DAIRY FARM RECORD KEEPING

1.Identification of animal record
2.Growth record
3.Health record
4.Animal death record
5.Calf death record
6.Breeding and calving record
7.Recording of dairy milk yield
8.Recording of concentrate feed and mixture feeding
9.Labour maintenance record
10.Water requirement record
11.Recording of culling animal
12.Recording of selling animal
13.Recording of buying animal

CULLING OF DAIRY ANIMALS

Culling is elimination or weeding out of undesirable animals from the herd, for reasons of uneconomic,, poor production, or very poor reproductive ability, with sterility problems and breeding, irregularities, very poor conditions, stunted growth, suffering from incurable illness, or disease animals found to be positive for serious infections diseases like Tuberculosis, Johnes disease, Brucellosis, lost one or more quarters and teats of the under due to chronic mastitis resulting in marked reduction in milk production. Undesirable breed characters present in young animal. When the herd is a pure bred herd leading to disqualifications family lines, exhibiting heritable characters like supernumerary teats, loose horns in cows of certain breeds. Disable animals due to injury or loss of organ, extreme lameness leading to unmentionable conditions, un healed fractured animals etc. come under the animal proposed or culling. The culled animals carry lower values and a separate list is made for such called animals and it is known as culling list.

When the culling cows for poor production, the entire lactation at yield is considered and preferably first two lactations are observed and if the lactation yield is less than what is expected from the breed or herd, The animal is included in the culling list. Very old animals are culled, as their maintenance will be uneconomical.

Male animals or other animals surplus in the farm or not useful in the farm and they are culled. Calves born with congenital defects like congenital fibrosis of the eye, total blindness or some other defects are included in the culling. Calves born much below the normal birth weight are included in the culling. Yearlings animals male or females, stunted much below their normal body weight, potbellied conditions bad confirmation are culled. Dairy Animal Management Valuation and culling is done on the farms every year at least once in year. In some farms culling is done twice a year however doing it once a year is must.

 (Source: http://bieap.gov.in/DairyAnimalManagementTheory.pdf )

Culling in dairy animals 10 points

• Do not move non-ambulatory animals to market under any circumstances.
• Make the decision to treat, to cull, or to euthanize animals promptly. Sick and injured animals should be segregated from the herd
• Delay transport of an animal that appears to be exhausted or dehydrated until the animal is rested, fed, and dehydrated.
• Milk all cows that are still lactating just prior to transporting to a packing or processing facility.
• Use a transportation company that is knowledgeable about your animal care expectations and provides for the safety and comfort of the animals during transport.
• Do not transport animals to a packing or processing facility until all proper treatment withdrawal times have been followed.
• Do not transport animals with a poor body condition, generally a Body Condition Score of less than 2 (1-5 scale).
• Do not transport animals that require mechanical assistance to rise and are reluctant or unable to walk, except for veterinary treatment. When using any handling device, abuse must not be tolerated.
• Do not transport animals with bone fractures of the limbs or injuries to the spine. Animals with a recent fracture unrelated to mobility should be culled and transported directly to a packing or processing facility.
• Do not transport animals with conditions that will not pass pre-slaughter inspection at a packing or processing facility. If unsure, consult with your veterinarian before transporting an animal to a packing or processing facility.

(Source:http://www.agmkt.state.ny.us/ai/Top_10_Considerations_Electronic_Version.pdf )

Article Credit:http://agritech.tnau.ac.in/

ECONOMIC CHARACTER IN DAIRY CATTLE

The various economic characters in Dairy Cattle management are
1. Lactation yield
2. Lactation period
3. Persistency of yield
4. Age at first calving
5. Service period
6. Dry period
7. Inter calving period
8. Reproductive efficiency
9. Efficiency of feed utilization
10. Disease resistance.

