Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. I

Thus in general rabbit semen tends to give a neutral or slightly
alkaline reaction unlike that of the bull whose normal semen is
slightly acid (Anderson, 1942)

The correlations between fertility and the .four semen traits
are generally lower than those obtained by Hulet and Ercanbrack
(1962) for the ram. It is difficult to explain the difference
in correlations between total sperm per ejaculate and fertility
obtained by the two methods; however the mean number of sperm
over a number of ejaculates is probably a better measure of
fertilizing ability than the number in a single ejaculate, particul-
arly when this is diluted prior to insemination. While a signific-
ant negative correlation was obtained between pH and litter size in
the present study, Hulet et al (1965) found no correlation between
ram semen pH and fecundity in the ewe. The significant negative
correlations between pH and other semen traits agree closely with
the observations of other workers on bull (Anderson, 1942) and ram
semen (Hulet and Ercanbrack, 1962). The latter workers found the
correlation between pH and fertility to be almost as high as the
multiple correlations for two fertility indexes derived.

Thus, while the determination of pH is probably as good
a single estimator of both semen quality and fertility as any other
semen trait, its usefulness as a predictor of the fertility of a
particular male is limited; in addition its repeatability is
rather low. The observations of Hulet and Ercanbrack (1962)
and Wiltbank, Rowden and Ingalls (1965) that it is difficult to
accurately predict the fertility of individual rams or bulls are
supported by the limited data of the present study.

REFERENCES,

Anderson, J. (1942). J. Agric. Sci. 32 : 298

Hulet, C.V. & Ercanbrack, S.K. (1962) J. Anim. Sci. 21 : 489

Hulet, C.V. Foote, W.C. & Blackwell, R.L. (1965) J. Reprod. Fert.
9 ¢ 311

Lambert, W.V. & McKenzie, F.F. (1940) Circ. U.S.D.A. No. 576

Mann, T. (1964) The biochemistry of semen and of the male

reproductive tract. Methuen, London & John Wiley,
New York.

More O'Ferrall, G.J. Meacham. T.N. & Foreman, W.E. (1968) J. Reprod.
Fertil. 16 : 243

Wiltbank, J.N. Rowden, W.W, & Ingalls, J.E. (1965) Univ. Nebr. Agr.
Expt. Sta. Res. Bull. 224,