The facts used by breeders can vary all the way from in-herd observations, to show results, to including actual performance and genetic evaluation indexes.
Such characteristics of embryos as protection by the zona pellucida, minute size, exposure only to a very circumscribed environment, and lack of body systems to host pathogens e.
In addition, it is possible to wash, treat, and physically examine the individual embryo, which provides additional, very effective safeguards.
Thus, importation of genetic material in the form of embryos is innately safer than importation of post-natal animals or semen Stringfellow, ; Hare and Seidel, Regulatory officials recognize this fact and are drafting realistic conditions for importation that are less time-consuming than those required for post-natal animals.
Health regulations pertaining to the collection and processing of the semen used to produce Sperm sexing cattle intended for export, however, may still apply. The decreased risk of compromising the health of national herds in itself makes embryo transfer the method of choice for importing breeding stock in many cases.
Other advantages are that the offspring will be percent of the desired genotype and will adapt more readily to the new environment because of passive immunity acquired from the recipient. There is still a potential for problems of unthriftiness and disappointing production if the type of cow is inappropriate for the new environment, as for example, a high-producing North American dairy cow would be for an extensive management system based on range foraging.
Costs of importing embryos are often lower than importing post-natal animals, and it is possible to change the breed of a herd within a single generation. Nevertheless, costs are still a great deal higher than importing semen, and conventional embryo transfer remains a less potent tool for genetic progress than artificial insemination programmes based on intensive selection.
Most MOET schemes require one or a few large nucleus herds. The resulting genetic improvement would be disseminated to the general population by embryo transfer, artificial insemination, or more practically by young bulls to be used in natural breeding.
MOET procedures rely on advanced technology, which at first seems inappropriate for less developed countries.
However, nearly all of the advanced technical procedures would be carried out at one or a few central sites, which may be especially appropriate for some applications in many less developed countries. To appreciate why MOET procedures are effective, it is necessary to consider briefly conventional animal breeding procedures.
Improved animals result from the following practices. Identify genetically valuable animals accurately so that the best can be used as parents of the next generation. This can be done by performance testing, progeny testing and pedigree analysis.
Performance testing measures the animal itself, e. Because there is some genetic component to such performance, a partial measure of genetic value is obtained. Advantages of performance testing include low cost, rapid availability of data and ability to test many or all of the animals in the population.
Disadvantages are low accuracy in many cases one measurement per animalconfusion by environmental factors in some cases deliberate manipulation in order to make certain animals look good and sex limitations, e. Progeny testing measures traits in offspring of animals and in many respects is the converse of performance testing.
It is not sex limited and can be done over a variety of environments in ways that are not likely to be misleading. However, it is expensive, data are not available until the next generation and only limited numbers of animals can be progeny tested.
Accurate progeny testing is difficult with cows because of limited numbers of offspring.
In many cases a performance test is used to pre-select animals for progeny testing. Pedigree analysis simply uses information available on relatives, for example, the genetic value of parents or siblings.
Use high selection intensity so that only the best animals genetically are selected as parents.Agriculture Center (Ag/Farm Costs/Plans, Soil, Water, Crops, Pastures, Machinery, Livestock, Fertilizer, Manure, Pesticides, etc.
Calculators, Spreadsheets, Databases. Dean explains there are about 30 million sperm cells in a conventional straw of semen, and about million of the highest quality sperm cells in a straw of sexed semen. The reason is cost; a single sexing machine goes for more than $, "We are using sex-sorted semen on 50% of our heifers and on 20% of the cows.
SexedULTRA 4M™ achieves the same or better average conception rate than conventional semen. We have used a bull like DETOUR in flushes and also for regular AI across the herd with great results ; 67% conception rate.
A complete veterinary guide to the flea tapeworm life cycle - includes flea tapeworm lifecycle diagrams and information on the treatment and prevention of flea tape worms in dogs and cats. Preface. Back to contents. These course notes were written as a supplement to Understanding Animal Breeding by R.
M. Bourdon (2 nd edition, Prentice Hall), which is an introduction to general breeding theory applying to all animal species. Although the basic principles of inheritance and breeding are the same for all animals, the implementation of breeding schemes differs considerably from.
How to Tell if a Cow or Heifer Is Pregnant. Determining pregnancy in cattle has two benefits: 1) A producer is able know which cattle will be the "keepers" and which need to be culled as soon as possible. All this because an open, unbred.