1.  Lactation yield:
The lactation yield in a lactation period is known as lactation yield. ‘The lactation yield in Indian breeds is very low compared to exotic breeds. This is dependent on no.. of calving, frequency of milking, persistency of yield .Normally in dairy cattle 30 - 40 % increase in milk production from first lactation to maturity is observed. After 3 or 4 lactation the production starts declining. For comparison of milk yield of different breeds and animals the milk yield should be converted into fat corrected milk (FCM). 4% FCM = 0.4 total milk + 15 total fat. After parturition the milk yield per day will be increased and reaches peak within 2-4 weeks after calving. This yield is known as peak yield. The maintenance of peak yield for more time is importance for better milk production. The lactation period in Indian breeds is low and so the production is also less and conversion.

2. Lactation period:
The length of milk producing period after calving is known as lactation period. The optimum lactation period is 305 days. The milk production will Breeding of dairy animals and farm records wil be less, if this period is shortened. Indian breeds will have less lactation period, but in some breeds this period is more with very little milk production.

3. Persistency of Milk Yield:
During lactation period the animal reaches maximum milk yield per day with in 2-4 weeks which is called peak yield. For high level of lactation yield, this peak yield should be maintained for longer period as far as possible, The maintenance of peak yield for long period is known as persistency, slow decrease in dairy milk yield after reaching peak yield in necessary. High persistency is necessary to maintain high level of milk production.

4. Age at first calving
The age o the animal at first calving is very important for high life time production. The desirable age at first calving in Indian breeds is 3 years, 2 years in cross breed cattle and 3 1/2 years in Buffaloes. Prolonged age at first calving will have high production in the first lactation) but the life time production will be decreased due to less no of  calving. If the age at first calving is below optimum, the calves born are weak, difficulty in calving and less milk production in first lactation.

5. Service period:
It is the period between -date of calving and date of successful conception. The optimum service period helps the animal to recover from the stress of calving and also to get back the reproductive organs back to normal For cattle the optimum service period is 60-90 days. If the service period is too prolonged the calving interval prolonged, less no. of calving will be obtained in her life time and ultimately less life time production.’ If the service period is too short, the animal will become weak and persistency of milk production is poor due to immediate pregnancy.

6. Dry Period:
It is the period from the date of drying (stop of milk production) to next calving. When the animal in pregnancy, before next calving. The animal should be given rest period to compensate for growth of foctus. A minimum of 2 – 2 ½ months dry period should be allowed) If the dry period is not given or too low dry period, the animals suffer from stress and in next lactation, the milk production drops substantially and also it gives weak calves. On the other hand if the dry period given is too high, it may not have that much effect on increasing milk yield in the next lactation, but it decrease the production in the present lactation.

7. Intercalving period:
This is the -period between two successive calving. It is more, profitable to have one calf yearly in cattle and at least one calf for every 15 months in buffaloes. If the calving interval is more, the total no. of carvings in her life time will be decreased and also total life production of milk decrease.

8. Reproductive Efficiency:
The reproductive efficiency means the more number of calves during life time, so that total life time production is increased, The reproduction or breeding efficiency is determined by the combined effect of hereditary and environment. Several measures of breeding efficiency like number of services per conception, calving interval, and days from first breeding to conception are useful. Reproductive efficiency has generally a low heritability value indicating that most of the variations in this trait is due to non genetic factors. In adverse environmental conditions, the poor milk producing animals may not be much affected compared to high effect in high milk yield.

9. Efficiency of Feed Utilization and Conversion into Milk:
The animal should take the feed more and utilize efficiently to convert into the milk.

10. Disease Resistance:
Indian breeds are more resistant to majority of disease compared to exotic cattle. Cross breeding helps to get this character.

