**12. Blood sampling in farm animals**

The farm animals used for blood collection should be more than 6 months old and preferably fully grown adults. They must be in good body condition and in good health.

Horses should be at least 3 years old and at least 400 kg body weight. Horses with a body condition score of 3 or less must not be bled.

Sheep and goats should be at least 12 months old. Sheep should weigh at least 40 kg. Goats vary greatly in size according to breed, so a minimum weight cannot be given for the species, but they should be in good body condition.

Cattle should be at least 18 months old and should weigh at least 250 kg if 18 to 24 months of age and at least 300 kg if older.

If growing animals are used their diet must be nutritious, supplemented with iron, and fed at appropriate above-maintenance levels to allow for replacement of blood as well as steady growth.

The animals to be bled must be accustomed to handling so that they are relaxed and calm throughout the harvesting procedure. Excitement and fear can cause splenic contraction which results in altered blood parameters.

The design of the bleeding facilities and methods of restraint must be such that the procedure can be carried out efficiently with the minimum of stress to the animals.

Cattle and horses must be standing when bled.

It is preferable to bleed sheep and goats in the standing position, but where large numbers of sheep and goats are bled, it may be acceptable to strap them in lateral recumbency.

The harvesting procedure should begin as soon as the animal is restrained, and animals should be kept under close supervision during the bleeding process to guard against inhalation of ruminal contents or the development of ruminal bloat. After release they should be allowed to return to their paddock at their own pace.

The skin over the sampling site may be clipped or shaved to facilitate placement of the needle and the site may be cleaned with disinfectant such as alcohol. It is important that time be taken to locate the vessel accurately and that it be distended by gentle pressure before the needle is inserted.

A needle with as large a bore size as possible should be used to ensure efficient blood withdrawal without collapsing the vessel, without causing haematoma formation and without causing blood pressure to drop too rapidly.

Immediately after removal of blood, all animals must have unrestricted access to water.

As concerning the volume and frequency of bleeding for adult animals, not more than 15% of the estimated circulating blood volume should be removed in any 4-week period, i.e. 0.9% liveweight in cattle and sheep and 1.1% liveweight in goats and horses.

Circulating blood volume (litres) can be estimated from body weight (kg) using a conversion factor of 0.06 for cattle and sheep, 0.07 for goats and 0.075 for horses. As a guide, 1% of body weight is the weight of 16 to 17% of the circulating blood volume in sheep and cattle; about 13% in horses and about 14% in goats.

If more than 15% of blood volume is removed, consideration should be given to fluid replacement using lactated Ringer's solution with 5% dextrose.

For young animals, the volumes removed should be relatively less. For animals 6 months old, not more than 10% circulating blood volume should be removed, with incremental increases to the maximums above when fully grown (more than 12 months old for sheep and goats, 18 months old for cattle and 3 years old for horses).

If too much blood is drawn too quickly or too frequently without replacement, animals may develop hyperpnoea (deep and rapid breathing) and may go into a state of hypovolaemic shock. In the longer term the removal of to much blood causes anaemia, muscle weakness, increased susceptibility to cold, reduced exercise tolerance and ill-thrift, particularly if management and nutrition are suboptimal.

If 15% to 20% of the blood volume is removed, cardiac output and blood pressure will be reduced. Removal of 30% to 40% can induce shock.

Inexpert bleeding techniques can result in bruising around the vein, haematoma formation and/or inflammation at the site.

### **12.1 Bleeding technique in cattle**

250 A Bird's-Eye View of Veterinary Medicine

The farm animals used for blood collection should be more than 6 months old and preferably fully grown adults. They must be in good body condition and in good health.

Horses should be at least 3 years old and at least 400 kg body weight. Horses with a body

Sheep and goats should be at least 12 months old. Sheep should weigh at least 40 kg. Goats vary greatly in size according to breed, so a minimum weight cannot be given for the

Cattle should be at least 18 months old and should weigh at least 250 kg if 18 to 24 months

If growing animals are used their diet must be nutritious, supplemented with iron, and fed at appropriate above-maintenance levels to allow for replacement of blood as well as steady

The animals to be bled must be accustomed to handling so that they are relaxed and calm throughout the harvesting procedure. Excitement and fear can cause splenic contraction

The design of the bleeding facilities and methods of restraint must be such that the

It is preferable to bleed sheep and goats in the standing position, but where large numbers of sheep and goats are bled, it may be acceptable to strap them in lateral recumbency.

