bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of slurry on the acceptability of swards to grazing cattle
Authors: Broom D. M. , Pain B. F. , Leaver J. D. 
Published: March 2009

SUMMARYGrass plots, designed to provide 4 days grazing for three heifers, were divided into four equal sub-plots which were dressed with cow slurry in March at rates between 0 and 100 t/ha. The heifers were put into the plots 7 and 13 weeks after slurry application and were able to choose in which of the sub-plots they spent their time and grazed.The main effect of slurry on the pasture at 7 weeks was to increase the height of the sward but to decrease herbage dry-matter production. Herbage dry-matter utilization over the 4 days ranged from 94% on the no-slurry sub-plot to only 41% when slurry had been applied at 100 t/ha. The heifers spent most time in and grazed more often in sub-plots with little or no slurry for the first 2 days, but as the grass was eaten down the frequency of grazing on areas with more slurry increased. This was reflected in the amount of grass removed by the heifers from each treatment on each day.At the beginning of the second grazing, grass height and herbage dry-matter production were both directly related to level of slurry application. The heifers did not distinguish between treatments up to 50 t/ha, but herbage utilization on the 100 t/ha sub-plot was reduced.
The interaction of nutrition and body condition at mating on ovulation rate and early embryo mortality in Scottish Blackface ewes
Authors: Gunn R. G. , Doney J. M. 
Published: March 2009

SUMMARYOne hundred and fifty-six Scottish Blackface ewes were differentially group-fed over a 2-month period to achieve three distinct levels of body condition (good, moderate and very poor). Over 5 weeks prior to mating, one group of good-condition ewes was maintained in that condition, one group of good- and one of moderate-condition ewes were brought down in condition by restricted feeding and one group of moderate and the very poor condition ewes were raised in condition by a high level of feeding. Ewes were therefore in good, moderately good or poor condition at mating. After mating, ewes were killed either on return to service or at 25 ± 5 days for counts of corpora lutea and viable embryos.Poor body condition, irrespective of feeding level, was associated with a delay or suppression of oestrus and with a high return-to-service rate. Ovulation rate was positively related to body condition at mating but not to the level of pre-mating food intake at the condition levels studied.Embryo mortality decreased as body condition at mating increased and the interaction between condition and the level of pre-mating food intake had a differential effect on mortality of single- and multiple-shed ova. The lowest rate of embryo mortality was found in ewes in moderately good condition which had been well-fed before mating.
Calcium and phosphorus balances of lactating ewes at pasture
Authors: Sykes A. R. , Geenty K. G. 
Published: March 2009

SUMMARYDifferences in maternal body weight (12–15 kg) were induced in two groups (n = 43–50) of ewes during pregnancy by controlled allowance of pasture. Following parturition equal numbers (9–12) were allocated to one of three herbage allowances in a 2 x 3 factorial design during 42 days of lactation. This design was employed on two occasions; in one (Expt 1) the sheep were machine-milked twice daily, in the second (Expt 2) they each suckled two lambs. Balances of Ca and P in the body were determined by comparative slaughter during early pregnancy, at parturition and after 42 days of lactation. Herbage Ca intake and milk Ca output were determined on a weekly basis.Mean daily milk production during the 42 days of lactation ranged from 1·48 to 2·68 kg/day amongst treatment groups. The general trend, irrespective of level of milk production, was for negative Ca balances, ranging from 0·71 to 1·42 g Ca/day. It is argued that variation in apparent absorbability (0·17–0·46) and in rate of absorption (30–113 mg/kg W per day) of Ca among groups suggest that these factors are not in themselves responsible for the poor Ca balances observed.It is suggested that demand for Ca from the diet during early lactation is reduced as a consequence of bone Ca resorption due to matrix osteoporosis resulting from a protein deficiency state. Negative Ca balances in sheep undernourished during pregnancy were similarly attributed to poor protein balances.Although negative P balances were observed these were not attributed to low P intake.
The effect of drilling date on the growth and yield of oil-seed rape (Brassica napus L.)
Authors: Lutman P. J. W. , Dixon Fiona L. 
Published: March 2009