(Source: http://bieap.gov.in/DairyAnimalManagementTheory.pdf )

Article Credit:http://agritech.tnau.ac.in/

Cattle Artificial Insemination

ARTIFICIAL INSEMINATION

Introduction
Artificial insemination is the technique in which semen with living sperms is collected from the male and introduced into female reproductive tract at proper time with the help of instruments. This has been found to result in a normal offspring. In this process, the semen is inseminated into the female by placing a portion of it either in a collected or diluted form into the cervix or uterus by mechanical methods at the proper time and under most hygienic conditions. The first scientific research in artificial insemination of domestic animals was performed on dogs in 1780 by the Italian scientist, Lazanno Spalbanzani. His experiments proved that the fertilizing power reside in the spermatozoa and not in the liquid portion of semen. Few further studies under research station conditions helped this technique to be used commercially allover the world including India.

Artificial insemination is not merely a novel method of bringing about impregnation in females. Instead, it is a powerful tool mostly employed for livestock improvement. In artificial insemination the germplasm of the bulls of superior quality can be effectively utilized with the least regard for their location in far away places. By adoption of artificial insemination, there would be considerable reduction in both genital and non-genital diseases in the farm stock.

SYMPTOMS OF HEAT
      The various symptoms of heat are

• The animal will be excited condition. The animal will be in restlessness and nervousness.
• The animal will be bellow frequency.
• The animal will reduce the intake of feed.
• Peculiar movement of limbo sacral region will b observed.
• The animals which are in heat will lick other animals and smelling other animals.
• The animals will try to mount other animals
• The animals will standstill when other animal try to mount.. This period is known as standing heat. This extends 14-16 hours.
• Frequent maturation (urination) will be observed.
• Clear mucous discharge will be seen from the vulva, sometimes it will be string like the mucous will be seen stick to the near the pasts of  valva.
• Swelling of the valva will be seen.
• 11 Congestion and hyperemia of membrane.
• The tail will be in raised position.
• Milk production will be slightly decreased.
• On Palpation uterus will be turgid and the cervix will be opened.

A.I. ADVANTAGES – DISADVANTAGES

Advantages and disadvantages:
Artificial insemination (A.I.) is deposition of semen into the female genital tract by means of instruments.

ADVANTAGES OF ARTIFICIAL INSEMINATION:
There are several advantages by artificial insemination over natural mating or servicing.

• There is no need of maintenance of breeding bull for a herd; hence the cost of maintenance of breeding bull is saved.
• It prevents the spread of certain diseases and sterility due to genital diseases.
• Eg: contagious abortion,  vibriosis.
• By regular examination of semen after collection and frequent checking on fertility make early detection of interior males and better breeding efficiency is ensured.
• The progeny testing can be done at an early age.
• The semen of a desired size can be used even after the death of that particular sire.
• The semen collected can be taken to the urban areas or rural areas for insemination.
• 7 It makes possible the mating of animals with great differences in size without injury to either of the animal.
• It is helpful to inseminate the animals that are refuse to stands or accept the male at the time of oestrum.
• It helps in maintaining the accurate breeding and cawing records.
• It increases the rate of conception.
• It helps in better record keeping.
• Old, heavy and injured sires can be used.

Disadvantages of A.I:

• Requires well-trained operations and special equipment.
• Requires more time than natural services.
• Necessitates the knowledge of the structure and function of reproduction on the part of operator.
• Improper cleaning of instruments and in sanitary conditions may lead to lower fertility.
• If the bull is not properly tested, the spreading of genital diseases will be increased.
• Market for bulls will be reduced, while that for superior bull is increased.

SEMEN COLLECTION METHODS AND EVALUATION:
Various methods of collection of semen have been devised from time to time. The older unsatisfactory methods have gradually replaced by the new modern techniques.

There are three common methods.

1. Use of artificial vagina
2. By Electro-stimulation method.
3. By massaging the ampulae of the duct us differences through rectal wall.
4. The ideal method of semen collection is use of artificial vagina which is safe for sire and the collector also.

