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Showing papers in "The Journal of Agricultural Science in 1969"


Journal ArticleDOI
TL;DR: The results show that body condition scores can provide an acceptable and useful estimate of the proportion of fat in the live animal, and that the level of prediction is superior to that afforded by live weight.
Abstract: Subjectively assessed body condition scores, determined on the live animal, were related to the percentages of chemical fat in the fleece-free empty bodies of 30 adult Scottish Blackface ewes. The results show that body condition scores can provide an acceptable and useful estimate of the proportion of fat in the live animal, and that the level of prediction is superior to that afforded by live weight.

1,339 citations


Journal ArticleDOI
TL;DR: The quantitative distribution of nitrogen between undigested dietary residues, bacterial residues, endogenous debris residues and the water soluble fraction was determined chemically and it was concluded that 57–81% of the non-dietary faecal nitrogen was associated with bacterial material.
Abstract: 1. Three methods, based on treatment with neutral detergent or acid detergent, or involving ultrasonic disintegration, are described and compared for the direct estimation of undigested dietary nitrogen in individual samples of sheep faeces. Estimates of the true digestibility of the nitrogen in several sheep diets derived from analyses performed with these methods agreed well with each other, and were in accord with published estimates, derived by extrapolation techniques. Two other methods, based on treatment with phenol–acetic acid–water, and lysozyme–trypsin, respectively, were found to be unsuitable for such estimates.2. The quantitative distribution of nitrogen between undigested dietary residues, bacterial residues, endogenous debris residues and the water soluble fraction was determined chemically. It was concluded that 57–81% of the non-dietary faecal nitrogen was associated with bacterial material.3. Indirect evidence suggested that most of the bacterial nitrogen in faeces originated in the rumen.

232 citations


Journal ArticleDOI
TL;DR: The higher level of feeding increased yields of milk and milk solids and solids-not-fat content in each period but had a smaller effect in mid- than in early lactation, a trend which was shown to continue further into later lactation.
Abstract: Eighty Friesian heifers were used to study the effect on milk production of two fixed levels of intake at two stages of the lactation. The rations were estimated to contain 7·9 and 6·2 kg starch equivalent per day, with adequate protein content. The heifers were allocated at random to these two levels of intake for weeks 1·9 of lactation and re-allocated at random to them for weeks 10–18 of lactation. Apart from minor variation the heifers were all fed alike for the remainder of the lactation.The higher level of feeding increased yields of milk and milk solids and solids-not-fat content in each period but had a smaller effect in mid- than in early lactation, a trend which was shown to continue further into later lactation. It also conserved body reserves.There was a residual effect in weeks 10–18 from the level of feeding in weeks 1–9 of lactation. This was directly additive to the effects of the current level of feeding. Those animals which had received the higher level of feeding in weeks 1–9 yielded more milk of higher solids-not-fat content than those which had had the lower level of feeding in weeks 1–9. The former group gained less live weight. The effect on milk production over the full lactation from additional feeding in early lactation was three times that observed in early lactation itself. Additional feeding in mid-lactation did not have a residual effect.The absolute output of milk per unit of food over the 18-week period was greatest for that group which had received the lower level of feeding throughout, followed by the group which received the higher level of feeding in weeks 1–9 only. This superiority was achieved at the expense of body reserves. There was a negative regression of live-weight change on milk production.Estimated intakes of metabolizable energy agreed closely with requirements for milk production as indicated by the Agricultural Research Council (1965).

116 citations


Journal ArticleDOI
TL;DR: Results can be interpreted as indicating that the level of food intake had a positive effect on both ovulation and lambing rates of lean ewes (condition 1½).
Abstract: Two-hundred-and-seventy-three Scottish Blackface ewes in three ages (5, 4 and 2 years) were differentially group fed over 6 weeks in such a manner that at 6 weeks before mating there were approximately equal numbers in each of six subjectively assessed body condition groups ranging from score 1 (lean) to score 3½ (moderately fat). Over the 6 weeks prior to mating these groups were either well fed, fed at about maintenance, or underfed so that at mating the maj ority of ewes were in either condition 1½ or 3.A predetermined random sample of mature ewes from each of the six original condition groups was killed 2–3 days post-mating for ovulation counts. Surviving ewes were fed above maintenance post-mating and the number of lambs recorded at birth. Condition at mating had a significant, positive effect on both ovulation and lambing rates but had no effect on infertility measured as the difference between them.The level of food intake prior to and at mating had no effect on either ovulation or lambing rates of moderately fat ewes (condition 3) but the results can be interpreted as indicating that the level of food intake had a positive effect on both ovulation and lambing rates of lean ewes (condition 1½).

