Some effects of fertilizer and frequency of defoliation on the botanical composition and yield of permanent grassland

Small plots of permanent pasture containing 50% Agrostis capillaris-Festuca rubra were defoliated frequently or infrequently during the growing seasons in 1978–80 and fertilized with 133, 125 and 125 kg N, P₂O₅ and K₂O respectively ha⁻¹ a ⁻¹ or not fertilized during 1978–81. Yields of herbage were assessed during 1979–80 and botanical composition assessed on three occasions in 1978, once in April 1979 and once in 1982.
Fertilizer application increased annual dry matter (DM) harvested from frequently cut plots by 40%, 53% and 65% in 1978, 1979 and 1980 respectively, and on infrequently cut plots it doubled hay DM harvested in 1978 and increased total DM harvested by 126% and 186% in 1979 and 1980 respectively. Infrequent cutting and fertilizer both decreased the proportion of A. capillaris but only fertilizer decreased the proportion of F. rubra. Fertilizer greatly increased the proportion of Holcus lanatus especially where plots had been cut frequently and of Alopecurus pratensis where they had been cut infrequently. It decreased the proportion of Luzula campestris. Infrequent cutting, especially with fertilizer, discouraged Cerastium fontanum ssp. glabrescens and Trifolium repens but encouraged Rumex acetosa.     

The effect of cutting and grazing managements on dry matter yield of white clover varieties (Trifolium repens) when grown with S23 perennial ryegrass

The effects of three defoliation treatments upon the performance of eight white clover varieties when grown with S23 perennial ryegrass were investigated. These treatments included a cutting only regime as used in National List trials and rotational and continuous sheep grazing.
There were significant ( P <0·001) differences between treatments, and the ranking of clover varieties also differed between the three treatments. The significance of this finding is discussed in relation to the evaluation of breeding material and varieties prior to recommendation to farmers.
Clover yields were less under grazing than cutting. This was due mainly to the selective grazing and removal of stolon material which occurred in the former treatments. Differences in the grass/clover balance resulting from the three treatments are discussed in relation to the degree of protection afforded to the clover stolons by the grass component.     

Alcohol and caffeine: effect on inferred visual dreaming

In seven subjects, a large amount of alcohol, taken at bedtime, reduced the total duration of stage 1 electroencephalographic-rapid-eye-movement periods in the first 5 hours of sleep; a moderate amount of caffeine produced no significant change.     

Plasma concentrations of thyroid hormones in growing pullets and laying hens reared under two tropical climates and fed on diets with different energy concentrations

1. Blood samples were taken from growing (14-week-old) and laying (36-week-old) hens reared in either a temperate or a hot, humid climate and fed on 2 dietary energy concentrations (10.03 or 11.7 MJ ME/kg) to determine the plasma concentrations of 3,3 ,5-triiodothyronine (T3) and thyroxine (T4) by radioimmunoassay. 2. Plasma T3 concentrations were higher in birds fed on the low energy diet and higher at 14 than at 36 weeks of age, while the effects of climate were complex. 3. Plasma T4 concentrations were higher at 14 than at 36 weeks of age and interactions with the dietary and climatic factors were observed. 4. Interactions between dietary and climatic factors were observed since plasma T3 and T4 concentrations were higher at 14 weeks under the hot, humid than under the temperate climate. Furthermore, at 36 weeks plasma T3 concentrations were higher under the temperate climate and plasma T4 concentrations did not differ. 5. These findings are not easy to explain. However it may be suggested that the energy content of the diet clearly affects the plasma concentrations of thyroid hormones and that this effect is modulated by the climate to a variable degree that is linked to the age and the physiological state of the birds.     

Increased tolerance to annual ryegrass toxicity in sheep given a supplement of cobalt

SUMMARY To determine whether oral cobalt supplements could modify the clinical onset of annual ryegrass toxicity, groups (n = 5) of sheep were dosed orally with 0, 4 or 16 mg cobalt/day. After 3 weeks on this treatment, toxic ryegrass seed was added to their feed to provide 0, 0.15 and 0.30 mg corynetoxins/kg body weight, daily. Sheep receiving cobalt ingested 30% more toxin than did unsupplemented sheep before clinical signs developed (P = 0.03). There was no significant difference between groups receiving 4 and 16 mg cobalt. The results showed that cobalt delayed, but did not prevent, the onset of clinical signs of annual ryegrass toxicity.