SummaryThe effects of drilling date (18 August–22 September) on the growth and yield of oil-seed rape (Brassica napus) was studied in a series of five experiments over three seasons. Autumn and winter growth of the crop, as measured by dry weight of tops and leaf area, was severely reduced by delayed drilling, especially if it was later than 10 September. However, during the spring and early summer the differences in crop weight due to drilling date declined and in four of the five experiments there were no detectable differences in seed yield between early- and late-sown crops. The yield decline in the fifth trial was small. Measurements of components of yield showed that later-sown crops had fewer pods per plant and slightly smaller seeds but apparently more seeds per pod. The practical significance and reasons for the recovery of late drilled crops from early poorer growth are discussed.
Seasonal variations in the composition of Pinus halepensis and Pinus sylvestris twigs and needles essential oil
Authors: Zafra María , García-Peregrín E. 
Published: March 2009

SUMMARYInfluence of season on the terpene composition of Pinus halepensis and Pinus sylvestris was investigated. The essential oil of twigs and needles from a preselected plot of pines was investigated from October to June. In P. halepensis, the average composition during this time was 27·2% α-pinene, 65·0% sabinene, 7·2% 3-carene and 0·5% β-pinene in the essential oil of twigs; 32·1% α-pinene, 35·9% sabinene, 18·5% terpinolene, 4·3% 3-carene, 3·1% β-pinene and 6·1% thujene, limonene, β;-phellandrene and γ-terpinene in the essential oil of needles. In P. sylvestris, the average composition was 49·2% α-pinene, 30·1% sabinene, 14·9% β-pinene and 7·9% limonene in the essential oil of twigs; 69·5% α-pinene, 14·9% camphene, 9·1% β-pinene, 3·6% sabinene and 2·8% limonene in the essential oil of needles. The maximum amount of sabinene coincides with the minimum of α-pinene, both in twigs and needles essential oil from P. halepensis and P. sylvestris. The month-to-month changes in the oil composition are statistically significant for the most part. It is of interest to point out the decrease of sabinene content of needles essential oil in comparison with the twigs essential oil, with the simultaneous increaseof terpinolene in P. halepensis and camphene in P. sylvestris.
Evaluation of Hereford and first-cross cows on three pasture systems. I. Calf growth and reproductive performance of young cows
Authors: Barlow R. , Hearnshaw H. , Arthur P. F. , Darnell R. E. 
Published: March 2009

SUMMARYHereford (H × H), Brahman × Hereford (B × H), Simmental × Hereford (S × H) and Friesian × Hereford (F × H) females born over a 5-year period (1973–77) were placed on pastures of high, medium or low nutritive value at Grafton, New South Wales, Australia, at weaning (7–8 months of age). The first mating of heifers on high pasture was at 15 months (1974) while that on medium and low pastures was delayed until 27 months of age (1975). This paper reports the reproductive performance of these cows up to 5 years of age and the preweaning growth of their calves which were sired by Hereford bulls at Grafton, Australia. In total, 1222 calving records were analysed.Most traits were subject to interaction between genotype and other main effects (pasture, year of birth of cow, cow age and sex of calf). Eyelid pigmentation was an exception, with calves from B × H cows having more than calves of other genotypes (73 v. 43%). There were significant genotype differences in calving difficulty among 2-year-old heifers only, with H × H (33%) requiring more assistance than F × H (15%) and SxH (10%) heifers, while B × H heifers did not require any assistance. Genotype differences in percentage of calves born and weaned were observed on low pastures only, where B × H (66% born, 65% weaned) exceeded H × H (48%, 39%) and S × H (39%, 38%) cows, with F × H (58%, 50%) cows being intermediate. Calves by H × H cows were the slowest-growing and were the lightest at weaning on all pastures, with mean gains of 759, 604 and 340 g/day, and mean weaning weights of 212, 188 and 110 kg, on high, medium and low quality pastures, respectively. F × H and S × H cows produced the fastest-growing calves on high quality pasture (966 and 936 g/day, respectively) while B × H cows produced the fastest-growing calves on medium (823 g/day) and low (679 g/day) quality pastures. F × H cows weaned the heaviest calves on high quality pasture (274 kg) while F × H and B × H weaned the heaviest calves on medium (230 and 229 kg, respectively) and low (162 and 169 kg, respectively) quality pastures. Differences in body measurements followed a pattern similar to weaning weight.
An examination of the effects of water stress on leaf growth of crops of field beans (Vicia faba L.):2. Mineral content
Authors: Farah S. M. 
Published: March 2009

