Culling methods in sheep and goat

1. CULLING OF SHEEP
AND GOAT
Dr. AKHILA M. R.
2018-MVM-01
Department of Animal Breeding and Genetics

2. Vital practice
Best means to improve bands of goats
Selection and culling keeps problems at minimum
Undesirable animals removed

3. Development of ideal breeding flock
10 – 20 % every year from healthy flock
Replacement by new lambs/ kids

4. DEFENITION
In Biology, Culling is the process of
segregating organisms from a group
according to desired or undesired characters
In Animal Breeding, Culling is the process of
removing or segregating animals from a
breeding stock based on a specific trait

5. To exaggerate desirable characteristics or remove undesirable
characteristics by altering genetic diversity of population
For livestock and wildlife, Culling often refers to act of killing
removed animals

6. CATEGORIES TO BE CULLED
Undesirable animals
Low producers – less amount of milk for young twins/ triplets
Repeat breeders
Animals with stunted growth
All animals except future breeding bucks at 16-18 Kg body wt. in
4-5 months

7. Low prolificacy animals – if not 1.6 kids per year
Problem animals
Does of longer inter-kidding intervals - > 1 year
Does of longer dry period

8. Suffering from incurable and contagious diseases
Paralysis affected animals
Lame/ deformed bones/ fractures
Teeth defects, feet and leg defects

9. History of abortion
Udder defects in females
Testicle defects in males
Fail to breed and produce offspring

10. Wean less weight and low grade offspring
Lack desirable conformation, breed characters/ sex characters
Develop incurable physical defects
Evidence of hereditary diseases

11. TYPES OF CULLING
Culling classified in to 3 types
Policy culling
Veterinary culling
Emergency culling

12. POLICY CULLING
Not true to breed/ type
Parentage not known
Genetic defects
Poor production/ reproduction

13. Surplus stock : males and females not selected for breeding and
those cast off after breeding
Age : sheep and goats of six years and above
Animals with gummers and broken mouth condition
Poor body weight and growth rate

14. VETERINARY CULLING
Disorders refractory to treatment
Incapacitated/ become unsuitable for normal production life
Weak and debilitated animals
Loosing weight, static weight during growing phase

15. Loosing 25% or more weight during adulthood
Suspected/ confirmed case of animals ailing from contagious/
infectious/ zoonotic diseases

16. EMERGENCY CULLING
Whose prognosis is grave
Involved in accidents, predatory attacks
Suffering from non-specific diseases
Confirmed cases of TB, JD, Brucellosis

17. Other types
Tandem method
Independent level method
Total score method

18. Tandem Method
A form of selective breeding
Breeder addresses one characteristic of the animal at a time
Select animals that measure above certain threshold of trait
Other traits kept constant

19. Tandem Method
When level of quality in single trait achieved, breeder focus on a
second trait
Cull based on second trait quality
Improvement of one particular trait without losing quality of others
Applied in each successive generation of progeny
Ensure improvement in single characteristic of breeding program

20. Independent Levels Method
Animal that falls below a given standard in any single characteristic
Regardless of level of excellence of other traits
Not used in a breeding program
With each successive mating, the threshold culling criteria is raised

21. Independent Levels Method
Improving breed with each successive generation
Measures several characteristics together

22. Total Score Method
Method where breeder evaluates and selects breeding stock
Based on a weighted table of characteristics.
Breeder selects most important qualities and assigns them a weight
Weights of all traits should add up to 100

23. Total Score Method
When evaluating an individual for selection, the breeder measures
the traits on a scale of 1 to 10
Scores then multiplied by their weights and added together
Individuals fail to meet a threshold are culled (or removed) from
program

24. Total Score Method
Total score gives breeder a way to evaluate multiple traits on an animal at
same time
Most flexible of the three

25. IMPORTANCE OF CULLING
Maintain flock size
More productive and easier to manage
Increase usefulness of animals
Helps maintain good breeding bands
Efficient grazing ability

26. REFERENCS
N. S. R. Sastry, C. K. Thomas; Livestock Production Management;
5th Edn; 2015; Kalyani Publishers, New Delhi; Pg no. 495-496
Jagdish Prasad; Goat, Sheep and Pig Production; 2011; Kalyani
Publishers, New Delhi; Pg no.77
P. N. Bhat, C. L. Arora; Sheep Production; 2009; Stadium Press
(India) Pvt. Ltd.; Delhi; Pg no. 96-98; 291
https://en.wikipedia.org/wiki/culling

27. THANK YOU…….