ARTIFICIAL VAGINA METHOD:
The artificial vagina has the following parts:

• A heavy hard rubber 2" lose, open at both ends with a nostle for air and water in and outlet.
• Inner sleeve of rubber or rubber liner.
• The semen receiving cone or rubber cone.
• Semen collection tube made of glass or plastic graduate in cc and its fraction correct to 0.1 CC
• Insulating bag Before using for semen collection all the parts are washed thoroughly and sterilized properly, and assembled as artificial vagina, the rubber liner is inserted into the hose; inverting both ends back by folding back from either side opening, and fastening with rubber bands. Now the space between the hard rubber hose and inner rubber liner forms a water tight compartment. The nostle at one end of the hose can be fixed .

PARTS OF ARTIFICIAL VAGINA
Turning through the threaded nut up or down. The water jacket of the Artificial -vagina is- filled with hot water at a temperature of 45°C (113°F) by opening the nostle. The graduated semen collection tube is fixed to the narrow end of the artificial vagina hose, and fastened by a rubber band. The inner side of the rubber liner on the anterior side of the artificial vagina is lubricated with sterile jelly to a length of 3 to 4 inches. Air is blown through the nostle into the water jacket, to create pressure in if, and the same is exerted the rubber linear, to simulate natural vagina.

The temperature of the artificial vagina is to be checked, at each collection, and it should simulate natural vagina at mounting time. If the artificial vagina is to mount later. If it is too cold ejaculate may not be there after a thrust, or even if ejaculate is there; it may be contaminated with urine, and becomes unfit for use.

SEMEN COLLECTION METHOD. (A.V.)
The cow or dummy is secured in service create. The artificial vagina assembled is held at 45° angle from the direction of penis, and the thrust is that angle. The artificial vagina is held with the left hand by a right handed person; and when the bull mounts the cow, the sheath of the bull will be graphed by the operator, directing the gland penis into the artificial vagina, and then the bull gives a thrust to ejaculate. The operator should evince care so as not to touch the exposed past of the penis. After the bull dismounts, the artificial vagina is taken off from penis and the air vent is opened to release the pressure from the jacket. The water from the jacket is also drained by opening the nostle. This allows the ejaculate to flow from the cone to the semen collection tube. The semen collection tube is detached from the cone, plugged with cotton wool, and taken to the laboratory for examination. The rubber cone and the semen collection tube can be protected from external contamination or heat or higher, by covering with an insulation bag with zip.

Semen Collection

SEMEN STORAGE
The discovery that bull semen could be successfully frozen and stored for indefinite periods has revolutionized AI in cattle. In 1949, British scientists discovered that addition of glycerol to the semen extender improved resistance of sperm to freezing. Glycerol acts to remove water from the sperm cell prior to freezing and prevents the formation of cellular ice crystals which would damage the sperm. There are two methods of freezing and storing semen: dry ice and alcohol (-100 degrees F) and liquid nitrogen (-320 degrees F). Liquid nitrogen is preferred because there is no evidence of fertility deterioration with age. Fertility gradually declines in semen stored in dry ice-alcohol.

Frozen semen can be stored indefinitely if proper temperature is maintained. A recent report told of a calf born from frozen semen stored for 16 years. Fresh, liquid semen can be successfully stored for 1 to 4 days at 40 degrees F. Semen is usually stored in glass ampoules. Other methods appear promising, particularly the French-straw. Several AI organizations have gone to this method exclusively. Artificial coloring is frequently added to semen extenders in order to distinguish one breed from another. Complete identification of the bull is required on each individual semen container.

INSEMINATION METHODS:
There-are different methods insemination in different species of animals i.e. speculum  method, vaginal method and recto vaginal method.

Insemination

RECTO VAGINAL METHOD:
In cattle the safe and best method of insemination is “Recto vaginal method of insemination”. Cow which is in heat is well controlled placing it in a Travis. The inseminator will get ready by wearing a plastic apron, gumboots and gloves. The semen straw after thawing (keeping the semen straw in warm water for a minute to convert the freezed semen into liquid and the sperms become motile) is loaded in a sterilized A.I. gum and is covered with a plastic sheath. The inseminator will insert the gloved left hand into the rectum after applying the soft soap or other lubricant on the glove and back racked the animal, and the hand is further inserted and will catch hold the cervix through rectal wall. The A.I gum loaded with semen straw is passed.

