Showing papers in "The Journal of Agricultural Science in 1970"
TL;DR: In this article, the free acid content of grass silages was reduced by the addition of sodium bicarbonate to the silage and increased by adding lactic acid, and it was concluded that the acids produced during the normal silage fermentation can limit the intake of the silages and suggested that chemical treatments to preserve wet grass without the presence or formation of large quantities of acids be investigated.
Abstract: The free-acid content of grass silages was reduced by the addition of sodium bicarbonate to the silage and increased by additions of lactic acid. In each of four comparisons the addition of sodium bicarbonate to increase pH from about 4·0 to about 5·4 resulted in significant increases in intake of dry matter which ranged from 9·7 to 20·7%. Intake of organic matter was consistently increased by this partial neutralization treatment, but the increases were not significant in all experiments. The addition of sodium as sodium chloride rather than sodium bicarbonate did not alter the intake of a highly acid silage. Addition of lactic acid to reduce the pH of a silage feed from 5·4 to 3·8 resulted in a decrease in dry-matter intake of 22%. The correlation between dry-matter intake and the silage characteristics: titratable acidity, total organic-acid content, lactic-acid content and pH were all significant.It is concluded that the acids produced during the normal silage fermentation can limit the intake of the silage and it is suggested that chemical treatments to preserve wet grass without the presence or formation of large quantities of acids be investigated.
108 citations
TL;DR: Combining data on young sheep and adults gave broadly based equations that could be used to predict the body composition of healthy sheep of all ages from 3 days to adults.
Abstract: Tritiated water (TOH) space was determined in sixty-one sheep of known age (3 days to 18 months). Representative samples of the minced carcass were subsequently analysed to determine body composition (water, fat, protein, ash and energy). The regressions of the weight of the various body components on TOH space and body weight reported here gave equations suitable for prediction. These were similar to equations derived from published results for adults. Combining data on young sheep and adults gave broadly based equations that could be used to predict the body composition of healthy sheep of all ages from 3 days to adults.
99 citations
TL;DR: In an experiment with ninetynine lambs the effects on the body composition of male and female lambs were examined when five diets containing different concentrations of crude protein (in the range 10-20%) were given at three levels of feeding as mentioned in this paper.
Abstract: 1. In an experiment with ninety-nine lambs the effects on the body composition of male and female lambs were examined when five diets containing different concentrations of crude protein (in the range 10–20%) were given at three levels of feeding and lambs were slaughtered at two live weights (27·5 and 40 kg).2. With lambs slaughtered at 27·5 kg there were significant increases in the rate of both nitrogen and fat retention with increases in levels of feeding. There were also linear increases in the rate of protein deposition and decreases in fat deposition with increases in the concentration of crude protein. This effect was particularly marked at the high level of feeding.3. With lambs slaughtered at 40 kg live weight there were also linear increases in fat and in nitrogen deposition with increasing feeding level but the effect of increasing the protein concentration on increases in nitrogen retention departed from linearity.4. While at 27·5 kg there were no significant effects of feeding level on nitrogen and ether-extract content of the bodies at slaughter, with animals slaughtered at 40 kg there was a significant linear decrease in ether-extract content with increasing feeding level and a corresponding linear increase in nitrogen content with increased level of feeding.5. Male lambs deposited more nitrogen and less fat than females. This was true of both rate of deposition and of carcass composition at 40 kg live weight.
87 citations
TL;DR: In this paper, the effects of supplementing low-protein teff (Eragrostis tef) hay with protein (egg albumin), urea and urea plus C4 and C5 branched-chain volatile fatty acids (VFA) on the cellulolytic flora of sheep conditioned to these diets and on the digestibility of cellulose and hemicellulose were made.
Abstract: A study was made of the effects of supplementing low-protein teff (Eragrostis tef) hay with (a) protein (egg albumin), (b) urea and (c) urea plus C4 and C5 branched-chain volatile fatty acids (VFA) on the cellulolytic flora in the rumen of sheep conditioned to these diets and on the digestibility of cellulose and hemicellulose. Addition of urea, as opposed to no supplementation, increased voluntary hay intake and the percentage digestibility of cellulose and hemicellulose, while counts of cellulolytic bacteria were not greatly affected. The proportion of ruminococci amongst the cellulolytic bacteria increased somewhat and that of the butyrivibrios decreased. When branched-chain VFA were added to the hay together with urea the numbers of cellulolytic bacteria per g rumen ingesta and the proportion of ruminococci increased over those for urea alone. This was accompanied by a further increase in voluntary hay intake. Percentage digestibilities of cellulose and hemicellulose were similar to those for the urea/hay diet. Supplementation with protein resulted in lower digestibility of α-cellulose and hemicellulose when compared with the urea-supplemented diets. The cellulolytic bacteria formed a lower percentage of the ‘total culturable’ counts than was the case for the other diets.
85 citations
TL;DR: The results agree reasonably well with estimates of protein requirements for lambs given by the Agricultural Research Council (1965) and the overall optimum dietary crude protein concentration for growth between 16 and 40 kg body weight was about 17·0, 15·0 and 11·0% when the mean digestible energy intake was 3·0.
