J.F. Mupangwa

Dry matter intake, apparent digestibility and excretion of purine derivatives in sheep fed tropical legume hay

Four ruminally cannulated wethers (31+/-1.3kg) were used in an experiment with a 4x4 Latin square design to estimate the DM intake, apparent digestibility, nitrogen balance, rumen ammonia and microbial protein production. The sheep had ad libitum access to either Cassia rotundifolia (Cassia), Lablab purpureus (Lablab), Macroptilium atropurpureum (Siratro) or Stylosanthes guianensis (Stylo). Dry matter intake of cassia was lower (P<0.001) than that of lablab, siratro and stylo hays. Organic matter intake was greater (P<0.001) for lablab, siratro and stylo hays than that of cassia. Dry matter digestibility was higher (P<0.05) for lablab hay, than that of cassia, siratro and stylo hays. The organic matter digestibility ranged from 0.579 for cassia hay to 0.617 for stylo hay and there were no differences (P0.05) among the legume hays. Nitrogen intake was highest (P<0.05) in sheep given stylo hay and least in sheep fed cassia hay. Animals given lablab, siratro and stylo hays had higher (P<0.05) faecal and urinary N compared to those on cassia hay. Rumen ammonia N concentration was highest (P<0.05) in sheep given lablab while sheep offered siratro and stylo had intermediate values, and least in animals fed cassia hay. The ammonia levels were above the recommended optimal level of 50mg N/l. The total purine derivative excretion in the urine and microbial N supply was not different (P0.05) among treatments. From the presented findings it is concluded that the intake and digestibility in sheep of the four legume hays are variable and provide adequate rumen ammonia N for maximum rumen microbial growth making then ideal protein supplements to ruminants fed low quality roughages.

Effects of Supplementing a Basal Diet of Chloris gayana Hay with One of Three Protein-rich Legume Hays of Cassia rotundifolia, Lablab purpureus and Macroptilium atropurpureum Forage on Some Nutritional Parameters in Goats

Growth and digestibility experiments were conducted on growing East African type goats offered Chloris gayana hay supplemented with one of three high-protein (119–128 g CP/kg DM) legume hays, Cassia rotundifolia (cassia), Lablab purpureus (lablab) or Macroptilium atropurpureum (siratro), and crushed maize to investigate the feed intake, digestibility, growth and urinary excretion of purine derivatives. Goats in the supplemented groups had higher total dry matter and nitrogen intakes and higher N retention and body mass gains than unsupplemented counterparts. The digestibility of dry matter, organic matter and neutral detergent fibre were increased by protein supplementation. Animals on supplemented diets had higher fractional outflow rates of particulate matter from the rumen. The production of protein by ruminal microbes and the efficiency of microbial N production were increased by supplementation. It was concluded that a mixture of low-quality grass hay (61.9 CP/kg DM) and either cassia, lablab or siratro hay, and maize grain can provide a productive balanced diet for growing goats.

Chemical composition and dry matter degradability profiles of forage legumes Cassia rotundifolia cv. Wynn, Lablab purpureus cv. Highworth and Macroptilium atropurpureum cv. Siratro at 8 weeks of growth (pre-anthesis)

Abstract Three forage legumes were harvested at 8 weeks of growth before flowering (pre-anthesis) and analysed for their chemical constituencies after either sun- (4 days) or over-drying (60°C for 48 h). An experiment was conducted with three rumen fistulated Friesian steers (440 ± 20 kg live mass) to estimate the rumen degradability characteristics of dry matter in the dried forage legumes using the nylon bag technique. The chemical composition of the legumes showed substantial variations. Crude protein (CP) content varied from 225 to 282 g/kg DM while neutral detergent fibre (NDF) ranged from 328 to 425 g/kg DM. The acid detergent fibre (ADF) ranged from 282 to 326 g/kg DM. There were no significant differences in acid detergent lignin (ADL), calcium (Ca) and phosphorus (P) content of the legumes. The drying method had a significant effect on crude protein, neutral detergent fibre, acid detergent fibre and ash content. The degradation constant b varied significantly from 363 to 431 g/kg DM while there were no significant differences in the degradation constants a and c . The potential degradable fraction, a + b , was highest for lablab, 842, followed by cassia, 779, and siratro, 746 g/kg DM. At a passage rate of 2% per hour, the calculated dry matter degradability differed significantly between 669 and 716 g/kg DM. At higher passage rates of 5 and 8% per hour the effective degradability of the forage legumes did not differ significantly. The drying method had no effect on the degradability of dry matter. These results suggest that the three forage legumes at pre-anthesis stage of growth have a high protein content which is highly degradable in the rumen to an extent which may meet the microbial protein requirements for efficient use of low quality roughages. However, their ability to provide nutrients to post-ruminal sites still needs to be assessed.