Recto-vaginal method of insemination.
Through the vulva to ‘vagina and cervix and observed with the hand in rectum that the A. I gum reaches the cervix, then the semen is deposited by injecting the gun, and after depositing the semen the gun is removed, the empty straw and sheath are disordered.

SPECTRUM METHOD:
In this method spectrum is placed in the vagina of the cow, which provides passage outside to the site of insemination, then inseminating tube is passed through the speculum and semen is deposited at the cervix insemination method.

VAGINAL METHOD:
Hand is passed through the vagina and the inseminating tube is guided by hand to the site of insemination and semen is deposited. Here there is a risk of contamination and injury of female genitalia.

FROZEN SEMEN AND STORAGE :
Freezing of semen for successful preservation of spermatozoa, for long periods, is of great importance in livestock breeding and farm management. It has made it possible” to make available the use of outstanding proven sizes for larger number of cows, covering larger area, frozen semen shipment has become possible to different continents in the globe to any place connected with any service. Now a day if farmer wants to use of an outstanding size for inheritance of high milk yield, he can go in for frozen semen service provided his area is, covered by Artificial insemination, with supply of frozen semen.

At present frozen semen is used in most of the states in India. The technique of semen preservation in straws was developed in France . Freezing of semen is done with a special diluents, which has the following composition.
 

Sodium citrate dihydrate (angular) 2.4 y. 2.0 gm 8.0 ml 25.0%byvolume 50,000 units per 100 ml of semen Fructose Glycerol Egg Yolk Penicillin dilulent. Dihydro-streptomycin 50.0 mg per .100m1 of semen dilulent. Distilled water double glass distilled 100.Om1. The addition of glycerol to the dilulent makes the cells more resistant to the rigours of freezing and icy crystals, which form are smaller and smoother thus creating less damage to the spermatozoa. The addition of fructose to the diluent luprores sperm resistance to glycerol; and also provides nutrition.

Frozen semen is packed in single dose glass vials or plastic straws at +5°C. The final level of glycerol should be 7.0 to 7.6% during the freezing process. The antibiotics are added to inhibit bacteria and to kill pathetic organisms. The semen to be diluted in such a way that one ml. of extended semen will contain 20 million motile spermatozoa. The semen must be cooled carefully for spermatozoa to remain with life. The final temperature is lowered to -79°C or still lower. Quick freezing is done for a period of 3 to 5 minutes to -75°C with the help of atmosphere created by liquid nitrogen. In the slow freezing  technique cooling is done at the rate of 1 °C per minute from +5°C to -15°C. From -15°C to -31 °C at the rate of 2°C per minute. From -31°C to 75°C at the rate of 4 to 5°C per minute. Thus taking 40 minutes in total, further cooling to -96°C can be done quickly as it is not critical after freezing. Before freezing the diluted semen in equilibreated for 3 to 5 hours or for the best 16 to 20, hours period in refrigerator at 5°C. Frozen semen facilitates the percent use of the semen diluted and frozen, and thus the delivery price is reduced, and it can be supplied with the gaps of months to the A.I technicians as against the supply of fluid semen every days or alternate days. Liquid nitrogen plays a vital role for storing the frozen semen straws, at a temperature of -196°C for longer periods.

(Source: http://bieap.gov.in/DairyAnimalManagementTheory.pdf )

Artificial insemination (AI) of cattle 
Artificial insemination (AI) is the process of collecting sperm cells from a male animal and manually depositing them into the reproductive tract of a female. One can cite a number of potential benefits from the use of artificial insemination.

 

Increased efficiency of bull usage:

During natural breeding, a male will deposit much more semen than is theoretically needed to produce a pregnancy. In addition, natural breeding is physically stressful. Both of these factors limit the number of natural mating a male can make. However, collected semen can be diluted and extended to create hundreds of doses from a single ejaculate. Also, semen can be easily transported; allowing multiple females in different geographical locations to be inseminated simultaneously, and semen can be stored for long periods of time, meaning that males can produce offspring long after their natural reproductive lives end.

