ewes, 2–7 oestrous periods.

It is concluded that the breeds showed a differential response to the two treatments and that Treatment 2 had a marked adverse effect on the reproductive potential of the Border Leicester ewes.

Field trials on hexoestrol implantation were conducted in the Waikato area of the North Island of New Zealand during 1958–59, involving 260 two and three year old Aberdeen Angus steers from nine farms. Two levels of hormone implantation were studied, namely, 30 and 45 mg. The trials ranged in duration from three to five months with an average of four months.

Pronounced differences were apparent between farms in the overall growth rates and carcass quality scores of the cattle.

Hexoestrol implantation led to a significant increase in carcass weight, estimated at approximately 22 lb., with little evidence of real differences between farms in the average response to the hormone.

Response to the higher as compared with the lower dose of hexoestrol varied markedly among the separate farms. In general, the lower dose of 30 mg. tended to yield the greater increase in carcass weight.

A small, but consistent, depression of carcass quality scores was manifest under hormone treatment, with no real differences between the two dosage levels.

Studies were made on detopped sunflower plants to see whether the depolarizing effect of NH4 on the trans-root potential is the result of increasing H2PO4 uptake and to determine the effect of NH4 on the flux of NO3 and SO4 in xylem exudate. Increasing the NH4 in the medium increased the H2PO4 flux in the exudate, but decreased NO3 and SO4 fluxes. Ammonium and NO3 influenced the uptake of each other but NH4 had the greater effect. These NH4 effects were attributed wholly or in part to blockage of the root metabolism which may have affected the permeability of root cell membranes. Therefore, the stimulation of H2PO4 flux by NH4 was probably not attributable to any specific effect of NH4 on H2PO4 uptake. Enhanced H2PO4 and decreased uptake of NO3 and SO4 reflects toxic effects of NH4 on the root metabolism.

Vicia faba, in common with other grain legumes, rarely gives economic yield increases in response to soil application of nitrogenous fertilizer either before sowing or at flowering (McEwen, 1970a, b; Day, Roughley & Witty, 1979). The lack of response was attributed to poor uptake of the applied fertilizer particularly at flowering (Day et al. 1979). Garcia & Hanway (1976), however, increased the yield of soya beans from 3695 to 5225 kg/ha with foliar sprays containing N as urea, P, K and S applied during the seed-filling period. Day et al. (1979) using four foliar sprays of the same composition increased yield of V. faba by 361 kg/ha (8·6%) following the uptake of 15% of the 80 kg N/ha applied. However, Robertson, Hinson & Hammond (1977) reported no yield responses of soya beans with up to five foliar sprays of the same composition and noted that those containing ammonium polyphosphate and KNO3 caused leaf damage that significantly reduced yield.

Field experiments on efficiency of fertilizer N applied as calcium ammonium nitrate (CAN) and urea to no-tillage maize (Zea mays) were conducted under humid (Onne) and subhumid (Mokwa) conditions. At both the locations the rate of N was 150 kg/ha.

A comparison of apparent crop recovery of applied N indicated that CAN was a more effective N source than urea under subhumid conditions (Mokwa) but that urea was more effective under humid conditions (Onne). In 1981, percentages of applied N recovered by the maize crop at Onne were 28 and 50% from CAN and urea, respectively, whereas the recovery at Mokwa was 46 and 34%, respectively. Total recovery by crop and soil (0–120cm) of CAN at Onne with divided application was equivalent to that at Mokwa with single application at planting (54%). However, the total recovery of urea was much lower at Mokwa (40%) than at Onne (60%). The results in 1982 followed similar trends. Excessive N leaching loss from CAN under humid conditions and volatilization loss from urea under subhumid conditions are considered to be the reasons for poor efficiency of fertilizer N.

1. An experiment was conducted at Jealott's Hill from 1945 to 1956 to study yield trends of cereals grown continuously and in four-course rotations including 1-year ‘renovation’ treatments in the form of (a) grazed ley, (b) ley cut for hay and grazed, (c) rape grazed, (d) mustard for green manure, (e) fallow.

Winter wheat, spring oats and spring barley were successive test crops common to all rotations and followed the ‘renovations’ or spring barley in the corresponding phase of the continuous cereals system. Main plot (rotation) comparisons were confounded with two levels of nitrogen fertilizer (0·2 and 0·4 cwt. N/acre) and three straw treatments (straw removed, burned or ploughed in) which were applied to all three cereal test crops.

All plots except those in fallow received 0·3 cwt. P2O5 and 0·3 cwt. K2O/acre every year. From 1945–48, leys, rape and mustard received 0·2cwt. fertilizer N/acre; from 1949 this dressing was doubled.

Grazing of leys and rape was by sheep.

2. In the earlier years the highest yields of wheat were obtained in the rotations containing rape, mustard or fallow, but in the later years yields after leys were superior to those in all other rotations. Wheat yields in the continuous cereals rotation soon declined and remained at the lowest level throughout, due largely to severe incidence of ‘take-all’ disease.

In the later years yields of barley and oats following 1-year ley were also superior to those in all other rotations.