Abstract: The live-weight gains of male and female lambs were measured during growth from 16 to 40 kg live weight when five cereal-based diets varying in dietary crude protein concentration (from 10 to 20%) were given at three levels in a 5×3×2 factorial design.Males grew faster than females by about 15% (P < 0·001); this difference increased with age and with the amount of feed given (P < 0·05). Growth rate responded linearly to increase in feeding level (P < 0·001) and curvilinearly to increase in dietary protein concentration (P < 0·01). A significant interaction (P < 0·01) occurred whereby growth increased with higher protein concentrations as feeding level increased.At the highest feeding level (near ad libitum) the results suggest that the optimum dietary crude protein concentration for growth was about 17·5, 15·0, 12·5 and 12·5% at body weights of 20, 25, 30 and 35 kg respectively. The overall optimum dietary crude protein concentration for growth between 16 and 40 kg body weight was about 17·0, 15·0 and 11·0% when the mean digestible energy intake was 3·0, 2·6 and 2·1 Mcal/day.The results agree reasonably well with estimates of protein requirements for lambs given by the Agricultural Research Council (1965).
80 citations
TL;DR: The inclusion of white clover in the sward increased the yields of dry matter and crude protein at the low nitrogen rates, but decreased the responses, with the result that the yields and responses of the grass + clover sward were not significantly different from those of the pure-grass sward at nitrogen rates above about 300 lb/ acre (336 kg/ha).
Abstract: A series of twenty-one nitrogen fertilizer rates ranging from 0 to 800 lb nitrogen/acre (897 kg/ha)/annum was applied on a pure S. 23 perennial ryegrass sward and on an S. 23 ryegrass sward containing S. 100 white clover. Total yields of herbage dry matter and crude protein from both swards at all the nitrogen rates were determined each year by cutting the herbage five times at approximately the same stage of growth on each occasion. Four-parameter growth curves relating herbage yield to nitrogen rate were fitted to the data, and are presented for the first 3 years of the experiment. On the pure-grass sward the response of dry-matter yield to nitrogen rate was almost linear between the 0 and 300 lb nitrogen/acre (336 kg/ha) rates, then it decreased steadily, becoming non-significant about the 500 lb/acre (560 kg/ha) rate. In contrast the response of crude-protein yield was virtually linear from the 0 to the 600–700 lb nitrogen/acre (673–785 kg/ha) rates. The inclusion of white clover in the sward increased the yields of dry matter and crude protein at the low nitrogen rates, but decreased the responses, with the result that the yields and responses of the grass + clover sward were not significantly different from those of the pure-grass sward at nitrogen rates above about 300 lb/ acre (336 kg/ha). In terms of profitability at present fertilizer prices the optimum nitrogen rate for dry-matter production on both swards was estimated to be 400–450 lb/ acre (448–504 kg/ha), whereas that for crude-protein production was greater than 600 lb/acre (673 kg/ha). The value of clover in a sward receiving nitrogen fertilizer is discussed.
74 citations
TL;DR: Differences between varieties and growth phases of the ryegrasses and between grasses and legumes were related less to the nature of the cellulose-lignin complex and more closely to the percentage of the total digesta deriving from cellulose.
Abstract: The relationships between the cellulose-lignin complex, voluntary consumption and dry-matter digestibility were examined using forages of two varieties of Italian ryegrass and two legumes, lucerne and sainfoin. These forages had previously been shown to exhibit different intake-digestibility relationships. The cellulose, acid detergent lignin and acid detergent fibre contents of these forages as well as their digestibility coefficients were determined. Lignins were extracted from the fibre fractions and their ultraviolet difference spectra determined.Changes in maturity of a forage during a single growth phase, produced changes in dry-matter digestibility which were closely associated with changes in the digestibility of the cellulose and inversely related to the lignin content of the forage. Differences in digestibility between varieties of forage were less closely associated with lignin content. As the grasses matured a lignin fraction forming a difference peak at 350 mμ became evident and this was associated with decreased cellulose digestibility.Differences in voluntary food consumption resulting from changes in maturity of a single forage variety, in one growth phase, were also closely correlated with both dry matter and cellulose digestibility and inversely with lignin content. Differences between varieties and growth phases of the ryegrasses and between grasses and legumes were related less to the nature of the cellulose-lignin complex and more closely to the percentage of the total digesta deriving from cellulose.Sainfoin was characterized by the formation post-ruminally of an artifact that analysed quantitatively as lignin and qualitatively resembled a non-conjugated phenolic lignin fraction. The production of this artifact apparently disturbed fibre digestibility estimates and may have affected dry-matter digestibility estimates. Degradation of lignin apparently occurred both in the rumen and in the hind gut.
58 citations
TL;DR: Analysis of data from an extensive trial involving perennial ryegrass varieties grown under various treatments at several locations throughout Great Britain reveals that the relative performance of the varieties depends mainly upon whether they are grown as spaced plants or swards.
Abstract: SUMMARY Recently developed regressional techniques suggest that some of the problems posed by genotype-environment interactions may be solved. These techniques have been applied, therefore, to data from an extensive trial involving perennial ryegrass (Lolium perenne) varieties grown under various treatments at several locations throughout Great Britain. Analysis reveals that the relative performance of the varieties depends mainly upon whether they are grown as spaced plants or swards. Even though the genotype-environment interactions are large, much of their effects could be reduced to an essentially linear scale. These results are considered in the light of the known characteristics of the varieties concerned, whilst the wider implications are also discussed.
56 citations
TL;DR: Although a general correlation existed between iodine value and melting-point the relationship broke down in some cases, and the ratio of monoene to saturated fatty acids of carbon chain length 16 and 18 is suggested as a better chemical index of softness due to causes other than dietary lipid.
