Quick Review on Animal Breeding

TERMINOLOGY

• Animal breeding: Branch of animal science that addresses the evaluation (using best linear unbiased prediction and other methods) of the genetic value (estimated breeding value, EBV) of domestic livestock.
• Backcross: Backcross is the mating of a two–breed animal back to one of the two parental breeds
• Crossbreeding: Mating of different breeds to produce multi-breed offspring.
• Dominance: A dominant gene affects the appearance of the phenotype.
• Estimated Breeding Value (EBV): An estimate of an animal’s genetic merit for a particular trait based on the individual’s performance and the performance of relatives.
• Expected Progeny Difference (EPD): The expected difference between the progeny performance of a breed average animal and the performance of an individual’s progeny for any given trait(s). An animal’s EPD is ½ of its EBV and is equal to ½ (Sire EPD + Dam EPD).
• F1: Progeny resulting from the mating of a purebred ram and a purebred ewe of different breeds.
• Gnotype: The actual genetic make-up of an individual as determined by its genes.
• Half-sibs: Individuals who have the same sire or dam (i.e. half brothers and half sisters).
• Heredity: The transmission of characteristics from parents to their offspring through genes.
• Heritability: Is the proportion of a measured or observed trait that is transmitted to the offspring by genes.
• Heterosis (Hybrid Vigour): The increase in performance observed for a specific crossbred above the average performance of the parental lines.
• Heterozygous: Each gene of a specific gene pair is different in an individual (i.e. Aa).
• Homozygous: Each gene of a specific gene pair is the same in an individual (i.e. AA).
• Inbreeding: Production of progeny from closely related parents.
• Linebreeding: A form of inbreeding which increases the average relationship of the individuals in a flock to an outstanding ancestor or line of ancestors.
• Linecross: Progeny produced by crossing two or more inbred lines.
• Multiple Trait Selection: Selection for more than one trait at the same time.
• Mutation: A rare change in the DNA. Extent to which mutations influence the inheritance of farm livestock is not known precisely.
• Outcrossing: Mating of individuals within a breed that are not closely related.
• Persistency: The degree to which milk yield is maintained from month to month by the cow during her lactation.
• Pnetrance: The ability of a gene or group of genes to cause their characteristic to develop under the conditions of a particular environment.
• Pure breeding: Also straight breeding. The mating of purebreds of the same breed
• Random Mating: A mating system where all ewes have the same chance of being mated to any ram used.
• Rotational Crossbreeding: Systematic crossing of two or more breeds in which the crossbred ewes are mated to rams of the breed contributing the least genes to that ewe’s phenotype.
• Sibs (Full Sibs): Brothers and sisters from the same sire and dam.
• Super-ovulation: The administration of a hormone causing a female to develop and release more eggs than normal

Cell

• DNA molecule: 4 bases + a peptone sugar + A phosphate group
• Lysosomes (animal only) - production of intracellular digestive enzyme
• Mitochondria (rice shape)- Energy production (Kreb’s cycle), also called power house of cell which provide the 90% of the energy requirements
• Ribosome-Site of protein synthesis
• Plasma membrane- permeable membrane
• The smallest body cells are found in blood stream, while, and largest are nerve cells.
• Cell is the individual unit of living structure
• Robert Hooke of England applied the term “cell”
• Bases: Purines
• Adinine
• Guanine
• Pyrimidines
• Cytosine
• Thymine

@ In RNA Uracil is replaced by Thymine of DNA and pentose ribose is replaced by deoxyribose

@ RNA:

• m-RNA: Carry coded information from DNA to ribosomes
• r-RNA: Part of ribosome
• t-RNA: or soluble RNA (s-RNA) recognize specific amino acids in the cytoplasm

@ There is at least one specific S-RNA for each amino acid.

