bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of feeding diets containing Crotalaria retusa L. seed to broiler chickens
Authors: Ross A. J. , Tucker J. W.
Published: March 2009

Seeds of the plant Crotalaria retusa L., containing 4·4% of the pyrrolizidine alkaloid monocrotaline, were fed in a finely ground form to broiler chickens at 0·005, 0·01, 0·05, 0·10 and 0·50% by weight of the diet continuously for 8 weeks.

Feeding 0·005% and 0·01% had no effect on the growth performance of the birds. A non-significant reduction in live-weight gain, one death and chronic disease resulted from feeding 0·05%. At 0·10% and 0·50% there was high mortality and reduced voluntary feed intake, live-weight gain and feed conversion efficiency, the severity of the response being greater at 0·50%.

Feather development was inhibited in birds fed 0·10% and 0·50% C. retusa seed.

Until further research is done to determine the effect of feeding between 0·01% and 0·05% ground C. retusa seed in the diet of broiler chickens, it is suggested that the maximum should be 0·01%.
The response of dairy cows grazing a nitrogen fertilized grass pasture to a supplement of protected casein
Authors: Stobbs T. H. , Minson D. J. , McLeod M. N.
Published: March 2009

Twenty-one Jersey cows in their 6th–8th week of lactation grazed Chloris gayana pastures fertilized with nitrogen and were treated in three ways, no casein (control), casein (1 kg/cow/day) or formal-casein (1 kg/cow/day) in seven 3 x 3 Latin squares to measure the effect of protein protection on milk yield and milk composition. Additional animals fitted with oesophageal and rumen fistulae were used to determine composition of the diet selected and rumen characteristics on three treatments.

Cows ingested herbage containing 20% crude protein with a protein solubility of 40%. The untreated casein supplement increased milk yield by 3%, fat 5% and protein 2·4%. Formal-casein produced 20% (3·3 kg/day) more milk than the control, a 13% higher yield of butterfat and 27% more protein. Rumen ammonia concentrations in the afternoon were similar for the control and formal-casein supplemented cows (21 and 23mg/100ml) but significantly higher when casein was fed (74 mg/100 ml) indicating extensive deamination of the untreated protein.

Yields of C4–C16 fatty acids in milk fat were 8 and 21% higher for the casein and formal-casein treatments than for the controls, which together with the higher live weight of formal-casein supplemented cows indicated that the milk yield response to the protein supplements was mainly due to a higher daily intake of herbage.
A colorimetric technique using chromium-ethylene diamine tetra acetate for measuring rumen volume
Authors: El-Shazly K. , Ahmed E. I. A. , Naga M. A. , Borhami B. E. A.
Published: March 2009

A method is described for the determination of rumen volume using Cr-EDTA colour measurement in a spectrophotometer at 550 nm. The results of several determinations of rumen volume comparing this method with Cr-determination as chromate and polyethylene glycol as markers gave similar values with differences ranging from 1 to 14% with an average of 6%. Direct measurements through evacuating rumen contents gave values 20·68% higher than those estimated by the colour method. The values were similar when corrected for dry matter.
Effect of plant spacing and soil application of aldicarb on nitrogen fixation by spring-sown field beans (Vicia faba L.)
Authors: Witty J. F. , Roughley R. J. , Day J. M.
Published: March 2009

Vicia faba cv. Minden was precision planted at densities of 12–100 plants/m2 in 1977 and 30–60 plants/m2 in 1978 with and without seed-bed applications of aldicarb (10 kg/ha).

Nitrogenase activity per plant decreased significantly with increased plant density but this was compensated for on an area basis by increased numbers of plants. When expressed on the basis of area, nitrogenase activity was higher with closely, than with widely spaced plants both early and late in the season. Irrespective of planting density nitrogenase activity reached a peak during vegetative growth of the plant and a second peak during rapid pod and seed development. In 1977 the second peak was interrupted by very dry soil conditions but later activity increased following rain.

Aldicarb consistently increased nitrogenase activity at all harvests after Sitona damage to the nodules was evident. Over this period plots treated with aldicarb had twice the nitrogenase activity of untreated plots in 1977 and 55% more in 1978.
Yield, nutrient concentration and quality of mustard crops as influenced by nitrogen and sulphur fertilizers
Authors: Aulakh M. S. , Pasricha N. S. , Sahota N. S.
Published: March 2009

Field experiments were made for 3 years (1975–8) on soils deficient in both available N and S to test the effects of these nutrients applied as fertilizers on yellow mustard (Brassica campestris L.) and mustard (Brassica juncea L.).

