Effects of fossil shell flour supplementation on heat tolerance of dohne merino rams

Abstract

This study evaluated the effects of fossil shell flour (FSF) supplementation on heat tolerance of Dohne Merino sheep. Twenty-four (n = 24) Dohne Merino rams of about 4 months old, weighing 22.3 ± 0.43 kg were confined in individual pens using complete randomized design for a period of 100 days. The rams were subjected to four varying inclusion levels of fossil shell flour (0 g/kg, 20 g/kg, 40 g/kg and 60 g/kg. Water and feed intake were recorded throughout the period of successive feeding. On days 0, 45 and 90, blood samples were collected for analyses. The parameters monitored included the average daily water intake (ADWI), average feed intake (ADFI), skin temperature (ST), respiration rate (RR), pulse rate (PR), rectal temperature (RT), total plasma protein (TPP), blood glucose (GLU), red blood cell (RBC),white blood cell (WBC), Heamaglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), Packed cell volume (PCV), and mean corpuscular volume (MCV). The inclusion levels of FSF affected ADWI and ADFI, revealing high water intake and feed intake in rams subjected to 40 g/kg of FSF followed by 60 g FSF/kg, 20 g FSF/kg and 0 g FSF/kg (P< 0.01) respectively. All the physiological parameters (ST, RT, RR and PR) decreased with increase in inclusion levels of FSF (P< 0.01). The TPP and GLU increased as the levels of FSF increases (P< 0.01). The RBC and WBC were higher in rams subjected to FSF supplemented diets compared to the control (p<0.05). We conclude that water and feed intake increase with increasing levels of the FSF while the physiological parameters decline as levels of FSF increases. Hence, fossil shell flour could be used as a supplement in Dohne-Merino rams’ diet to mitigate heat stress and promote overall productivity of the sheep.