Cardiovascular effects of intermittent or continuous treadmill conditioning in horses

Nine mature Quarter Horse mares were trained for ten weeks by continuous (n=4) or intermittent (n=5) treadmill work. Both groups of horses trotted at 3.3m/sec. The continuous work was performed at a 3% incline while the intermittent work was done at a 9% incline. Heart rate, cardiac output and blood lactate concentration were measured during a standard exercise test that included work on both treadmill grades before and after five and ten weeks of training. The two conditioning programs did not produce differences in the measured parameters of the two groups of horses. However, there was an overall conditioning effect observed in both groups of horses throughout the ten weeks of treadmill conditioning. Heart rate decreased (P<.05) during exercise on both treadmill grades after ten weeks of training. Lactate concentration decreased (P<.05) during the 9 percent grade trot after five weeks of training. Only slight further decreases occurred between week five and week ten of conditioning. Cardiac output increased (P<.05) between rest and exercise on both grades but there was no conditioning effect.     

The Impact of Natural Deep Eutectic Solvents and Extraction Method on the Co-Extraction of Trace Metals from Fucus vesiculosus

In recent years, natural deep eutectic solvents (NADES) have been widely investigated for the extraction of food and medicinal plants as well as seaweeds. However, the ability of NADES for trace elements co-extraction from natural sources is not well investigated. The aim of this study was to investigate the ability of common NADES for trace elements co-extraction from Fucus vesiculosus. All of the tested NADES did not recover As and Co (concentration <LOQ). Moreover, all of the tested NADES provided a low recovery (<9%) of Ba, Ca, Fe, Mg, Mn, Sr, and Zn. The method of extraction had not shown a statistically significant effect on the co-extraction of all elements (excluding Ba and Ca). In contrast, the water content in NADES was significantly affected on the recovery of Ba, Ca, Mg, Mn, Sr, and Zn. The recovery of Al and Cr was relatively high and considerably varied (from 1.5 to 59.9%). NADES comprising lactic acid:glucose:H₂O (5:3:1) provided the lowest contents of all elements, and the highest extracted amounts were obtained employing water contents of 60–80%. The calculated daily intake of all the elements contained in NADES extracts were less than the daily dose risk estimators. The hazard quotients, hazard indexes, and carcinogenic risk calculated for all trace elements and their combination were considerably less than 1. This evidences no health risk, and carcinogenic risk after topical application of all studied NADES. For the first time, the results of the current study demonstrated that NADES extracts of F. vesiculosus contain a lower amount of trace metals and are safer than the extracts obtained with water and 70% acetone. This indicates a significant advantage for NADES compared with the other solvents.     

The effects of the severe drought of 1976 on the vegetation of some moorland pools in The Netherlands

The effect of the extreme drough of 1976 has been studied to obtain information on the reaction of the vegetation of moorland pools following a fall in the ground water level. The degree of change appeared to be dependent on the nutrient status of water and soil and on the relief. The vegetation of metatrophic and guanotrophic moorland pools showed the most drastic change.     

The effect of delayed autumn harvest on the survival of varieties of perennial ryegrass

The reactions of five early and five late varieties of perennial ryegrass to stimulation of bulky autumn growth and deferment of harvesting were compared in terms of spring growth and subsequent recovery during three winters. Winterkill was marked in 1971–72, particularly when harvesting was deferred to late November, in early varieties S24 and Presto Pajbjerg and in the late variety S23. Least affected among early varieties were Premo and Barvestra (tetraploid) and among late varieties, Perma and Barpastra (tetraploid). All varieties showed rapid recovery. The results are discussed in terms of the significance of winterkill, and the effects of age of sward, variety susceptibility and deferment of autumn defoliation. It is concluded that the form of winterkill which occurs in the west of Scotland can have serious consequences to farm productivity in severe winters. Autumn growth left standing into November can also lead to winterkill. Under good management, varietal differences are unimportant. In a severe winter, no varieties of perennial ryegrass are reliable.     