The harvesting procedure should begin as soon as the animal is restrained, and animals should be kept under close supervision during the bleeding process to guard against inhalation of ruminal contents or the development of ruminal bloat. After release they

The skin over the sampling site may be clipped or shaved to facilitate placement of the needle and the site may be cleaned with disinfectant such as alcohol. It is important that time be taken to locate the vessel accurately and that it be distended by gentle pressure

A needle with as large a bore size as possible should be used to ensure efficient blood withdrawal without collapsing the vessel, without causing haematoma formation and

As concerning the volume and frequency of bleeding for adult animals, not more than 15% of the estimated circulating blood volume should be removed in any 4-week period, i.e.

Circulating blood volume (litres) can be estimated from body weight (kg) using a conversion factor of 0.06 for cattle and sheep, 0.07 for goats and 0.075 for horses. As a guide,

Immediately after removal of blood, all animals must have unrestricted access to water.

0.9% liveweight in cattle and sheep and 1.1% liveweight in goats and horses.

procedure can be carried out efficiently with the minimum of stress to the animals.

**12. Blood sampling in farm animals** 

condition score of 3 or less must not be bled.

of age and at least 300 kg if older.

before the needle is inserted.

which results in altered blood parameters.

Cattle and horses must be standing when bled.

should be allowed to return to their paddock at their own pace.

without causing blood pressure to drop too rapidly.

growth.

species, but they should be in good body condition.

Blood can be collected from the jugular vein in cattle of all ages or from the tail (coccygeal) vein of older cattle.

A variety of collection devices may be used: vacutainers, bleeding tubes, syringe and needle. Restraint should ensure quick, easy and safe collection of the sample causing minimal distress.

This may involve use of a bail, race, or crush for tail bleeding. For jugular bleeding the animal may require minimal restraint (e.g. halter) or may need to be restrained in a crush with head bail and the employment of a halter or nose grips. Use of nose grips should be avoided wherever possible.

Operators should use gloves and disinfect them between animals to prevent the transmission of blood-borne diseases. Equipment such as vacutainer holders should also be cleaned between animals.

Jugular bleeding - The animal must be restrained with the head elevated and the jugular groove exposed. The jugular vein is raised by pressure at the base of the jugular groove. The needle is passed through the skin and into the vein by a firm thrust directed an angle of 20o to the skin surface and the blood sample is withdrawn.

Tail bleeding - Restraint should prevent the animal from moving away during the procedure. The tail must be raised vertically with one hand until it is horizontal with the ground.

Approximately 150 mm from the base of the tail, the groove lying in the ventral midline of the tail is located. Midway along the body of a coccygeal vertebra, the needle must be inserted perpendicularly to the surface of the skin to a depth of a few millimetres and the

Local Anesthesia for Husbandry Procedures and Experimental Purposes in Farm Animals 253

Microchips to identify cattle are becoming a feasible option to replace branding for identification and their placement will be less painful than branding. However, they are not really suited to everyday identification and it will take some time before hand-held identity

Another alternative for animal identification is DNA testing. The cost of DNA testing is

Immunocastration vaccines for lambs are likely to become available in the near future and they could be used to eliminate the pain caused by castration if their use is acceptable throughout the production and consumption chain and provided that they are cheap

It is possible to breed sheep with reduced wool in the perineal area and for shorter and less woolly tails. This would reduce the necessity of docking to reduce flystrike, but shearing

Identity microchips may reduce the need for ear marking and tagging in the future, but they are economically and practically difficult to use on large commercial sheep farms at present. The Australian wool industry aims to phase out mulesing by 2010. This will be facilitated by breeding Merino sheep with fewer wrinkles in the perineal area and the use of anti-fly

Immunocastration is a possible alternative to surgical castration in pigs and may become

A combination of using specific genetic lines of laying hens that have a low tendency to feather peck, and the use of particular environmental features, might reduce cannibalism to

Although it is generally seen as preferable for the future not have to perform surgery to achieve husbandry outcomes, there are several reasons why the use of local anesthesia