SUMMARYThe mineral content of N, P and K in leaves, stems, roots and seed of field beans, subjected to four watering regimes were compared in 1976 and 1977, and of a foliar nutrient spray in the latter year.N, P and K content increased in all treatments with the increase in plant size and then declined at about the time of podding and death of the leaves.Water shortage reduced the amounts of N, P and K throughout the growth period and for the seed at final harvest; the decrease was more pronounced in 1976 than in 1977. The plants under stress conditions benefited from the foliar nutrient spray more than the unstressed plants.
Effect of autumn nitrogen on the growth and yield of winter barley in the north of Scotland
Authors: Walker K. C. , Matthews S. 
Published: March 2009

SUMMARYIn experiments conducted between 1982/83 and 1984/85 on the winter barley cv. Igri, nitrogen, including slow release forms, applied at several growth stages in the autumn, increased vegetative growth, including vegetative tiller numbers, nitrogen content and greening, particularly in the early sown crops. By spring, these effects were less apparent and only very infrequently did autumn nitrogen applications result in an increase in fertile tiller number and yield, although the autumn nitrogen treatments had been tested in combination with several different sowing dates and spring nitrogen levels. Studies on leaf production over the winter showed that the additional leaf produced after nitrogen application was subsequently lost through leaf senescence (especially in the severe winter of 1984/85) and therefore the treated and untreated plots often recommenced growth in the spring with similar amounts of live leaf tissue. It is argued that the use of autumn nitrogen on winter cereals in the north of Scotland cannot be supported agronomically and may also be undesirable for environmental reasons.
The potential for using n-alkanes in tropical forages as a marker for the determination of dry matter by grazing ruminants
Authors: Laredo M. A. , Simpson G. D. , Minson D. J. , Orpin C. G. 
Published: March 2009

SUMMARYThe intake of temperate forages by herbivores can be determined using the C33 alkane naturally present in the forage and dosed C32 alkane. To determine whether the technique can be used with tropical forages, the concentrations of C33 alkane were determined in seven species.The leaves of Brachiaria decumbens, Digitaria decumbens, Pennisetum glaucum and Stylosanthes scabra contained sufficient C33 alkane (> 50 mg/kg DM) for the estimation of dry matter intake. Low concentrations of C33 alkane were found in the leaves of Setaria sphacelata, Sorghum sp. and Leucaena leucocephala. Setaria sphacelata was found to contain high concentrations of C27 alkane and therefore intake could be estimated by using C28 as the dosed alkane although the intake would possibly then be underestimated by c. 8%. Leaves of Sorghum sp. contained > 50 mg C31 alkane/kg DM and, with C32 as the dosed alkane, intake would possibly be underestimated by c. 5%. Leucaena leucocephala contained insufficient alkanes to estimate forage intake. The concentration of n-alkanes in Pennisetum glaucum and Sorghum sp. leaves decreased with age.It was concluded that some tropical forages contain insufficient C33 alkane for the measurement of intake by the double alkane technique. In these species, a shorter chain length alkane can sometimes be used, but only with a reduction in accuracy in estimating intake.
A method for the analysis of barley kernel growth data from designed experiments
Authors: Koesmarno H. K. , Sedcole J. R. 
Published: March 2009

SummaryThe growth of kernels at selected positions along the spike of barley was studied using three models: segmented, logistic and Gompertz. The segmented model divides the growth period into three segments: an initial constant stage, a middle period of ‘linear growth’, and a final constant stage. The identification of a period during which growth is approximately linear - the ‘linear phase’ - was estimated from the curvilinear functions by imposing some criterion to determine the period of ‘linear growth’ in order that the results were similar to those from the segmented model. From this a model of final growth, growth rate and duration of growth as a function of kernel position was developed and fitted to data from four different thinning treatments at five sowing dates. The model of final growth and growth rate was shown to have a family of gamma functions. The analysis of these models showed that there were marked interactions between sowing and thinning treatments for growth rate, less so for grain yield, but there was no substantial interaction for duration.
A quantitative analysis of the effects of nitrogen on the growth, development and yield of oilseed rape
Authors: Allen E. J. , Morgan D. G. 
Published: March 2009

