ALBERT

Description: SUMMARYThe effects of an altered rumen dilution rate (D) upon the molar proportions of volatile fatty acids (VFA) in rumen liquor, VFA production rate, microbial protein synthesis and carbohydrate digestion within the rumen were studied using adult wether sheep.Dilution rate and VFA proportions were unaltered by the infusion of up to 121 water/day into the rumen of sheep fed dried grass and concentrate (9:1). There was a small but significant (P 〈 0·05) increase in the rumen volume when the infusion rate was increased from 8 to 12 1/day.The intraruminal infusion of artificial saliva (41/day), or artificial saliva containing 4% or 8% w/v polyethylene glycol (PEG) caused a significant increase in D with an associated decline in the molar proportion of propionate (Pr) in the rumen liquor. A similar effect was obtained with the intraruminal infusion of 2·5% w/v sodium bicarbonate. The overall regression of Pr on D was highly significant: Pr = 32·5–82·1D; r = –0·99, P 〈 0·001.A diet of flaked maize: dried grass (6:4) was offered to three sheep each fitted with a rumen cannula and with a re-entrant cannula at the proximal duodenum. The intraruminal infusion (4 1/day) of artificial saliva containing 4% w/v PEG caused a significant (P 〈 0·01) increase in D and a significant (P 〈 0·01) depression in Pr in two animals. The dilution rate and Pr in the third animal were virtually unaltered by infusion. The regression of Pr on D for the three animals was highly significant: Pr = 34·8–136·8D; r = –0·98, P 〈 0·001. Each increase in D was associated with an increased flow of α-linked glucose polymer, total amino acids and total microbial amino acids into the small intestine and with an increased efficiency of microbial protein synthesis within the rumen.

Description: 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.

Description: summaryMesomorphic, stress-sensitive Pietrain pigs were found to have a lower insulin secretory response to intravenous tolbutamide, glucose and arginine, when compared with ectomorphic, stress-resistant Large White pigs. Pietrain pigs have also been observed to be insulin-insensitive in comparison with Large White pigs. The combination of a low production of and low sensitivity to insulin in the Pietrain breed could account for their enhanced sensitivity to lipolytic agents and for their reduced ability to deposit body fat.

Description: SUMMARYCalves 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.

Description: SUMMARYS.24 perennial ryegrass was conserved by ensiling directly (control) and after treatment with a solution of formaldehyde at the rate of 6 g HCHO/100 g crude protein. After storage for 90 days, part of the formaldehyde-treated silage was dried in a high-temperature drier.The quantitative digestion of the energy, carbohydrate and nitrogen moieties of the three diets and the production of volatile fatty acids and microbial protein within the rumen were measured using five sheep fitted with re-entrant cannulae at the proximal duodenum and terminal ileum.Treatment with formaldehyde depressed organic matter and energy digestion within the rumen compared with untreated silage (P 〈 0·001) and a further depression was observed on the dehydrated material. Both formaldehyde-treated silages showed enhanced flows of total amino acids into the small intestine compared with the control silage and net absorption from the small intestine was elevated by 13 and 21% respectively on these two diets. On the untreated silage over 71% of the protein entering the small intestine was microbial in origin whereas, due to depressed microbial growth and increased protection of feed protein from rumen fermentation, microbial protein comprised only 17% of duodenal protein on the two formaldehyde-treated silage diets. Fifteen and 81 % of the dietary protein passed undegraded through the stomachs to the duodenum on the control and the two formaldehyde-treated silage diets respectively.Total VFA production within the rumen was not significantly influenced by the treatments imposed, but on the untreated silage only 56% of the energy apparently digested in the rumen was converted to VTA energy whilst a mean value of 74% was recorded on the other two diets.Estimates of the total energy absorbed gave values of 10·6, 11·9 and 10·7 MJ/kg D.M. for the control, formaldehyde and dried, formaldehyde silage diets with absorbed protein energy representing 21, 22 and 26% of the total absorbed energy respectively.

Description: SUMMARYA multifactorial experiment sown to winter wheat cv. Hustler in autumn 1978 tested the effects of combinations of the following eight factors, each at two levels: drill type, sowing date, amount of nitrogen, division of nitrogen, irrigation, autumn pesticide (aldicarb), summer aphicide (pirimicarb), and fungicide (carbendazim, maneb and tridemorph).The mean grain yield of all plots was 9·7 t/ha and the best eight-plot treatment mean was 11·3 t/ha. The factors that had the greatest effect on yield were aphicide and fungicide, mainly from the control of Metopolophium dirhodum and Septoria spp. respectively. Both factors increased grain size and their effects were more than additive and greater with 250 than with 160 kg N/ha. Aphicide and fungicide also temporarily decreased the numbers of microbes on the developing ears. Autumn pesticide gave good control of aphids in the winter and some control in the summer: it also decreased nematode populations and slightly increased yields.Precision sowing compared with random distribution of seeds along the row had little effect on growth or yield. Sowing on 21 September compared with 13 October greatly increased growth early in the season but had less effect after anthesis; it was the only factor that increased yield when aphicide and fungicide were applied. There was negligible infection by barley yellow dwarf virus in crops sown on either date. The amount and division of N fertilizer affected N uptake early in the season and had small effects on the production and survival of tillers. Three N applications instead of one slightly increased grain yields but did not affect total N uptake by grains plus straw, which averaged 190 kg N/ha. The larger amount of N always increased N uptake but decreased yield in the absence of aphicide and fungicide. Irrigation slightly decreased yield despite prolonging the duration of green leaf area.