Abstract: SUMMARY Iodine values, melting (slip) points and fatty acid analyses for back (‘bung’) and perinephric (kidney) fats from 114 pure and cross-bred pigs are reported. In most cases the effects of breed were small, but half-Hampshire crosses showed a high proportion of pigs producing abnormally soft and highly unsaturated fats, though others were normal. Although a general correlation existed between iodine value and melting-point the relationship broke down in some cases, and the ratio of monoene to saturated fatty acids of carbon chain length 16 and 18 is suggested as a better chemical index of softness due to causes other than dietary lipid.
55 citations
TL;DR: Three experiments were carried out with adult sheep in order to estimate the effect of light and darkness in determining the incidence pattern of rumination and showed that rumination was greatest during the second half of each 12 h period of darkness.
Abstract: Three experiments were carried out with adult sheep in order to estimate the effect of light and darkness in determining the incidence pattern of rumination.In the first experiment the jaw movements of four sheep were recorded when they were housed in cages in a single room. Continuous records were made before and after black-out was applied to the room in order to investigate the effects of times of lighting and of feeding. The results showed that under these conditions the pattern of ruminating behaviour changed with the lighting system used and that the different feeding times had no effect upon rumination.The first experiment was repeated with four sheep. Equal 12 h light or dark periods running from 10.00 and 22.00 h were applied and also days of continuous light or darkness. Food was given as equal meals at the beginning of each 12 h period. The results confirmed those of the first experiment and showed that rumination was greatest during the second half of each 12 h period of darkness. With permanent light or darkness rumination was least in the period from 10.00 to 16.00 h.An attempt was made in the third experiment to impose a 16 h cycle on four sheep. The results showed no adaptation to a 16 h ‘day’. Instead, behaviour was circadian and probably based on cues external to the experimental room.
50 citations
TL;DR: The results indicate that the stage of lactation is an overriding factor governing the response to increased nutrition and that body condition of ewes at parturition acts as a buffer between nutrient intake and nutrient requirements for lactation.
Abstract: In each of two years, 36 Blackface ewes were brought to a high state of body condition at mating and in early gostation. At approximately 16 weeks prepartum the ewes were divided into two similar groups and fed to maintain the live weight and body condition of one group (fat), and to decrease that of the other group (lean). At 8 weeks prepartum mean differences of 14kg live weight and two scores of body condition had been created between the groups. During the last 6 weeks of pregnancy food was rationed to all ewes per unit of live weight to provide the theoretical requirements of Blackface ewes in late pregnancy. Both groups of ewes made similar live-weight gains in late pregnancy and blood plasma F.F.A. values confirmed that the ewes had been similarly nourished regardless of live weight or body condition. During early lactation food was restricted to fat and lean groups of ewes for either a 2- or 4- week period followed by ad lib . feeding for the remainder of lactation. A lamb-suckling technique was used to measure milk production during a 10-week lactation. During the first and second weeks of lactation the mean milk production of groups of both fat and lean ewes was approximately 2·1 and 1·3 kg/day for twin- and single-suckled ewes respectively. Ad lib . feeding following restricted feeding during the first 2 weeks of lactation resulted in increased milk production of fat and of lean ewes to mean maximum values of approximately 2·7 and 1·7 kg/day for twin- and single-suckled ewes respectively. In contrast, groups of ewes which had restricted feeding for the first 4 weeks of lactation showed almost no increase in milk production when fed ad lib . During the extended period of restricted feeding the milk production of twin-suckled ewes which were fat at parturition was significantly greater than that of twin-suckled lean ewes but there was no difference with singlesuckled ewes. All groups of ewes lost similar amounts of live weight and body condition during their respective periods of restricted feeding. In the respective 6-week periods following ad lib . feeding the live-weight gain of the lean ewes was significantly greater than that of the fat ewes (339 v . 222 and 356 v . 250 g/day for twin- and single-suckled ewes respectively), but they did not attain parity of live weight by the end of lactation. When fed ad lib . the mean intake of all groups of ewes attained similar maximum values of approximately 2·2 kg D.O.M./day. The results indicate that the stage of lactation is an overriding factor governing the response to increased nutrition and that body condition of ewes at parturition acts as a buffer between nutrient intake and nutrient requirements for lactation. It is suggested that when body reserves of ewes are severely depleted, factors other than nutrient intake may become limiting to milk production.
TL;DR: Embryonic mortality and reproductive performance were studied in 150 mature Merino ewes and groups of which were restricted to approximately 15% of their maintenance requirement from days 0to7, 6to13 and 13to20 (group 4) respectively.
Abstract: 1. Embryonic mortality and reproductive performance were studied in 150 mature Merino ewes, groups of which were restricted to approximately 15% of their maintenance requirement from days 0to7 (group 1), 6to13 (group 3) and 13to20 (group 4) respectively. Groups 2and5 were controls. Ovulation point counts, returns to service, pregnancy test by laparotomy at day 40 and lambing performance were used to assess and apportion the embryonic loss.
TL;DR: For example, in this article, the authors investigated the effect of water management on a sandy loam, using adequate fertilizer, and found that when water content was kept near field capacity, a measure of the departure from field capacity (limiting deficit, De) produced no detectable change in yield.