90 citations


Journal ArticleDOI
TL;DR: Estimates of natural cross-fertilization ranged from 35·8 to 42·1%, indicating that self-pollination did not lead to complete self fertilization.
Abstract: The percentage of the total buds produced that dropped before reaching the mature pod stage was estimated as 86·7% in Baladi, a local strain of field beans, and 93·7% in Giza 1, a variety introduced from Egypt. The drop was appreciable both before and after fertilization. There were indications that both inadequate insect pollination and inter-ovary competition contributed to the reduction of pod yield.Self pollen was detected on the stigma in the bud stage 2–3 days before the flower was open. Estimates of natural cross-fertilization ranged from 35·8 to 42·1%, indicating that self-pollination did not lead to complete self fertilization. Hand manipulation of the flowers increased pod set in most of the cases but the line 1W did not respond to this treatment and proved to be highly autofertile.

64 citations


Journal ArticleDOI
TL;DR: The T1 tiller occurred most frequently in the newest variety, Deba Abed, and least in the oldest one, Spratt Archer, while Survival rates of the shoots were highest in M, followed by T2, T1 and T3.
Abstract: Two field experiments have been conducted to investigate the pattern of tillering, ear emergence and survival of the component tillers of three barley varieties, representing old and new varieties. The varieties were grown under contrasting nitrogen fertilizer levels and plant spacings. The results reported are for the variety means and variety x nitrogen and variety x spacing interactions. After the main stem (M) the most frequently occurring tiller was the tiller appearing in the axil of the first true leaf (T2), followed by the coleoptile node tiller (T1) and the tiller in the axil of the second true leaf (T3). The T1 tiller occurred most frequently in the newest variety, Deba Abed, and least in the oldest one, Spratt Archer. Survival rates of the shoots were highest in M, followed by T2, T1 and T3. Higher-order tillers occurred relatively infrequently and had low survival rates. M contributed the largest percentage of the grain yield, followed by T2, T1 and T3. The 13% grain yield advantage of Deba Abed over Spratt Archer was mainly accounted for by the difference in production by the T1 tiller. The results are discussed in. relation to the only other known paper on component tillers in barley.

61 citations


Journal ArticleDOI
TL;DR: The sheep that lost weight and then recovered it were, over-all, about 86% as efficient in their use of food to maintain body energy and produce wool as the sheep that maintained their original weight.
Abstract: The body composition of eight Merino wethers was estimated from the tritiated water (TOH) space and live weight at intervals during a cross-over experiment in which they were fed to either maintain a uniform live weight (about 34 kg) or to lose and, later, recover live weight over a 17-week period. The diet was a pelleted mixture of lucerne and wheat.The multiple regression equations used for these estimates were established from the chemical analysis of 24 sheep, including six from the cross-over experiment, which were killed at intervals during these two feeding regimens. The inclusion of TOH space in addition to live weight in the regression equations decreased the standard error of the estimates of body water, fat and energy by two-thirds. Correction of TOH space and live weight for gut water did not increase the precision of the equations.Shoop which ate, during the first 4 weeks of the experiment, one-third of the amount of food required to maintain their original live weight, lost 16% of their weight and 30% of their total body energy. This weight loss consisted of 45% water, 39% fat and 13% protein. It appeared that tissue was mobilized inefficiently to meet a sudden energy deficit.When food was offered ad lib. to these sheep after they had maintained a liveweight deficit of about 11 kg for 8 weeks, they regained their weight in 5 weeks but only 75% of their energy deficit. This was due to the high content of water (60%) and low content of fat (23%) in the regained tissue.The sheep that lost weight and then recovered it were, over-all, about 86% as efficient in their use of food to maintain body energy and produce wool as the sheep that maintained their original weight.

56 citations


Journal ArticleDOI
TL;DR: There was a significant negative relationship between the volume of rumen contents and theVolume of uterus plus abdominal fat plus other abdominal organs in ewes slaughtered.
Abstract: SUMMARY Twenty-seven ewes in various states of fatness, and either non-pregnant or between 72 and 144 days pregnant, were slaughtered and the volumes of digesta and abdominal organs were measured. There was a significant negative relationship between the volume of rumen contents and the volume of uterus plus abdominal fat plus other abdominal organs.

51 citations


Journal ArticleDOI
TL;DR: In this paper, the relationship between potential cellulose digestibility and in vivo cellulose metabolite digestibility was explored for a range of grasses for a single incubation of 6 days duration and was found to reach a maximum value after 5 days incubation in vitro.
Abstract: SUMMARY The potential digestibility of cellulose is defined as the maximum digestibility obtainable when the conditions and duration of digestion are not limiting factors. Techniques for measuring potential cellulose digestibility were examined and the relationship between potential cellulose digestibility and in vivo cellulose digestibility was explored for a range of grasses. Cellulose digestibility was found to reach a maximum value after 5 days incubation in vitro. No further cellulose was digested when the residues from an initial incubation for 6 days were incubated with a second rumen liquor inoculum. The values measured after a single incubation of 6 days duration were similar to cellulose digestibility coefficients measured by the suspension of ground forage samples in nylon bags in the rumen for 6 days. Plant factors appear to limit further digestion and the residue from prolonged digestion in vitro consisted only of lignified and cutinized tissue. Potential cellulose digestibility measured by either of the above techniques was higher than cellulose digestibility in vivo. The difference varied between forages and when the difference was large, the digestibility of cellulose in faeces was high. It is suggested that measurements of the potential digestibility of cellulose in feed and faeces may be of use in estimating the digestibility of grazed herbage.