Description: SUMMARYEighteen individual feedstuffs and 19 mixed diets were used in a study attempted to relate determined energy values to various chemically determined measures. For cereals the level of fibre could be used to predict digestible and metabolizable energy (DE and ME). In the case of DE the relationships with crude fibre and modified acid detergent fibre (MADF) based on 14 feeds were:DE (kcal/kg D.M.) = 4179–86 MADF (%): r =–0·96; P 〈 0·01,DE (kcal/kg D.M.) = 4228–140 x crude fibre (%): r =–0·97; P 〈 0·01.For all feeds the following equations gave the best prediction of energy values from dietary analysis (on the basis of correlation coefficients and residual standard deviations):DE (kcal/kg D.M.) = 109·9 x crude protein (%) + 149·3 x acid ether extract (%) + 90·1 x nitrogen-free extract (%)–5030: R = 0·95; P 〈 0.01.ME (kcal/kg D.M.) = 99·5 x crude protein (%) + 144·7 x acid ether extract (%) + 87·8 x nitrogen-free extract (%)–4795: R = 0·94; P 〈 0·01.Digestible nutrients were closely related to DE and ME, e.g.DE (kcal/kg D.M.) = 52·9 x digestible crude protein (%) + 108·3 x digestible ether extract (%) + 39·4 x digestible crude fibre (%) + 39·9 x digestible nitrogen-free extract (%) + 183·7: R = 0·99; P 〈 0·01.

Description: SummaryLate Triassic Radiolaria have been recovered from a bedded chert collected early in 1977 in the South Orkney islands. This is the first reliable palaeontological evidence for the age of the so-called basement complex that forms most of the exposed rock of a microcontinent on the southern limb of the Scotia Ridge. The fossils place a lower limit on the age of deformation of at least part of the complex as post-Karnian or Norian. The basement is overlain by undeformed Jurassic to Cretaceous conglomerates, which suggests this event took place during the early Mesozoic Gondwanian orogeny.The new data are consistent with the interpretation that the basement complex of the South Orkney Islands represents part of a subduction complex and was accreted to the Pacific margin of Gondwanaland during the late Triassic or early Jurassic time.

Description: There is at present a need to develop a better technique for measuring the rate of icing on structures such as, for example, overhead transmission lines. For aircraft and helicopter icing, the most widely used method of measurement is the rotating cylinder. However, for measuring the icing of structures, this method is difficult to apply and also less accurate due to lower wind velocities. Different approaches are now being developed using fixed cylinders.Icing tests were conducted with fixed and rotating cylinders in a wind tunnel. The rate of icing was obtained through measurements of volume, accretion cross-section and time of deposition. Tests were made using five different liquid water contents and droplet diameter spectra, and four cylinder diameters, keeping the wind velocity and temperature constant. The rate of icing is presented as a function of the diameters of the fixed and rotating cylinders for each of the liquid water contents tested. Results indicate that at lower wind velocities the accretion rate is overestimated for the smaller rotating cylinders. This difference is probably due to the variation of the collection efficiency with diameter. From these results it is suggested that the rate of ice accretion on structures should be based on at least two fixed cylinders of different small sizes in order to take into account the effect of the collection efficiency.

Description: There is at present a need to develop a better technique for measuring the rate of icing on structures such as, for example, overhead transmission lines. For aircraft and helicopter icing, the most widely used method of measurement is the rotating cylinder. However, for measuring the icing of structures, this method is difficult to apply and also less accurate due to lower wind velocities. Different approaches are now being developed using fixed cylinders. Icing tests were conducted with fixed and rotating cylinders in a wind tunnel. The rate of icing was obtained through measurements of volume, accretion cross-section and time of deposition. Tests were made using five different liquid water contents and droplet diameter spectra, and four cylinder diameters, keeping the wind velocity and temperature constant. The rate of icing is presented as a function of the diameters of the fixed and rotating cylinders for each of the liquid water contents tested. Results indicate that at lower wind velocities the accretion rate is overestimated for the smaller rotating cylinders. This difference is probably due to the variation of the collection efficiency with diameter. From these results it is suggested that the rate of ice accretion on structures should be based on at least two fixed cylinders of different small sizes in order to take into account the effect of the collection efficiency.