Abstract: SUMMARY Experiments on a sandy loam, using adequate fertilizer gave: (a) Crop yield when soil water content was kept near field capacity. (b) A measure of the departure from field capacity (limiting deficit, De) that produced no detectable change in yield. (c) Responses to irrigation: (i) conventional, as δγ/δΙ (ii) a theoretical maximum, k, after allowing for De in the water balance. (d) Other information, botanical and technical. Sugar beet (a) Best yields of sugar: 1963, 9; 1963, 10; 1964, 8 t ha-1. (b) Limiting deficit can increase to ca. 10 cm by end of September. (c) (i) Best δγ/δΙ. 1963, 0·18 t ha-1 cm-1 (some need); 1964, 0·62 t ha-1 cm-1 (great need); 1965, slightly negative (no need); (ii) inferred k = 0·4 t ha-1 cm-1 for sugar, and ca. 1·0 t ha-1 cm-1 for total dry matter. For the period sowing to harvest the values of e are 0·7 and 1·8 x 10-2 respectively. (d) Excess water (as in 1964) seems to depress the sugar yield slightly. Potatoes, main crop (part of an experiment on control of nematodes, under continuous cropping) (a) Best fresh weight yields of tubers: 1966, 46 (without irrigation); 1967, 38 (with irrigation); 1968, 33 (with irrigation), t ha-1. (b) Evidence inadequate. (c) Responses were small, or negative; (i) best response, in 1967, 0·7 t ha-1 cm-1; (ii) evidence inadequate. (d) Decreased yield in 1966 may be caused by early summer leaching: the effect was about equal to removing half of the nitrogen fertilizer applied. Potatoes, early (Arran Pilot) (a) Best fresh weight yields of tubers: 1960, 32; 1961, 37; 1962, 16 t ha-1, all at larger of two nitrogen dressings, and after normal cultivation. (b) De ≃ 2·5 cm. (c) (i) Best δγ/δΙ. 1960, 1·7; 1961, 2·0; 1962, 1·1 t ha-1 cm-1, (ii) k = 1·8 t ha-1 cm-1 for nitrogen at 0·6 cwt acre-1; k = 2·11 ha-1 cm-1 for nitrogen at 1·2 cwt acre-1. Inferred values of ɛ are 1·15 and 1·45 x 10-2. (d) Weed control by chemical means was not successful: all yields and responses were decreased by about one-third. Barley, spring (Proctor, Maris Badger) After early potatoes, some plots has a crop of trefoil, ploughed in (crops of 1961–3). In 1968, barley was test crop in an experiment on fumigants. Cropping in 1960 and 1964 was normal. (a) Best yields of grain, 3·4–4·8 t ha-1 (without trefoil); 4·1–5·4 t ha-1 (after trefoil). (b) De ≃ 4 cm before ear emergence, and unimportant thereafter. (c) (i) Best δγ/δΙ, in 1962, ca. 0·20 (no trefoil), and 0·30 (after trefoil) t ha-1 cm-1, both at upper of two nitrogen dressings; (ii) k (for variety Proctor only, and no trefoil) ≃ 0·20 t ha-1 cm-1, and may be independent of nitrogen treatment. (d) Previous management of early potatoes did not affect barley yields. For 1961–3—average yield of all treatments = 3·53 t ha-1—the average responses were: to trefoil, 0·46 t ha-1; to nitrogen, 0·76 t ha-1; to water 0·95 t ha-1. Trefoil halved the response to nitrogen, and may have increased the response to water. Within limits, water and nitrogen seem to be interchangeable as management factors. Wheat, spring (1965, Opal, in a normal experiment. 1966, 1967, Kloka in an experiment with a dwarfing compound, CCC. Four levels of N fertilizer) (a) Best yields of grain, 1963, 4·5; 1966, 5·8; 1967, 5·9 t ha-1. (b) De ≃ 4 cm before ear emergence, and ca. ET/4: thereafter. The evidence is flimsy. (c) (i) Best δγ/δΙ. 1965, 0·11; 1956, 0·16; 1967, 0·12 t ha-1 cm-1; (ii) evidence is inadequate to derive values of k, but it seems to be very small with N1 (0·4 cwt acre-1 N), and perhaps of order 0·2 t ha-1 cm-1 at all the bigger dressings (2–4 x N1). (d) On average, CCC had no effect on grain yields, but it decreased straw yields. In 1967 many sub-plots gave very large yields: the average of nine was 12 t ha-1 as total dry matter; three were not irrigated, and had no CCC; three had CCC and were irrigated. None was at the smallest N treatment. Spring wheat responds to water like any other crop when given enough N (ca. 0·8 cwt acre-1 N, or a little more). The need continues after ear emergence. Beans, winter 1960, spring 1961, 1962, 1968 (a) Best yields of grain, 1960, 3·7; 1961, 3·1; 1962, 3·6; 1968, 3·0 t ha-1. (b) De ≃ 4 cm. (c) (i) Best δγ/δΙ. 1960. 0·18 (late watering); 1961, 0·15 (early watering); 1962, 0·22 (late watering); 1968, 0·02 (early watering and then rain in excess); (ii) k = 0·17 t ha-1 cm-1. (d) There is no evidence to show that irrigation is more important either before or after flowering (early and late, in (c)). General Exception for the main-crop potatoes, all crops responded to irrigation as expected, with gains of 50–100% in the driest summers. In English units, the values of the limiting deficits were, approximately, up to 4 in by the end of September for sugar beet, 1 in for early potatoes, 1½ in for barley before ear emergence, 1½ in for wheat before ear emergence and up to about 3 in 5 weeks later, and 1½ in for beans.