47 citations


Journal ArticleDOI
TL;DR: It is suggested that, when large proportions of cereals are fed, the proportions of VFA bear no clear relationship to the crude fibre content of the ration but that an association with rumen pH may exist.
Abstract: Three dry cows, each fitted with a permanent rumen fistula, were fed hay and flaked maize or hay and rolled barley in widely different proportions. All rations were offered at 7 kg dry matter daily for 3 weeks following hay alone. The cows refused all cereal 3 or 4 days after introduction of rations including 80 and 100% flaked maize; recovery of intake occurred in most instances within a further 3–10 days. On the 100% flaked maize ration, the refusals were associated with very low pH and high concentrations of lactic acid in the rumen.Refusalsof rolled barley were small and showed no clear pattern. Rumen fermentation was reasonably stable during the last week of each period except with the 100% barley rations. On the rations containing flaked maize, molar proportions of volatile fatty acids (VFA) varied widely but on only one occasion did the proportion of acetic acid fall below 55% and in two cows that consumed flaked maize alone, the proportion of acetic acid in the rumen exceeded 60%. On the rations containing rolled barley, increasing proportions of barley were associated with large decreases in the proportion of acetic acid and increases in the proportion of propionic acid. The maximum proportion of n-butyric acid was found on the rations containing 50% cereal. It is suggested that, when large proportions of cereals are fed, the proportions of VFA bear no clear relationship to the crude fibre content of the ration but that an association with rumen pH may exist.

46 citations


Journal ArticleDOI
TL;DR: In this paper, a ryegrass pasture was strip-grazed intensively by cattle and the other was mown, and the fouled area had 2·8% of its surface covered by faeces.
Abstract: On three occasions in May—July one half of a ryegrass pasture was grazed intensively by cattle and the other was mown. In August and September these areas, designated fouled (F) and clean (C) respectively, were each strip-grazed by two groups of five cows. One group on each area had a herbage allowance of 11·4 kg dry matter per cow per day (C11 and F11) and the other 20·4 kg (C20 and F20).Before the August-September grazing the fouled area had 2·8% of its surface covered by faeces. After this grazing 23 % of the F n area and 34 % of the F20 area were classified as having been rejected by the cows. However, the upper parts of the sward on these rejected areas were in fact grazed. There were only small differences in N and soluble-carbohydrate contents between the herbages offered and rejected.Organic-matter digestibility (%) and intake (kg/cow per day) for the four groups were: C11, 73·0 and 10·5; C20, 74·9 and 11·7; F11 , 74·4 and 9·6; F20, 77·0 and 10·6. The C11 cows consumed all the herbage allowed to them, but the F11 rejected 13%. Digestible organic matter intake was affected more by grazing intensity than by fouling; this was the case also for milk yield, milk composition and the live-weight change of the cows.

Journal ArticleDOI
I. Rhodes1
TL;DR: The relationships between yield and both leaf length and chlorophyll content are presented and the physiological basis of inter-genotypic and inter-population differences in production are discussed.

Journal ArticleDOI
TL;DR: In this article, the correlations between faecal and urinary sodium losses, sodium excretion in the milk, digestible sodium and sodium balance and 75 other nutritive factors were analysed for each of the 55 different experimental diets.
Abstract: Statistical analyses were carried out on the data obtained under strictly controlled conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2–6 months earlier and whose daily milk production ranged from 11 to 20 kg. The authors have calculated and studied the correlations between faecal and urinary sodium losses, sodium excretion in the milk, digestible sodium and sodium balance and the 75 other nutritive factors which were analysedfor each of the 55 above mentioned experimental diets. The most important factor in the fate of sodium is the amount of dietary sodium. Sodium digestibility is neither total nor constant: faecal losses and digestible amounts are enhanced when sodium intake is increased and faecal losses are also positively correlated with dry matter and nitrogen intakes. An increase in digestible sodium benefits both urinary excretion and balance, the latter being reduced by an increase in dry matter and nitrogen intake. Sodium balance is always negative when sodium content of the diet is lower than 0.1% in the dry cows and 0.2% in the lactating cows. In our experimental conditions, the sodium requirements for milk production do not influence sodium digestibility, but are met above all to the detriment of urinary losses.