 

Increased potential for genetic selection:

Because artificial insemination allows males to produce more offspring, fewer males are needed. Therefore, one can choose only the few best males for use as parents, increasing the selection intensity. Furthermore, because males can have more offspring, their offspring can be used in a progeny test program to more accurately evaluate the genetic value of the male. Finally, individual farmers can use artificial insemination to increase the genetic pool with which his or her animals can be mated, potentially decreasing effects of inbreeding.

 

Decreased costs:

Male animals often grow to be larger than females and can consume relatively larger amounts of feed. Also, male animals are often more strong, powerful, and potentially ill-mannered and thus require special housing and handling equipment.

 

Increased safety for animals and farmers:

As mentioned, male animals can become large and aggressive. These factors mean that maintaining a bull on a farm may be dangerous. Also, because of the relatively larger size of adult males than females, natural mating is more likely to result accidents and injury to either the cow or the bull than is artificial insemination.

 

Reduced disease transmission:

Natural mating allows for the transfer of venereal diseases between males and females. Some pathogens can be transmitted in semen through artificial insemination, but the collection process allows for the screening of disease agents. Collected semen is also routinely checked for quality, which can help avoid problems associated with male infertility. 
 

Artificial insemination has some potential drawbacks, however, that must be considered. First, it can be more laborious. Male animals instinctively detect the females that are in the correct status for conception. With artificial insemination the detection work falls on the responsibility of the farmer. Poor detection results in decreased rates of fertility. Also, increasing the number of offspring per male has selective advantages only if the best males can be accurately determined. Otherwise this process only decreases the genetic variability in a population. Increasing the number of offspring per male always reduces the gene pool. The benefits of more intense selection must be balanced against the negative effects of decreased variation.

( Source: www.naweb.iaea.org)

ARTIFICIAL INSEMINATION TECHNIQUES

The technique of inseminating a cow is a skill requiring adequate knowledge, experience and patience. Improper AI techniques can negate all other efforts to obtain conception. Semen must be deposited within the tract of the cow at the best location and at the best time to obtain acceptable conception rates. Early methods of AI involved deposition of the semen in the vagina, as would occur in natural mating. Those methods are not satisfactory. Fertility is low and greater numbers of sperm are required. Another method which gained popularity was the "speculum" method. This method is easily learned, but proper cleaning and sterilizing of the equipment is necessary, making it more impractical to inseminate than with the rectovaginal technique which is the most widely used AI method today.

In the recto-vaginal technique a sterile, disposable catheter containing the thawed semen is inserted into the vagina and then guided into the cervix by means of a gloved hand in the rectum. The inseminating catheter is passed through the spiral folds of the cow's cervix into the uterus. Part of the semen is deposited just inside the uterus and the remainder in the cervix as the catheter is withdrawn. Expulsion of the semen should be accomplished slowly and deliberately to avoid excessive sperm losses in the catheter. The body of the uterus is short; therefore, care should be taken not to penetrate too deeply which might cause physical injury. In animals previously inseminated, the catheter should not be forced through the cervix since pregnancy is a possibility. Since research data show little variation in conception rates when semen is placed in the cervix, uterine body or uterine horns, some people recommend incomplete penetration of the cervical canal and deposition of semen in the cervix.

The recto-vaginal technique is more difficult to learn and practice is essential for acceptable proficiency but the advantages make this method of insemination more desirable than other known methods. With practice, the skillful technician soon learns to thread the cervix over the catheter with ease. If disposable catheters are used and proper sanitation measures are followed, there is little chance of infection being carried from one cow to another.

Timing of Insemination for Maximum Conception

A frequent question concerning AI is: What time during estrus should cows be bred for greatest chance of conception? Since estrus may last from 10 to 25 hours there is considerable latitude in possible time of insemination. Much research work has been conducted on this subject.