In all the 3 years, grain yield of both mustard crops significantly increased with increased N rates. The grain response to added S was not consistently significant, however; maximum yields were obtained only when high rates of N and S were applied together. N and S fertilizer significantly increased the concentration and uptake (kg/ha) of N and S in grain, and there was a significant positive N × S interaction. Adequate N/S ratio appears to be 7·5:1 or less for the grain of these mustard crops. Protein content of grain improved markedly with applied N and S. Application of 60 kg S/ha increased the oil content by 12% in yellow mustard and 16% in mustard. Although N had little effect on percentage oil, total oil production increased many fold. The combined application of N and S had the largest effect in determining the concentration and uptake of N and S, and on protein and oil content in grain. This study indicated that additions of 60 kg S/ha to mustard crops receiving adequate fertilizer N are likely to improve their yield and quality.
Effect of different intensities of Alternaria blight on yield and oil content of sunflower
Authors: Balasubrahmanyam N. , Kolte S. J.
Published: March 2009

Alternaria blight of sunflower caused by Alternaria helianthi (Hansf.) Tubaki and Nishihara is the most important disease of monsoon-grown sunflower crops in India (Kolte & Mukhopadhyay, 1973; Narain & Saksena, 1973). It is also reported to occur in Rumania (Hulea, Iliescu & Bunescu, 1975), Tanzania (Allen, 1974) and Brazil (Ribeiro et al. 1975). The present studies were carried out to assess the effect of different disease intensities on yield and oil content of the sunflower crop.
Differences between sheep and cattle in digestibility, voluntary intake and retention time in the rumen of three tropical grasses
Authors: Rees M. C. , Little D. A.
Published: March 2009

In the assessment of the nutritive value of feeds for animals, measurement of digestibility has been a basic index since 1860 (Schneider & Flatt, 1965). In this laboratory, measurements of digestibility and voluntary feed consumption using sheep have been the basis of feed evaluation procedures for over 20 years (e.g. Milford, 1960). The plants with which our group is concerned, however, are mainly grazed by cattle, and it is important to establish the degree to which extrapolation of results from sheep to cattle is justified for tropical pasture species. Many comparisons between sheep and cattle in terms of digestibility of dry matter and other aspects of feed utilization have been made using temperate pasture species hays, silages, grains and mixed rations; this area has been thoroughly reviewed by Schneider & Flatt (1965). Very few such studies have been made using tropical species, and most of those in Australia have involved the native species Heteropogon contortus (Siebert & Kennedy, 1972) or mixed H. contortus and Bothriochloa decipiens (Playne, 1978), providing material of low quality, containing less than 1% nitrogen. Playne (1970) used one introduced tropical species, buffel grass (Cenchrus ciliaris), and in that work only one of three harvests contained over 1% nitrogen. In the present work three introduced tropical species have been examined, covering a wider range of quality than has been reported previously.
Nigrosin eosin as a stain for differentiating live and dead spermatozoa
Authors: Campbell R. C. , Dott H. M. , Glover T. D.
Published: March 2009

1. The proportion of stained spermatozoa in a ram semen-nigrosin-eosin mixture has been found to increase with the time of exposure to the stain. Five minutes is considered to be a suitable interval for practical use.

2. The value obtained for the proportion of dead cells can be considerably affected by the selection of fields that are easy to count; fields should be chosen at random.

3. The variation between, counts on the same smear is much larger than that expected for binomial proportions. This may be due partly to the ‘clumping’ of the dead spermatozoa and partly to the difficulties of interpretation caused by the presence of many partially stained cells.

4. A significant difference was found between the estimates of the proportion dead obtained by the two experimental workers; this is thought to be due to a difference of interpretation of ‘stained’ and ‘unstained’.

5. Tables are given by which to determine the approximate accuracy of counts made on a range of numbers of spermatozoa, smears and subsamples, separate tables being necessary for ram, boar and bull semen.
Winter feeding of the in-lamb ewe
Authors: Large R. V. , Alder F. E. , Spedding C. R. W.
Published: March 2009

1. Three winter feeding experiments (1954–57) were carried out using small flocks of Border Leicester x Cheviot ewes tupped by a Suffolk ram.

2. The feeds used were various combinations of (a) silage, (b) hay, (c) ‘winter grass’, and (d)concentrates. Their value in late pregnancy was compared in terms of performance of the ewe and the birth weight of the lambs.

3. In addition, in one year (1956–57) the effect of level of nutrition in early pregnancy and during the first 28 days of lactation was studied.

4. It was found that ‘winter grass’ could replace silage and hay where a concentrate ration was being fed.

5. Satisfactory results were obtained with a concentrate ration of ⅜ lb. per head per day rising to ¾ lb. per head per day by lambing time.

6. In the mild winter of 1956–57 a group of ewes produced normal healthy lambs when fed entirely on ‘winter grass’ during the latter half of pregnancy.

7. The intensity of grazing of the ewes in early pregnancy affected their live-weight gain, but this seemed to have little effect on lamb production.

8. A high plane of nutrition during early lactation resulted in a significantly greater live-weight gain of lambs over this period. The difference had been reduced to a non-significant level by mid-June.