Cell division

1.      Mitosis: Division of somatic cells when 2 daughter nuclei are formed with same chromosome as parent cell

Stages:

• Interphase: Chromosomes are visible, centrosome divides into 2 parts of centrioles
• Prometaphase: Spidle mechanisms are formed
• Metaphase: Each chromosome 2 chromatids with single centromere
• Anaphase: 2 sister chromatids are converted to independent chrosomomes
• Telophase: Spindle disappear

Karyokinesis: Nuclear division

Cytokinesis: Cytoplasmic division

2.      Meiosis: Division I: Prophase I:

• Leptonema: Bead like structure
• Zygonema: Synapsis, Zipper like
• Pachynema: Crossing over
• Diplonema: Chiasmata
• Diakinesis: Termination completed

Metaphase I, Anaphase I, Telophase I

Division II: Equational like mitosis cell division

• Zygote:  Fertilized egg before first cleavage
• Synapsis: Pairing of homologous chromosomes during prophase of meiosis I
• Sex limited traits: Traits controlled by gene located on the X-chromosome
• Sex limited gene expression: Heritable traits determined by only one sex (Beard in man)
• Sex influenced dominance: Dominance in one sex and recessive to other (Baldness in man)
• Pleiotropy: Where a single gene produced 2 or more phenotypic effects
• Multiple allele: 3 or more possible alleles (ABO blood group in humans)
• Autosomes: The chromosomes present in the same number in both sexes of any species
• Gregor Johann Mendel is called “father of Genetics”
• Law of segregation: Tall × Dwarf In mono hybrid cross: 3:1 (F1) and 1:2:1 (F2) ratio

INDIGENEOUS BREEDS OF LIVESTOCK & POULTRY

CATTLE

1. Siri (Local hilly cow):

• Black and white in colour
• Famous draft breed of esteem hills of Nepal (Ilam District)
• Fairly good milkers (360kg/lactation @1.5kg milk/day)
• Av. Body wt. 315kg, age of 1st calving 63 months, C.I-12-20 months

2. Achami:

• World smallest breed of cow found in Nepal only
• They are less than 1 meter in height at withers
• Suitable in hill condition and low input system (Achham, Doti, Bajura)
• Body colour is varies from black and white.
• Maximum body wt. is 150 kg
• Av. Milk yield is 1.5 kg/day

3. Khaila:

• Found in Himalayn region of Nepal particularly in Mustang, Humla & Mugu districts (suitable for mid-hills)
• Good draught type animal located in far-western region of Nepal
• Larger indigenous breed in the country and difficult to handle
• Bulls and cows  are breed with Naks and Yaks
• Av. Milk yield is 2.5 kg/day

4. Terai:

• They are light coloured animal mostly white and suitable for terai region (hot climate)
• They are low milk yielder (2.1 kg/day)  and good draught breed
• Use terai cattle for genetic improvement to the 62.5% of exotic breed & 37.5% to 50% terai cattle

5. Lulu:

• Small size Bos taurus cattle found in high mountains of Nepal (suitable for cool & dry place and good for low input system)
• This is the only breed of cattle in the country that is humpless.
• They are located in the Mustang and some parts of Manang & Dolpa
• Av. Milk yield is 1.6 kg/day

6. Phadi:

• They are mostly black in colour
• Located across the hills conditions and good draught breed
• Av. Milk yield is 1.1 kg/day

7. Yak and Nak:

• They are the mountains (14,000-20,000 ft) cattle and localized in the northern belt of the country
• Body colour is varies from black and white.
• Chauries are good milk yielders and Jhopkyos are sterile & good for transportation as pack animals
• Wool production of Yak and Nak is 1.2 & 0.7 kg respectively
• Maximum body wt. is 355 (Yak) and 325 (Nak) kg
• Av. Milk yield is 0.6 kg/day with fat 6.6%

Mating of Yak (male) × hill cattle (female)

• Urang Chauri (female, fertile)
• Urang Jhopkyos (male, sterile)

Mating of Nak (female) × hill cattle (male)

• Dimgo Chauri (female, fertile)
• Dimgo Jhopkyos (male, sterile)

Mating of Yak (male) × Dimgo Chauri (female)

• Tolmu Chauri (female, fertile)
• Tolmu Jhopkyos (male, sterile)

BUFFALO

1. Lime:

• This buffalo is grey in colour with white hair colour around the jaw and brisket region
• Body medium sized with sickle shaped horns cuverd toward the back
• Can withstand under low pasture condition and resistant to disease
• Live wt. 250-400 kg, MY-255ltr/lactation, @2.1 ltr/Day, Fat 7.5%, CI-80wks, Calving period- Swrawa- Aswin, age of 1st calving- 4 years

