One hundred and fifty cattle bulls B with an body weight of The animal category did not affect the profitability of the system, although the bulls provided lower revenues than cull cows. In view of the great competition between crop and livestock and the high demand for land, the feedlot stands out as a good option in beef cattle farming, because when the adequate management techniques are applied and investments are made at the right time, this rearing system becomes economically viable Silva et al. Like any activity of the livestock sector, in order to maintain competitiveness, this activity must be constantly evaluated, especially with respect to economic aspects. In this regard, the production costs of the activity, including the net revenue and the rate of return of the invested capital, are important factors for the success of any production system Silva et al. In the Cerrado region, most producers do not have the habit to finish cull cows in feedlot, since they are old, unappreciated animals.
|Published (Last):||15 February 2005|
|PDF File Size:||11.21 Mb|
|ePub File Size:||12.93 Mb|
|Price:||Free* [*Free Regsitration Required]|
Artificial insemination AI and embryo transfer ET are the most widely used biotechnologies in the world with the goal of increasing genetic gain and improving reproductive efficiency of beef and dairy herds. The protocols for ovulation synchronization for timed AI TAI or ET TET are tools that allow artificial insemination or transfer of a high number of embryos in a pre-established moment and without the necessity of estrous detection.
With the use of TAI, it was possible to verify that the percentage of artificially inseminated females in Brazil went from 5. The ET market also presented considerable growth in the last 20 years. There was an increase of approximately 8 fold in the number of produced embryos, escalating from 50, in to , in In this period, there was a significant increase on the in vitro embryo production, which represented TET increases significantly the number of recipients suitable to receive an embryo.
With the intensification of the use of these biotechnologies, it is possible to obtain elevated reproductive efficiency with increase on the genetic gain, which determines greater productivity and economic return for dairy and beef farms.
However, the challenge to keep the market growing in the next decade could depend on some factors, such as: increase of the extension services for producers and of the extension training for specialists, improvement of the technological advances to develop more efficient and cost-effective products and practical protocols, increase the integration between universities, research institutes, veterinarians and industries and also, asses market demand for production of animal protein with higher quality, efficiency and environmental and economic sustainability.
The accelerated growth of the world population is generating a significant increase in the demand for food, causing concern for the production of animal proteins to meet the growing number of people on the planet FAO, In this context, Brazil is relevant because it is the fifth largest country in territorial extension and has the largest commercial cattle herd in the world In , the number of bovine slaughters in Brazil reached Despite this positive scenario, Brazilian beef cattle production still has low production efficiency, and ranks second in the world classification of meat production, led by the United States, which produce The national production of fluid milk was In this context, each animal contributed with only 5.
These numbers rank Brazil as the fourth largest milk producer falling behind the United States, India and China , despite having the world's largest cattle herd. Also, Brazil is not self-sufficient in the production of cattle milk, and in this scenario, importation is necessary to supply the domestic market IBGE, Thus, it is essential to develop and improve technologies that collaborate with increasing productivity on farm, optimizing the breeding systems and the profitability of the herds.
Among the developed technologies, reproduction biotechnologies are noticeable. Artificial insemination AI is the most widely used reproductive biotechnology in the world and its application brings great benefits to the herds when compared to the use of natural service Lima et al. The technique allows the use of the semen of genetically superior bulls, accelerating the genetic gain and resulting in more productive calves, which generate greater economic return to the meat and milk producer Baruselli et al.
In addition, AI prevents the transmission of venereal diseases Vishwanath, and allows better control of the herd, increasing the uniformity of calves when compared to natural service Rodgers et al.
In order to facilitate the use of AI in rural properties, timed artificial insemination TAI was developed Pursley et al. This reproductive biotechnology eliminates the necessity of estrous detection and allows anestrous cows to be inseminated, increasing the reproductive efficiency of cows and heifers Rhodes et al. Furthermore, the use of TAI anticipates and concentrates conception at the beginning of the breeding season, increasing the reproductive and productive efficiency of farms Baruselli et al.
Embryo transfer ET allows the dissemination of high value genetic material from both males and females, increasing the genetic gain of animal breeding programs when compared to AI.
Furthermore, ET associated with the advent of genomic technology and endocrine markers AMH allows the use calves as oocyte donors to produce embryos from young cattle, which is an important strategy to accelerate genetic gain by decreasing generation intervals Batista et al. The ET has presented considerable growth in the last decades, mainly due to the scientific and technological development of innovative processes of embryo production.