9. None of the treatments imposed had any very marked effect on the nematode egg-output of the ewes.
A note on the adaptability of native and cross-bred sheep to hot summer conditions of semi-arid and arid areas
Authors: Singh Manohar , More T. , Rai A. K. , Karim S. A.
Published: March 2009

Relative adaptability of Chokla and Rambouillet × Chokla half-breds was compared by observing their responses on exposure to summer stress for 6 days and also under accentuated stress by deprivation of drinking water till the animals lost 30% of their body weight. Responses of both the breed groups were similar on 6 days exposure. Accentuated summer stress resulted in decreased feed intake followed by 15, 26 and 31% loss in body weight on 1st, 2nd and 3rd day of exposure, respectively. Progressive decline in faecal moisture, increase in rectal temperature and decrease in morning respiration rate were also noted in both the breeds while an increase in pulse rate was recorded only in the cross-breds. Increase in respiratory or pulse rate for unit rise in rectal temperature was found to be higher in the cross-breds. On accentuated thermal stress, haematocrit values were higher in the cross-breds and blood potassium concentration was higher in the Chokla while blood glucose decreased in both the groups. Under the conditions of short-term exposure to summer stress the cross-breds maintained homoeothermy as well as the Chokla.
Selection of bulls for artificial breeding on basis of semen storage characteristics
Authors: Probine M. C. , McCabe W. J. , Shannon P.
Published: March 2009

1. Analysis of spring mating data in 1955 indicated that the fall in conception rate associated with the use of older semen was a serious problem.

2. The fall in conception rate in 1955 was more marked in bulls of below average conception rate than in those with above average conception rate.

3. Results for groups used in two successive years indicate that this decline is highly repeatable.

4. Bulls which have ‘good keeping quality’ semen can be selected on the records of a previous season. Where there is no previous record, it has been shown that an individual can be classified as a ‘good keeper’ or a ‘poor keeper’ by measuring the fructolysis index of the semen on the day after collection. If the fructolysis index is above some minimum figure (1·05 mg. fructose/hr./109 sperm has been adopted in this case for second-day semen), the bull can be used for delayed inseminations with good prospects of success.

5. The best method of classification would appear to be: (i) initial classification by fructolysis index; (ii) subsequent rejection of bulls of low fertility in this group after fertility records are available.
The effect of lime and phosphate on soils and sown species in the Falkland Islands
Authors: McAdam J. H.
Published: March 2009

Experiments to determine the effects of a range of applied lime and phosphate treatments on the establishment of species and the subsequent herbage production in the first and second seasons following sowing on four sites in the Falkland Islands are described and the results discussed.

Festuca rubra, Dactylis glomerata, Phleum pratense and Poa pratensis established, successfully yielding up to 4·5 t D.M./ha per year with inputs of 55 kg N, 50 kg P and 20 kg K/ha. Applied P increased the yield of herbage and produced a small, though significant, increase in P status of the soil.

The lowest level of applied lime (0·63 t/ha) increased the soil pH to 5·0 and although this did not affect the yield or botanical composition of the grass component of the sward it did affect the presence and nodulation of white clover.

The problems of establishing white clover are presented in view of the severe limitations on the use of lime and fertilizer in the Islands. The implications of grazing this improved pasture are discussed in relation to increased pasture production and improved soil fertility.
The use of internal markers to estimate herbage digestibility and intake: 1. Potentially indigestible cellulose and acid insoluble ash
Authors: Penning P. D. , Johnson R. H.
Published: March 2009

Concentrations of potentially indigestible cellulose (PIC) and acid insoluble ash (AIA) were determined in samples of feed and faeces in a study to determine their value as internal markers. PIC and AIA were then used to predict the organic-matter digestibilities (OMD) of samples of perennial ryegrass (Lolium perenne) and lucerne (Medicago sativa)of known OMD which had been determined using wether sheep. The mean values for OMD (%) measured in vivo were 67·2 and 62·8 for ryegrass and 58·0 and 55·8 for lucerne at intakes of 15 and 25 g D.M./kg live weight, respectively.

The in vitro digestibility technique, using rumen liquor, gave OMD values of 69·5 and 57·4 for ryegrass and lucerne which are in close agreement with the in vivo values at the lower level of intake.

The mean differences between OMD measured in vivo and that estimated using PIC were: -1·1 (± 0·65) and -1·6 (± 0·46) percentage units for ryegrass and lucerne respectively, and using AIA were: -1·4 (± 0·57) and -3·5 (± 1·61).

For the two feeds tested, OMD was predicted more precisely by PIC than by AIA or the in vitro digestibility technique. However, the PIC technique required the use of rumen-fistulated animals and 10 days to digest samples of faeces; this may make the technique impractical if large numbers of determinations of PIC are required.
Effects of NaCl and NaHCO3 on food intake, growth rate and acid-base balance in calves
Authors: Kellaway R. C. , Thomson D. J. , Beever D. E. , Osbourn D. F.
Published: March 2009

Calves were reared on milk replacer up to 5 weeks of age and given ad libitum access to pellets and chopped straw from 1 to 10 weeks of age. Major ingredients of the pellets were ground barley (B) or ground barley and grass meal in a 6:4 ratio (G). Included in these two basal diets were NaCl or NaHCO3, each at 2, 11, 20 or 29 g Na/kg D.M.

Calves on G diets ate more than those on B diets but grew at a similar rate. The replacement value of grass meal for ground barley was 1·36:1. Most responses to Na inclusions were unaffected by the basal diets.

Before weaning there were linear increases in food intake and growth rate related to Na level in the diet. At 29 g Na/kg D.M., total D.M. intake/kg0.75 and growth rate were respectively 31 and 23% greater than at 2 g Na/kg D.M. After weaning there were differential responses to the two salts. With NaHC03 there were linear increases in food intake and growth rate up to 20 g Na/kg D.M., at which level total D.M. intake/kg0.75 and growth rate were respectively 36 and 44% greater than at 2 g Na/kg D.M. With NaCl the only significant response was that total D.M. intake at 11 g Na/kg D.M. was 16% higher than at 2 g Na/kg D.M.