2. Parkote:

• This buffalo is mainly black in colour with long face, black muzzle and flat head white hair colour around the jaw and brisket region
• Body medium sized with sword shaped horns directed toward the back
• Suitable for hills, high milk yielders, adaptable to brash environment
• MY-2.0-2.5 kg/day

3. Gaddi:

• They are located in the far western region in Nepal
• This buffalo is mainly black in colour with white round patches on the forehead.
• Long face, flat face and horns are long half curved
• Suitable for hills, high milk yielders, adaptable to brash environment
• MY-4.6 kg/day

GOAT

1. Khari:

• They are located in the Mahabharata, mid hills region of Nepal & represent 56% of the total goat population of the country
• They are prolific and good for meat purpose of 30 kg body wt and 3.5% fat in milk
• They are hardy and well adopted in local environment
• Body color varied from white (Seti) to black (Kali)

2. Terai:

• They are light coloured (mostly white) breed located in the Terai region
• Good meat types of breeds of 30 kg body wt.
• From conservation point of view they are at risk as it is difficult to find as a pure form

3. Sinhal:

• Found in south hill mountains (1500-3000 m) of Nepal as pack animals
• They are heaviest native breed of goat and represent 16% of the total goat population of the country
• They are good meat and draught types of breeds of 35 kg body wt.

4. Chyangra:

• Found in hill hills of Nepal as pack animals along with Bhyanglung type of sheep
• They represent 1% of the total goat population of the country
• They are used for meat and Mohair or Pashmina (cashmere=500-740gm) production
• Body color varied from pure white to pure black of 25-40 kg body wt.

SHEEP

1. Kage:

• Suitable for lower hills, hardy, short tailed breed, course wool type & suitable for making radi/pakhi (Blankets)
• They represent 21% of the total sheep population of the country
• They are mainly used for wool and smallest among the indigenous breed with better prolificacy (18% twining)
• It is the purest Neplease breed of sheep
• Male are sickle shaped horns and female are polled.
• The coat colour is white except in the head region (brown)
• Av. Wt. is 16-24 kg, 3 lambing/2years, 700gm.year

2. Lampuchhre:

• They extremely heat tolerance and suitable for terai region, hardy, long tailed (0.5-0.6m) breed, good fighting quality, meat type
• They represent 12% of the total sheep population of the country
• The body colour is mostly white
• Av. Wt. is 25-30 kg

3. Baruwal:

• Suitable for hills, hardy, good grazing instinct, wool suitable for making radi/pakhi
• They represent 63% of the total sheep population of the country and concentrate in mountains (41%) & hills (22%)
• They are also used as pack animals
• Av. Wt. is 40kg (male) & 30kg (female) kg, Wool production 1.65kg (male) &  1.2kg (female)

4. Bhyanglung: (Tibetan Sheep)

• Suitable for high hills (2500 -4000 m), hardy, carpet wool type
• They represent 4% of the total sheep population of the country
• Av. Wt. is 60-90 kg, Wool production 1.0kg/2shearing

5. Bhote:

• Found in the Northern part of Nepal

PIG

1. Hurrah:

• They are the largest sized pig amongst indigenous breeds
• Suitable for terai, hardy, suitable for backyard rearing
• They are mainly used for meat
• They represent 23% of the total pig population of terai
• They are rust brown in colour, well suited for scavenging conditions
• Body wt. is 40-55 kg, produce 7 piglets in a litter with Av. Wt. of 0.8 kg

2. Chwanche:

• Suitable for hills, hardy, suitable for backyard rearing
• They represent 58% of the total pig population of the country
• They are black in colour, hardy and well suited for local environment
• Body wt. is 25-40 kg, produce 5 piglets in a litter with Av. Wt. of 0.6 kg

3. Bampudke (Sano bandel):

•  They are the smallest hog breed in the world
• They are found in both wild and domestic form and are very hard animal, meat quality
• Found in Chitwan, Nawalparasi
• Body wt. is 18-25 kg

Poultry: Sakini, Pwankhulte, Ghantikhuile