TL;DR: Tests with the sheep anti–L antibody showed that the L–antigen system, which controls active potassium transport in sheep red cells does not appear to act in cattle red cells.
Abstract: The distribution of red cell potassium concentrations in ninety–one Jersey cows was examined, and shown to be consistent with two populations, a high (HK) and low (LK) type. In tracer potassium uptake experiments the HK type cells were shown to have a higher active K+ uptake, and lower passive K+ leak than LK type cells. Tests with the sheep anti–L antibody showed that the L–antigen system, which controls active potassium transport in sheep red cells does not appear to act in cattle red cells.
TL;DR: In this paper, a general theory of the interrelationships of growth and water, and growth and radiation, leads to an expressionk = 39e t ha−1 cm−1, as the maximum possible response to irrigation in terms of total dry matter produced, where ǫ is the fraction of solar radiation fixed by the crop.
Abstract: Results are given for a second period of 9 years, 6 on the pattern of 1951–9, with the last 3 years used for ad hoc management experiments. The meteorological specification of a year of ‘irrigation need’ was satisfied in 4 years: there were good responses in 5 years. During the first 6 years, out of twenty-four sets of crop yields (from eight different crops), very good responses were obtained on nine, good responses on eight, and zero or very slightly negative responses on the other seven.A general theory of the inter-relationships of growth and water, and of growth and radiation, leads to an expressionk = 39e t ha−1 cm−1,as the maximum possible response to irrigation in terms of total dry matter produced, where ɛ is the fraction of solar radiation fixed by the crop (ɛ has a range 50–100 × 10−4 for good to very good farming) when irrigation is needed. The ‘need’ is defined throughY = k(ET + De − Dm),where Y is the yield, ET is the total potential evaporation, De is a limiting deficit up to which there is no check to growth, and beyond there is no growth, and Dm is the maximum deficit experienced by the crop at the time of measuring Y. The agronomic object of the experiments is to determine De, i.e. what reserve of soil water can be used by the crop before irrigation is necessary.
TL;DR: Emphasis is placed on the very strong linear relation between yield (of water or dry matter) and meter reading within any one pasture at any one time in a new method, which overcomes the bias associated with prediction equations, for estimating pasture yields.
Abstract: SUMMARY Modifications to the New Zealand meter (Campbell, Phillips & O'Reilly, 1962) are briefly described and the results obtained with the modified meters presented. Water was shown to have the dominant influence on meter reading—dessication of the plant material reduced readings, application of water increased readings. The relation between yield of water (W) and meter reading (MR) depended on the circuitry of the meter used and was similar to that between capacitance change induced by a variable capacitor and meter reading. With the new meters this relation was strongly linear. For individual species the simple correlation of W on MR was generally superior to that for weight of dry matter. Regression coefficients for weight of water on meter reading differed between species and/or days but were correlated with the relative water content of the species (RW). Inclusion of RW in addition to that of W increased the variation accounted for (V%) when all species were included from 76·0 to 86·9%. However, the multiple regression did not eliminate bias. For individual species, there was no benefit in including the RW term. The inclusion of height of herbage (H) in a multiple regression equation with weight of water greatly improved the V% when compared with the regression of meter reading on weight of water alone for oats dressed with three levels of nitrogen. The V% increased from 71·3% for W alone to 90·0% when W, H and H2 were included in the regression. Further testing using height of herbage over a wide range of species will be required to confirm this improvement for use in an overall regression. Emphasis is placed on the very strong linear relation between yield (of water or dry matter) and meter reading within any one pasture at any one time. Use is made of this relation in the presentation of a new method, which overcomes the bias associated with prediction equations, for estimating pasture yields. This entails establishing the mean reading for any pasture and cutting for yield estimation three samples having such a mean. The limitations of the method for use with mixtures is discussed.
TL;DR: Calorimetric experiments were made with a complete extruded diet for ruminants, ‘Ruminant Diet A’ prepared by Messrs U.K. Compound Feeds Ltd, and it was found that the diet had a metabolizable energy value of 2–32 kcal/g organic matter, and the net availabilities of its metabolizableenergy were 42–7 % for fattening and 68–0 % for maintenance.
Abstract: SUMMARY Calorimetric experiments were made with a complete extruded diet for ruminants, ‘Ruminant Diet A’ prepared by Messrs U.K. Compound Feeds Ltd. Twelve determinations of energy and nitrogen retention were made using sheep and it was found that the diet had a metabolizable energy value of 2–32 kcal/g organic matter, and the net availabilities of its metabolizable energy were 42–7 % for fattening and 68–0 % for maintenance. These values agreed well with those predicted from equations published by the Agricultural Research Council. On a dry basis the starch equivalent was 38–3 %.
TL;DR: Ova containing pronuclei as well as apparently normal cleaved ova were recovered following in vivo fertilization attempts in the ewe, and growth medium proved superior in terms of final maturation.
Abstract: Maturation studies were carried out on 241 cattle oocytes. Media used were bovine follicular fluid and growth medium. Both media supported a resumption of meiosis in ca. 80 % of cases, but growth medium proved superior in terms of final maturation.Fertilization attempts were carried out on 564 oocytes following culture (27–32 h) in growth medium. In vitro fertilization attempts (107 oocytes) and in vivo fertilization attempts (82 oocytes) in the rabbit yielded negative results. Following in vivo fertilization attempts in the ewe, ova containing pronuclei as well as apparently normal cleaved ova were recovered.
