Grazing system and floor type effects on blood biochemistry, growth and carcass characteristics of Nguni goats

OBJECTIVE Purpose was to determine the effects of grazing system and floor type on concentrations of blood metabolites, activity of creatine kinase, body weight and carcass characteristics of castrated Nguni goats. METHODS Forty eight, 7 month old goats were randomly allocated to herding and tethering treatments from 0800 to 1300 hours and accommodated on slatted and earth floors daily. Blood samples were collected by jugular venipuncture every fifteenth day for metabolite analysis. Slaughter was done at a commercial abattoir following 5 months of monitoring. RESULTS Tethered goats had significantly higher concentrations of urea (5.19 mmol/L) (p< 0.001), creatinine (55.87 μmol/L) (p<0.05), total protein (64.60 g/L) (p<0.01), and globulin (49.79 g/L) (p<0.001), whereas herded goats had higher glucose (3.38 mmol/L) (p<0.001), albumin (15.33 g/L) (p<0.05), albumin/globulin ratio (0.34) (p<0.01), and body weight (24.87 kg) (p< 0.001). Slatted floors caused higher (p<0.01) albumin at 15.37 g/L. The interaction of grazing system and floor type affected creatinine, total protein, globulin at (p<0.01) and albumen/globulin ratio at (p<0.01). The least creatinine concentration and albumin/globulin ratio was in herded and tethered goats that were accommodated on earth floors, respectively. The highest total protein and globulin concentrations were in serum of tethered goats that were accommodated on earth floors. The highest (p<0.05) dressing percentage (45.26%) was in herded goats accommodated on slatted floors. CONCLUSION Herding of goats lowered globulin concentration, improved estimated feed intake, blood glucose and albumin concentrations, albumin globulin ratio, increased body weights and weight related carcass characteristics. Floor type had very little effects on metabolites where earth floors only reduced albumin concentration. Tethering and housing goats on earth floors resulted in double stress that increased chronic infections.