Epidural administration of fixed volumes of xylazine and lidocaine for anesthesia of dairy cattle undergoing flank surgery

Dose-dependent effect of romifidine on intraocular pressure in clinically healthy buffalo (Bubalus bubalis)

In the present study, changes in intraocular pressure (IOP) associated with romifidine sedation in buffalo were evaluated. Eighteen healthy adult, non-pregnant, buffalo without ocular abnormalities were used in a prospective randomized trial. Buffalo were allocated into three groups (six each). Buffalo in the treated groups received an intramuscular injection (IM) of romifidine at 40 or 50 μg/kg. The control group was administrated an equivalent volume of sterile saline (0.9% NaCl; 0.4 ml/100 kg). Baseline IOP (T0) values were obtained using applanation tonometry. Immediately afterwards, romifidine was administered and IOP values of both eyes were measured at 5, 15, 30, 45, 60, 90, 120, and 180 min post-administration. The pre-administration values (T0) of IOP for both the left and right eyes ranged from 30-36 (mean, 33 ± 1.5) mmHg and 30–35 (mean, 33.7 ± 1.4), respectively. IOP values decreased significantly after administration of both doses of romifidine compared with the placebo (P < 0.01). Compared with the control, the IOP decreased significantly in animals treated with both doses from 5-90 min post-administration in both eyes (P < 0.05). In the right eye, the lowest IOP value in the romifidine treated groups was observed at T30 (21.6 ± 1.0 and 23.3 ± 1.4 mmHg), respectively. In the left eye, the lowest IOP was observed at T60 (22.5 ± 3.0 and 23.3 ± 2.8 mmHg), respectively. In conclusion, romifidine could be recommended as an alternative analgesic in buffalo, especially for ocular affections associated with increased IOP. A dose of 40 μg/kg could be used at a low cost.

Efficacy of xylazine in neonatal calves via different routes of administration

Intramuscular (IM) injections may be more aversive than subcutaneous (SC) and intra-nasal (IN) routes. Xylazine is commonly used as a sedative for cattle, but little is known about efficacy via these routes. The first aim of this study was to compare efficacy using these different routes of administration. The second aim was to determine whether a simple behavioural assessment was associated with physiological responses. Using a within-subject design, the effects of xylazine (0.2mg/kg) were assessed in 12 Holstein calves (6.2±2.8days old) administered via IM, SC, IN drip tube (IN) and IN spray (INs). Sedation was assessed on a scale based on recumbency and eyeball rotation. Heart rate (HR), respiratory rate (RR) and rectal temperature (RT) were recorded for 2h after treatment. Intramuscular and SC routes produced an equivalent mean±standard deviation (SD) onset of sedation (IM: 4.8±2.0min vs. SC: 6.8±2.2min) and duration of sedation (IM: 60.3±25.5min vs. SC: 61.9±23.3min). IN treatments produced less consistent and longer onset times (IN: 33.0±26.9min, and INs: 31.0±15.1min) and a shorter duration of sedation (IN: 42.0±31.5min, and INs: 26.7±21.8min). Behaviour scores were moderately correlated with changes in HR (r=-0.52; CI -0.60, -0.43) and changes in RR (r=-0.42; CI -0.51, -0.32), but not with changes in RT (r=-0.09, CI -0.20, 0.02). We conclude that SC is a viable alternative to the more aversive IM route, and that a simple clinical scale can be useful for assessing xylazine sedation.

Comparative antinociceptive and sedative effects of epidural romifidine and detomidine in buffalo (Bubalus bubalis)

In this study, comparative antinociceptive and sedative effects of epidural administration of romifidine and detomidine in buffalo were evaluated. Eighteen healthy adult buffalo, allocated randomly in three groups (two experimental and one control; n=6) received either 50 μg/kg of romifidine or detomidine diluted in sterile saline (0.9 per cent) to a final volume of 20 ml, or an equivalent volume of sterile saline epidurally. Antinociception, sedation and ataxia parameters were recorded immediately after drug administration. Epidural romifidine and detomidine produced mild to deep sedation and complete antinociception of the perineum, inguinal area and flank, and extended distally to the coronary band of the hindlimbs and cranially to the chest area. Times to onset of antinociception and sedation were significantly shorter with romifidine than with detomidine. The antinociceptive and sedative effects were significantly longer with romifidine than with detomidine. Romifidine or detomidine could be used to provide a reliable, long-lasting and cost-effective method for achieving epidural anaesthesia for standing surgical procedures in buffalo. Romifidine induces a longer antinociceptive effect and a more rapid onset than detomidine. Consequently, epidural romifidine may offer better therapeutic benefits in the management of acute postoperative pain.

