摘要:

AbstractIn the first experiment the buffering effect of Italian and perennial ryegrass to fonnic acid was determined with three varieties (Leda, S24 and Presto) cut at weekly intervals throughout the growth cycle. The buffer curves showed no significant differences between the three varieties at any one stage of growth and the results were combined to produce regression equations predicting pH values for the three ryegrasses cut at first ear emergence (e.e.), 50% e.e. and 100% e.e. after addition of formic acid.In the second experiment Italian ryegrass was harvested at three stages of growth, wilted to four different DM contents and ensiled in laboratory silos with five levels of formic acid. The interaction of stage of growth, formic acid level and DM content on the water‐soluble carbohydrates, ethanol and volatile N contents of tbe resultant silages is discusse

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01116.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of exit temperature of a rotary‐drum‐drier and of the length of pre‐drying storage time on chemical composition and digestibility of dried grass cobs was investigated in two experiments. Increasing exit temperature from 77 to 166°C reduced WSC, NFE and available lysine content and increased CF content of dried grass.In vitroandin vivoDM digestibility was reduced by 16.4 and 24.5 percentage units respectively. Increasing length of pre‐drying storage time also reduced WSC and available lysine content and reducedin vitroandin vivoDM digestibility by 2.4 and 5.1 percentage units respectively. The greatest reduction inin vivodigestibility in both experiments occurred in the CP

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01117.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractInvestigations were conducted into the seed reserves, shoot and seminal root growth ofLolium perenne, Festuca arundinacea, Holcus lanatusandPoa trivialis. Data are presented for the caryopsis, palea and lemma weights of these species. Shoot lengthsof LoliumandFestucawere very similar but seminal root lengths ofLoliumwere longer and emerged earlier than those ofFestuca. The caryopsis inLoliumlost weight much more rapidly in germination thanFestuca. Seedlings ofLoliumandFestucashowed similar increases in shoot length butLoliumhad more rapid rates of seminal root growth and weight loss from the caryopsis. It is suggested that poor field establishment ofFestucamay be due to poor mobilization of seed reserves and consequential poor seminal root growth. The possibility of selecting for good seminal root development inFestucato improve establishment is suggested.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01118.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractSix varieties oiLoliumperenne, three ofL. multiflorumand one hybrid (L. multiflorum × L. perenne) were assessed for diseases over two harvest years. Crown rust (Puccinia coronata) and mildew (Erysiphe graminis) occurred on some varieties in 1973. Leaf spotting (Drechsleraspp.) was common, but slight on most varieties, in both years. Ryegrass mosaic virus (RMV) and its mite vector,Abacarus hystrixwere present on all varieties in the second year. The relative susceptibility of varieties to RMV was similar in the field and in glasshouse tests

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01119.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractA comparison was made of the digestibility, voluntary intake and concentration of N in faecal organic matter in castrated male sheep and non‐lactating cows offered herbagead libitum. The sheep ate 22% more herbage DM per kg liveweight than the cows. In general, the sheep and cows digested the organic matter of the herbage to the same extent, although on two occasions significantly higher digestibilities were observed in cows than in sheep. Similar concentrations of N in faecal organic matter in sheep and cows were matched by similar digestibilities of herbage organic matter. Regression equations relating herbage organic matter digestibility to faecal N concentration were not significantly different between sheep and cattl

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01120.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe regrowth of Italian ryegrass following a cut in late April was studied at weekly intervals up to 14 weeks. There were four levels of applied N: 28, 84, 140 and 196 kg ha‐1. The proportion of green leaf blade declined from 80% of DM yield after 2 or 3 weeks of regrowth to 5% after 13–14 weeks. About three‐quarters of the increase in DM yield of total herbage from week 3 to week 11 was attributable to increased yield of ‘stem’. The level of applied N had little effect on the proportion of crop fractions except during the period immediately before and after the begiiming of ear emergence when the higher rates of N increased the proportion of ‘stem’ and reduced that of green leaf. The most digestible crop fractions were green leaf, inflorescence and immature ‘stem’. D‐value of ‘stem’ declined by about 20 units from week 1 to week 14, while D‐value of green and dead leaf declined at about half this rate and there was little or no decline in D‐value of inflorescence. The N content of green leaf was consistently higher than that of the other fractions. The N content of ‘stem’declined markedly to around 0.5% by week 12. The N content of dead leaf and inflorescence was intermediate between that of green leaf and mature ‘stem’. The N content of all fractions was increased by applying more N. The tiller population increased during the flrst 3 weeks of regrowth and declined during the next 4. Applying more N increased both till

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01121.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractFeed consumption (I). of a group of eight non‐lactating Jersey cows strip‐grazing oats at three stages of growth was estimated from number of eating bites (N) and bite size (5) measurements using the expression,I= N × S. N was measured with four non‐fistulated animals whileSwas determined independently with four oesophageal fistulated animals. These estimates were compared with herhage consumption estimates using a cutting technique (fourteen samples of both herbage offered and refused).Eating behaviour estimates of intake based onNandSwere 29% higher than cutting estimates due to fistulated animals having a high number of mastication bites with the head up during sampling and a large diurnal variation in bite size. After allowing for these sources of error eating behaviour estimates were only 2% higher than cutting estimates.Sampling variability was similar for both cutting and eating behaviour techniques; on an individual plot basis the percentage coefficients of variation were 11.2 and 10.1 for cutting and eating behaviour techniques, respectively. Methods of reducing sample variability are discussed and tables of numbers of animals required to detect true differences in intake at various levels of precision are presented.It is concluded that herbage consumption by grazing ariimals can be obtained from measurements of eating beh

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01122.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe spatial distribution of excreta from intensive cattle grazing was recorded and was described by a negative binomial function. This enabled the proportion of a pasture surface affected by excreta to be calculated for various grazing periods. Where the effect of excreta on the sward was short‐lived, as for urine N, or where the total area covered by excreta remained small, as for dung, then little overlapping of effective excreta patches could be expected. Appreciable overlapping of effective patches could, however, occur for the long‐lived urine K effect and this should be taken into account when estimating the proportion of a pasture surface affec

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1976.tb01123.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY