Cysteamine hydrochloride increases bodyweight and wool fibre length, improves feed conversion ratio and reduces methane yield in sheep

Abstract

Developing processes which reduce enteric methane production without compromising animal productivity has become critical for sustainable livestock production. It was hypothesised that administrating cysteamine hydrochloride (CSH) to sheep would decrease methane yield (MY) and plasma concentration of somatostatin (SRIF) while increasing bodyweight gain (BWG) and daily wool growth. In the first experiment, 30 Merino × Dorset lambs were randomly divided into three groups receiving different dosages of CSH; 0 mg/kg BW, 80 mg/kg BW daily, or 80 mg/kg BW every third day; for a period of 35 days. The effect on BWG, feed conversion ratio (FCR), daily wool growth, voluntary feed intake (VFI), and MY (g CH4/kg DM intake) were studied. Treatment with CSH daily increased BWG (P < 0.05) and daily wool growth (P < 0.05), improved FCR (P ≤ 0.01), and reduced MY (P < 0.01). Administering CSH every 3 days increased BWG (P < 0.05) and reduced MY (P < 0.01). There was no CSH effect on VFI. In the second experiment, CSH equivalent to 80 mg/kg BW was administered once to eight Merino × Dorset lambs. Blood samples were collected at -24, -16, 0, 2, 8, 24, and 48 h of administration. Plasma concentrations of SRIF were significantly reduced (P < 0.01) within 2 h of CSH ingestion and remained at reduced levels 48 h after administration. These results show that CSH rapidly reduces plasma SRIF concentration, which is likely to leading to an increase in animal production traits while reducing enteric MY. This experiment constitutes a novel and potentially significant investigation into the control of livestock greenhouse gas emissions while increasing livestock productivity.