Journal ArticleDOI
TL;DR: In this article, a local strain of field beans (Baladi) and two Egyptian varieties (Rebaya 40 and Giza 1) were compared in a path-coefficient analysis to partition the correlation coefficients and compare the relative importance of the primary yield components in predicting yield.
Abstract: The components of yield were studied in a local strain of field beans (Baladi) and two Egyptian varieties (Rebaya 40 and Giza 1). Although no significant differences between varieties were detected in yield per plant, there were differences in components of yield. The Egyptian varieties produced heavier seeds but less pods and seeds than the local strain. The higherpod number in Baladi resulted from a capacity to produce more pods per stem rather than from anability to produce more stems per plant.Correlations between yield and other plant characters and between components of yield were computed. The path-coefficient analysis was employed to partition the correlation coefficients and to compare the relative importance of the primary yield components in predicting yield. Pods per plant showed the highest correlation with yield and selection for high yield can be based on it. Seed weight was negatively associated with pod number and seeds per pod but the r values were too low to be of predictive value. Multiple correlations indicated that 95–98% of the variability in yield was accounted for by the components pod number, seeds per pod and seed weight.

Journal ArticleDOI
TL;DR: The relationship between intake and digestibility of the alfalfa and grass hays was used to illustrate how voluntary intake of metabolizable energy from hay of pure or mixed species may be predicted from in vitro digestibility.
Abstract: The effect of maturity on the nutritional quality of hay from two alfalfa varieties and four grass species was studied. Each hay was harvested at six different stages of growth, chopped in 4–6 cm lengths, and fed to sheep in quantities of 10% in excess of voluntary intake. The relationship between intake (Y) and digestibility (X) of dry matter was best expressed by regressions of the form: Y = a + b1X + b2X2. The rate of intake declined 1·5 g daily per kg0·75 of body weight per unit decrease in digestibility percentage, and was the same for both alfalfa and grass hays. However, the intake of alfalfa hay was about 10% higher than that of the grass hays of similar digestibility. No differences in the relationship between intake and digestibility (P < 0·05) were observed between the two alfalfa varieties or between the four grass species. When the nutritional quality was expressed as voluntary intake of digestible organic matter daily per kg0·75 of body weight, and time of harvest as day-number of the year, the difference in quality between the six kinds of hay was very small or absent at the beginning of the season (immature to prebloom) and increased toward maturity (dough stage to seed ripe). The decline in quality of alfalfa hay was slower than that of grass hay, and ceased at the mature to overripe stage. On the average, voluntary intake of digestible organic matter declined 0·29 g daily for each day delay in harvest time; this decline varied from 1·2% of the daily intake of digestible organic matter in the beginning of the season to 0·6% at the mature stage. Time of harvest ‘accounted for’ 77–89% of the variation in the quality of the hays. The confounded effect of maturity and leanness on the nutritional quality of the hays was expressed best by concave, second degree polynomial regressions. On the average a unit decline in percent leaves corresponded to a decline of 0·58 g and 0·73 g respectively in the daily intake of digestible organic matter from alfalfa and grass hay. This varied from over 1 g early in the season to less than one tenth of a gram late in the season. The confounded effect of leafiness and growth stage ‘accounted for’ over 75% of the variability in nutritional quality. The relationship between intake and digestibility of the alfalfa and grass hays was used to illustrate how voluntary intake of metabolizable energy (percent of requirement for maintenance) from hay of pure or mixed species may be predicted from in vitro digestibility.

Journal ArticleDOI
TL;DR: The relationship between ME intake and energy retention was linear for each diet as mentioned in this paper, and it was concluded that the beneficial effect of maize oil on the efficiency of energy utilization is due to a reduced heat increment rather than a reduction in the basal component of the heat production.
Abstract: Experiments to determine the net availabilities of the metabolizable energy (NAME) of a cereal-based diet and a maize-oil diet for maintenance and lipogenesis and the effect of environmental temperature on the NAME of the cereal-based diet are described. Four 1- to 2-year-old Light Sussex cockerels were used.The relationship between ME intake and energy retention was linear for each diet. The NAME'S of the cereal-based diet given at 22° and 28 °C (70.6 ± 1.83 % and 73.6 ± 3.54%, respectively) were significantly (P < 0.05) lower than the NAME of the maize-oil diet (84.1 ± 1.85%). It is concluded that the beneficial effect of maize oil on the efficiency of energy utilization is due to a reduced heat increment rather than a reduction in the basal component of the heat production. The higher efficiency from the maize-oil diet led to an increase in the energy retained as fat.The mean fasting heat production at 28 °C was 15 % lower than at 22 °C (43.2 ± 1.45 and 51.2 ± 1.09 kcal/kg/day, respectively). The NAME of the cereal-based diet was not significantly different when the birds were kept at 22° or 28 °C. The lower metabolic rate at 28 °C was reflected in a lower maintenance requirement and in an increase in the deposition of body fat.

