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The objective of the study was to investigate the effect of feeding fibrous diets on growth performance and occurrence of aggressive behaviours in growing pigs. Sixty healthy castrated pigs (initial body weight: 46.7±4.35 kg) were used. A basal diet was diluted with maize cobs to two levels (0 and 160 g/kg dry matter). Behavioural activities were observed using video cameras for three weeks, 8 h/d starting at 0800 h. Pigs subjected to control diet gained more weight compared to pigs receiving fibrous diet in week 1 (0.47 vs 0.15 kg, respectively) and 2 (1.37 vs 1.04, respectively) (p<0.05). Average daily gain was not affected by treatment diet in the third week. Pigs on high fibrous spent more time eating, lying down, standing, walking and fighting (p<0.05) compared to pigs on control diet. Time spent eating increased as the weeks progressed whilst time spent lying down decreased. Time of day had an effect on time spent on different behavioural activities exhibited by all pigs on different treatment diet (p<0.05). Inactivity was greatest in 5th (1200 to 1300 h) hour of the day for all the pigs on different dietary treatments. Skin lesions appeared the most on neck and shoulder region followed by chest, stomach and hind leg region, and finally head region (p<0.05). Pigs on high fibre diet had more skin lesions in all body regions compared to pigs on control diet (p<0.05). It can be concluded that the high fibrous diet with maize cobs did not affect growth performance and also did not reduce aggressive behaviours. Aggressive behaviours emanated out of frustration when queuing on the feeder. The findings of this study suggest that maize cobs can be included at a level of 160 g/kg in diets of pigs. However, to reduce the level of aggression more feeding space should be provided.

The objective of the review was to assess the potential of indigenous browse trees as sustainable feed supplement in the form of silage for captive wild ungulates. Several attempts to use silage as feed in zoos in temperate regions have been conducted with success. Information on silage from the indigenous browse trees preferred by wild ungulates in southern Africa is scanty. The use of silage from the browse trees is of interest as it has potential to reduce or replace expensive feed sources (pellets, fruits and farm produce) currently offered in southern African zoos, game farms and reserves, especially during the cold-dry season. Considerable leaf biomass from the indigenous browse trees can be produced for silage making. High nutrient content and minerals from indigenous browsable trees are highly recognised. Indigenous browse trees have low water-soluble carbohydrates (WSC) that render them undesirable for fermentation. Techniques such as wilting browse leaves, mixing cereal crops with browse leaves, and use of additives such as urea and enzymes have been studied extensively to increase WSC of silage from the indigenous browse trees. Anti-nutritional factors from the indigenous browse preferred by the wild ungulates have also been studied extensively. Indigenous browse silages are a potential feed resource for the captive wild ungulates. If the browse trees are used to make silage, they are likely to improve performance of wild ungulates in captivity, especially during the cold-dry season when browse is scarce. Research is needed to assess the feasibility of sustainable production and the effective use of silage from indigenous browse trees in southern Africa. Improving intake and nutrient utilisation and reducing the concentrations of anti-nutritional compounds in silage from the indigenous browse trees of southern Africa should be the focus for animal nutrition research that need further investigation.

Growth performance and carcass characteristics of South African mutton merino fed graded levels of macadamia oil cake were assessed. A total of 60 South African mutton merino lambs were used in the experiment (initial live weight 25.0 ± 0.45 kg). Five diets with different inclusion levels of macadamia oil cake (MOC) were formulated: T1 (0% MOC, control), T2 (5% MOC), T3 (10% MOC), T4 (15% MOC) and T5 (20% MOC). Effects of inclusion level of MOC on average daily gain (ADG) and average daily feed intake (ADFI) were not significant (P > 0.05). Effects of inclusion levels of MOC on feed conversion ratio (FCR) of sheep were significant (P < 0.05). Highest proportion (71.2%) of sheep in the study had a carcass fat classification of 2, followed by a proportion of 17.3% sheep with a carcass fat classification of 3 and lastly 11.5% sheep had carcass fat classification of 4. Warm and cold carcass mass, chest circumference, carcass length and dressing percentage were higher in sheep fed on 5% MOC compared to other treatment diets (0, 10, 15 and 20% MOC) (P < 0.05). Fat rib eye had a greater area in sheep fed on 5% MOC (P < 0.05). It was concluded that 5% MOC provided the best results in terms of carcass characteristic measurements in sheep.