Observations on acid-base balance and water intake indicated that inclusions of NaCl or NaHCO3 up to 20 g Na/kg D.M. were well tolerated by calves. Above this level there was a sharp increase in water intake, and with NaHCO3 there was a large base excess and high pH in the blood.
An investigation into the loss of activity of 14C-labelled volatile fatty acid (VFA) tracers used to measure VFA production rates in the rumen of sheep
Authors: Wilson S. , Macrae J. C.
Published: March 2009

Few problems have been reported with the use of the isotope dilution technique for measuring volatile fatty acid (VFA) production in the rumen of sheep. However, early studies carried out in this laboratory, using a standard technique (Leng & Leonard, 1965) showed serious limitations associated with losses of activity from the infusates. Subsequent inquiries suggested that other laboratories had experienced similar problems (J. D. Sutton, National Institute for Research in Dairying, Shinfield, and D. E. Beever, Grassland Research Institute, Hurley, personal communication). When solutions of [U-14C]Na acetate, [l·14C]Na propionate and [l·14C]Na butyrate obtained from the Radiochemical Centre, Amersham, were each diluted with deionized water to provide 0·5 μtCi μtmol/ml (hereafter designated 14Ac, 14Pr and 14Bu respectively) and left to stand at room temperature for 6 h, losses of activity of C, 15 and 3% respectively were found.
Effects of molybdenum concentration in fresh herbage, hay and semi-purified diets on the copper metabolism of sheep
Authors: Suttle N. F.
Published: March 2009

In Expt 1, four groups of seven hypocupraemic ewes were repleted with a semipurified diet containing 7·2 mg Cu, 3·5 gS and 0·5, 2·5, 4·5 or 8·5 mg Mo/kg D.M. as ammonium molybdate for 65 days. The first increment in Mo caused the largest reduction in plasma Cu repletion and the second completely inhibited repletion but the final increment led to a partial recovery. The highest Mo level caused marked increases in plasma Mo and reduced rumen sulphide concentrations.

In Expt 2, five groups of four hypocupraemic ewes were repleted with hays containing 7–8 mg Cu, 3–3·4 g S and 0·4, 2·8, 4·3, 14·2 or 18·7 mg Mo/kg D.M. for 21 days. The hays were made in June from pasture sprayed earlier with 0–800 g Mo/ha as sodium molybdate. Qualitatively the changes in plasma Cu distribution and Mo content showed the same curvature with increases in dietary Mo as those in Expt 1.

In Expt 3, four groups of five hypocupraemic ewes were repleted on pastures which had received a spring foliar dressing of 0–800 g Mo/ha. Herbage in the four plots was grazed in July, when it contained 0·7, 3·5, 5·9 or 12·4 mg Mo, 6'4 mg Cu and 2·7 g S/kg D.M. and again in September. Quadratic responses to Mo were demonstrated on both occasions, but, for a given Mo level, responses in caeruloplasmin synthesis were much lower than in Expt 2.

It is concluded that Cu absorption is inhibited most by 4–6 mg Mo/kg D.M. and that inhibition of S2- production at higher Mo levels may give rise to a recovery in Cu absorption. Semi-purified diets give responses which lie roughly between those for fresh herbage and hay.
Effects of plant type, plant population density and application of phosphate fertilizer on growth and yield of pigeon pea
Authors: Singh A. , Prasad R. , Saraf C. S.
Published: March 2009

A field experiment was made with pigeon pea (Cajanus cajan (L.) Millsp.) at the Indian Agricultural Research Institute, New Delhi, during the rainy seasons of 1975 and 1976 to study the effects of plant type, plant population density and the application of phosphate fertilizer on growth and yield of pigeon pea. Cultivars BS-1 and UPAS-120 produced significantly more grain with 100 × 103 plants/ha, whereas the cultivar Prabhat produced most when 200 × 103 plants/ha were grown. Application of 13 kg P/ha increased most growth and yield attributes and increased the grain yield significantly over the control to which no P was given; however, no additional increase was obtained when 26 kg P/ha was given. The highest-yielding cultivar BS-1 benefited most from phosphate fertilizer.
A comparison of the organic matter, biomass, adenosine triphosphate and mineralizable nitrogen contents of ploughed and direct-drilled soils
Authors: Powlson D. S. , Jenkinson D. S.
Published: March 2009

Soil samples were taken from four field experiments on the growth of cereals in direct-drilled and in mouldboard-ploughed soil. When sampled, one of the experiments had run for 5 years, one for 6, one for 8 and one for 10 years. Sampling was to just below plough depth and was done on an ‘equivalent depth’ basis, i.e. the more compact direct-drilled plots were sampled more shallowly than the ploughed plots in such a way that both samples represented the same weight of soil per unit area. No significant differences in total nitrogen or in total organic carbon were observed between cultivation treatments at any of the four sites.

