Hypodermic needle

Shortly after birth calves underwent a complete clinical examination to confirm the suitability for inclusion in this study, and were weighed on an electronic scale. Inclusion criteria were clinical health at birth as determined by one investigator (T.S.) and female gender of the calf. Gender selection was necessary because bull calves routinely left the research farm at two weeks of age. To be able to identify a possible gender effect on any of the studied parameters a small number of male calves were also selected for inclusion. As gender specific differences have not been reported for any of the key parameters of this study, data on which to base a power analysis were not available. A number of 5 male calves to be included in this study was arbitrarily determined based on availability and practicability on the experimental farm.
Blood samples were obtained once a week at a standardized weekday and time of the day. Blood sampling was always preceded by a physical examination. Blood was obtained by venipuncture of a jugular vein with a hypodermic needle (18 G; Henry Schein Inc., Melville, NY, USA), and collected in lithium heparin- and K₃-EDTA tubes (10 mL Li Heparin and 4 mL EDTA K; Sarstedt AG & Co. KG, Nürnbrecht, Germany).

In all cows, IVRA was administered in the right distal hind limb using the common dorsal digital vein for aseptic intravenous administration of local anaesthetics [9 (link), 18 , 20 , 26 , 27 ]. The injection site was washed, shaved, and degreased with medical alcohol and disinfected with iodine. A trained surgeon (N.K.) placed a rubber tourniquet (Esmarchbinde, 6 cm width, 1.1 mm thickness, Wirtschaftsgenossenschaft deutscher Tierärzte, Garbsen, Germany) circumferentially in the middle of the metatarsus and punctured the vein distally from the tourniquet with a hypodermic needle (1.0 × 40 mm, Henry Schein, Gillingham, UK). Under gentle flexion of the fetlock joint, blood was drained through the needle until the pressure dropped as indicated by slow dripping rather than blood running out of the hub. Twenty millilitres of procaine hydrochloride 2% (Procasel 2%, Selectavet, Weyarn-Holzolling, Germany) were injected slowly. The injection site was compressed with an iodine soaked cotton swab for 30 s after removing the needle to avoid unintended drainage of the local anaesthetic from the punctured vein or formation of a haematoma.

For the slightly modified technique of hindfoot four-point nerve block anaesthesia according to Raker [28 (link)] in the right hind limb injection sites were surgically prepared as described above. Procaine (Procasel 2%, Selectavet) was injected perineurally (hypodermic needle, 0.8*40 mm, Henry Schein) next to the medial and the lateral plantar nerves (each 10–15 ml), both continuations of the tibial nerve (at approximately the middle of the metatarsus, between the suspensory ligament (interosseous m.) and the flexor tendons on the medial and lateral aspect of the limb). Anaesthesia of the superficial and deep fibular (peroneal) nerves was little more proximal than described by Raker [28 (link)]. Perineural injections of about 15 ml procaine anaesthetized the superficial fibular nerve (subcutaneously, latero-dorsally, 2 cm proximally to the tarsocrural joint) and of about 10 ml the deep fibular nerve (dorso-medially in the proximal third of the metatarsus, between the tendons of the long digital extensor and the metatarsal bone, in the longitudinal sulcus of the metatarsus).