Holistic Environmental Management in a Communal Grazing Scheme

22 Rangelands About the Grazing Area The Chikukwa communal area is located on the southeastern border of Zimbabwe with Mozambique and on the northern end of the Chimanimani range of mountains. The communal area has approximately 700 households, deriving livelihoods from diverse agricultural activities practiced on deep, mainly clay, soils. The area is found in agro-ecological region 1, receiving between 1,200 mm and 1,500 mm of rainfall per annum. Temperatures are relatively low, ranging from 15°– 25°C. It is one of the prime agricultural zones of Zimbabwe, but under siege from environmental degradation as a result of soil erosion, steep slopes, and inappropriate farming practices. The vegetation is characterized by open grasslands and scattered woodlands of various indigenous and exotic species. The Chikukwa people were allocated Jantia Farm in 2003 by the government as a grazing area for their cattle. This was done to solve grazing problems emanating from a shortage of grazing land. Jantia farm is 1,120 ha in extent, much of which is hilly and broken hills with a number of streams starting from the hills. Over 100 ha are for homesteads and cropping, leaving 881 ha of grazing land. Jantia can hold between 300−400 livestock units (LU). One livestock unit is equivalent to 500 kg live weight. The Chikukwa grazing committee planned 6 paddocks in Jantia farm ranging from 88−194 ha. Each paddock has one or more water points for cattle.

Feature ArticlesHolistic Environmental Management in a Communal Grazing Scheme: From isolation to consolidation

22 Rangelands About the Grazing Area The Chikukwa communal area is located on the southeastern border of Zimbabwe with Mozambique and on the northern end of the Chimanimani range of mountains. The communal area has approximately 700 households, deriving livelihoods from diverse agricultural activities practiced on deep, mainly clay, soils. The area is found in agro-ecological region 1, receiving between 1,200 mm and 1,500 mm of rainfall per annum. Temperatures are relatively low, ranging from 15°– 25°C. It is one of the prime agricultural zones of Zimbabwe, but under siege from environmental degradation as a result of soil erosion, steep slopes, and inappropriate farming practices. The vegetation is characterized by open grasslands and scattered woodlands of various indigenous and exotic species. The Chikukwa people were allocated Jantia Farm in 2003 by the government as a grazing area for their cattle. This was done to solve grazing problems emanating from a shortage of grazing land. Jantia farm is 1,120 ha in extent, much of which is hilly and broken hills with a number of streams starting from the hills. Over 100 ha are for homesteads and cropping, leaving 881 ha of grazing land. Jantia can hold between 300−400 livestock units (LU). One livestock unit is equivalent to 500 kg live weight. The Chikukwa grazing committee planned 6 paddocks in Jantia farm ranging from 88−194 ha. Each paddock has one or more water points for cattle.

Holistic Environmental Management in a Communal Grazing Scheme: From isolation to consolidation

22 Rangelands About the Grazing Area The Chikukwa communal area is located on the southeastern border of Zimbabwe with Mozambique and on the northern end of the Chimanimani range of mountains. The communal area has approximately 700 households, deriving livelihoods from diverse agricultural activities practiced on deep, mainly clay, soils. The area is found in agro-ecological region 1, receiving between 1,200 mm and 1,500 mm of rainfall per annum. Temperatures are relatively low, ranging from 15°– 25°C. It is one of the prime agricultural zones of Zimbabwe, but under siege from environmental degradation as a result of soil erosion, steep slopes, and inappropriate farming practices. The vegetation is characterized by open grasslands and scattered woodlands of various indigenous and exotic species. The Chikukwa people were allocated Jantia Farm in 2003 by the government as a grazing area for their cattle. This was done to solve grazing problems emanating from a shortage of grazing land. Jantia farm is 1,120 ha in extent, much of which is hilly and broken hills with a number of streams starting from the hills. Over 100 ha are for homesteads and cropping, leaving 881 ha of grazing land. Jantia can hold between 300−400 livestock units (LU). One livestock unit is equivalent to 500 kg live weight. The Chikukwa grazing committee planned 6 paddocks in Jantia farm ranging from 88−194 ha. Each paddock has one or more water points for cattle.