Dose-dependent antinociceptive and sedative effects of epidural romifidine in cattle

The objective of this study was to evaluate the antinociceptive and sedative effects of epidural administration of romifidine in dairy cattle. Twenty-four dairy cows, divided randomly into four groups (three experimental and one control; n=6) received one of three doses of romifidine (30, 40 or 50 μg/kg) diluted in sterile saline (0.9 per cent) to a final volume of 25 ml or an equivalent volume of sterile saline. Antinociception and its anatomical extent was assessed by applying a standard stimulus (needle pin pricks) in different areas and by applying an electrical stimulus to the flank. The antinociceptive effect of romifidine was produced not only in the tail, anus, perineum, vulva and inguinal area but extended up to the coronary band of the hindlimbs and chest areas. Epidural romifidine induced mild-to-moderate sedation at 30 and 40 μg/kg doses and deep sedation at the 50 μg/kg dose. The antinociceptive and sedative effect was dose-dependent in terms of intensity and duration. Thus, epidural administration of romifidine was effective in providing antinociception and sedation in cattle, and can be used in standing flank and udder surgery in cattle.

Measurement of the puncture profile and extradural pressure of cattle during extradural anaesthesia

OBJECTIVE

To measure the pressure profile during caudal extradural puncture and subsequent extradural anaesthesia in cattle and to investigate the presence of extradural pressure waves.

STUDY DESIGN

Prospective experimental study.

ANIMALS

Eleven cattle aged 4.1 +/- 2.5 years (range 0.8 to 8.8 years), with a body weight of 613 +/- 162 kg (range 302-840 kg).

METHODS

Caudal extradural puncture was performed. To measure the extradural pressure profile, the needle was connected to an electronic pressure transducer placed at the height of the base of the tail. The pressure profile was recorded for 3 minutes following extradural puncture. Lack of resistance to injection of saline was assessed. One minute and 10 minutes after extradural anaesthesia with procaine extradural pressure was recorded. Correct extradural needle placement was assessed by clinical response.

RESULTS

Three minutes after extradural puncture the median pressure was -16 (range -25 to 25) mmHg. Pressure in the extradural space 1 minute after the lack of resistance, 3 seconds after injection, and 10 minutes after injection was -15 (-24 to 33) mmHg, 8 (-17 to 84) mmHg, and -7 (-25 to 27) mmHg respectively. Pressure waves were visible after puncture, after lack of resistance, 3 seconds and 10 minutes after injection, in 4, 6, 8 and 7 cattle respectively. Pressure after testing lack of resistance, after the injection of local anaesthetic, as well as at the end of the measurement, period was significantly higher than baseline. All cattle showed clinical signs indicative of successful extradural needle placement.

CONCLUSION AND CLINICAL RELEVANCE

Extradural pressure was sub-atmospheric in 82% of the animals. Pressure waves were not consistently present before or after extradural injection, which limits their usefulness to confirm correct extradural needle placement. Extradural pressures increase significantly after injection of local anaesthetic solution. However, the clinical significance of the increase in extradural pressures was not clear.

Successful introduction of modified dorsolumbar epidural anesthesia in a bovine referral center

This study describes the successful use of modified dorsolumbar epidural anesthesia with a fixed volume of anesthetic in a bovine referral center. Among the 130 Holstein cattle scheduled for flank surgery, 90 cattle received a mixed anesthetic consisting of 1 ml of xylazine hydrochloride and 3 ml of lidocaine hydrochloride by modified dorsolumbar epidural anesthesia. Eighteen cattle with dehydration and/or lameness received a mixed anesthetic containing 0.5 ml of xylazine and 3 ml of lidocaine. Infiltration anesthesia was performed in 22 cattle whose epidural space could not be reached in order to perform the flank surgery. The surgeries began about 12 min after the administration of the anesthetic and lasted for about 36 min. The modified method using a fixed volume of anesthetic was successfully introduced and effectively used in a bovine referral center. This modified method will allow veterinarians to save time and effort, thus lowering the cost of each surgery.