Journal ArticleDOI
TL;DR: The chances of survival of a tiller diminished with delay in the time of its appearance, but some early tillers died while later ones survived and produced ears, and the chances of Survival of later tillers were greater at low density and high rates of nitrogen.
Abstract: SUMMARY Various rates of nitrogen fertilizer were applied in early and late spring to two densities of winter wheat to examine their effects on grain yield and its components. A severe attack of ‘sharp eyespot’ (Rhizoctonia solani) allowed an assessment of the effects of the treatments on the incidence of this disease. The disease level was much higher where nitrogen was applied early and increased with increase in nitrogen up to 120 units applied; it was slightly higher at the higher density. Grain yield was slightly greater where nitrogen was applied late; early application gave more, but smaller, ears. Main shoots produced at least 70% of the grain in the high-density plots but less than 50% at the low density. Tillers appearing after early March contributed little to grain yield at the higher density but substantially at the lower one. Tillers produced after early April died without heading. In general, the chances of survival of a tiller diminished with delay in the time of its appearance, but some early tillers died while later ones survived and produced ears. The chances of survival of later tillers were greater at low density and high rates of nitrogen.

Journal ArticleDOI
TL;DR: It is concluded that the technique merits further consideration, and that, with more precise knowledge of FFA concentrations in maintenance-fed sheep and of the FFA: food intake response curve, it could provide a useful alternative means of estimating maintenance requirements.
Abstract: The objective of the investigations reported in this paper was to examine the possibility of using plasma free fatty acid concentrations as a means of estimating food requirements for maintenance purposes in sheep. Estimates derived in these investigations are considered to be less satisfactory than those based on live-weight change. It is concluded, however, that the technique merits further consideration, and that, with more precise knowledge of FFA concentrations in maintenance-fed sheep and of the FFA: food intake response curve, it could provide a useful alternative means of estimating maintenance requirements.

Journal ArticleDOI
TL;DR: It is postulated that environment, genotype and agronomic practice affect yield according to whether they increase or decrease the extent to which the sink size and the supply of assimilates are out of phase.
Abstract: Variety, water and spacing were treatments in two experiments with cotton in 1963 and 1964 in which fruiting points, flowers and bolls were counted and the dry weights and leaf areas of plants were measured at intervals during the season.Until leaf-area index, L, started to decrease, the equation described how dry weight, W, changed. The equation gave smoothed estimates of crop growth rate, C, which were consistent with estimates of photosynthesis made with de Wit's (1965) model. The relationship between G and L conformed to , derived from Beer's Law, rather than C = aL — bL2 derived from the linear regression of E on L. When L > 3 the crop appeared to use most of the available light, so that C approached a maximum. Treatments initially affected dry-matter production through the numbers and types of branches and nodes, which in turn affected the sinks available and thus the proportion of dry matter reinvested in new leaf. This initial period, when growth was simple to describe in conventional terms, was denned as the vegetative phase of growth.The start of the reproductive phase of growth overlapped the vegetative phase. The change from one to the other was completed when the rate of dry weight increase of the bolls, CB, equalled C. This indicated that the sink formed by the bolls had increased sufficiently in size to use all the assimilates available for growth. Sink size increased as the crop flowered and was estimated from the product of the number of bolls and the growth rate of a single boll.When CB equalled C, bolls were shed which prevented the size of the sink to increase beyond the ability of the plant to supply it with assimilates. This agrees with Mason's nutritional theory of boll shedding. Because of the crop's morphology and because age decreased the photosynthesis of the crop, the size of the sink inevitably increased out of phase with the supply of assimilates. The extent to which this was so determined when CB equalled C. It is postulated that environment, genotype and agronomic practice affect yield according to whether they increase or decrease the extent to which the sink size and the supply of assimilates are out of phase.

Journal ArticleDOI
TL;DR: A study on the effect of source, time of lifting and post-harvest treatment of apparently virus-free Arran Pilot seed potatoes on subsequent crop growth was carried out in this article, where the authors found that the potato tubers from the more southern region, which were older and showed greater sprout development at planting, gave plants with a higher stem number at soil level, a higher tuber number and a greater percentage of the tuber yield as seed grade than northern-produced seed.
Abstract: Studies were carried out on the effect of source, time of lifting and post-harvest treatment of apparently virus-free Arran Pilot seed potatoes on subsequent crop growth. The experiments were carried out in 1961–2 and 1962–3 at Efford, Sutton Bonington and Edinburgh. Seed tubers from the more southern region, which were older and showed greater sprout development at planting, gave plants with a higher stem number at soil level, a higher tuber number and a greater percentage of the tuber yield as seed grade than northern-produced seed. High bulking rates were associated with early emergence, high tuber numbers and late apparent time of tuber initiation. In 1962 southern seed produced plants which initiated tubers early and had low bulking rates and low final yields. In 1963 seed source had little effect on the time of tuber initiation of resulting plants, and southern-produced seed gave plants with high bulking rates and high final yields. Early lifted and greened tubers gave rise to plants with the same pattern of response as seed produced at the southern centre. It is suggested that this variation in response between years was due to the climatic conditions at the time of tuber initiation in the field crop.Seed of a required state at planting can usually be obtained by growth at the centre of ware production provided disease can be controlled and the time between harvesting of seed and planting is longer than about 3 months.