Controlled investigations were conducted by Trim Berger and Davis at Nebraska in 1943. These and other studies show that conception rate is lower when cows are bred prior to mid estrus or later than 6 hours after cessation of estrus (standing heat in this case). Maximal conception is obtained when cows are inseminated between mid estrus and the end of standing estrus, with good results up to 6 hours after estrus. 
            
Success in insemination timing is dependent upon a good heat detection program. In large herds, this means assigning individual responsibility for heat detection and a continued education program for labor. A successful heat detection program and subsequent proper timing of insemination will pay dividends in increasing reproductive efficiency.

A practical recommendation for timing of insemination

Cows showing estrus	Should be inseminated	Tool late for good results
In morning	Same day	Next day
In afternoon	Morning of next day or early afternoon	After 3 p.m.

(Source: www.world-agriculture.com)

Article Credit:http://agritech.tnau.ac.in

CATTLE REPRODUCTION

Selection for breeding

Heifers 
 

Heifer is a young female cow before she has had her first calf. Heifers should be selected on the basis of the potential of the sire and milk production of the dam. The heifers should have proper growth, good health and be free from genetic abnormalities. Heifers, which have conceived within 24 months of age alone, may be retained.

Cows 
 

Most important economic trait to be looked into, while selecting a cow is 'milk production'. The present average daily milk production of the cross breed cows is around 5.5 liters. For economic milk production a cow producing not less than 2500 kg milk in 305 days lactation period is desirable. In general, selecting a newly calved cow yielding ten liters per day may have 2000-2500 kg lactation yield and cow yielding 15 liters per day initially may have a lactation yield of 3000 kg. A peak yield of at least 12 kg milk per day can be used as a criterion for this. Age at first calving should be less than 3 years. The interval between two successive calving should be 12 to 15 months. The cow should not have any physical deformity and should possess dairy conformation like well developed udder, prominent milk vein, squarely placed teats, ease in milking and good temperament. Old and unproductive cows are to be replaced by young cows. The calves reared in the farm itself are usually used for replacement. Normally, 20 percent of the stock has to be replaced each year. When calves are insufficient or when the general performance of the herd is poor, cows from outside can be purchased and added to the herd.

Bulls 
 

Bulls contribute 50 percent of the inheritance to the next generation. Most of the genetic improvement in a population comes through proper bull selection. It is not very practicable to have intense selection of the females for breeding i.e., almost all the heifers will have to be reared and used for breeding in a situation where age at first calving and calving interval are not optimum. Hence most care is to be given for bull selection. To achieve the goal of average 305 days milk yield of 2500 kg/lactation from the present 1600 kg for crossbreds in Kerala, the bulls used should be proven bulls or of high pedigree. The young bulls used for breeding should be from dams with lactation milk production not less than 4500 kg and bulls with higher sire index. If 1000 cows with this production performance are available in the State, this bull dam selection becomes feasible. Other economic traits like milk fat and SNF, age at first calving, calving ease, incidence of diseases etc., should be included in evaluation.

The farmers should be aware of the quality of bull used for breeding and all Artificial Insemination centres/bull stations should display the details of breeding value of the bulls used. Breeding value is generally expressed as a deviation from the population average. It is to be borne in mind that pedigree selection is the most important of all kinds of selection. Progeny testing is the most accurate method and as a rule bulls for progeny testing are selected based on the pedigree. Selection should be continuous and applied in all generations. Any slack in selection will result not only in the stoppage of genetic improvement but also in creating negative trends.

(Source: www.vuatkerala.org )

CATTLE BREEDING
Cattle’s rearing is an important subsidiary to agriculture in India. It has been playing a significant role in India's rural economy. Despite its vast cattle population, India's place regarding cattle productivity is at the rock-bottom vis-a-vis other countries, especially western ones. One of the major reasons for this is the lack of good breeding stock as well as technologies in our villages. The follwing poits describes different aspects of scientific breeding of cattle and buffaloes.