TL;DR: The digestibility of some fats (beef tallow, HEF, herring oil, soyabean oil and maize oil) were studied in balance trials with sheep which had been maintained on the diets for a 35 day period of acclimatization to establish "steady state" conditions.
Abstract: The digestibility of some fats (beef tallow, HEF, herring oil, soyabean oil and maize oil) were studied in balance trials with sheep which had been maintained on the diets for a 35 day period of acclimatization to establish ‘steady state’ conditions. Corrected digestibility coefficients for the individual fats were calculated from a knowledge of the intake and output of lipid on a low-fat basal ration. The difference between the intake of fat and the corrected lipid output (total lipid output minus lipid output on basal ration) expressed as a percentage gave the corrected digestibility coefficients.It was found that the corrected digestibility coefficients for beef tallow was 85%; HEF, 74%; herring oil, 84%; soyabean oil, 83%; and maize oil, 70%. The values for beef tallow and HEF were comparable to similar estimates in pigs. The digestibility of the highly unsaturated soyabean and maize oil were markedly lower in comparison with non-ruminant species. Extensive hydrogenation of dietary unsaturated fatty acids was confirmed. For soyabean and maize oil the corrected output of stearic acid exceeded the dietary intake.
TL;DR: In this article, the authors measured the sweating rate and the electrolyte content of secretions from the skin of cattle by absorbing secretions into filter papers under polythene disks applied to shaved skin areas on the shoulder, sacral and lumbar regions for 5 min.
Abstract: Sweating rate and the electrolyte content of secretions from the skin of cattle have been measured on five Bos taurus and five B. indicus cross-bred cows by absorbing secretions into filter papers under polythene disks applied to shaved skin areas on the shoulder, sacral and lumbar regions for 5 min. The increase in weight of the filter paper was taken as a measure of sweating rate and the distilled water eluate from the filter paper was analysed for sodium and potassium. Animals were exposed for 4 h to air temperatures of 20-45 °C at 30% r.h. and for 5-7 h to air temperatures of 40 and 45 °C at 40% r.h. Estimated sweating rates were low by comparison with previously reported values, probably due to rising levels of humidity under the polythene disks during exposure to the skin. B. indicus cross-bred cows had higher sweating rates than B. taurus cows at high air temperatures but the difference between the groups was not significant statistically. Sweating rates were generally highest on the shoulder and lowest on the lumbar region. The amounts of sodium and potassium recovered from filter papers were small and very variable at low air temperatures but increased significantly with air temperature (P < 0.01). No significant differences in the amounts of electrolyte recovered from filter papers were recorded between the species groups or between different sites of collection. The secretions from cattle skin at high ambient temperatures contained at least four to five times as much potassium as sodium. Total sodium and potassium loss through the skin of these experimental animals at the highest ambient temperatures was estimated to be no more than 1-3 % of the sodium and potassium intake in the feed. Absorbing sweat on to filter paper as a method of measuring sweating rate and sweat composition is rather less satisfactory for use with cattle than with man.
TL;DR: In this article, the effect of fatty acid chain length and unsaturation on digestibility in sheep were examined using partially purified samples of lauric, myristic, palmitic, stearic, oleic and linoleic acids.
Abstract: The effect of fatty acid chain length and unsaturation on digestibility in sheep were examined using partially purified samples of lauric, myristic, palmitic, stearic, oleic and linoleic acids. The digestibility of the fatty acids was relatively constant with only a very slight decrease on increasing chain length. There was an extensive hydrogenation of the unsaturated fatty acids.The corrected digestibility coefficients for lauric acid was 91%, myristic 86%, palmitic 87% and stearic acid 81–83% whereas the corrected digestibility coefficients for oleic and linoleic acids were calculated at 87 and 93% respectively. The digestibility coefficients for the saturated fatty acids are higher than similar estimates that have been reported for non-ruminants. It is suggested that the ruminant is better able to utilize saturated fatty acids than the non-ruminant.
TL;DR: A field experiment in each year from 1963 to 1967 in Suffolk, England, tested the effect on yield of sugar beet of sowing dates ranging from 13 March to 11 May and harvest dates from 20 September to 8 December as discussed by the authors.
Abstract: A field experiment in each year 1963 to 1967 in Suffolk, England, tested the effect on yield of sugar beet of sowing dates ranging from 13 March to 11 May and harvest dates ranging from 20 September to 8 December. Sowings in March or early April gave similar yields of sugar but with later sowings yield decreased progressively faster. The relationship is represented by the equationy = 106·3 (±2·24) + 0·212 (±0·184)x-0·009 (±0·003)x2,y = yield as percentage of mean (60·1 cwt/acre of sugar), x = number of days after 12 March.Delayed harvest increased sugar yield; the relationship is represented by the equationy = 80·22 (±1·51) + 0·836 (±0·09)z-0·006 (±0·001)z2,z = number of days after 19 September. This represents an increase of 0·247 cwt/acre/day of sugar in October and 0·083 cwt/acre/day in November, equivalent to about 2½ tons/acre of roots in October and 1 ton/acre in November.The effect on sugar yield of different lengths of growing period, which ranged from 138 to 271 days, is represented by the equationy = 38·7 (±26·6) + 1·045 (±0·267)a-0·0017 (±0·0007)a2,a = number of days between sowing and harvest.On average, sowing date had negligible effect on sugar percentage at harvest. In 3 years sugar percentage increased after the first harvest to a maximum and then decreased; in 2 years it decreased with consecutive harvests.