In three of the four sites, there was no significant difference in microbial biomass carbon, adenosine 5'-triphosphate (ATP), or mineralizable nitrogen between directdrilled and ploughed soils. In the fourth, which contained more clay than the others, there was slightly more biomass carbon and ATP in the direct-drilled soil. As microbial biomass carbon (or ATP, which is closely correlated with microbial biomass carbon) responds more rapidly to changes in management than do total carbon and nitrogen, a change in biomass carbon should provide early warning of changes in soil organic matter, long before changes in total carbon and nitrogen become measurable. That no such change was observed, with one partial exception, is evidence that a change from traditional methods of cultivation to direct drilling has little effect on soil organic matter other than altering its distribution in the soil profile.
Cotton growth and nutrient uptake following Temik aldicarb application
Authors: Ragab S. M.
Published: March 2009

The feasibility of enhancing cotton (Gossypium hirsutum L.) growth and nutrient uptake with Temik aldicarb was investigated using sand culture with a continuous flow of 1/5 strength of Hoagland solution. Aldicarb was incorporated in the nutrient solution at different rates, and was applied to the plants when they were 30 days old for a period of 1, 3, 5, or 7 days. The cation exchange capacity of the fresh roots of treated plants as well as the ionic permeability of the untreated plants as influenced by aldicarb application were also studied. Low rate of aldicarb provided a stimulus effect on the plant and enabled it to grow faster and to take up more N, P, K, Ca, Mg, and Na than the control. This suggested a direct effect of aldicarb on mineral metabolism especially those processes involving N and P. Maximum dry-matter yield and nutrient uptake occurred at the 5 mg aldicarb rate for all times of treatments. At a rate of 7middot;5 mg aldicarb, growth and nutrient uptake were inhibited, suggesting a toxicity of assimilatory processes within the plant which might have reduced its ability to take up and assimilate nutrients. Aldicarb facilitated the transfer of Na to the stem and leaves resulting in a more uniform distribution of Na throughout the treated plants compared with the control.
Studies on reproduction in prolific ewes
Authors: Robinson J. J. , McDonald I. , Fraser C. , Crofts R. M. J.
Published: March 2009

Seventy-nine Finnish Landrace x Dorset Horn ewes in lamb to Suffolk rams were used in a comparative slaughter experiment to assess the effects of numbers of foetuses on the growth of the products of conception. The mean number of foetuses was 2·7, with a range from 1 to 5. The ewes were individually penned and given a standard diet with metabolizable energy concentration 7·7 MJ/kg and N concentration 21 g/kg, rationed at 2 kg/day during the first month and 1·25 kg/day during the second and third. Allowances beyond that time were on two scales and depended on the number of foetuses being carried as diagnosed by radiography. The ewes were slaughtered between 50 and 145 days of gestation. The gravid uterus was dissected into foetal, placental, foetal fluid and empty uterus components. Equations were fitted to the weights of each component to describe the effects of stage of gestation, litter size and ewe weight. For the mean weight per foetus (Y, kg) the preferred equation is

In (Y)= 2·419–17·574e-0.01976t–00079ft+0–0046w,

where tis the time in days from conception, / is the number of foetuses and wis the weight (kg) of the ewe at mating. This is a version of the Gompertz equation, with additional terms to express the effects of / and w.The weights of the placenta and of the empty uterus were similarly fitted by versions of the Gompertz equation but the mean weight of fluids per foetus (Z, kg) or, rather, its natural logarithm was best described by a third degree polynomial, which is

In(Z) = –11·518 + 0–326t;–0·00316t2+0·0000102t3.

None of the weights was significantly affected by the level of feeding in late pregnancy.

Estimates of mean weights from the equations and of daily rates of gain in weight from the first differentials of the equations are tabulated against stage of gestation and litter size, and the forms of the weight, growth rate and specific growth-rate curves are illustrated graphically.

The equation for foetal weight estimates that at the end of pregnancy the mean weight per foetus is reduced by a factor of 0–89 for each additional foetus being carried. The mathematical model implies that the differences originate in early pregnancy, when the factor is very close to unity, and that the mean weights gradually diverge. In the absence of direct evidence this would appear to be the simplest hypothesis, rather than the assumption in most of the earlier literature that the effect is entirely confined to the last 4 or 5 weeks of gestation.

Just before parturition the total daily weight gain of quadruplet foetuses was about 250 g and was associated with a similar gain in weight of foetal fluids, the ratio of fluid weight to foetal weight appearing to increase with litter size. The ewes were clearly under considerable physical stress. It is suggested that this aspect must be closely considered when greater prolificacy is sought.
Studies on reproduction in prolific ewes
Authors: Wenham G.
Published: March 2009

A radiographic study was made of the skeletons of 216 Suffolk x (Finnish Landrace x Polled Dorset Horn) sheep foetuses of known gestational age within the range 50–145 days. They comprised 10 singles, 42 twins, 105 triplets, 44 quadruplets and 15 quintuplets.

The ages at which the primary and secondary centres of ossification first appeared are presented together with a description of the normal pattern of skeletal development. Attention is drawn to the variations which are found from one foetus to another. The main anatomical features of ovine foetal bone development are illustrated by line drawings and charts.

