RAM 2000 BU Series Bedienungsanleitung PDF herunterladen (Seite 2)

 e e ect of di erent extenders on the motility and morphology of ram sperm frozen or stored at 4 °C

178

Introduction

Akkaraman is a fat-tailed, indigenous breed

constituting 45% of the sheep population in Turkey.

Most lamb meat production is from this breed

(1). However, this breed generally produces low

yields.  erefore, studies on crossing Akkaraman

sheep with high-producing sheep breeds have been

widely used to improve their yield traits. Arti cial

insemination (AI) allows for the rapid dissemination

of genetic material from a small number of superior

sires to a large number of females (2). Semen from

farm animals used for this purpose can be stored in

liquid form at 4 °C for a short time or it may be kept

for a long period in a cryopreserved state with liquid

nitrogen (3).

For the e ective use of arti cial insemination

techniques in the sheep industry, investigation on

the methods of ram semen dilution and freezing

is necessary. Many extenders have been used for

freezing ram semen. Semen has been usually diluted

with Tris plus egg yolk, glucose phosphate solution,

egg yolk-citrate solution, homogenized whole milk,

fresh and dried skim milk, lactose solution, and

commercial diluents (3-5).

 e successful storage of ram semen in liquid

and frozen forms depends on the composition of

the extender used.  e recommended maximum

storage time without impaired fertility a er AI

has traditionally been said to be as short as 6-12

h. Storage diluents and techniques have been

developed and adapted with the aim of improving

the cryopreservation of ram semen, but fertility

a er cervical AI with frozen-thawed sperm remains

signi cantly lower than that achieved with fresh

semen. Some factors that contribute to the reduced

viability of cryopreserved ram sperm include

extender composition, cryoprotectant concentration,

egg yolk from di erent avian species, and the

cooling, freezing, and thawing rates, as well as the

quality of semen used. Di erent cryoprotectants or

extenders have been used to prevent cryoinjuries.

 e most common cryoprotectant in use for sperm

cryopreservation is glycerol. A suitable diluent is

a basic necessity for the successful preservation of

spermatozoa and for obtaining higher conception

rates in  eld trials using diluted semen (5-8).

Although information is available on stored

ram liquid semen up to 24 h, there is a need to

further investigate the short-term and long-term

preservability of Akkaraman ram semen for the

extensive utilization of this valuable germplasm by

arti cial insemination.

 is study was designed to evaluate and compare

the quality (subjective motility and total abnormality)

of Akkaraman ram spermatozoa preserved at 4 °C

for up to 48 h and at freezing temperatures using 4

di erent extenders.

Material and methods

Animals and semen collection

 e rams were housed at the Education Research and

Practice Farm in the Faculty of Veterinary Medicine

at the University of Ankara.  e rams were kept

under natural light and maintained under a uniform

and constant nutritional regime, with each ram being

fed a daily diet of 1 kg of concentrate, dried grass, salt

lick, and water ad libitum.

Using an arti cial vagina, semen samples were

obtained from 3 mature Akkaraman rams (3 and 4

years of age) with proven fertility. A total number of

21 ejaculates were collected from the animals during

the non-breeding season (summer). Semen samples

were pooled to eliminate individual di erences. From

this, 7 pooled ejaculates were included in the study.

Semen evaluation

 e ejaculates were evaluated and accepted if the

following criteria were met: a volume of 0.75 mL, a

sperm concentration >2.5 × 10

spermatozoa/mL;

sperm motility >70%, and a total morphological

abnormality frequency of <20.

Sperm motility was assessed using a phase contrast

microscope (×400 magni cation), with a warm stage

maintained at 37 °C. A wet semen mount was made

using 2 μL of semen placed directly on a microscope

slide and covered by a cover slip. For each sample, at

least 5 microscopic  elds were examined by 2 trained

observers.  e mean of the 2 successive evaluations

was recorded as the  nal motility score (9).

For the sperm morphology assessment, a small

drop of semen was added to Eppendorf tubes

containing 0.5 mL of Hancock’s solution (10). A

1 2 3 4 5 6

Research Article 1
References 6

Kommentare zu diesen Handbüchern

Keine Kommentare

RAM 2000 BU Series Bedienungsanleitung Seite 2

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Audioverstärker RAM 2000 BU Series