TL;DR: For large grain yields, sorghums are needed that will produce heads with sufficient grains to accommodate all the assimilate that the leaves produce at the end of the rains when crop growth rates are increasing.
Abstract: A Nigerian, long-season, sorghum produced 15 tons of dry matter/acre in about 155 days, but the grain yield was small (2000 lb/acre or 2242 kg/ha) because only part of the dry matter formed after heading went into the grain. In contrast, an American, short-season hybrid which formed only from one-half to one-third as much dry weight as Farafara, gave over 4000 lb of grain/acre (4484 kg/ha) in 100 days. A Nigerian sorghum of intermediate height and a long-season hybrid, produced by crosses between Nigerian varieties and an American, short-season sorghum, gave larger yields than the tall variety because they formed more heads/unit area and more grains/head.
Crop growth rates of the three long-season sorghums sown in June increased to a peak in July, but declined sharply to very small values in September, and then increased again very rapidly at the end of September as heads emerged. The most important factors causing the decline were a decrease in radiation and a loss in dry weight from decay and detachment of dead leaves. An increase in radiation at the end of September and developmental changes associated with head emergence contributed to the increase in growth rates just before heading.
A large proportion of the dry weight formed after heading in Farafara accumulated in the stem but a smaller proportion in the other long-season variety and the longseason hybrid. There was an inverse relationship between the increase in stem weight and the yield of grain. For large grain yields, sorghums are needed that will produce heads with sufficient grains to accommodate all the assimilate that the leaves produce at the end of the rains when crop growth rates are increasing
TL;DR: Variations in shoot and root characteristics were markedly influenced by single genes affecting the duration of the vegetative growth period as well as by polygenic systems.
Abstract: The growth characteristics of root systems were studied in the wheat varieties Chinese Spring' Hope and the chromosome substitution lines of Hope into Chinese Spring. The growth patterns varied considerably between the lines and this was due to the fact that the plants formed different numbers of tillers and grew for different periods of time. A correlation existed between the development of the shoot and root systems although some lines differed widely in their shoot root ratios. Differences between the lines in the early stages of growth were small and they reacted uniformly to different levels of phosphorus supply. The relation between shoot and root growth was also shown by the fact that the conclusions from genetical analyses were very similar. These showed that the method of control was largely additive in nature. It was concluded that variations in shoot and root characteristics were markedly influenced by single genes affecting the duration of the vegetative growth period as well as by polygenic systems.
TL;DR: A detailed analysis of the individual components of the nitrogenous fraction was undertaken using both conventional methods of ion exchange chromatography and techniques developed especially for this purpose (see Hughes, 1969) as discussed by the authors.
Abstract: The nitrogenous composition of the water soluble fraction of maturing grass silage was investigated in detail. Empirical methods of group analysis demonstrated the complete absence of water soluble proteins, and that the major changes, involving the formation of amino acids and volatile amines, were completed within the first 2 months of ensiling. These methods were unable to account for a high proportion of the soluble nitrogen. Changes occurring within the soluble carbohydrate and volatile fatty acid fractions indicated that while secondary fermentations occurred some 8 months after ensiling they did not have any marked influence on the nitrogenous components.A detailed analysis of the individual components of the nitrogenous fraction was undertaken using both conventional methods of ion exchange chromatography and techniques developed especially for this purpose (see Hughes, 1969). Selective degradation of the amino acids liberated by the proteolysis of the grass proteins occurred. The volatile basic nitrogen content was comprised of ammonia. The non-volatile amine fraction, which accounted for a considerable proportion of the soluble nitrogen, was mainly composed of putrescine and cadaverine. There was no free histamine and only low concentrations of bound histamine were found. Evidence suggested that these amines were being further metabolized during the storage of the silage.
TL;DR: The results suggest that the site of evaporation was at the skin except in very hot humid indoor environments when some free moisture may have been present in the hair.
Abstract: Moisture content of the coats of cattle, expressed as the percentage of the dry weight of hair, has been measured in a wide variety of environmental conditions in summer, springand winter. Strips of coat were clipped from 25 Jersey, 15 Zebu x Jersey crossbred and 9 Hereford heifers in a shed, in a climate room under warm, hot dry and hot humid conditions and outdoors both in sun and shade. Moisture content, weight of coat per unit area, depth of coat, skin and rectal temperatures, sweating and respiratory rates, air temperatures and vapour pressures were measured.The mean moisture content of the coats varied in the different environments from 5·8 to 27·5 % and mean sweating rates from 28 to 438 g m-2 h-1. Moisturein summer coats out of doors in the sun averaged 11·2% and was about the same as that outof doors in the shade. In the shed, coat moisture was also low (average 11·8%) and amounted to less than half of the moisture content of clipped hair in equilibrium with a near saturated atmosphere. Herefords that had been fed a low plane ration from winter to summer, retained their long winter coats and these, in summer, had only half the moisture content of the short coats of normally fed Herefords. In the hot room, the moisture content of summer coats was usually higher than out of doors and varied around 18%.The inner part of the coat had more moisture than the outer part and estimates of moisture gradients were made. Calculation of the contribution of sweating to total moisture in indoor environments showed that, at rapid rates of sweating, it was about 8% and was higher in winter andspring coats than in summer coats (Fig. 3). It was estimated that sun and wind reduced the moisture content of summer coats by about 3% in outdoor summer environments. The effect of sun and wind on moisture content of winter coats in the same environment was estimated at nearly 9%.The results suggest that the site of evaporation was at the skin except in very hot humid indoor environments when some free moisture may have been present in the hair.
