In situ dry matter, protein and neutral detergent fibre degradation kinetics of Cholistan Desert grasses

Global climate change is evident and poses serious threats to the sustainability of traditional rangeland livestock production systems. This study tested the feeding potential of perennial grasses of Cholistan Desert for various species of ruminants at different physiological stages. Eight common and nutritionally important grass species (Cenchrus ciliaris, Stipagrostis plumose, Panicum antidotale, Cymbopogon jwarancusa, Cenchrus pennisitiformis, Lasiurus scindicus, Ochthochloa compressa and Vetiveria zizanioides) were investigated for in situ degradation parameters according to Nordic feed evaluation system (NorFor) standards. The collected, dried and milled grass samples were incubated for 0, 4, 8, 16, 24, and 48 hours to determine dry matter and crude protein biodegradation and additionally for 96 and 168 hours for neutral detergent fibre degradation in the rumens of lactating Nili-Ravi buffalo and Cholistan Desert cows and heifers (two from each species and from each physiological stage). All of these grass species influenced the dry matter, crude protein and neutral detergent fibre degradation fractions significantly. The overall effective degradability of dry matter for asymptotic extent of degradation did not differ. However, the potentially degradable but insoluble fraction and rate of degradation were influenced significantly by the species of the animals. All the proximate parametric characteristics of perennial desert grasses were within the nutrient range for typical ruminant diets except for crude protein. It was concluded that rumen availability of grasses was highly influenced by grass species. However, these grasses are equally nutritionally important for various species of ruminants for example buffalo versus cattle at different physiological stages and heifers versus lactating animals.Keywords: buffalo, Cenchrus ciliaris, desert cows, desert forage, feeding value

Effect of Diet Quality and Housing on Water Status in Sudanese Desert Sheep and Goats

Two independent experiments were carried out using Sudanese Desert sheep and goats to investigate water metabolism (total body water, TBW and water turnover, WTO) and internal water compartments using radioactive water (tritium), under natural grazing conditions in a semi-desert area. The second trial was carried out on confined sheep, fed high (Lucerne) and poor quality (desert grasses) diets. The body weights, rectal temperature and water parameters were monitored in both trials and species under the Sudanese summer conditions. The grazing animal’s body weights were reduced compared to confined ones. Hyperthermia was pronounced in goats (9%) compared to sheep (6%). The goat hyperthermia was associated with high water turnover, indicating the poor heat tolerance of this species of high evaporative cooling. The confined animals, however, maintained their body weights and did not show signs of hyperthermia. The poor diet (desert grasses) was associated with reduced water intake whereas the Lucerne was associated with high water turnover and high feed intake. The extracelluar compartment (ECV) was higher with the poor diet but was lower than the grazing group. The intracellular compartment (ICV) was higher in the Lucerne group. The study indicated that Sudanese Desert sheep are more tolerant to high temperatures and grazing system than goats.