3. In the six cropping rotations compared, all three cereal crops showed very marked responses to applied fertilizer nitrogen, particularly in the later years as the natural fertility of the site declined.

On soils dominated by high proportions of clay and organic matter, soil acidity and poor nutrient use efficiency have a major impact on output potential. Due to the inherent chemical properties of these soils, reducing soil acidity and the prevalence of undesirable metallic cations poses challenges. As a result, these soils have a large capacity for phosphorus (P) fixation, therefore reducing plant P availability. Limestone (CaCO3 or MgCO3) is applied to agricultural soils to counteract soil acidity and reduce P fixation. The current study investigates the effects of four contrasting annual P application rates (0, 50, 100, 150 kg P/ha); split (50:50) between spring and summer, across soils with a range of soil pH values from a previous liming trial. The effect of soil pH ranges and P treatment rates on seasonal herbage growth and herbage P concentration was investigated over three years. Soil nutrient status was also investigated. Soil pH had a significant impact on the rate of mineralization and soil P concentration across each site. A soil pH of 6.2 caused a 1.8 mg/l increase in soil test P. An annual P application was necessary to maintain sufficient herbage P concentration for animal dietary requirements (0.35% DM), however there was no effect of P application or liming rate on herbage productivity across the three sites as all sites possessed sufficient soil P reserves. The current experiment has shown that despite optimal soil fertility status, ensuring sufficient plant available P is a problem on these particular soils.

Kinetic studies of thiaminase I in extracts of ruminant faeces showed that the affinity for one substrate varied with the concentration of the other substrate in the manner of a two-step transfer mechanism. When the alternate substrate concentration was optimal, the apparent Michaelis constant (Km) for thiamine was 176 μΜ and the apparent Km for aniline was 3·19 mΜ. It is recommended that in routine thiaminase assays, the thiamine and aniline concentrations should be at least 1·5 and 25 mΜ, respectively. When non-saturating concentrations of thiamine are used in thiaminase assays the results should be reported as unimolecular reaction constants since the enzyme activity can be calculated only if suitable Km data have been determined.

Improved radioactive and colorimetric thiaminase assays with saturating substrate concentrations gave similar results. The analytical variation of the colorimetric method was rather high but this method may be useful for laboratories which lack radioactive isotope facilities.

Thiaminase assays were performed on cultures of 14 species of rumen bacteria. Only Megasphaera elsdenii had thiaminase activity and its cosubstrate specificity was different from the rumen thiaminase associated with cerebrocortical necrosis in ruminants. It was concluded that the source of rumen thiaminase in that disease has yet to be identified.

In areas where water is scarce, the use of regulated deficit irrigation, combined with decision support system tools, may decrease the impact of agriculture on natural water resources, as well as on energy consumption, thereby improving the profitability of farms. With this aim, the SUBSTOR-Potato model (incorporated in the DSSAT Program) was evaluated with a 2-year field test (2011 and 2012) conducted in a semi-arid area (Albacete, Spain) applying four irrigation levels (120, 100, 80 and 60% of irrigation requirements). Subsequently, the model was used for simulating the potato yield under several deficit irrigation strategies (ISs) during 30 years of a semi-arid climate (1988–2017) and determining the most profitable option. The considered ISs were deemed those most suitable from the yield and water productivity point of view by some authors. The model performance for tuber yield was satisfactory with an index of agreement >0.91 and errors between 0.71 and 3.06 × 103 kg/ha. The ISs simulated with SUBSTOR-Potato showed that slight deficit irrigation (5–10%) may increase the water productivity and profitability of the farms. Moreover, tuber formation (from onset of tuber initiation to harvest) was shown to be the most sensitive stage, therefore it is highly recommended to avoid deficit during this stage, which would cause a large reduction in yield (around 8 t/ha, depending on the level of deficit suffered by the crop).

1. Of a large number of cultivated soils examined, chiefly from the south-east of Scotland, the majority had a pH between 5 and 6·5, a “lime requirement” of 0·05 to 0·25 per cent. CaCO3 and an exchangeable calcium content of 0·1 per cent, to 0·45 per cent. CaO.

2. A general agreement was observed between these three sets of figures although numerous exceptions occurred.

3. The reaction of a district of six square miles was studied in detail and of a single farm in still greater detail.

4. Long unploughed soils were found to have a low pH, a low content of exchangeable calcium and a high “lime requirement.”

5. Woodland, hill and heath soils were characterised in their surface layers by an extremely low pH (below 5 as a rule), a low content of exchangeable calcium (usually less than 0·1 per cent. CaO) and a high “lime requirement.”