TL;DR: When compared at the same empty body weight, the protein content of the fat-free body of lambs given diet C was significantly higher than that of lamBS given diet A, and this effect of dietary-protein concentration could not be explained by differences in the amounts of protein stored as wool.
Abstract: Nineteen male cross-bred lambs, aged between 2 and 5 days, were allotted to each of three dietary treatments. The protein contents of the diets (on a dry-matter basis) were 12·0% (diet A), 28·5% (diet B) and 45·5% (diet C). The energy intakes of groups of lambs within each dietary treatment varied from below maintenance to ad lib.The experimental period was of 3 weeks and the composition of the live-weight gain was estimated by the comparative slaughter method.Body composition within each dietary treatment was highly correlated with empty body weight, but not with the previous energy intake. The fat content of the gain decreased, and the water and protein contents increased, as the dietary-protein concentration increased.When compared at the same empty body weight, the protein content of the fat-free body of lambs given diet C was significantly higher than that of lambs given diet A. This effect of dietary-protein concentration could not be explained by differences in the amounts of protein stored as wool.
TL;DR: The effect of nitrogen fertilizer on the yield of sugar beet was tested in 170 experiments done between 1957 and 1966; results of 88 experiments, some testing five and six amounts of N, have not previously been published as discussed by the authors.
Abstract: The effect of nitrogen fertilizer on the yield of sugar beet was tested in 170 experiments done between 1957 and 1966; results of 88 experiments, some testing five and six amounts of N, have not previously been published. On most sites, nitrogen increased sugar yields sharply and almost linearly up to an optimum beyond which yield changed little or decreased only slightly up to 1·8 cwt N/acre, the largest amount tested. In the two series of experiments giving most information, the mean increase from sub-optimal amounts of N was 2·5 cwt sugar/0·1 cwt N/acre. Usually 0·4–0·8 cwt N/acre was enough for maximum yield; more was needed on a few sites and on about a fifth of them nitrogen fertilizer was not needed. In 7 of the 10 years, the average optimum was 0·6–0·8 cwt N/acre; less was needed in the other years, the driest three years of the decade. In most, though not all, years, site-to-site differences in response between 0·9 and 1·8 cwt N/acre were no greater than could be expected from experimental error alone; much of the apparent difference in response between seasons were also attributable to this source. After taking account of experimental error, there were substantial between-site differences in response to amounts of N up to 0·9 cwt/acre, but attempts to explain them in terms of weather, soil and husbandry factors had little success. There was slight evidence of diminished responses to N where sugar beet followed crops other than cereals, and of responses somewhat greater than average on Chalky Boulder Clay soils of the Hanslope and Stretham Series; no other relationships were large or consistent enough to be useful for prediction. As between-site differences in response are largely unpredictable, and because a grower risks much greater crop losses by applying too little N than by applying too much, the recommended dressing is 1·0 cwt N/acre, substantially more than is needed, on the average, to obtain maximum yield. More N should be given on soils of the Hanslope and Stretham Series and on light sands poor in organic matter; less need be applied where crop residues are likely to supply much nitrogen.
TL;DR: The caecal microflora from sheep fed the same diet did, however, yield enzyme extracts which readily hydrolysed isolated hemicellulose or xylan preparations, but were not capable of hydrolysing the hemiceLLulose in undigested particulate plant material or polysaccharides isolated from the digesta.
Abstract: In sheep fed red clover hay nearly 40% of the feed hemicellulose left the rumen undigested and scarcely any of this hemicellulose was digested in the postruminal digestive tract. The caecal microflora from sheep fed the same diet did, however, yield enzyme extracts which readily hydrolysed isolated hemicellulose or xylan preparations. These caecal and rumen microbial extracts, were capable of hydrolysing the hemicellulose in undigested particulate plant material but were not capable of hydrolysing, to any extent, the hemicellulose in undelignified digesta particles from various parts of the postruminal digestive tract. The hemicellulose in delignified postruminal digesta and the hemicellulose polysaccharides isolated from the digesta were hydrolysed by both rumen and caecal hemicellulases. The results are discussed in the light of observations on the postruminal digestion of hemicellulosic material in roughage- and cerealfed animals.
TL;DR: The authors have calculated and studied the correlations between total water intake, faecal and urinary water losses, absorbed and available water, and the seventy-five other factors which were analysed in each of the eighty-five rations.
Abstract: SUMMARY Statistical analyses were carried out on the data obtained, under strictly controlled conditions in metabolism stalls, from 219 adult non-pregnant dry cows fed on seventyone different rations. The authors have calculated and studied the correlations between total water intake, faecal and urinary water losses, absorbed and available water, and the seventy-five other factors which were analysed in each of the seventy-one rations. Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements. Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements. Faecal water losses are strongly correlated with the dry-matter intake and on the faecal dry matter. Moisture content of the diet has no significant effect but increasing pentosans and crude-fibre intake enhance the losses. Urinary water excretion is closely related to the amount of absorbed water and to the dry-matter content of the diet; a highly significant correlation also exists between urinary water and urinary nitrogen and potassium. The amount of water excreted in the urine may affect the utilization of digestible nitrogen and potassium. Available water is increased logarithmically when total water intake rises arithmetically. Feeds with high moisture content thus enhance the amount of available water.