Firstly, genetic improvement takes time. Even for a trait such as polledness in cattle, where only a few genes control the polled condition, there would be a significant time lag following the identification of the gene(s) and development of a test before homozygous breeding animals were disseminated throughout the cattle population. There is also likely to be some time delay before the development and implementation of some of the non surgical

Removal of blood is one of the most common procedures performed on animals for experimental purposes. The choice of a technique appropriate for the purpose and the species, by a trained staff, and the use of local anesthesia are essential for ensuring that any

Minimisation of such adverse effects is important for scientific as well as ethical and legal reasons, since they can cause biological changes which may affect the blood sample, and hence the validity of the research results and the number of animals used to achieve the

chip readers become a widely used tool on cattle farms.

would still be impeded by the presence of the tail.

vaccination or long-lasting insecticides.

the degree that beak trimming is not necessary.

approaches currently under investigation.

pain, distress or discomfort is kept to a minimum.

more a widely accepted practice.

should not be discounted.

scientific objective.

enough.

steadily falling and it may become economically feasible in the future.

blood sample is withdrawn. Pressure must be applied to the venipuncture site after withdrawal of the needle until the bleeding stops.

Fig. 6. Tail bleeding in cattle

## **13. Conclusion**

Most of the husbandry procedures used today were developed many years ago. They were usually selected to be carried out quickly, easily, cheaply and with inexpensive equipment, and to be generally safe for the animals and people involved.

At the time of their development, little significance was attributed to any associated animal pain. Since the mid-1990s, many advances have been made in the field of animal pain research but much remains to be done.

It is necessary a full analysis of matters that should be considered when deciding whether or not, and how, to undertake particular painful husbandry procedures.

Public attention on the welfare consequences of surgical husbandry procedures used on farm animals is increasing. This suggest that alternative approaches must be considered.

The best way to reduce the pain and distress caused by horn injuries or horn removal would be to select for polled cattle. At present the common dairy breeds, Friesian and Jersey, are horned. It may be possible for such breeds to be bred polled if an effort were made to do so and this would completely remove the necessity for disbudding or dehorning.

A possible alternative to castration in cattle could be the use of immunocastration. The vaccines used for this are now available, and it is a matter of seeing whether this practice is acceptable to producers and consumers.

Also spaying heifers could be avoided by rendering the cows infertile: this is now possible immunologically.

Tail docking of dairy cows is prohibited in some countries and in many natural and organic programmes. It is a procedure that should be phased out, because there is no scientific justification for it.

blood sample is withdrawn. Pressure must be applied to the venipuncture site after

Most of the husbandry procedures used today were developed many years ago. They were usually selected to be carried out quickly, easily, cheaply and with inexpensive equipment,

At the time of their development, little significance was attributed to any associated animal pain. Since the mid-1990s, many advances have been made in the field of animal pain

It is necessary a full analysis of matters that should be considered when deciding whether or

Public attention on the welfare consequences of surgical husbandry procedures used on farm animals is increasing. This suggest that alternative approaches must be considered.

The best way to reduce the pain and distress caused by horn injuries or horn removal would be to select for polled cattle. At present the common dairy breeds, Friesian and Jersey, are horned. It may be possible for such breeds to be bred polled if an effort were made to do so

A possible alternative to castration in cattle could be the use of immunocastration. The vaccines used for this are now available, and it is a matter of seeing whether this practice is

Also spaying heifers could be avoided by rendering the cows infertile: this is now possible

Tail docking of dairy cows is prohibited in some countries and in many natural and organic programmes. It is a procedure that should be phased out, because there is no scientific

and to be generally safe for the animals and people involved.

not, and how, to undertake particular painful husbandry procedures.

and this would completely remove the necessity for disbudding or dehorning.

withdrawal of the needle until the bleeding stops.

Fig. 6. Tail bleeding in cattle

research but much remains to be done.

acceptable to producers and consumers.

immunologically.

justification for it.

**13. Conclusion** 

Microchips to identify cattle are becoming a feasible option to replace branding for identification and their placement will be less painful than branding. However, they are not really suited to everyday identification and it will take some time before hand-held identity chip readers become a widely used tool on cattle farms.

Another alternative for animal identification is DNA testing. The cost of DNA testing is steadily falling and it may become economically feasible in the future.