The milk production is strongly influenced by the dairy cow welfare related to a good nutrition and the analysis of the digestibility of feeds allows us to evaluate the health status of the animals. Through faeces’ visual examination it is possible to estimate the quality of diet fed in terms of lacking in fibre or too high in non-structural carbohydrates. The study was carried out in 2021, on four dairy farms in central Italy. The purpose of this work is the classification and evaluation of dairy cow faeces using RGB image analysis through an artificial intelligence (AI) (convolutional neural network (CNN)) algorithm. The main features to analyse are pH, colour and consistency. For the latter two RGB imaging was combined with deep learning and AI to reach objectivity in samples’ evaluation. The images have been captured with several smartphones and cameras, under various light conditions, collecting a data set of 441 images. Images acquired by RGB cameras are then analysed through CNN technology that extracts features and data previously standardized by a faecal score index assigned after a visual analysis and based on five classes. The results achieved with different training strategies show a training accuracy of 90% and a validation accuracy of 78% of the model which allow us to identify problems in bovine digestion and to intervene promptly in feed variation. The method used in this study eliminates subjectivity in field analysis and allows future improvement of increasing the data set to strengthen the model.

The objective was to evaluate steer performance, meat nutritional value, land-use, food–feed competition and both economic and environmental sustainability within temperate pasture-based suckler weanling-to-beef systems with or without (forage-only) concentrates. Post-weaning, 8-month-old, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) – slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) – slaughter age, 24 months (SIL + GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) – slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated were used to parameterize a farm-level beef systems model. Concentrate DM intake was 1187, 606 and 0 kg/head for GRAIN, SIL + GRAIN and FORAGE, respectively. The forage-only (FORAGE) system offers several advantages, including improved farm profitability, enhanced meat fatty acid profile and only utilized inedible human feed. Consequently, associated greenhouse gas (GHG) emissions per net human edible food produced were more favourable for FORAGE. However, compared to GRAIN, the FORAGE system had an older age at slaughter and associated increased pasture land-use and GHG emissions per animal, meat weight gain and essential amino acids gain. There are therefore inevitable trade-offs, as one beef system does not improve all sustainability and GHG emission metrics.

1. Three fistulated and four unfistulated crossbred sheep were each fed once daily with diets of lucerne or wheat.

2. A pre-feeding sample of the rumen liquid was examined for its content of protozoa, of various chemical components and for its enzymic activity on glucose and on soluble starch. Several samples were taken from each sheep at intervals over periods of up to 8 weeks, during which time the sheep were maintained solely on the single diet.

3. Considerable variation occurred, both between sheep and between samples from the same sheep, in the concentrations of ciliate protozoa and of lactic acid, especially on the wheat diet.

4. Analyses for nitrogen, pH, dissolved C02, volatile fatty acids and for the molar proportions of acetic and propionic acid showed differences due to diet.

The design and analysis of rotation experiments present problems which are not encountered in annual experiments. The problems of design have been discussed by Yates (1949) and Stevens (1951 b). This paper is concerned with problems of statistical analysis. The experiment described is sufficiently general in its design for it to serve usefully as a basis of discussion of methods of analysis, both of the mean yields and of the measures of secular trend. It is shown that rotation experiments, without replicates within series, can be adequately analysed.

The adsorption of oxamyl under various conditions of time, pH, temperature, organic matter and exchangeable cations on illites and kaolinites was examined. The first order reaction indicated diffusion-controlled adsorption, maximum adsorption occurring at pH 6–5 which is near the pK value of oxamyl. Exchangeable cation in the order Na > H > Ca, organic matterand increasing temperature decreased adsorption. Adsorption isotherms and the molecular structure of oxamyl point to a reaction mechanism for oxamyl association with acid- and base-saturatedclays which involve either protonation or co-ordination of exchangeable clay cations to the carbonyl of the amide structure.

Forages produced in the north central interior of British Columbia are low in percentage crude protein (CP). Growing lucerne (Medicago sativa L.) should increase forage percentage CP, but many of the soils are considered too acidic for this species. The objective of three field experiments, conducted at the Prince George experimental farm, was to evaluate management practices that might accommodate the growth of lucerne on acid soils without the expense of liming. Experiment 1 compared three legume species (lucerne, alsike clover (Trifolium hybridum L.) and red clover (T. pratense L.)), preinoculated lime-coated seed (GNRTM, Grow Tec Ltd, Nisku, Alberta), and soil liming on root nodulation and forage dry matter (DM) yield. Experiment 2 compared lucerne genetic lines, seed preinoculation and soil liming on root nodulation and forage DM yield and percentage CP. Experiment 3 compared lucerne rhizobia genetic strains, seed preinoculation and soil liming on root nodulation, forage DM yield and percentage CP.

For effective nodulation, lucerne required seed preinoculation, whereas alsike clover and red clover did not. Lucerne persisted longer than alsike or red clover. In Expts 2 and 3, the combination of lime and preinoculation increased lucerne DM yield by 136% and %CP from 9·2 to 15·4. The addition of lime alone increased lucerne DM yield by an average of 130% and %CP from 9·2 to 16·3. With preinoculation alone, lucerne DM yield increased by 100% and %CP increased from 9·2 to 12·7. Although using preinoculated lime-coated seed alone is not as effective as lime alone, coated seed may be the preferred method, based on ease of application and cost. Neither the six lucerne lines nor the three rhizobial strains evaluated resulted in improved root nodulation under acidic conditions.