By anatomical grouping the number of ossification centres was reduced to 80, including 40 primary and 40 secondary centres. Scores were obtained for each foetus by taking the numbers of primary and secondary centres that were present as percentages of the possible totals. The primary score was linearly related to foetal age up to about 100 days, and the secondary score was linearly related to foetal age beyond about 100 days. The relationships to foetal weight were similar but less close.
The effect of a wide range of fertilizer nitrogen application rates and defoliation intervals on the dry-matter production, seasonal response to nitrogen, persistence and aspects of chemical composition of perennial ryegrass (Lolium perennecv. S.24)
Authors: Bartholomew P. W. , Chestnutt D. M. B.
Published: March 2009

A small-plot experiment was made to assess the influence on dry-matter output from grass of a wide range of fertilizer nitrogen and defoliation interval treatments. There were five defoliation treatments, 22, 28, 45, 75 and 112-day regrowth intervalsroughout the growing season each at six levels of nitrogen application, ranging by 300 kg increments from 0 to 1500 kg/ha/year.

There was a marked interaction effect between treatments; a positive dry-matter response was maintained to a higher level of applied nitrogen with more frequent defoliation. In 2 years out of 3 maximum dry-matter yield was produced under a 75·day defoliation interval although the mean yield advantage over a 45-day defoliation system was only 11%. Mean yield of digestible dry matter appeared to reach a maximum under a 45·day defoliation interval at 600 kg N/ha but at the lower levels of N the maximum yield was reached at the longest growth interval.

Seasonal response to nitrogen under the 22–day and 28–day defoliation systems measured as the increase in yield resulting from increased N at each cutting date reached its peak in July–August. Application for these short growth periods early and late in the growing season appeared to be a relatively inefficient use of nitrogen.

The less frequently the sward was harvested and the higher the nitrogen application the greater was the reduction in ground cover as estimated by eye at the end of the growing season, this reached an estimated 25% reduction under 112·day defoliation at 300 kg N/ha/year.

In relation to published figures nitrate content of herbage did not reach dangerous levels until nitrogen application reached levels beyond those at which maximum dry·matter yield was achieved.
Some effects of leaf posture on the yield and water economy of winter wheat
Authors: Innes P. , Blackwell R. D.
Published: March 2009

Selections for erect-(E) and lax-leaf (L) posture in winter wheat were made from a cross between parents which contrasted in the character. By the F5 generation there were consistent, heritable differences between E and L lines. The lines were evaluated in three field experiments and a glasshouse experiment.

In an experiment in which plots were automatically sheltered from rain and in which there were three irrigation treatments, there was no treatment-posture interaction, and over all treatments E lines outyielded L lines by 0·26 t/ha. When fully irrigated the water use of both E and L lines between 1 May and maturity was approximately 280 mm. Withholding water caused a reduction in water use and a corresponding reduction in grain yield for both E and L lines.

When the four most erect- and the four most lax-leaved lines were considered over all three field experiments, E lines maintained a slight, though not significant, grain yield advantage of 0·17 t/ha over L lines. However, the E lines produced significantly more biomass, averaging 0·7 t/ha more than L lines, and this extra biomass was not produced at the expense of additional water requirement. However, results from the glasshouse experiment suggested that the E lines may be more susceptible to a substantial pre-anthesis drought.

It is concluded that varieties of winter wheat with the erect-leaf habit may provide an opportunity of increasing biomass production. In an environment in which a preanthesis drought is unlikely to occur, such varieties may give the highest yields. However, on light soils prone to early drought or at sites which would not permit the maximum expression of leaf area index at anthesis, varieties with a lax-leaf posture may give greater yield.
The early weaning of pigs: III. The influence of protein supply during two stages of growth on the performance of pigs from 9 lb. to bacon weight
Authors: Smith H. , Lucas I. A. M.
Published: March 2009

1. The main experiment described was a 4 × 2 factorial designed to test levels of 18, 21, 25 and 28% crude protein in diets fed from 25–50 lb. live weight and to compare an all-vegetable diet with one containing white fish meal for pigs of 50–100 lb. live weight.

Forty-eight pigs were used in the experiment. They were weaned at an average weight of 9 lb. and were fed a standard 29% protein diet until they each weighed 25 lb. Between 100 lb. and slaughter at 200 lb. they were fed a standard all-vegetable diet containing 14% protein.

Live weights and food-consumption figures for each pig were recorded throughout the experiment and carcass-quality measurements were taken.

2. Forpigs of 25–50 lb. there was no advantage in raising the level of crude protein above 18% in a diet based on white fish meal, dried skim milk, rolled oat groats, ground barley and fine millers' offals. Level of protein fed during this stage of the experiment did not affect performance at any subsequent stage, nor did it affect carcass quality.

3. For pigs of 50–100 lb. rates of live-weight increase and food-conversion efficiency were poorer by 13 and 14%, respectively, on an all-vegetable diet containing 17% crude protein than on a diet including 7·5% white fish meal and containing 15% crude protein. This difference was not affected by level of protein fed before 50 lb., and in its turn it did not affect either growth performance from 100–200 lb. or carcass quality measurements.

4. The following notes relate to the overall performance of early weaned pigs during this experiment: After being weaned at an average of 9 lb. when 10 days old, the pigs reached 25 lb. at 36 days old and 50 lb. at 58 days old. They each ate an average of 29 lb. of the 29% protein diet 1A and 59 lb. of the diets 2 A–D fed from 25–50 lb. Between 50 and 200 lb. food-conversion efficiencies were lower than is usual for individually fed pigs at the Rowett Institute, but rates of live-weight increase were satisfactory when considered in relation to the plane of feeding followed, and the average age at 200 lb. was 185 days. Of the carcasses 85% graded A.