SUMMARYTwo experiments carried out in 1968 and 1969 are described which examined, through growth and yield analysis, the effect of nitrogen on the growth of oilseed rape. The results of the second experiment, when 0, 105·5 and 211·0 kg N/ha were compared, are presented and discussed. The application of nitrogen increased the yields of seed and oil, principally through increased production of seeds by a larger number of pods. However, the application of nitrogen had little effect on average pod weight or average seed weight. Crop growth rates were increased by the application of nitrogen and reached their highest levels during the period of pod development when the leaf areas had declined to very low levels. The order of effects of nitrogen (N 2 > Nl > NO) was similar for LAI, number of pods per plant and number of seeds per pod and it is likely that the effect of nitrogen was achieved indirectly through an increase in the supply of assimilates to the flowers and young pods. This suggests that the maintenance of a large and photosynthetically efficient leaf area during the period of flowering is necessary for high yields in this crop.The results also suggest that once pods are macroscopic they produce much of the assimilates needed for their own growth.The implications of these findings with regard to both practice and further research are discussed.
Weather factors affecting the development of maize from sowing to flowering
Authors: Hough M. N. 
Published: March 2009

SUMMARYThe phenological development from sowing to flowering of the eaxly maize hybrid INRA 200 is related to the weather conditions. Plot trial data from Wytham, near Oxford, England, and weather information from that and nearby sites formed the basic data.The mean rate of development per day from sowing to emergence is related by linear correlation analysis to the mean values of soil temperature at 5 cm depth and soil moisture deficit. A range of temperature thresholds for emergence development exist, which depend upon the soil moisture, and which differ from the true physiological threshold.Between omergence and flowering the mean rate of development per day is related by linear correlation analysis to mean air temperature, solar radiation and potential transpiration estimated from weather data. All correlations are significant, but the parameters which combine radiation and temperature are statistically better.
Induction of early breeding in sheep by standard and modified progestagen-PMS treatments
Authors: Gordon I. 
Published: March 2009

SUMMARYThe oestrous response and subsequent lambing performance of 264 sheep was studied after treatment with intravaginal sponges and PMS during July (period of late anoestrus). Four progestagen treatments were employed, each in combination with one or other of four dose levels of PMS (0, 250, 500 and 750 i.u.) given at pessary withdrawal; the sixteen resultant treatments were applied in each of seventeen flocks. Modification of standard ‘Cronolone’ (9α-fluoro-11β-hydroxy-17α-acetoxy-progesterono; G. D. Searle) pessaries to ensure thorough dispersion of the compound resulted in a significantly higher mating response and lambing outcome. The highest lambing outcome followed the use of 500 i.u. PMS. The onset of heat, relative to progestagen withdrawal, was affected both by progestagen treatment and PMS dose level. The conception percentage was highest in sheep which were bred on the second day after treatment. The implications of the data, in explaining some previous results with standard ‘Cronolone’ sponges, are briefly discussed.
Relationship between light interception, ground cover and leaf area index in potatoes
Authors: Firman D. M. , Allen E. J. 
Published: March 2009

SUMMARYIn field studies of two varieties in Cambridge, UK, in 1985 and 1986, the percentage of total incident radiation intercepted by potato canopies with complete ground cover was as low as 80% for some plots but approached 100% in dense canopies. Although percentage ground cover is useful for assessing canopy growth, it is not wholly suitable for estimating light interception and may lead to serious errors in calculation of efficiency of conversion into dry matter.
Effects of the timing of ploughing-in temporary leguminous pastures and two winter cover crops on nitrogen mineralization, nitrate leaching and spring wheat growth
Authors: Francis G. S. , Haynes R. J. , Williams P. H. 
Published: March 2009

