Urea supplementation effects on the utilization of low‐quality forage and lamb production in patagonian rangelands

Abstract

The effect of feeding a urea-based supplement for the last 8 weeks of pregnancy was examined on ewes grazing the grass-shrub steppes of NW Patagonia, Argentina. The productivity of ewes and lambs and the utilization rate of the major, less preferred, grass species (Stipa speciosa, 27% cover) was analysed. In a paddockscale experiment, ewes grazed two areas of 450-500 ha from 15 August to 15 February at a stocking rate of 0·5 ewes ha Ϫ1 . From 15 August to 10 October, one group of ewes was given access to a urea-based supplement containing 300 g kg Ϫ1 urea, 320 g kg Ϫ1 salt, 30 g kg Ϫ1 molasses and 300 g kg Ϫ1 bone meal. Average supplement consumption was 3·5 g ewe Ϫ1 d Ϫ1 . The performance of 100 ewes in each of the two areas was evaluated. Supplemented ewes gained 4·2 kg more live weight than the control ewes between 15 August and 10 October (prepartum) (liveweight gain was 10·3 vs. 6·1 kg ewe Ϫ1 , P < 0·05). The number of live lambs at 8 weeks of age, as a proportion of ewes mated, was 15% higher in the supplemented than in the control group (0·634 vs. 0·553, P < 0·05). A similar increase in the live weight of lambs at 8 weeks of age in the supplemented group compared with the controls was also observed (12·1 vs. 10·6 kg, P < 0·05). In the paddock with the supplemented ewes, there was a significant increase in the proportion of Stipa speciosa plants defoliated (0·62 vs. 0·38, P < 0·05) and in the intensity of defoliation of these plants. It was concluded that urea-based supplements increased productivity of ewes and that this was likely to be associated with an increase in the intake, and possibly digestibility, of the less preferred species such as Stipa speciosa.

Effect of concentrate and urea molasses mineral block (UMMB) supplementation on the growth and feed consumption of Mecheri lambs under intensive rearing

“…Urea molasses products/ UMMB has been suggested a versatile supplement for sheep and goat by many earlier researchers (Golluscio et al, 1998;Currier et al, 2004). Since there was no significant difference in the body weights between concentrate supplemented (T 1 ) and UMMB supplemented (T 2 ) groups at the end of the experiment, it can be inferred that UMMB could be successfully used to replace the concentrate feed for sheep.…”

Effects of Grazing Intensity and Environmental Factors on Species Composition and Diversity in Typical Steppe of Inner Mongolia, China

“…In contrast, S. grandis is characterized by a relatively low nutritive forage value owing to high concentrations of fibre and lignin and thus has low digestibility [39]. Therefore, S. grandis is less-preferentially grazed by sheep compared with L. chinensis [42], [43]. However, it should be taken into account that current-year species sampling was done in July inside exclosures, and therefore any grazing-related effects on species would have been determined by the previous year’s grazing, rather than grazing in the current year.…”

Long-term dynamics of a semiarid grass steppe under stochastic climate and different grazing regimes: A simulation analysis

“…Basal perimeter (cm) Height of the vegetative portion (excluding panicles) (cm) Proportion of standing dead biomass in the tussock (dfrac) Defoliation (0, no defoliated; 1, slightly defoliated; 2, intermediately defoliated; and 3, intensely defoliated) (see Golluscio et al, 1998b) ''Vitality'' (0, a dead tussock; 1, low; 2, medium; 3, high vitality; and 4, very high vitality). Such categorical variable represents a qualitative assessment of the potential productivity of the tussock.…”