ARTIFICIAL INSEMINATION IN FARM ANIMALS - Phenix-Vet

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156Artificial Insemination in Farm Animalsachieve a desirable CI. The second component comprises an average of 285 days, varyingonly according to the genetics of both the matrix and the player and can only be reduced byinducing premature parturition.To get an CI for 365 days, the interval between delivery and conception should not be longerthan 80-85 days. A key factor for achieving these goals is good nutrition. A study conductedin Florida stressed the importance of dry matter intake for cows in early cyclicity. Cows withhigher dry matter intake returned to cycle faster and lost less weight postpartum (Staples etal., 1998). Care of the dry matter intake and body condition is essential and should beginwell before birth in the last 100 days of lactation. So there will be enough time to adjust bodycondition and prepare all the cows in their dry period and lactation next breeding season.The relationship between energy balance and ovulation is directly related to the pattern ofLH secretion, which is the gonadotropin responsible for follicular maturation and ovulation.After delivery, there is limited secretion of LH, but as approach the time of first ovulation,the basal concentration of LH secretion increases and the pattern becomes more pulsatile.The LH pulse frequency should occur at hourly to support follicular maturation andovulation. The first ovulation occurs two weeks after the increased frequency of LH pulses.Thus, it should provide a well balanced diet and palatable to cows to meet their metabolicneeds as soon as possible after birth, stimulating consumption fractionated into four meals aday until the cows to produce milk and ovulate early, reducing the CI (Butler and Smith,1989).Another factor that must be considered is the diagnosis of pregnancy, IE this should be doneup to 30 days after artificial insemination, and the empty livestock referred for proceduressuch as fixed-time artificial insemination. Resynchronization of repeat breeder cows is alsoan alternative to reduce the CI, because prior to the diagnosis of pregnancy can identifyanimals that are empty and reinseminated them, improving conception rates and shorteningthe CI (Chebel et al., 2006). Furthermore can mention other factors that influence theduration of the CI as appropriate handling and deposition of semen, the ability of artificialinsemination, animal care not to subject him to stress management, such as abuse, alsocontribute a good mineralization for the appearance of fertile estrus, improvement in thedesign and decrease the CI.4. Application of fixed-time artificial inseminationThe fixed-time artificial insemination (FTAI) has become very popular because of reducedmanpower and independence of estrus detection, since there are many difficulties to detectcows in heat, especially at night. The rates of detection of estrus and submission to artificialinsemination are limiting factors due to the type of installation, which limit the expression ofestrus, or lack of skilled labor for estrus detection. For artificial insemination programs aresuccessful in herds not using hormonal intervention, the rate of estrus detection shouldexceed 70%. Most programs result in FTAI pregnancy rates similar to those obtainedfollowing the detection of natural estrus.The inefficiency of reproductive cows causes great frustration and losses for farmers. Evenunder ideal conditions, the reproductive process is far from perfect, considering the myriadfactors involved in producing a live calf. The reproductive efficiency involves not onlyproper management of cows, but also management of carers and inseminate. Theconception rates of lactating dairy cows declined from the 50's in the USA, while the annualyield per cow increased 3.3 times (Lucy, 2001). Given the inverse relationship of milk yield
Particularities of Bovine Artificial Insemination 157and fertility, there is a genetic antagonism between milk yield and reproductive traitsmanifested primarily in first lactation cows, but good management practices such as use ofFTAI, can overcome this inverse correlation and allowed its acceptable levels ofreproductive efficiency.The programmed insemination is a method that plans and manages a program of artificialinsemination of a herd. This lineup of estrous cycles has some advantages such asconvenience of scheduling tasks and use of manpower, control the occurrence of estrus,ovulation, or both, and knowledge of the estrous cycle and reproductive status of females inthe herd. The categories of reproductive status are scheduled to open cows at first artificialinsemination, cows inseminated to be subjected to pregnancy diagnosis, cows scheduled toopen re-insemination; open cows destined for disposal (will not be inseminated) and cowsconfirmed pregnant. Thus, the programmed insemination can be applied in two distinctgroups: cows that are scheduled for their first insemination and cows confirmed to beopened after diagnosis of pregnancy and scheduled for re-insemination. The programmedinsemination involves hormonal timing of estrus, ovulation, or both. In the USA, FTAIprograms are used in 90% of herds, with 86% of synchronizing first services, 77% of resynchronizationof repeaters and 59% of treatments for cystic cows in anovulatory oranestrus (Caraviello et al., 2006).The best program is the simplest and easiest to apply, varying with the level of training ofofficials of the farm. In this case, simplicity means lower number of manipulations in cowsduring the implementation of a protocol. Employees should be trained to take a disciplinedapproach and comprehensive programs work, i.e., the implementation of the protocolsshould be approximately 100% to achieve a greater number of pregnant cows and fewerdischarges of pregnant cows.Some studies have evaluated the cost-effectiveness of fixed-time artificial inseminationprotocols. One study estimated the value of a pregnancy in a flock where half of the cowswere inseminated only after the detection of natural estrus, compared to the application ofFTAI the other half of the cows. In herds with low estrus detection, the cost of pregnancywas significantly reduced with the use of FTAI compared detection only. In herds with highrates of detection of estrus, the cost of pregnancy was higher with the use of FTAI, but therewas a better reproductive performance of cows treated. The highest costs of pregnancy wereassociated with damage resulting from longer periods opened and account for up to 83% oftotal costs (Tenhagen et al., 2004). Thus, the use of a system of FTAI is considered aprofitable alternative for large commercial flocks in the estrus detection rates are low.5. Breeding seasons and calvingThe breeding season or insemination consists of a period of the year in which breedingfemales are exposed to males or are inseminated, and calving season is closely correlated,because the births are concentrated in a pre-determined by the breeding season orinsemination. It is a strategy for increasing productivity in terms of number of weanedcalves, zero cost, rationalizing the reproductive activity of animals with the concentration ofdeliveries, facilitating and regulating the management of livestock.The most widely used method of breeding in central Brazil is one where the bull stays withthe herd throughout the year. As a result, births are distributed throughout the year, despitea higher concentration during the months from July to September. The occurrence of birthsat times inappropriate affect the calves, due to higher incidence of diseases and parasites, or
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VIContentsChapter 9Evaluation of a
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ARTIFICIAL INSEMINATION IN FARM ANIMALS - Phenix-Vet

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