G.L. Morgan

Effects of intraovarian infusion of insulin-like growth factor-I on ovarian follicular function in cattle☆

The objective of this study was to determine if increased secretion of intraovarian insulin-like growth factor-I (IGF-I), experimentally induced via minipumps, affects follicular function in cattle. Fourteen cycling Holstein cows were divided equally into two groups: Control, osmotic minipumps (containing vehicle) surgically inserted into each ovary, or IGF-I treated, osmotic minipumps as in Controls but pumping 2.0 microg of recombinant human IGF-I per hr for 7 days. All cows were synchronized with prostaglandin F(2alpha) 0.10) between Control and IGF-I-treated cows during Days 2 to 6 of treatment. IGF-I treatment increased (P<0.05) estradiol concentrations in follicular fluid of small follicles, but had no effect (P<0.10) on estradiol concentrations in follicular fluid of large follicles, or on progesterone, androstenedione, or IGF binding protein concentrations in small or large follicles. We conclude that a 7-day infusion of IGF-I directly into the stroma of the ovary altered follicular growth and follicular fluid estradiol concentrations.

A comparison of two combinations of xylazine–ketamine administered intramuscularly to alpacas and of reversal with tolazoline

OBJECTIVE To evaluate the anesthetic and cardiorespiratory effects of two doses of intramuscular (IM) xylazine/ketamine in alpacas, and to determine if tolazoline would reduce the anesthetic recovery time. STUDY DESIGN Prospective randomized crossover study. ANIMALS Six castrated male alpacas. METHODS Each alpaca received a low dose (LD) (0.8 mg kg(-1) xylazine and 8 mg kg(-1) ketamine IM) and high dose (HD) (1.2 mg kg(-1) xylazine and 12 mg kg(-1) ketamine IM) with a minimum of one week between trials. Time to sedation, duration of lateral recumbency and analgesia, pulse rate, respiratory rate, hemoglobin oxygen saturation, arterial blood pressure, blood-gases, and the electrocardiogram were monitored and recorded during anesthesia. With each treatment three alpacas were randomly selected to receive tolazoline (2 mg kg(-1) IM) after 30 minutes of lateral recumbency. RESULTS Onset of sedation, lateral recumbency and analgesia was rapid with both treatments. The HD was able to provide > or =30 minutes of anesthesia in five of six alpacas. The LD provided > or =30 minutes of anesthesia in three of six alpacas. Respiratory depression and hypoxemia occurred with the HD treatment during the first 10 minutes of lateral recumbency: two animals were severely hypoxemic and received nasal oxygen for 5 minutes. Heart rate decreased, but there were no significant changes in arterial blood pressure. Tolazoline significantly shortened the duration of recumbency with the HD. CONCLUSIONS The HD provided more consistent clinical effects in alpacas than the LD. Intramuscular tolazoline shortened the duration of lateral recumbency in alpacas anesthetized with the HD combination. CLINICAL RELEVANCE Both doses of the combination were effective in providing restraint in alpacas and the duration of restraint was dose dependent. Supplemental oxygen should be available if using the HD and IM administration of tolazoline will shorten the recovery time.

Development of Teaser Bulls Under Field Conditions

A teaser bull is a term describing a bull whose reproductive system has been surgically altered to render him sterile. The purpose of such bulls is to aid in detection of cows in estrus to facilitate when to artificially inseminate. The bull is sterilized by either vasectomy or caudal epididymectomy. In addition to sterilization, other surgical options are described that prevent intromission and the spread of venereal disease. This article describes briefly some of those options. The procedures described are those preferred by the authors and can be performed in the field. Some of the pros and cons of these procedures are discussed.