5. In a pilot trial pigs were changed over from the 29% protein diet 1A to the 18% protein diet 2D at 13, 17, 21 or 25 lb. live weight.

There was a linear trend towards slower rates of live-weight increase as the weight at change-over was reduced, and pigs changed at 13 lb. took 7 days longer than those changed at 25 lb. to reach 40 lb. live weight. Overall food-conversion efficiency was best when the change was made at 25 lb., but because of the high cost of diet 1 A in relation to diet 2 D there was a linear trend for the total cost of food per pig to be lower as the weight at change-over was reduced.

6. The results of the pilot trial were discussed in relation to the effects on the lightest pigs in a group of changing to diet 2 D as the average weight per pig reached 25 lb.
Reproduction in farmed red deer. 2. Calf growth and mortality
Authors: Blaxter K. L. , Hamilton W. J.
Published: March 2009

The sex and number of calves born to a breeding herd of red deer kept under farm conditions are analysed together with information on mortality and on growth rate of the calves until weaning in September–October. The results showed some anomalous deviations of the sex ratio from a 50:50 expectation. Birth weight was related to the weight of the hind at the time of the rut, and so too was the subsequent daily rate of gain of the calf. Stag calves weighed more than hind calves and there was no effect of age of hind on birth weight once weight of hind had been discounted. Mortality was divided into two components; perinatal mortality included stillbirths, deaths at parturition and during the first 24 h of life and an unidentified mortality representing failure to find a calf although the hind had calved. Postnatal mortality was defined to include all deaths from after 24 h of life to weaning. Mortality was related to the weight of the calf at birth, being 100 % for calves weighing less than 4·0 kg and declining to 5 % for calves weighing 6·0–7·0 kg. The data are discussed and the effect of size of hind at the time of the rut on her fertility, the time at which she calves, the birth weight and growth rate of her calf and its survival rate are combined to estimate the annual number of viable weaned calves and the total weight of calves produced by herds of hinds of different weights. An increase in hind weight of 50 % (from 60 to 90 kg) results in a doubling of the number of calves born and surviving to September and an increase in the weight of the calf crop by 160%. Reasons are given to suggest that total calf mortality could be reduced to 7 %.
The influence of dietary antibiotics on the activity of the cellulose-splitting bacteria in the intestine of the bacon pig
Authors: Evans R. E. , Maguire M. F.
Published: March 2009

The present investigation is concerned with the influence of procaine penicillin and aureomycin on digestion. In particular, the effect of antibiotics, in amounts generally included in feeding-stuffs, on the bacterial digestion of cellulose in the large intestine of the pig, was investigated.

The digestibility of a basal diet composed of fine bran, maize meal, dried lucerne meal and whitefish meal was determined with and without the addition of antibiotic. No effect was noted on the digestibility of any food constituent.

The diet fed in four digestion trials contained 500 g. of shredded fodder cellulose. The digestion coefficient for the crude fibre, in these diets rich in cellulose, was 76·2% when 18 mg. of procaine penicillin was added per lb. of meal and 76·8% when no antibiotic was added.

The nitrogen-free extractives in the fodder cellulose are mainly if not entirely composed of xylan. If the nitrogen-free extractives and crude fibre are combined to give ‘cellulose’ as defined by Norman & Jenkins, the digestion coefficients for the cellulose were 85·7, 83·4, 85·7 and 87·2%, respectively, thus showing little difference between treatments.

There is no warrant for assuming that the antibiotics had any bactericidal or bacteriostatic effect on the cellulose-splitting organisms.
Studies on lucerne and lucerne-grass leys II. The nitrogenous manuring of a lucerne-cocksfoot ley
Authors: Ridgman W. J. , Hanley F. , Barker M. G.
Published: March 2009

An experiment, carried out to determine the effect of dressings of sulphate of ammonia on an established lucerne-cocksfoot ley grown in narrow rows on heavy gault clay soil, is described and the results discussed. The experiment was carried out over 3 full years (1948–50) and the first crop of the following year. The results suggest that it is possible to increase the yields of grass and total produce without decreasing the yield of lucerne but that no marked increase in the yield of nitrogen per acre is to be expected. Of the times of application tested February proved the most effective.
Short day-length and egg production in the fowl
Authors: Sykes A. H.
Published: March 2009

1. The effect of a short, unchanging day-length of 6 hr. on age at sexual maturity and egg production has been observed.

2. The birds matured at the same age as the controls but at a lower body weight.

3. Egg production over 58 weeks was considerably reduced.

4. An increase in day-length between December and August always increased production.

5. A decrease in day-length between February and August always decreased production; this decrease was greater the later in the year that the change occurred.