The effects of dredging operations on the benthic community of a chalk stream

Sampling of the benthic fauna showed that dredging operations produced relatively short-term effects on invertebrate population levels. The behaviour of the animals was immediately affected, the differences between species were noted and the implications of dredging at different times of year are discussed.     

INTERACTIONS BETWEEN FIRST AND SECOND APPLICATIONS OF FERTILIZER NITROGEN AND IMPLICATIONS IN EFFICIENCY OF NITROGEN USE

DM yield and N uptake data are presented from primary growth and two successive regrowths of perennial ryegrass treated with combinations of three N treatments for the primary growth viz. 0, 50 and 100 kg N/ha (PN) and four N treatments applied for the second growths, viz. 0, 33, 66 and 100 kg N/ha (SN). Primary growth gave a response of 24·2 kg DM/kg applied N to PN50 with only a further l±0 kg DM/kg applied N from the second PN increment. A significant interaction between PN and SN treatments was shown in second growth. The residual DM response to PN was highest at SN0 and reduced as the level of SN was raised. Substantially greater residual responses to PN treatments were shown in the third growth. Third growth DM responses to SN treatments were high. High apparent recovery of fertilizer N reached 111% of primary N where SN66 followed PN50. High available soil N is partly responsible for both high apparent recovery of N and high DM response. The latter appears to be associated with inclusion of growths given no fertilizer N so that the full residual effects of fertilizer N and ‘priming’ of available soil N can be realised.     

INVESTIGATIONS ON THE DRYING OF HERBAGE AT TEMPERATURES UP TO 50°C*

Experiments to determine the exposed layer drying rate of cut leaves and stems of a tetraploid (Sabel) and diploid (S23) ryegrass are described. Drying was achieved by passing air through the crop; the changes in weight were monitored continuously. Airflow was fixed throughout the experiments at 37·5 ft/min (0·190 m/s) and the temperatures were controlled in the range 25°C to 50°C. Comparisons were also made of the drying rates at different stages of maturity. Drying curves were determined and moisture content was shown to decay exponentially with time, the relationship approximating closely to a two term exponential.     

STUDIES OF RESPONSE TO FERTILIZER NITROGEN

The effects of 59, 118 or 177 kg N/ha were measured on 7 occasions from 8 to 57 days after application to a perennial ryegrass sward in terms of changes in composition. The first increase Dt of N significantly raised percentages of CP, non-protein N, K, P, Ca, Na and Mg and significantly depressed percentages of DM, OM and OM digestihility. The second increment of N resulted in a further rise in the percentages of CP, true protein, non-protein N, K, P, Ca, Na and Mg; the percentages of DM and OM were further depressed but OM digestihility was not significantly depressed. Percentages of P and Na showed increased responses for the more mature herbage; while percentage non-protein N showed a more marked response in younger herbage. As herbage matured percentages of OM and Na rose, the latter only from days 16 to 45. All other attributes showed falling percentages to levels which could be inadequate for a 500 kg dairy cow yielding 15 kg milk. CP percentage reached this critical level (1.4% N) at days 37, 45 or 56 given 59, 118 or 177 kg N/ha; P percentage became critically low (< 0.36%) at days 27, 35 or 38, respectively; Mg percentage fell to the critical level (0.12%) at days 23, 35 and 46. Na percentage showed the reverse trend, being deficient (< 0.13%) in the earliest samples and becoming satisfactory from days 23 or 27 at 118 and 177 kg N/ha but it remained inadequate at 59 kg N/ba.     

THE ELECTRONIC MEASUREMENT OF SMALL HERBAGE YIELDS USING A HIGH SENSITIVITY CAPACITANCE METER

The capacitance meters available in the past for estimating herbage yields have lacked sensitivity at the extremes of their range of measurement. The preliminary evaluation of a highly sensitive capacitance meter described here indicates that accurate measurement is possible in the range 0.1100 kg DM/ha. The implications of this development for the measurement of herbage of low availability are discussed.