Applied Animal Genetics Quiz

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Questions and Answers

How does understanding DNA contribute to genetic improvement in animals?

Understanding DNA allows identification of animals with high genetic merit, enabling farmers to select for desirable traits.

What physical trait is characteristic of Aberdeen Angus cattle and how is it determined genetically?

Aberdeen Angus cattle are naturally polled, determined by a dominant gene that prevents horn development.

Explain the concept of performance testing in cattle evaluation.

Performance testing involves comparing a bull's weight gain and feed conversion ratio with others under similar conditions.

What is the difference between performance testing and progeny testing?

Performance testing evaluates a bull's direct performance, while progeny testing assesses the performance of its offspring. Signup and view all the answers

Define line breeding and its significance in animal genetics.

Line breeding is a form of selective breeding that focuses on specific bloodlines to enhance desirable traits. Signup and view all the answers

Why is progeny testing considered more reliable than performance testing?

Progeny testing evaluates the genetic potential of breeding animals based on their offspring, offering a clearer indication of hereditary traits compared to performance testing, which relies on the individual's performance alone. Signup and view all the answers

Discuss how selective breeding can impact the genetic diversity of a population.

Selective breeding can diminish genetic diversity by favoring specific traits and narrowing the gene pool. Signup and view all the answers

Why is it important for farmers to monitor feed conversion ratios in bulls?

Monitoring feed conversion ratios helps determine the efficiency of feed use, impacting overall farm profitability. Signup and view all the answers

What is natural selection and how does it influence breeding practices?

Natural selection refers to the process where organisms best adapted to their environment survive and reproduce, influencing breeding by favoring traits that enhance survival and fitness. Signup and view all the answers

What is a deleterious gene and how does it affect animal fitness?

A deleterious gene is one that negatively impacts an organism's fitness, making it less likely to survive and reproduce, such as the Brachyspina gene in Holsteins affecting embryonic development. Signup and view all the answers

Describe the process of cloning and its significance in agricultural biotechnology.

Cloning involves creating genetically identical individuals, which is significant in agriculture as it enables the propagation of desirable traits in plants and animals uniformly. Signup and view all the answers

What was the significance of Dolly the sheep in the context of cloning?

Dolly was the first cloned animal from a somatic cell, demonstrating the possibility of creating genetically identical animals and raising ethical and scientific discussions in biotechnology. Signup and view all the answers

What is genetic modification and its application in livestock?

Genetic modification involves inserting new genes into an organism's genome, and in livestock, it has enabled the production of pharmaceuticals, like Atryn, from genetically modified goats. Signup and view all the answers

What are the two main types of carbohydrates found in animal feeds?

Soluble and insoluble carbohydrates. Signup and view all the answers

What role does lignin play in animal nutrition?

Lignin is indigestible and reduces the digestibility of other dietary components. Signup and view all the answers

What are triglycerides composed of?

Triglycerides are composed of one glycerol backbone and three fatty acids. Signup and view all the answers

Name one essential amino acid and one non-essential amino acid.

Essential: Arginine; Non-essential: Glycine. Signup and view all the answers

What happens to excess ammonia in an animal's body?

It is converted to urea and excreted in urine. Signup and view all the answers

How does bile assist in the digestion of fats?

Bile activates lipase and helps emulsify fats into smaller globules. Signup and view all the answers

What is the purpose of measuring Digestible Energy (DE) in animal feed?

DE measures the proportion of feed energy that is not lost in feces. Signup and view all the answers

What are the two types of triglycerides based on fatty acid composition?

Simple triglyceride and mixed triglyceride. Signup and view all the answers

Study Notes

Genetics

DNA serves as the genetic blueprint for living organisms.
Identifying animals with high genetic merit through DNA is essential for breeding and improvement.

Genetic Improvement

Knowledge of animal genetics helps farmers enhance the genetic traits of livestock, improving farm profitability.
Physical traits, such as being polled in Aberdeen Angus cattle, are dominated by specific genes, influencing farmer selection.

Selective Breeding

Line breeding involves breeding within a specific lineage to enhance desirable traits.

Performance Testing

Evaluates bulls based on weight gain and feed conversion ratios compared to peers in similar conditions.
Key performance indicators include growth rate and feed conversion ratio (FCR).

Progeny Testing

Assesses the performance of a bull's offspring against other bulls' offspring under controlled conditions.
Generally more reliable than performance testing alone.

Genotyping and Genomic Selection

Utilizes genetic information to select for superior traits in breeding programs.

Natural Selection

Describes "survival of the fittest," where well-adapted organisms pass on desirable traits.
Example: Holstein breed's introduction to Irish dairy herds increased milk yield, yet it also led to fertility and lameness issues.
Deleterious genes, like Brachyspina in Holsteins, can adversely affect animal development and survival.

Agricultural Biotechnology

Cloning results in genetically identical organisms; this has applications in horticulture and animal breeding.
Dolly, the first cloned sheep, was created in 1996 using somatic cell nuclear transfer.

Genetic Modification

Involves inserting new genes into an organism's genome, with limited methods approved for livestock.
Example: Atryn, a drug produced from genetically modified goats' milk, prevents blood clotting and demonstrates the potential of genetic modification in agriculture.

Components of Feeds and Forages

Important to understand the basic nutritional components provided by feeds and forages.

Carbohydrates (CHO)

Classified into simple and complex forms.
Lignin is indigestible, negatively impacting the digestibility of fiber and protein.
Whole grain cereals are rich in starch, particularly amylose and amylopectin contained in the endosperm.

Energy, Protein, and Fibre

Grass, barley, and cottonseed meal are significant sources of energy and protein.
Protein in the diet primarily consists of amino acids.

Fat and Energy in the Diet

Fat is predominantly found as triglycerides, composed of glycerol and three fatty acids.
Simple triglycerides contain identical fatty acids, while mixed triglycerides contain different fatty acids.
Functions of fat in the diet include providing energy, aiding in nutrient absorption, and supporting cellular structures.

Digestion of Fat

Fat globules are initially hard to digest, requiring them to move directly from the stomach to the small intestine.
Pancreatic lipase breaks down fatty acids; bile facilitates the enzyme's action by emulsifying fats.

Protein

Proteins are chains of amino acids; they are essential for various bodily functions.
Essential amino acids must be consumed through the diet, while non-essential amino acids can be synthesized by the body.
Excess protein is broken down into ammonia, which is converted to urea for excretion.

Metabolism and Measurement of Energy in Ruminants

Digestible Energy (DE) is the portion of energy from feed that is absorbed and not lost in feces.
Understanding feed energy partitioning is crucial for assessing nutritional efficiency in ruminants.

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Description

Test your knowledge on the principles of applied animal genetics, focusing on DNA structure and its implications for genetic improvement in livestock. Explore how understanding animal genetics can enhance farm productivity and profitability.