CROSS BREEDING:
This is mating of animals from the two different established breeds
Eg.: Jersey (b) x Kangayam (c) : Jersey (c) x Holstein Friesian (b). The cross bred animals
will exhibit the mixture of qualities of both the parents breeds. The progeny will improve in
production performance and will exhibit marked disease resistance characteristics of
the native breed and is well adpated to with mstand local climatic condition. 62.5% of exotic blood & 37.5% local blood – ideal .
Jersey x local breed.- F1- 50% ND(c) x J (75%) + 25% ND – F1 50 J 50 ND x 100 J (B) So cross breeding is also taken up to evolve new breed.
Age at maturity Economic traits
1.Age at 1st calving : Age in days of the cow or buffalo on the date of 1st calving.
2. Lactation Length : Days in milk from the date of calving to the final drying off or
or cessation of milk (305 days)
3. Lactation Yield : Milk yield in Kgs from the date of calving to the date of drying (corrected to 305 days)
4. Dry period : Days from the date of drying to the date of calving
5. Inter calving period: Days from the date or one calving to the date of next calving (1st,2nd )
6.Peak yield : The highest daily yield in Kgs during lactation period
7. Average Fat% : Average Fat %
8.Service period : The interval between calving and subsequent service resulting in conception
9.Breeding efficiency : Measured as the No. Services/Conception
Breeding : Production of off springs / young ones
Scientific breeding is needed to get better performance in livestock – milk – meat – wool – Egg
Inbreeding : mating of closely related animals in the same breed such as brother – sister mating
ii. parents off spring mating- when the mates have common ancestors -with in generations this results in inbreeding
Advantage : A pure line of a particular breed can be maintained
Dis advantage : Loss of vigour, size, production fertility problems
Out breeding : Mating of unrelated animals in the same breed but with no common ancestor for a minimum of 4-6 generations.
Grading : Grading is a farm of out crossing, where in bulls of a distinct breed are bred on non descript cows from generation to generation, so that in course of time a populations essentially resembling the breed from which the Bulls are used.
Non descript cow x Jersey Bull
F1 50% ND + 50% Jersey x Jersey Bull
F2 25% ND + 750% Jersey x Jersey Bull
F3 12.5% ND + 87.5% Jersey x Jersey Bull
After 5-6 generations the off springs will have 96.9 & 98.3% of the hereditary characters of
„Pure Breed‟
So grading is a process by which a few „Pure Breed‟ sires can rather quickly transform
local variety of animals into a „Group‟ resembling the pure breed.
Economic Traits
Oestrus cycle
Proestrum🙁 2 days) Period of building up growth of graffian Follicle which helps for the
nourishment of ovum fluid contains hormone called „oestrogen‟. It causes changes in uterus, blood supply.
Oestrum: ( 1 day) During which the female is ready to receive male.
Metoestrum 🙁 4 days) Implantation of the embryo takes place C.L. takes place. Prevents the growth of graffian follicle thereby arrests oestrus cycle.
Diestrum : ( 14 days)Further development of uterus takes place. If the animal has not
conceived involution of uterus take place.
Symptoms of Heat:
1.Off feed 2. Drop in milk yield 3. restless and excited 4. Bellowing 5. Oedema / swelling of
genitalia 6. frequent utination 7. Transparent mucous discharge 8. cow/buffalo which are in heat will mount on other animals and allows mounting of other animals.
OPTIMUM TIME FOR CROSSING
Egg/ova from ovary – released about 12-18 hours after the onset of symptoms of heat. Ovum will survive upto 16 hours after the release. Sperm live for 12-14 hours.
Morning signs of heat are exhibited – AI done in the evening : 12 hours delay.
Proestrum : This marks the animal – coming in heat. GF – Ovary – growing – increased -secretion of follicular fluid – Estradiol – increase No.of Cilia – increased Vascularity of uterus
– increase in thickness ofEpithlial wall of vagina .
The vaginal wall adjustemnt is well filled to prevent possible damage to the wall when coitus occurs.
Oestrum : This is the period of desire. „Graffian Follicle‟ – Ripe or very turgid
This period is brought to an end by the rupture of the follicle (or) ovulation. Vulva becomes
swollen. Vulva and Vagina – congested.
Met Oestrum : This is the period when the organ returns to normal non congested condition.During this period the cavity of the GF from which ovum has been expelled becomes recognized and forms a new structure known as C.L.
1. It prevents the maturation of further graffian follicle
2. It is essential for the implantation of the fertilized egg.
3. It is intimately concerned which the development of mammary gland.
Diestrum :Longest part of estrus cycle
Implantation – uterine milk –for the nourishment of the embryo prior to implantation. Absenceof pregnancy. – returns to normal and thus the cycle continues.
ARTIFICIAL INSEMINATION.
Artificial insemination is the deposition of male reproductive cells
(sperm) in the female tract by mechanical means rather than
“Natural Service”
ADVANTAGES :
1.Increases usefulness of superior sires to extra ordinary degree.
2.Services of Superior Sires are greatly extended.
If the sires are used for Natural Service the animal can serve only 50-60
animals/year but under Artificial Insemination the amount of
semen secreted by the animal can be used to satisfy the
requirements of 1000 animals per year
DILUTION OF SEMEN
Average of Sperm/mL : 1000 million
Total volume of semen/2 ejaculate :6 mL
No. of motile Sperms : 90 %
Total number of motile sperms : 5400 million.
Expected wastage during processing : 10 %
(i.e.) filling and sealing
Net no.of sperms available : 5400-540= 4860
Minimum No. of sperms required / dose : 30 Million.
@ this rate no. of doses that could be prepared : 4860 /30 = 160 doses
So, total no. of doses that can be : 160 x 52 weeks = 8320 doses.
prepared / week
Frozen semen required / dose : 1 mL
3.No need to maintain Breeding Bull.The frozen semen can be stored in the Liquid Nitrogen1960C.
4.Semen can be quickly and easily transported by air to different continents.
5.Spreading of diseases is absolutely- NIL.
6.Overcomes the difficulty of size and weight between Dam and Sire.
7.Increase the rate of Conception because in the artificial insemination the semen is being
deposited in the mid cervix .
8.Outstanding animals located apart can be mated.
9.Helps in better record keeping.
10.Old and heavy sizes bulls ,injured / disabled sires can be used.
MERITS:
1.Semen can be stored in the frozen state , so progeny can be obtained even after the transfer, WHY even after death of bull-15-20 years.( atomic, radioactive, X-ray unit)
2.Semen is expanded and no. of animal can be crossed.
3.Frozen semen can be transported to destination once in a month from the semen bank.
DISADVANTAGES.
1.Some bulls semen may not freeze well.
2.If inferior bull semen is frozen and used –Extensive damage is caused.
3.Maintenance of frozen semen bank is not economical for a small area of operation.
4.Requires well trained technical personnel‟s and special equipments and hygienic measures are to adapted in preparation.
5.Improper cleaning of instruments and unsanitary condition may lead to lower fertility and may be nucleus for the spreading of diseases