Journal ArticleDOI
TL;DR: In this article, a total of 512 pigs were given from 50 lb live weight one of 16 diets, i.e. with 4 lysine levels at each of 12, 14, 16 and 18% protein, at one of four levels of intake.
Abstract: A total of 512 pigs were given from 50 lb live weight one of 16 diets, i.e. with 4 lysine levels at each of 12, 14, 16 and 18% protein, at one of 4 levels of intake. They were killed at 100, 150, 200 or 250 lb live weight.Live-weight gain was not improved significantly by increasing the protein level above 16, 14, 12and 12%, respectively, for the 50–100, 100–150, 150–200and200–2501bstages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the protein to 18%. Gain in lean meat and in the efficiency of conversion of feed to lean meat were improved by increasing the above protein levels slightly.Live-weight gain was not improved significantly by increasing the lysine level above 1·04, 0·74, 0·70 and 0·59%, respectively, for the 50–100, 100–150, 150–200 and 200–250 lb stages. However, conversion of feed to live-weight gain was improved significantly during the 50–100 lb stage by increasing the lysine level to 1·22%. Raising the lysine level at each level of protein had no significant effect on the rate and efficiency of lean meat gain.Live-weight gain was significantly improved by increasing the level of feed intake almost to ad libitum levels for the 50–100, 100–150 and 150–200 lb stages. There was a suggestion of a similar effect in the 200–250 lb pigs although it was not statistically significant. Conversion of feed to live-weight gain was improved in the 50–100 lb pigs only by increasing the level of feed intake: in the older pigs increasing the level of feed intake caused a worsening in feed conversion ratio. Increasing the level of feed intake gave a significant improvement in rate of lean meat gain but a significant worsening in the efficiency of conversion of feed to lean meat during all stages up to 200 lb.Interaction effects of these factors and sex, on growth performance, are described.

Journal ArticleDOI
TL;DR: Eight feeding trials on cattle showed that the response in live-weight gain was curvilinear when protein or energy level was varied independently in rations based on poor quality roughages to which cereals and groundnut were variously added to give a range of protein and energy intakes.
Abstract: Eight feeding trials on cattle showed that the response in live-weight gain was curvilinear when protein or energy level was varied independently in rations based on poor quality roughages to which cereals and groundnut were variously added to give a range of protein and energy intakes. Live-weight gain was increased by 0·12 lb/day for each 0·1 lb additional digestible crude protein/day at levels of intake below 0·7 lb/day and by 0·03 lb/day at higher levels. It was increased by 0·4 lb/day for each additional 0·1 lb starch equivalent daily/100 lb live weight at total intakes below 0·9 lb daily/ 100 lb and by 0·2 lb/day at higher levels. Over the range 0·5–2·0 lb digestible crude protein daily and 0·7–1·2 lb starch equivalent daily/100 lb live weight the effects of these nutrients were additive.A Latin square nitrogen balance trial demonstrated that a portion of the nitrogen from a protein supplement was retained in the body despite the excretion of the greater part of it in the urine and a further part in the faeces. Nitrogen retention was increased by a supplement of readily available energy through a decrease in urinary nitrogen loss. Nitrogen balance was not increased by a supplement of a fibrous energy source because this induced an increase in faecal nitrogen loss.In a further feeding trial milk yield was found to be affected in a similar manner to growth. At a yield of 30 lb/day the response per lb starch equivalent added to the diet was 0·5 lb milk including 0·05 lb solids not fat and to an increase of 0·1 lb digestible crude protein daily it was 0·25 lb milk including 0·025 lb solids not fat.

Journal ArticleDOI
TL;DR: In this article, the effect of age, temperature and water on the development of the mainstem of a cotton crop was investigated. And the results were used to develop the idea that morphological change and increase in dry weight, two aspects of the growth of cotton which are often studied separately, must be linked to explain or predict crop performance.
Abstract: Variety, sowing date, irrigation water and plant spacing were the variables in five experiments over three seasons in southern Arabia. The results are used to develop the idea that morphological change and increase in dry weight—two aspects of the growth of cotton which are often studied separately—must be linked to explain or predict crop performance. A straight line related the number of flower buds counted at any time to the number of mainstem nodes on a plant. The mainstem was therefore a simple parameter for the effect of age, temperature and water on the development of plant structure. The relationship was explained by a model in which fruiting branches compete with one another. The structure of the crop plants, as measured by the types and number of nodes, developed along a course in time determined by variety and spacing at a rate dependent on temperature. The rate decreased with age, but was independent of the quantity of water available, until a critical amount had been used, when development stopped abruptly. Accumulated day degrees accounted for the differences between dates of sowing in the subsequent production of nodes. This relationship was consistent with work on temperature elsewhere. Date of sowing effected the position of the first fruiting branch in the variety Bar XL 1 but not in Wild's Early. The position of the first fruiting branch and spacing affected the number of vegetative branches. Wider spaced plants produced flower buds faster only because they had more fruiting branches, a result in turn of more vegetative branches. The ratio between the mean rates of production of nodes on vegetative branches, and on fruiting branches were varietal constants and agreed with results elsewhere in contrasting conditions.

