388 SUPEROVULATION TREATMENT BY A SINGLE INJECTION OF FSH WITH ALUMINUM HYDROXIDE GEL IN HOLSTEIN CATTLE

Abstract

The objective of this study was to examine the effect of administration of FSH in aluminum hydroxide gel (Gel; an adjuvant and adsorbent of large molecules) by a single injection on superovulatory response and embryo recovery in cattle. In this study, cloprostenol-synchronized (PGF; Clopromate C; Sumitomo Pharmaceuticals Co., Tokyo, Japan) nonlactating Holstein cows were divided into 2 groups (Gel-treated and Controls) between Days 8 and 11 after estrus in 2 experiments in a crossover design. In Experiment 1, 40 mg FSH (Antrin-R10; Kawasaki Mitaka Pharmaceutical Co., Tokyo, Japan) was mixed with 10 mL aluminum hydroxide suspended in saline at a concentration of 3 mg Al mL-1 and administered by a single IM injection (n = 12; 10 mL-Gel group). Blood samples were collected at 0, 1, 2, 4, 8, and 12 h, and thereafter every 24 h until embryo recovery for measurement of FSH levels in a time-resolved fluoroimmunoassay. In Experiment 2, 40 mg FSH was mixed with 5 mL Gel and injected into fat in the inguinal region (n = 8, 5 mL-Gel group). The Control group in both experiments (n = 2 and n = 8, respectively) received 40 mg FSH twice daily for 4 days in decreasing doses (8, 8, 6, 6, 4, 4, 2, and 2 mg) by IM injection (Experiment 1), or in the inguinal region (Experiment 2). PGF (0.75 mg) was administered twice on the third day of treatment, and cows were inseminated 48 and 60 h after second PGF dose; embryo recovery was performed 7 days later. Follicular development was monitored ultrasonically every 24 h from the first FSH treatment to ovulation, and the numbers of medium (MF, 5–8 mm) and large (LF, >8 mm) follicles, and corpora lutea (CL) were counted on the day of embryo recovery. Data were analyzed by Student's t-test. In Experiment 1, there were no differences in the mean (� SD) number of CL or transferable embryos between the 10 mL-Gel (10.5 � 9.6 and 6.0 � 8.0, respectively) and Control (14.8 � 9.6 and 9.0 � 6.6, respectively) groups (P > 0.1). The growth of LF and MF in the 10 mL-Gel group occurred 24 h earlier than in the Control group (24 and 48 h after initiation of FSH treatment, respectively; P < 0.05). However, follicle growth stopped at 72 h in the 10 mL-Gel group and at 96 h in the Control group (P < 0.01). FSH concentrations in the 10 mL-Gel group increased markedly to 2.0 � 0.7 ng mL-1 at 12 h, remained there at 24 h, and decreased to 1.0 � 0.3 ng mL-1 at 72 h, whereas FSH concentrations in the Control group increased gradually to 1.1 � 0.3 ng mL-1 at 24 h, remained at 1.2 � 0.3 ng mL-1 from 24 to 96 h, and then decreased to baseline (0.9 � 0.3 ng mL-1) at 120 h (P < 0.05). In Experiment 2, no significant differences in number of CL or transferable embryos were found between the 5 mL-Gel (11.8 � 13.0 and 4.1 � 4.0, respectively) and Control (12.0 � 11.0 and 4.0 � 3.1, respectively) groups, and follicular growth profiles did not differ between groups (P > 0.4). Results suggest that administration of FSH in 5 mL Gel by a single injection in the inguinal region is effective in inducing superstimulation in Holstein cattle. This work was supported by a grant of the Research Project for Utilizing Advanced Technology (04-1676).