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SEMEN COLLECTION IN BULLS
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Different semen collection methods in bulls are
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Vaginal method ( Spoon or Sponge technique)
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The simplest and earliest method of semen collection was from vagina.
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In this method, the bull is allowed to mount the cow in or out of oestrus naturally and the semen is collected from vagina by means of a spoon or Sponge or syringe with a long nozzle.
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This technique is unsatisfactory because selectively small volume of semen is mixed with large volume of vaginal mucus.To avoid this female out of oestrus can be used.
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Later, Breeder’s bag and urethral fistular methods of semen collection were used.
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All these methods were crude and danger of contamination and disease transmission was considerable.
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Keeping quality of the semen will be very poor.
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Ampullary Massage technique
Procedure
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Before starting semen collection by massage method ensure that the bull has not ejaculated either by natural service or by some other method for two to three days to ensure that ampulla is full of spermatozoa.
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Secure the bull in a suitable stanchion
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The preputial hair should be clipped
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By tapping the preputial sheath stimulate the urination and empty the bladder
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Properly wash the preputial sheath with warm water and carefully dry it with a clean towel
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The operator should trimmed his nails quite closely can pass his hand into rectum after wearing a clean rubber sleeve on his arm and remove all dung from the rectum
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The operator can carefully massage the seminal vesicle, prostate, cowper’s gland to stimulate some secretion of seminal fluid to rinse the bull’s urethra.
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The seminal vesicles are gently massaged for few times with fingers by backward and downward strokes towards urethra and a cloudy fluid is expelled.
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Then the ampullae is massaged one by one by gentle, slow and rhythmic manner.
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The ampullae is squeezed/stripped by pressing over floor of the pelvis and the pelvic urethra may be massaged.
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The massage can be done for 5 minutes. After the massage of the ampullae the S-curve of the penis should be straightened to allow the escape of semen.
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An assistant holding a glass funnel fitted to a collection vial directly beneath the bull’s sheath can collect the semen during massaging.
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The quantity of fluid collected from seminal vesicle ranged from .5 to 21 ml and ampullae ranged from .5 to 23 ml.
Advantages
Disadvantages
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Chances of contamination by urine or sand.
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Seminal vesicles secretion leads to unbalanced semen components than ejaculated semen.
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Poor concentration and poor keeping quality.
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Requires skill on the past of operator or training on the past of bull.
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Excessive massage will cause inflammation of the organs.
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Electroejaculator method
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Electrical stimulation of ampullae and seminal vesicle is also a method of collecting semen from bulls.
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This method was used by Gunn in 1936 for rams. Later it was modified by Rowson and Murdock, Marden, Dzuik for collection of semen in bulls.
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Thibault et al. (1948) successfully used this for bulls.
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Electro ejaculator consists of
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The instrument consists of a rectal probe with paired rings of copper.
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There are 30 rings which are insulated from each other with ebony.
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Sixty cycles alternate current is used. Voltage is increased rhythmically and returned back to zero in 3-5 seconds interval.
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The next increase will be higher than the previous one. A bipolar electrode was devised by Dzuik et al. (1954) for collecting semen.
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At one end it contained 6 metal rings spaced at 4.5 cm apart. These metal rings work alternate as positive and negative electrodes.
Procedure
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The animal is restrained in a trevis/chute
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The rectum of the animal is flushed with normal saline
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The preputial hairs may be clipped, washed and dried
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Teasing or sexually stimulating the bull before applying electro ejaculate may help to inform the quality and quantity of semen
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After cleaning the rectum the glove hand with the electrodes is inserted and passed forward upto 30 cm and the electrodes can be pressed down on the floor of the rectum directly over the two ampullae between the two diverting seminal vesicles
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An alternate current is passed starting at 5 voltage and return back to zero every 5 to 10 seconds.
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Subsequent stimulations should go high and again come back to zero.
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This is gradually increased up to 15 volts. Generally the erection and ejaculation occurs at 10-15 volts when 0.5 to 1 ampere current is flowing.
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The semen is collected in a clean sterile glass with a glass funnel.
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The first portion generally consists of merely the watery secretion of the accessory glands and can be discarded.
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The portion is usually containing semen is collected and used.
Advantages
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Semen can be collected from males that refuse to donate semen in artificial vagina, lowered sex libido or when injuries or deformities make this impossible.
Helps to collect the semen from bulls that are not able to mount
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Bulls that are recumbent but having good pedigree can be collected by this method
Disadvantages
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The technique may be painful to bulls. It can not be practiced frequently, since frequent use of this method may affect the health status of the bulls.
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The quality of semen collected by electro ejaculation cannot be compared with semen obtained by AV method because the non accessory sex gland secretion.
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The semen collected by this method is usually more in volume and less in sperm concentration. The contamination of semen will also be more.
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Artificial vagina (AV) method
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The AV method of semen collection has replaced all the old, cumbersome and unreliable procedures.
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The AV provides the most satisfactory method of collecting semen from bulls.
This is the most widely used and preferred method for routine semen collection.
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This method has several advantages over other methods and a normal, clear ejaculate can be collected.
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Artificial vagina is very convenient and is more near to the natural service i.e. it contributes the threshold of warmth, pressure and friction simulating the normal characters of female reproductive passage.