Journal ArticleDOI
TL;DR: In this article, the role of the prediction equation in estimating daily milk consumption of lambs is discussed and the regression equation is used to estimate the milk consumption over the range of lamb body weights and lamb body-weight changes studied.
Abstract: Milk yield data obtained by the lamb-suckling technique on twenty-four ewes over a period of 5 consecutive days in the second and third week of their lactation have been related to lamb body weights and lamb body-weight changes over the same period. The regression equation obtained wasThe equation was used to estimate the milk consumption of lambs over the range of lamb body weights and lamb body-weight changes studied. The standard errors of these estimates have been computed for comparison with those obtained directly from the lamb suckling technique.The role of the prediction equation in estimating daily milk consumption of lambs is discussed.

Journal ArticleDOI
TL;DR: There was an indication that classes low in copper concentration, notably Blackfaces and mothers of swayback lambs, showed a relatively steeper decline in copper levels during the winter than did other sheep.
Abstract: The concentration of copper in the blood of more than 300 sheep of a grassland flock was determined on each of five occasions between May 1965 and June 1966. Six breed classes, Scottish Blackface, Cheviot and Welsh Mountain, and the three crosses among these breeds, were involved.Breeds differed significantly in blood copper concentration with the Blackface having consistently the lowest and the Welsh the highest values. Crossbred sheep showed marked heterosis. Their levels were mostly at or near to the concentration of the parental breed with the higher value. Within breeds there was a positive regression of blood copper level on live weight of ewe.Ewes which had produced lambs affected by swayback in 1964 had lower levels of copper in their blood than ewes which had produced normal lambs. The difference was significant and most marked in winter.Ewes which were barren had, subsequently, higher blood copper concentrations than ewes with lambs. Ewes with single lambs had on average slightly higher levels than those with twins (but not significantly so), however, the effect differed among the breeds. Blood copper levels differed significantly on most occasions with the week in which ewes lambed in relation to the date of bleeding. Age of ewe had significant effects on copper concentration only at one bleeding (January 1966).There was an indication that classes low in copper concentration, notably Blackfaces and mothers of swayback lambs, showed a relatively steeper decline in copper levels during the winter than did other sheep.

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TL;DR: Control-environment experiments showed that development of the coleoptile node tiller (T1) was suppressed much more than that of the tiller appearing in the axil of the first true leaf (T2) by high temperature, reduced photoperiod or by low light intensity, but minimally in the newest variety, Deba Abed.
Abstract: Controlled-environment experiments showed that development of the coleoptile node tiller (T1) was suppressed much more than that of the tiller appearing in the axil of the first true leaf (T2) by high temperature (24/15 °C; 19/10 °C; 10/6 °C), by reduced photoperiod (16 h; 12·5 h) or by low light intensity (1100 ft-c; 1000 ft-c), but minimally in the newest variety, Deba Abed. Unlike previous field experiments, the T1 tiller appeared on more Spratt Archer than Maris Badger plants. Maris Badger plants produced more T1 tillers in a high-low temperature regime (19/10 °C; 10/6 °C) than in continuous low temperature (10/6 °C). In a field experiment T1 tiller number (and yield), but not the number of other major shoots, were severely reduced by late sowing of Spratt Archer, progressively reduced in Maris Badger, but minimally in Deba Abed. This seemed to be associated with higher temperatures at later sowings.

