H.H. Meissner

Utilization of Lolium multiflorum by sheep 1. Influence of dry matter content and correlated factors on voluntary intake

The intake by young sheep of Lolium multiflorum cv. Midmar (ryegrass) with dry matter (DM) contents of between 10.2% and 20.5% was studied. Intake was measured on pasture, while at the same time herbage was cut and fed either fresh or dry indoors. Additional variables were sward height at pasture and chop length indoors. Quality parameters did not change much between DM contents studied. Intake of wet herbage remained fairly constant irrespective of DM content, suggesting that moisture levels exert a controlling influence on intake. Organic matter (OM) intake increased dramatically with DM content, from 47.4 to 87.4 g kg−1 W0.75 day−1. Sward height did not influence OM intake significantly, but chop length of cut herbage did. At low DM content the long chop length depressed intake, possibly because of increased chewing and rumination times, while no effect was observed at higher DM contents. It was concluded that if the intake of Midmar ryegrass is to be maximized the DM content of pasture should be at le...

Voluntary intake of several planted pastures by sheep and an assessment of NDF and IVDOM as possible predictors of intake

The aim was to study the quality and quantity of pasture selected by sheep on various planted pastures. A further aim was to assess NDF and IVDOM as easy measurable parameters for use in equations to predict intake. Pasture samples were collected using oesophageal‐fistulated sheep and from knowledge of the in vitro digestibility of these samples and the total faeces voided as measured with faeces bags, intake was calculated. Pastures observed included ryegrass, cocksfoot, C. dactylon, Smuts finger, triticale, E. curvula, Eragrostislucerne combination, lucerne and sainfoin. Nitrogen content of oesophageal samples varied between 2,3 and 5,1%, NDF between 33 and 65% and IVDOM between 50 and 80%. Intake of grass DOM varied from 24,4 to 43,3 g/kg W0,75/day for lambs and from 29,0 to 37,4 g/kg W0,75/day for mature wethers. DOM intake on the two legumes was generally poor and varied between 13,7 and 22,9 g/kg W0,75/day. Although some of the variation in voluntary intake is accounted for by the variation in NDF a...

Utilization of Lolium multiflorum by sheep 2. The effect of drying the herbage on soluble nitrogen content and partial digestion

The amount of soluble N and the effective degradation of fresh and dry herbage of Lolium multiflorum cv. Midmar (ryegrass) was determined by the nylon bag technique. In another experiment the digestion and disappearance of organic matter (OM) and nitrogen (N) were measured on fresh and dry ryegrass herbage fed to sheep either ad lib or at ad lib‐20%. The amount of soluble N was reduced by drying at 60°C but the effective degradation remained unaltered. The disappearance of OM and N components in the digestive tract was not significantly influenced by treatment but the effect of level of intake was significant. There was, however, no significant treatment × feeding level interaction. The soluble N content of ryegrass did not affect non‐ammonia N absorption in the small intestine significantly. It was concluded that amino acid absorption from the small intestine will not be limiting at dry matter contents of Midmar ryegrass of 18–20%.

the utilization by sheep of winter and spring Smuts finger and Kikuyu pastures

Abstract An experiment was conducted on Smuts finger (Digitaria eriantha ssp. eriantha) and Kikuyu (Pennisetum clandestinum) pastures during a winter and spring period to study the effect of postruminal energy and/or protein supplementation on the selection pattern and performance of sheep. In a further experiment the digestion and utilization of these pastures were quantified. Voluntary intake on both pastures was not significantly affected by postruminal addition of casein but glucose tended to depress intake. In vitro digestibility of organic matter (IVDOM) and crude protein content of oesophageal samples were not significantly influenced by either casein or glucose. Consequently, it was concluded that postruminal amino acid and energy supply do not alter the quality of pasture selection but, depending on circumstances, the amount eaten may be affected. The amount of non‐ammonia nitrogen (NAN) in winter and spring samples flowing through the abomasum was proportional to the nitrogen (N) content in the ...

Nutrient composition and in vitro methane production of sub-tropical grass species in transitional rangeland of South Africa

The development of greenhouse gas mitigation strategies has become an important issue globally. Enteric methane (CH4) emissions from livestock do not only contribute substantially to the environmental footprint of livestock production but it also represents a loss of energy that could be channelled towards animal growth and production. In this study 14 sub-tropical grass species typical of transitional rangeland regions of South Africa were characterised in terms of ecological status, chemical composition, in vitro total gas and CH4 production. The aim of the study was 2-fold: to identify grass species that could be selected for low enteric CH4 production; evaluate the influence of rangeland ecological status on the methanogenic potential of a rangeland. Grass samples were collected by hand, air-dried, milled and analysed for nutrient composition, in vitro organic matter digestibility (IVOMD) and in vitro gas and CH4 production. Cenchrus ciliaris and Urelytrum agropyriodes produced the highest 48-h in vitro CH4 of 17.49 and 14.05 mL/g DM digested respectively. The lowest 48-h in vitro CH4 was produced by Andropogan gayanus and Bothriochloa bladhii with 5.98 and 6.08 mL/g DM digested respectively. The evaluated grass species were overall of poor quality with low CP concentrations ranging from 2.4% for Trachypogon spicatus to 6.7% for Digitaria eriantha and IVOMD ranging from 22.5% for Andropogon gayanus to 42.2% for Urelytrum agropyriodes. Decreaser grass species presented with higher in vitro CH4 production compared with Increaser I and Increaser II grass species in the present study. The results of the study emphasise the importance of including the nutritional potential of grass species for improved livestock production when evaluating grass species for possible greenhouse gas mitigation strategies.