Limitations
History and type of artificial vagina
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Russians (Kumorov and Nagev, 1932) designed the first artificial vagina. Various workers made different types of AV.
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The Cornell University workers developed Cornell Model and in US “Danish model” was developed.
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In tropical countries the “short model” was developed
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Russian model of Artificial Vagina
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Made of rigid rubber cylinder
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60 cm long and 5.5 cm inner diameter.
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The inner side of rubber cylinder was covered by a thin walled rubber liner, the ends was turned back over the outer cylinder to form water tight jacket
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The jacket was filled with hot water enough to bring the inside of AV to also body temperature.
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Danish model of artificial Vagina
Disadvantage
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Semen receptacle is exposed to light and ambient temperature
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Damage of cold shock to spermatozoa during collection in cold weather.
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Cornell model of Artificial Vagina
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Developed by scientists of Cornell university
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Length – 71.20 cm
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Outer diameter – 6.25 cm
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Inner diameter – 5.7 cm
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This model overcome the advantage of Danish model by covering the collecting receptacle and exposing to outside environment
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Parts of Artificial Vagina
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Rubber hose pipe or cylinder 
- Inner liner
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Directors cone 
- Collection vial
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Insulation bag 
(Click here for video demonstration )
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The parts AV should be sterilized before it is used for semen collection to avoid the contamination and disease transmission.
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After sterilization all parts should be dried and stored in a dust free cabinet or incubator.
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The inner liner should be inserted into the AV and both the ends are turned back over the ends of the cylinder
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Rubber bands may be attached on both the ends so as to form a jacket between the liner and rubber cylinder.
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The director cone is fastened over one end of the AV and the glass semen collecting vial is attached to the smaller end of the cone.
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After assembling AV, half the jacket is filled with warm water of about 65-70 ⁰ C is poured to get the final temperature of 42.5 to 45 ⁰ C inside the AV.
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The remaining half of the jacket is filled with air. The temperature of AV may vary depending upon the season, time semen collection and air temperature. (Click here to view picture).
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The insulation bag is used in colder or hotter environment to avoid cold/heat shock to the spermatozoa.
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After assembling the AV, sterile lubricating jelly is applied for 3 to 5 inches of the interior of liner.
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Excessive lubrication will cause the contamination over semen samples by carrying the jelly through the AV over the bull’s pelvis.
Lubricants may be
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K.Y. Jelly 
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Sterile white vaseline jelly 
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White mineral oil 
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Preparation of bull
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Semen collection is done in the early morning. The animals will be active and the stomach will be empty in the morning hours which help in better semen collection.
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The scheduled bulls will be carried from their paddocks to washing area.
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The animals should be washed to remove all the dirt.
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They should be tied surrounding the collection shed and should be dried.
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The bulls should be tied with bull apron and the prepuce should be cleaned with normal saline
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The bulls are allowed to watch the other bulls mounting which will stimulate the bull. The forward and backward movement of dummy will also stimulate the bull.
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The protrusion of penis from prepuce will indicate the bull is ready to mount.
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Semen collection
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The teaser should be restrained in a chute.
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The right handed operator can approach the bull from right side by holding the AV on his right hand
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When the bull mounts and ready to make the thrust, the operator using the left hand drawn the penis from sheath and directs it into the AV which is held at an angle that it is in have with the testis.
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During the entire process the testis itself should not be touched as it will leads to refusal to service.
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The AV should be directed in such a way that the semen should be ejaculated in director cone or directly on collection vial
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On completion of the thrust the collection tube is immediately doubled back on the cone so as to exclude any semen that might has been deposited on testis should not enter inside the collection vial (as it carries bacteria from penis and sometimes lubricating jelly)
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After collecting the semen the collection vial is disconnected immediately, closed with clean stopper / sterile aluminum, plastered with details of bulls, placed in a beaker containing water of about 34 ⁰ C and examined as soon as possible.
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Species
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Artificial vagina hose
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Artificial vagina liner
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Artificial vagina cone
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Length
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Diameter
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Length
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Diameter
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Length
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Diameter
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Cattle
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35 cm
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6.5 cm
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54 cm
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5.5 cm
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24cm
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Upper: 5.0 cm
Lower: 1.5- 2.0 cm
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Buffalo
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30 cm
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6.5 cm
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54 cm
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5.5 cm
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Stallion
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54 cm
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13 cm *
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Sheep
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20 cm
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4.5cm
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30 cm
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3.0 cm
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Goat
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15 cm
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4.5cm
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30 cm
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3.0 cm
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* The diameter at the distal end is only 8.5cm.
Hygiene and precautions at collection
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The bull and the location of semen collection should be clean, dry and free from dust and mud.
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Collection yard should not be overcrowded with bulls and new persons.
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The semen collector should wear protective clothing and gum boots
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The hind portion of the dummy should be as clean as possible.
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During collection the penis should be prevented from coming in contact with the dummies hind quarter. For this the bull apron can be used. (Click here to view picture)
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More than two ejaculates cannot be collected from a bull in one day.
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Don’t grasp the unsheathed penis at the time of collection
The semen collector should not enter into the lab. The semen should be given through the pass box.
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Preparation of Artificial Vagina
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Participants