Immunocastration vaccines for lambs are likely to become available in the near future and they could be used to eliminate the pain caused by castration if their use is acceptable throughout the production and consumption chain and provided that they are cheap enough.

It is possible to breed sheep with reduced wool in the perineal area and for shorter and less woolly tails. This would reduce the necessity of docking to reduce flystrike, but shearing would still be impeded by the presence of the tail.

Identity microchips may reduce the need for ear marking and tagging in the future, but they are economically and practically difficult to use on large commercial sheep farms at present.

The Australian wool industry aims to phase out mulesing by 2010. This will be facilitated by breeding Merino sheep with fewer wrinkles in the perineal area and the use of anti-fly vaccination or long-lasting insecticides.

Immunocastration is a possible alternative to surgical castration in pigs and may become more a widely accepted practice.

A combination of using specific genetic lines of laying hens that have a low tendency to feather peck, and the use of particular environmental features, might reduce cannibalism to the degree that beak trimming is not necessary.

Although it is generally seen as preferable for the future not have to perform surgery to achieve husbandry outcomes, there are several reasons why the use of local anesthesia should not be discounted.

Firstly, genetic improvement takes time. Even for a trait such as polledness in cattle, where only a few genes control the polled condition, there would be a significant time lag following the identification of the gene(s) and development of a test before homozygous breeding animals were disseminated throughout the cattle population. There is also likely to be some time delay before the development and implementation of some of the non surgical approaches currently under investigation.

Removal of blood is one of the most common procedures performed on animals for experimental purposes. The choice of a technique appropriate for the purpose and the species, by a trained staff, and the use of local anesthesia are essential for ensuring that any pain, distress or discomfort is kept to a minimum.

Minimisation of such adverse effects is important for scientific as well as ethical and legal reasons, since they can cause biological changes which may affect the blood sample, and hence the validity of the research results and the number of animals used to achieve the scientific objective.

**14** 

 *USA* 

**Artificial Insemination and Its Role in** 

Tanja Opriessnig, Luis G. Giménez-Lirola and Patrick G. Halbur *Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa,* 

Artificial insemination (AI) in swine is not a new technique and reports as early as the 1930s (Lush, 1925) describe collecting semen for AI. However, because of farm structure changes, increasing farm sizes and separation of production stages, interest in intensive pig production is growing and AI has become a critical component in modern pig production. In 2001, nearly 60% of North American swine herds utilized AI (Singleton, 2001), a drastic increase from the estimated 5% in the 1990's (Flowers & Esbenshade, 1993). This is still relatively low compared to the 90% or greater use of AI in Western Europe (Madsen, 2005; Maes et al., 2008). The extensive use of AI in pig reproduction in the last decade has facilitated the exchange of desirable genetic characteristics at an international level, allowing producers to make greater use of superior genetics at a lower cost than some natural-service systems (Gerrits et al., 2005). However, the growth in use of AI has increased the risk of quick and widespread transmission of venereally transmissible pathogens (Thacker et al., 1984). It has been reported that the porcine male reproductive tract is highly susceptible to viral infections (Phillips et al., 1972; Spradbrow, 1968). This, coupled with the ability of boars to produce tens to thousands of insemination doses per week and the widespread distribution of the processed semen (both nationally and internationally), further increases

Many viruses have been reported to be present in boar semen (Yaeger et al., 1993; Lucas at al., 1974, Madson et al., 2008) and have the potential of being transmitted to susceptible breeding animals during AI, particularly when the boar is viremic or clinically sick. Viral shedding may also continue long after clinical signs have abated. In addition, infertility or reduced reproductive performance have been reported in boars with detectable virus in their semen (Guerin & Pozzi, 2005; Larsen et al., 1980). The potential economic impact and liability associated with transmission of diseases through semen has created great interest and investment in testing boars for viral diseases prior to entry and while at AI centers.

In many countries, foot-and-mouth disease virus (FMDV), porcine reproductive and respiratory syndrome virus (PRRSV), Japanese B encephalitis virus (JBEV), pseudorabies virus (PRV), classical swine fever virus (CSFV) and African swine fever virus (ASFV) are of particular importance. Accurate monitoring of boars in AI stations is essential to reduce the

the risk of wide transmission of viral pathogens by semen.

**1. Introduction** 

**Transmission of Swine Viruses** 

#### **14. References**