SUMMARYTwo field experiments at Canterbury, New Zealand during 1991–93 investigated the effect of the timing of ploughing a 4-year-old ryegrass/white clover pasture and the effect of two winter cover crops on subsequent N mineralization, nitrate leaching and growth and N uptake of the following wheat crops.Net N mineralization of organic N (of plant and soil origin) increased with increased fallow period between ploughing and leaching. The total amount of N accumulated in the profile by the start of winter ranged from 107 to 131 and from 42 to 45 kg N/ha for fallow treatments started in March and May respectively. Winter wheat (planted in May) had no effect on mineral N contents by the start of winter, whereas greenfeed (GF) oats (planted in March) significantly reduced the mineral N content in one year.Cumulative leaching losses over the first winter after ploughing-in pasture varied markedly between years in relation to rainfall amount and distribution. Leaching losses were greater from the March fallow (72–106 kg N/ha) than the May fallow treatments (8–52 kg N/ha). Winter wheat did not reduce leaching losses in either year. GF oats did not reduce losses in 1991/92, but losses in 1992/93, when major drainage events occurred late in the winter, were only c. 40% of those under fallow.Incorporation of a large amount (> 7 t/ha dry matter) of pasture or GF oat residue in spring depressed yield and total N uptake of the following spring wheat, largely due to net N immobilization which could be overcome by the application of fertilizer N.First-year treatments had very little residual effect in the second year. Leaching losses over the second winter (mean 142 kg N/ha) were largely unaffected by the extent of first year leaching losses. Second year leaching losses were greater than first year losses, probably due to the greater amount of mineral N at depth in the soil before the start of the second winter.
Comparative water consumption and efficiency in three divergent sheep types
Authors: Schoeman S. J. , Visser J. A. 
Published: March 2009

SUMMARYCumulative feed and water intakes and body weights of 30 growing ewe lambs of three different breeds were recorded weekly for 34 weeks between October 1990 and June 1991 at the Experimental Farm of the University of Pretoria. The results were analysed to obtain water efficiencies on both an absolute and metabolic weight gain basis. On an absolute basis, Mutton Merino sheep consumed 145% and Dorper 109% more water than Blackhead Persian sheep. On a metabolic weight gain basis, the corresponding differences were 92 and 66%, respectively. Mutton Merino and Dorper lambs also consumed 69 and 41% more water per kg feed intake than the Blackhead Persians, respectively. Weekly water consumption increased twice as much per 1 °C increase in ambient temperature in the Dorper and Mutton Merino lambs as in the Blackhead Persians. These results suggest that sheep of the Blackhead Persian, and probably also other indigenous breeds, balance their water requirements at a more economical level and would be a more appropriate choice than those breeds currently being managed in sustainable sheep production systems in areas where water availability is limited.
Energy values in pig nutrition:I. The relationship between digestible energy, metabolizable energy and total digestible nutrient values of a range of feedstuffs
Authors: Morgan D. J. , Cole D. J. A. , Lewis D. 
Published: March 2009

SUMMARYNineteen feedstuffs were evaluated for total digestible nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) using growing pigs. DE values, on a drymatter basis, ranged from 1570 kcal/kg D.M. (grassmeal) to 4890 kcal/kg D.M. (BP Grangemouth protein). ME averaged 97·4% of DE for cereal feeds and 81·9% of DE for protein feeds, the ratio of DE to ME being significantly affected by the crudeprotein content of the feedstuff:ME/DE × 100 = 99·7–0·18 × crude protein (%): r = –0·94; P < 0·01.TDN was more closely related to ME than DE:DE (kcal/kg D.M.) = 45 TDN + 156: r = 0·92; P < 0·01,ME (kcal/kg D.M.) = 43 TDN + 71: r = 0·98; P < 0·01.ME values were corrected to both 30% and 0% nitrogen retention. Correction to 30% retention caused a maximum change of 3% in ME value while correction to 0% retention had a variable effect related to protein content of the feedstuff:(ME(N0)/ME) × 100 = 98·3–0·113 × crude protein (%): r = –0·80; P < 0·01.