Administration of low and high doses of heparin causes changes in plasma non-esterified fatty acid concentration in merino and terminal sired lambs

S Stewart1, G Gardner2, P McGilchrist3, D Pethick4

1Instituto de Ciencias Agropecuarias, Universidad Autonoma Del Estado De Hidalgo; 2Facultad de Medicina Vterinaria, Universidad Nacional Autonoma de Mexico; 3Biosimetrics Ltd. SRUC Building; 4Colegio Superior Agropecuario del Estado de Guerrero

The objective of this study was to evaluate the impacts of a low and high dose heparin administration on plasma non-esterified fatty acid (NEFA) response in lambs. The anticoagulant properties of heparin have led to the routine use of heparinised saline flushes to prevent thrombus formation and prolong the patency of indwelling cannulas. However, limited work exists on very low dose heparin used to retain cannula patency for the purpose of repeated blood sampling for metabolic studies. Of particular interest is whether very low dose heparin will cause artificial increases in plasma NEFA concentration. This is most relevant in metabolic studies involving repeated sampling, as this may erroneously elevate the apparent plasma NEFA concentrations. Fourteen Merino (n = 7) and Terminal (n = 7) sired lambs, balanced for sex within sire type were selected from the Katanning, Western Australia site of the Meat and Livestock Australia genetic resource flock. Lambs were subjected to 3 treatments; low heparin (0.25mL, 250IU), high heparin (1mL, 1000IU) or control (1mL of 0.9% NaCl saline), with each challenge randomly allocated over 1.5 days. Blood samples were collected at the following time points; -30, -15, -10, -5, 0, 2.5, 5, 10, 15, 20, 30, 45, 60, 90, 120, 125 and 130 minutes relative to the administration of the challenge (time 0) and tested for NEFA concentration. A derived exponential function was fitted to the raw data, enabling the plasma NEFA concentration response curve to be modelled at different time points, pre and post challenge to quantify the NEFA response. Results indicated that heparin as an anticoagulant should be avoided where frequent blood samples are required within intervals less than 1 hour. However, for repeated sampling at intervals greater than 1 hour, judicious flushing with heparinised saline is unlikely to have an impact on plasma NEFA levels.


Sarah, a former cattle Veterinarian, completed her PhD investigating the “influence of pre-slaughter stress on lamb meat quality and carcass yield”. Currently, Sarah leads the eating quality program within the Advanced Livestock Measurement Technologies project at Murdoch University, where she is investigating objective technologies to measure eating quality in beef, lamb and pork.

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