6. It is concluded that age at sexual maturity is not affected by the absolute length of the day, and that egg production is affected both by the absolute length and by the change in length.
Field studies on 14C assimilate fixation and movement in oil-seed rape (B. napus)
Authors: Chapman J. F. , Daniels R. W. , Scarisbrick D. H.
Published: March 2009

The roles of leaves, stems and reproductive parts in 14CO2 fixation and its subsequent movement in winter oil-seed rape, cultivar Jet Neuf, were investigated in two field experiments carried out on the Wye College Farm. The relative importance of these organs changed with time. At early flowering the leaves were the most important photosynthetic organs (66·8% 14CO2 activity). Midway between flowering and maturity the stems became the major supplier of photosynthates, a role eventually taken over by the developing siliquae (pods).

These data stress the importance of keeping all photosynthetically active surfaces free from disease if efficient resource utilization and higher yields are to be achieved.
Effect of stage of maturity of forage oats on crude protein content and dry-matter yield
Authors: Haile A.
Published: March 2009

The management of non-leguminous annual forage crops can affect dry matter (D.M.) yields, chemical composition, and nutritive (feeding) values largely because of the stage of maturity at which the crop is harvested. After studies for selecting high-yield forage oat varieties for a highaltitude tropical climate (Haile, 1976), it was considered necessary to look into the management of forage oats so that the time of harvesting for maximum forage and crude protein yield could be established.
Digestibility of ozone-treated sorghum stover by ruminants
Authors: Bunting L. D. , Richardson C. R. , Tock R. W.
Published: March 2009

A variety of chemical reagents and treatment methods have been tested for their potential to enhance the digestibility of crop residues. The most universally used chemicals for animal experimentation in residue treatment are sodium or ammonium hydroxide (Chandra & Jackson, 1970; Koers, Prokop & Klopfenstein, 1972; Klopfenstein, 1978; Arndt & Richardson, 1982). These chemical treatments usually improve digestibility of roughages by solubilizing hemicellulose, and increasing the extent and rate of cellulose and hemicellulose digestion (Klopfenstein, 1978). Delignification is not usually considered to be an important aspect of chemical treatment (Klopfenstein et al. 1972), and increases in digestion are usually attributed primarily to breaking of bonds between lignin and carbohydrates rather than lignin removal. The aromatic nuclei of the lignin molecule are quite susceptible to oxidative attack (Sarkenen & Ludwig, 1971), and crop residues may be significantly delignified by oxidative chemical reagents (Sullivan & Hershberger, 1959; Sherrod et al. 1978; Ben-Ghedalia, Shefet & Miron, 1980). Ozonation is a chemical treatment method which is known to oxidize lignin and disrupt the lignocellulose complex. Several researchers have successfully applied the delignifying capability of ozone to improve the in vitro digestibility of roughages (Weakley & Owens, 1975; Ben-Ghedalia & Miron, 1981; Tock et al. 1982). Very little, however, is known of the actual in vivo feeding value of crop residues treated with ozone. These studies were conducted to determine the effect of ozone treatment on the feeding value of sorghum stover.
Some effects of genetic variation in drought-induced abscisic acid accumulation on the yield and water use of spring wheat
Authors: Innes P. , Blackwell R. D. , Quarrie S. A.
Published: March 2009

Selection for high-(H) and low-(L) drought-induced abscisic acid (ABA) accumulation in spring wheat was made from a cross between parents which contrasted in the character. By the F5 generation H and L selections were homozygous for ABA accumulation, which differed between the classes by 80%. The selections were evaluated in field experiments in which the amount of available water was varied.

In one experiment, in which plots were automatically sheltered from rain, H selections outyielded L selections by an average 0·36 t/ha both when fully irrigated and when water was withheld between anthesis and maturity. The extra grain yield of the H selections was not produced at the expense of additional water requirement in either treatment. When water was withheld during the 4 weeks preceding anthesis, the grain yields of H and L selections were similar, but H selections used less water between 1 May and maturity. Averaged over all treatments the ratio of grain yield to water use was greater for H selections than for L selections by 0·12 t/ha/100 mm. Withholding water caused a reduction in water use and a corresponding reduction in biomass production in both sets of selections.

In two trials in which plots were either irrigated weekly or received natural rainfall only, the ratio of grain yield to water use was again greater for H than for L selections, by an average 0·10 t/ha/100 mm.

It is concluded that in spring wheat, selection for high levels of ABA accumulation in response to water stress may provide an opportunity of increasing grain yield and water-use efficiency.
Nutritional characteristics of kura clover (Trifolium ambiguum Bieb.) compared with other forage legumes
Authors: Allinson D. W. , Speer G. S. , Taylor R. W. , Guillard K.
Published: March 2009

Kura or Caucasian clover (Trifolium ambiguum Bieb.) is a perennial, rhizomatous legume indigenous to Caucasian Russia and adjacent regions (Kannenberg & Elliott,1962; Bryant, 1974). Those agronomic characteristics that lend it potential significance, namely an extensive root-rhizome system, winter-hardiness, resistance to numerous and serious clover pests, and the production of nectar-rich flowers, were enumerated by Parker & Allen (1952). These authors also pointed out that usage of kura clover was hampered by ineffective nodulation. However, in recent years commercial and effective inoculant preparations have become available. Consequently, it has been suggested that kura clover could have potential as a pasture legume and for soil conservation purposes (Bryant, 1974; Spencer et al.1975). Pertinent literature on kura clover is scanty. The present study evaluated the nutritional characteristics of kura clover relative to otherforage legumes.