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

APPLICATION OF EOSIN FOR DIFFERENTIAL STAINING OF BUFFALO
SPERMATOZOA
Part III. Background stains for differential staining of buffalo
semen.
NOUR EL-DIN A. ALY, ABBOUD, M.Y., OMAR, M.A. and YOUNES, A.A.
Animal Science Research Institute, U.A.Re., Dokki.

In the practice of artificial inseminaticn, many stain mixtures
are used for differential staining of spermatozoa. Under U.A.R.
environmental conditions, selection of a stain mixture for buffalo
semen, leading to a correct correlation between motility rating and
percentage of unstained sperm, and in the mean time facilitating the
live-dead count, is of high importance in the practice of artificial
breeding in buffaloes.

The background stains nigrosin, methyl blue and congo red com-
bined with eosin yellowish were tested for their suitability as

compound steins for differentiation of buffalo spermatozoa.

Experimental. Three background stains (10% nigrosin, 7% methyl blue
and 2% congo red), each combined with 1.7% eosin yellowish and
dissolved in normal saline solution were used for differential
staining of buffalo spermatozoa. 123 ejaculates were collected from
10 buffalo bulls over a period of 19 months. Fresh non-diluted semen
was evaluated initially by the motility test. From every ejaculate
3 semen smears, stained with the 3 stain mixtures were prepared.
Fixation was practiced by simple air drying. In this way 369 smears
of stained buffalo semen were prepared and directly microscopically
examined by performing the live-dead count. The correlation between
percentage of live sperm and motility rating was also determined

for each compound staein separately.

Results. l.Average motility rating was 67.80=0.51%.
2.The highest percentage of live sperm was 67.92:0.20%, obtained by

using eosin-nigrosin mixture.