Journal ArticleDOI
TL;DR: An experiment to study the utilization by beef cattle of high concentrate diets containing different amounts of milled barley straw and of protein found that food conversion ratio, expressed as total dry matter consumed per kg live-weight gain, tended to increase with increasing proportion of straw in the diet.
Abstract: Summary 1. An experiment consisting of two separate trials was carried out to study the utilization by beef cattle of high concentrate diets containing different amounts of milled barley straw and of protein. For each trial twenty-four Friesian steers, initially weighing about 270 kg, were divided into three groups and the animals within each group then allocated at random to eight dietary treatments. The treatments were based on an all-concentrate diet and three others containing 10, 20 and 30% of milled (1 in screen) barley straw. Four of the treatments consisted of giving the same concentrate mixture with each level of straw, and the other four involved giving concentrate mixtures with increasing levels of protein so that the percentage of protein in the diets was maintained. All the diets were fed ad libitum until slaughter. 2. Performance in terms of live-weight gain was considered as the net result of a number of factors, notably the total intake of dry matter, the digestibility of the dry matter, the efficiency of utilization of the end products of fermentation in the rumen and the composition of the live-weight gain. The inclusions of 20 and 30% of straw in the diet were associated with lower rates of gain than on corresponding all-concentrate and 10% straw treatments but the differences obtained did not attain significance. Total intakes of dry matter were greater on treatments containing 10 and 20% of straw than on corresponding all-concentrate treatments, but then declined with further increase in level of straw to 30%. This trend was significantly curvilinear (P < 0·01), the equation for the relationship being Y = 5·881 + 0·131X - 0·004X2, with Y being the daily intake of dry matter (kg) and X the percentage of straw in the diet. The maximum intake of dry matter was calculated to occur with a level of 16·4% straw in the diet and represents an increase in total dry matter intake of 18·2% over that on an all-concentrate diet. Food conversion ratio, expressed as total dry matter consumed per kg live-weight gain, tended to increase with increasing proportion of straw in the diet. 3. The mean digestibility of organic matter fell sharply with the inclusion of 10% straw in the ration, the decrease being 8·2% where the protein level was not maintained and 9·1% where it was maintained. Further reductions in digestibility occurred on the 20 and 30% straw diets, but the magnitude of the reductions were considerably less than those brought about by the initial introduction of straw into the ration. 4. The molar percentage of acetic acid in the steam volatile acids of rumen liquor increased markedly, and that of propionic acid decreased sharply from the all-concentrate to the 10% straw treatment with a similar level of dietary protein. Increase in the level of straw to 30% gave rise to a further increase in the proportion of acetic acid and reduction in that of propionic acid. Analysis of samples taken at 3, 6, 9 and 12 h after feeding showed appreciable differences in pattern between treatments. 5. Effects of treatment on killing-out percentage were different for each trial. In trial 1 the inclusion of straw in the diet did not cause any reduction in killing-out percentage, but the maintenance of protein level gave rise to a significantly higher killing-out percentage than was obtained with the lower protein groups. In trial 2 the killing-out percentages showed a significantly linear (P < 0·01) decrease with increasing proportion of straw in the ration, and maintenance of protein level did not give any improvement.

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TL;DR: It is concluded that complete diets for the self-feeding of dairy cows should contain a minimum of about 24 % of coarsely milled straw and that estimated metabolizable energy intake and production were depressed by including straw at higher levels.
Abstract: Complete diets were given ad libitum to dairy cows over a whole lactation in order to study the voluntary intake of food, lactation performance and efficiency of feed conversion The effect of including four levels 16, 24, 32 and 40 % of coarsely milled barley straw in the loose mix was studied for diets based mainly on barley or on sugar beet pulp, using a double 4 × 4 Latin square designThe results confirmed that cows can perform normally when given complete diets for extended periods Dry matter and digestible energy intake was depressed at the higher levels of straw inclusion and milk butterfat content at the lowest level The net efficiency of conversion of metabolizable energy (ME) into milk was higher at the higher levels of straw It is concluded that complete diets for the self-feeding of dairy cows should contain a minimum of about 24 % of coarsely milled straw and that estimated metabolizable energy intake and production were depressed by including straw at higher levels

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TL;DR: A positive correlation was found between the germination of cress seeds moistened with aqueous extracts from clusters of twenty sugarbeet plants and the growth characteristics of other clusters from the same plants as discussed by the authors.
Abstract: Evidence was obtained for the presence of germination inhibitors in the aqueous extract from sugar-beet clusters. A positive correlation was shown between the germination of cress seeds moistened with aqueous extracts from clusters of twenty sugarbeet plants and the germination characteristics of other clusters from the same plants. Inhibition was thus greater in extracts from clusters with poor rather than good germination, and also in extracts from immature clusters or those which had received overhead irrigation. The inhibitory effect was found to be located in the perianth and pericarp tissue rather than in the true seed.

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TL;DR: The best prediction of Mn uptake was provided by a combination of CH3COONH4-extractable Mn and pH; 52·9 % of the variability in Mn uptakewas accounted for by these two variables.
Abstract: SUMMARY Eight soil Mn tests, namely, CH3COONH4-, Mg(NO3)2-, H3PO4-, hydroquinone-, 3m-NH4H2PO4-,1·5m-NH4H2PO4- and EDTA-extractable Mn and total Mn were evaluated for their ability to predict Mn uptake by maize (Zea mays L.) on 63 soils of diverse origin. Regression equations were derived by comparing Mn uptake with each test in combination with pH. The best prediction of Mn uptake was provided by a combination of CH3COONH4-extractable Mn and pH; 52·9 % of the variability in Mn uptake was accounted for by these two variables. EDTA and H3PO4-extractable Mn were superior to the other soil Mn tests in predicting Mn uptake. The effect of soil properties on the extractability of soil Mn by each extractant was analysed statistically. Only with hydroquinone-extractable Mn did the soil variables investigated account for a major portion of the variability in the Mn test. The soil variables most often correlated significantly with the Mn test were pH and total Mn. Organic carbon and clay contents were significant only in determining EDTA- and Mg(NO3)2-extractable Mn, respectively.