17. Correlation Among Blood Parameters, GI Nematode EPG, and Cortisol in Pasture-raised Goats and Hair Sheep.

Abstract

Various blood parameters, prevalence of gastrointestinal nematode (GIN) parasites, and stress hormone are usually assessed separately to monitor the health status and wellbeing of pasture-raised goats and sheep. However, the interrelationship of these parameters is generally left out of scrutiny, which may be helpful to better understand and come up with effective approach for promoting animal welfare, health, and productivity. The objective of this study was to determine the correlation among various blood parameters, GIN prevalence, and stress in pasture-raised goats and hair sheep. Kiko does (20; live wt. 47 ± SE 3.2 kg) and Katahdin-St. Croix ewes (16; live wt. 43 ± SE 2.2 kg) were rotationally stocked in summer pastures for 70 days. Blood samples were collected on the very first day, in the middle, and on the last day of the study and analyzed for 15 blood parameters. Concomitantly, fecal samples were collected and analyzed for GIN parasite eggs per gram of animal feces (EPG) for determining GIN parasite prevalence. Hair samples were collected on the same days when other samples were collected and analyzed for hair cortisol to determine animal stress. Data were analyzed for Pearson Correlation Coefficients (r) (ɑ= 0.05) in SAS 9.4. In does, concentration of red blood cells (RBC) was found positively correlated with hemoglobin (HGB) (r = 0.90), mean corpuscular hemoglobin concentration (MCH) (r = 0.26), lymphocyte (r = 0.52), monocyte (r = 0.44), platelets (MPV) (r = 0.29), and hematocrit (r = 0.46) (P < 0.05). However, RBC concentration was negatively correlated with mean corpuscular volume (MCV) (r=-0.51), mean corpuscular hemoglobin (MCH) (r=-0.57), neutrophil (r=-0.47), hair cortisol (r=-0.39), and EPG (r=-0.37) (P < 0.01). In ewes, RBC concentration was found positively correlated with hematocrit (r = 0.64) and hemoglobin (r = 0.83) (P < 0.0001) and negatively correlated with MCH (r=-0.54) and mean corpuscular hemoglobin concentration (MCHC) (r=-0.40) (P < 0.01). Hair cortisol and lymphocyte concentration were negatively correlated (r=-0.36) (P < 0.05). EPG showed positive correlation with basophil (r = 0.37) (P < 0.05) and negative correlation with reticulocyte (r=-0.30) (P < 0.05). Results show that selected blood parameters, GIN EPG, and animal stress hormone – cortisol - are correlated with one another, and the correlation pattern and extent among these parameters occur differently in meat goats and hair sheep.