I. Introduction
Reproduction is an important consideration in the economics of cattle production. In the absence of regular breeding and calving at the appropriate time cattle rearing will not be profitable. A healthy calf each year is the usual goal. This is possible only by increasing the reproductive efficiency of the animals.

Successful reproduction encompasses the ability to mate, the capacity to conceive and to nourish the embryo and deliver the viable young ones at the end of a normal gestation period. In fact, interruption in this chain of events leads to failure of the cow either to conceive or the embryo to die or to have a premature delivery of the foetus.

Matting

The reproductive efficiency is a complex phenomenon controlled by both genetic and non-genetic factors, the non- genetic factors being climate, nutrition, and level of management. The reproductive efficiency varies not only between species and breeds but also among the animals within the Same breed. Even the best feeding and management can not coax performance beyond the genetic limit of an inferior animal. Improving the genetic merits of livestock populations is important at all levels of management. A sound breeding programme is a necessary part of the total animal production system. It is absolutely imperative to improve the productive capacity and physical appearance of the animal population.

II. Factors Affecting Breeding Efficiency 
The factors which influence the breeding efficiency of cattle are as follows:

1. Number of ova
The first limitation on the breeding efficiency of fertility of an animal is the number of functional ova released during each cycle of ovulation. Ovulation is the process of shedding of ovum from the Graffian follicle. In the case of cow, usually a single ovum is capable of undergoing fertilization only for a period of 5-10 hours. Therefore, the time of mating in relation to ovulation is important for effective fertilization.

2. Percentage of fertilization
The second limitation is fertilization of ova. Failure to be fertilized may result from several causes. The spermatozoa may be few or low in vitality. The service may be either too early or too late. so that the sperms and eggs do not meet at the right moment, to result in fertilization.

3. Embryonic death
From the time of fertilization till birth, embryonic mortality may occur due to a variety of reasons. Hormone deficiency or imbalance may cause failure of implantation of fertilized ova which die subsequently. Death may occur as a result of lethal genes for which the embryos are homozygous. Other causes may be accidents in development, over-crowding in the uterus, insufficient nutrition or infections in tile uterus.

4. Age of first pregnancy
Breeding efficiency may be lowered seriously by increasing the age of first breeding. Females bred at a lower age are likely to appear stunted during the first lactation, but their mature size is affected little by their having been bred early.

5. Frequency of pregnancy
The breeding efficiency can be greatly enhanced by lowering the interval between successive pregnancies. The wise general policy is to breed for the first time at an early age and to rebreed at almost the earliest opportunity after each pregnancy. In this way the lifetime efficiency is increased. Cows can be rebred in 9-12 weeks after parturition.

6. Longevity
The length of life of the parent is an important part of breeding efficiency, because the return over feed cost is greater in increased length of life. Also, it affects the possibility of improving the breed. The longer the life of the parents, the smaller the percentage of cows needed for replacement every year.

III. Management Practices to Improve Breeding Efficiency
Some of the management suggestions which will tend to improve breeding efficiency of cattle are listed below.

1. Keep accurate breeding records of dates of heat, service and parturition. Use records in predicting the dates of heat and observe the females carefully for heat.
2. Breed cows near the end of heat period.
3. Have females with abnormal discharges examined and treated by veterinarian.
4. Call a veterinarian to examine females not settled after three services.
5. Get the females checked for pregnancy at the proper time after breeding.
6. Buy replacements only from healthy herds and test them before putting them in your herd.
7. Have the females give birth in isolation, preferably in a parturition room and clean up and sterilize the area once parturition is over.
8. Follow a programme of disease prevention, test and vaccination for diseases affecting reproduction and vaccinate the animals against such diseases.
9. Practice a general sanitation programme.
10. Supply adequate nutrition.
11. Employ the correct technique.
12. Provide suitable shelter management.
13. Detect silent or mild heat, by using a teaser bull.

 (Source: www.world-agriculture.com )

Article Credit:http://agritech.tnau.ac.in/