Sundararaman et al.

semen characteristics including sperm morphology as

described earlier.

Since the first collection in January 2013, a total of

58 ejaculates were taken from the bull, till February

2014. Almost all the semen samples (96.6%) were

rejected because of poor sperm motility and high sperm

abnormalities, exceeding the 20% permissible level. The

average values recorded for the sperm characteristics

were 3.56 ml, 1085.28 million/ml and 18.4% for

ejaculate volume, sperm concentration and sperm motility

respectively.

The ejaculate from the bull collected for the present study

consisted of 4.4 ml of semen, containing 1367 million

spermatozoa per ml of semen. The sperm motility was

70%. The morphology evaluation of the stained sperm

slides revealed that majority of the spermatozoa were

abnormal of which the head and tail defects were in high

proportions (Table 1).

Table 1. Sperm abnormalities in the representative ejaculate of

the Jersey x Zebu crossbred bull

Type of abnormalities

Percentages

Loose heads

14.9

Microcephalic heads

14.5

Macrocephalic heads

1.80

Figure 1. Polymorphic sperm phenotype in a Jersey X Zebu

Pyriform heads

4.52

crossbred bull (A) Sperm with loose heads, microcephalic

All head defects

35.7

head and coiled tail (B) Sperm with loose heads and short tail

Coiled tail

16.7

(C) Microcephalic sperm head elongated (D) Microcephalic

sperm head rounded (E) Microcephalic sperm head rounded

Short tail

14.9

with short tail (F) Microcephalic sperm head conical with

Bent tail

4.52

coiled tail and a sperm with normal head and coiled tail (G)

Broken tail

0.90

Microcephalic sperm head with coiled tail and a sperm with

normal head with bent tail (H) Sperm with pyriform head

All tail defects

37.0

Overall abnormalities

72.7

Very high proportion of microcephalic sperm has already

been recorded in bulls (Hancock and Rollinson, 1949;

The polymorphic phenotypes of spermatozoa are depicted

Alun-Jones, 1962). Settergren and Nicander (1968) and

in the Fig. 1. Loose heads and microcephalic heads

Pant et al. (2002) found lower percentages of decapitated

were the main head abnormalities detected, while a few

sperm heads in bull semen. In our study also relatively

macrocephalic and pyriform heads were also seen. Most

lower proportion of loose heads (22.6%) was recorded.

of the tail defects were coiled tail and short tail and a few

Decapitated sperm defect was found to be a sterilizing

bent and broken tails were also noticeable. Only 27.1% of

defect in bulls (Hancock and Rollinson, 1949; Chenoweth,

the spermatozoa appeared normal in morphology. Nearly

2005) especially if present in very high proportion. Loose

50% of the loose heads were normal in shape and size and

heads, headless tail and abnormal alignment are due to

major proportion of the remainder were microcephalic.

abnormalities in sperm centrioles and the head-neck

junction due to genetic causes (Chemes, 2012). And the

290

Journal of Animal Research: v.5 n.2. June 2015