Sb

During 1998, when no hormone treatments were administered, urinary oestrogens increased over an 11-day interval to peak pre-ovulatory concentrations of 321 ng mg—1 Cr (Day 0), followed by a return to basal by Day +5 (Fig. 8.7a). Progestins increased by Day +14 and remained elevated (~19 ng mg—1 Cr) throughout the luteal phase. Proceptive behaviours were minimal, although bleating and chirping were observed on Day 0, and mating occurred three and four days later followed by AI on Day +5; no birth occurred.

In 1999, oestrogens increased (see Fig. 8.7b) above basal on Day —7 and peaked (185 ng mg—1 Cr) on Day 0. In an attempt to promote ovulation, hCG was administered (Day +2), the female mated one day later (Day +3), and AI was performed on Days +5 and +6. Oestrogens declined on Day +5 (36 ng mg—1 Cr), but a second hCG injection (Day +7) markedly boosted oestrogen excretion by Day +12 (167 ng mg—1 Cr), which remained elevated for a 15-day interval (peak on Day +26, 259 ng mg—1 Cr). Although urine specimens were not collected for the next ten days, oestrogens were basal by Day +37. Urinary progestins increased by Day +6 (28 ng mg—1 Cr) and remained elevated within the normal range (~24 ng mg—1 Cr) throughout the sampling interval. In addition to mating on Day +3, this female chirped on Days —3 through —1 and exhibited tail-up behaviours on Days +5 and +6; no birth occurred during 1999.

During 2000, oestrogens increased over an eight-day interval to peak pre-ovulatory concentrations of 256 ng mg—1 Cr (Day 0), followed by a return to basal concentrations by Day +3 (see Fig. 8.7c). Urinary progestins increased by Day +9 (26 ng mg—1 Cr) and remained elevated in the normal range (~12 ng mg—1 Cr). This female exhibited water play and scent-marking on Day —3, tail-up activity on Day —2 and lordosis/ tail-up behaviours on Day +2 and +5. Mating occurred on Day +3 followed by AI on Day +4. Twin cubs were produced (with only one surviving) 142 days after the day of mating.

Urinary corticosteroid measures in response to anaesthesia

Immunoreactive corticosteroids were assessed before, during and after female SB 371 was anaesthetised on three occasions from 1998 to 1999 to conduct AI and/or physical examination (Fig. 8.8).

Figure 8.7. Daily urinary oestrogens (♦) and progestins (□) in female SB 374: (a) 1998, control natural oestrus, mating and AI; (b) 1999, exogenous gonadotrophins, mating and AI; and (c) 2000, mating and AI. Values were aligned to day of peak oestrogen (Day 0), except for 1999 when values were aligned to the day of the first oestrogen peak (Day 0). !, mating; ! (bold), AI; +, hCG.

Figure 8.7. Daily urinary oestrogens (♦) and progestins (□) in female SB 374: (a) 1998, control natural oestrus, mating and AI; (b) 1999, exogenous gonadotrophins, mating and AI; and (c) 2000, mating and AI. Values were aligned to day of peak oestrogen (Day 0), except for 1999 when values were aligned to the day of the first oestrogen peak (Day 0). !, mating; ! (bold), AI; +, hCG.

Small sample size precluded statistical analysis, but excretion patterns were strikingly similar across years for all anaesthetic procedures. In general, corticosteroids were low (38-82 ng mg-1 Cr) pre-anaesthesia (from -10 to 0 hours, with Time 0 being the time of anaesthetic administration), increased eight- to ten-fold (to 543-648 ng mg-1 Cr)

Figure 8.8. Urinary corticosteroid values in female SB 371 before, during and after anaesthetic episodes: two for 1998 (a, b) and one for 1999 (c). Values were aligned to time (in hours) from anaesthetic administration.

during the ten-hour post-induction interval and then declined to basal (39-116 ng mg-1 Cr) within 10 to 20 hours post-anaesthetic induction.

Urinary androgen profiles in males

Weekly urinary androgen excretion is shown in Figure 8.9a for a male (SB 381) that sired an offspring the same year (1999). Average androgen concentrations were highest (p < 0.05) from January to April (58 ± 4 ng mg-1 Cr) compared to May to December (29 ± 2 ng mg-1 Cr). Androgen excretion in a male (SB 390) maintained in isolation from females (2000) is depicted in Figure 8.9b. The following year (2001; see Fig. 8.9c), this

Figure 8.9. Urinary androgens (mean ± SEM) aligned by month: (a) an adult proven sire (SB 381); (b) an adult (SB 390) maintained in isolation; (c) the same previously isolated male (SB 390) with access to adult females; and (d) a subadult male (SB 452) with female access but no mating.

same male mated, sired an offspring and served as a semen donor for AI. While isolated, mean urinary androgen was typically <25 ng mg-1 Cr (see Fig. 8.9b), although average androgen from March to June (14 ± 1 ng mg-1 Cr) was higher (p < 0.01) than from July to December (5 ± 1 ng mg-1 Cr). In 2001 (see Fig. 8.9c), androgen excretion was higher (p < 0.01) from April to May (20 ± 3 ng mg-1 Cr) compared to January to March (13 ± 1 ng mg-1 Cr). Interestingly, this male participated in a rare autumnal mating in 2001, but no urine samples were collected during this interval. No among-year differences (p > 0.05) in androgen concentrations were evident despite the lack of mating opportunities in 2000.

Androgen excretion patterns in a 5-year-old subadult male (SB 452) are presented in Figure 8.9d. This individual was exposed to an oestrual female but showed little interest and failed to mate. Although sample collections were inconsistent, his profile revealed higher (p < 0.01) androgen concentrations from January to March (26 ± 1 ng mg_1 Cr) compared to April to June (7 ± 1 ng mg_1 Cr).

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