Íslenskar landbúnaðarrannsóknir - 01.09.1981, Page 59

SEASONAL VARIATION IN TESTIS SIZE 57
TABLE 1. EfFect of season on testes diameter in two groups of adult rams (n=16 in each year).
Season Date Mean (cm) S.D. Range
AUTUMN .... 4 Oct. 1977 13.75 0.57 12.8—15.0
5 Oct. 1978 13.49 0.83 12.4—15.6
WINTER 19 Dec. 1977 13.18 0.72 11.7—14.4
4 Dec. 1978 13.19 0.75 12.0—14.9
SPRING 1 Apr. 1978 11.69 0.84 10.0—13.7
5Apr. 1979 11.13 0.80 9.8—12.5
SUMMER .... 29 June 1978 12.05 0.96 10.3—14.4
lOJuly 1979 12.23 0.67 11.2—13.8
AUTUMN .... 5 Oct. 1978 13.64 0.91 12.4—15.6
28 Sept. 1979 13.36 0.72 12.5—15.0
Fig. i. Seasonal variation in testes diameter in relation to daylength (10 rams for 24 months)
Z
22
20
18
„ 16
£ "2
bO
T. 10
° 8
6
14
! 3
12
3
2
1
0
Time of year
1979