Currently, in vitro embryo production IVEP represents In addition to the increase on the IVEP, there was the development of synchronization techniques for fixed-time embryo transfer TET , which increases the number of recipients suitable for receiving an embryo and eliminates the necessity for estrous detection, allowing the establishment of this biotechnology in beef and dairy farms Baruselli et al.
The Brazilian market for artificial insemination traded approximately 7. In , this market reached Still, compared to the previous year to , the semen market grew These data clearly demonstrate that artificial insemination has gained ground in Brazil over the years. In , the number of TAI reached The TAI market growth in also showed a significant increase of It is possible to verify that the TAI has grown fold in the last 16 years, bringing great advances and benefits to the entire meat and milk production chain.
In , which coincides with the beginning of data collection presented in Baruselli et al. However, in this figure reached This increase was mainly due to the use of timed protocols, which are highly reproductive efficient and facilitate the dissemination of artificial insemination.
In , it is estimated that approximately 9. An average of 1. In total, more than 15 million breeding females were inseminated using TAI in Brazil, Argentina and Uruguay in the year Mapletoft et al. This information indicates the consolidation of the technology in the market, resulting in economic gains and positive perspectives for livestock. These data were confronted with the number of semen doses commercialized for beef and for dairy herds disclosed by the Brazilian Association of Artificial Insemination ASBIA, For the analysis, 1.
The data show that Unexpectedly, there was a drop in the percentage of inseminated dairy cows in the last 5 years. On the other hand, the percentage of artificially inseminated beef females has increased almost two times in the last 10 years.
An average of 2. According to preliminary data from IBGE , Since there are many small producers, the low incidence of technology in small farms is proportionately higher, creating a budget constraint for the producer to invest in technology. For dairy cattle, The number of establishments with 50 head or less is also high for beef farms in Brazil Additionally, in the last 4-years, an increase in the cost of the food for dairy cows was observed and therefore, there was a reduction on the economic gain of the dairy farms CNA, , discouraging the use of technology in the milk production sector.
These facts corroborate with the evolution of the AI market, where it is possible to observe that beef cattle have a growing number of inseminated animals, and dairy cattle, in the last four years to , have had a decrease on the number of inseminated females.
It is calculated that this activity counts with 3, veterinarians specialized in animal reproduction acting on the farms considering 3, TAI per professional, Baruselli, b.
In addition to these direct economic impacts, there are benefits in increasing productivity that must be taken into consideration. In beef herds, there is an increase in the quantity and quality of calves produced with the introduction of TAI technology. Considering that TAI is used in In dairy herds, TAI also has great economic impact. Studies have shown that there is a reduction of approximately 1 month in the inter calving interval ICI of animals receiving TAI when compared to animals submitted to traditional systems of estrous detection or natural mating Nebel, ; Caraviello et al.
Considering that 3. From these data it is possible to calculate the return on investment of this biotechnology. Baruselli, b. These figures clearly demonstrate that the investment in TAI technology generates significant gains for Brazilian livestock.
Currently, TAI programs underwent various modifications to facilitate management and improve pregnancy rates. Numerous protocols have been developed for different breeds, animal categories and for the producer to adapt the best reproductive program to the farm production system.
Regarding the available TAI programs, many different protocols can be used with similar efficiency. Regarding the number of managements required to perform the synchronization for TAI, there are studies that have developed systems with 3 or 4 animal handlings. In general, the goal of the additional management is to administer prostaglandin PGF , anticipating luteolysis, and reducing serum P4 concentrations at the end of the protocol in cycling animals. The additional treatment with PGF in cyclic heifers and cows 2 or 3 days before the device removal four animal handlings increases the dominant follicle growth and the ovulation and pregnancy rates Mantovani et al.
However, some studies have demonstrated that it is possible to perform PGF treatment on day zero D0 of the protocol 3 animal handlings , causing luteolysis in animals with presence of a responsive corpus luteum CL at the beginning of synchronization, reducing blood P4 during the protocol, increasing the follicular growth, ovulation and conception and facilitating the management of TAI Carvalho et al.
However, recent studies have shown association between decrease in circulating progesterone concentration during the synchronization protocol and increase of dry matter intake Batista et al. Therefore, the positive effect of the PGF treatment to induce early luteolysis during the TAI protocol could be reduced in animals submitted to high dry matter intake. The EB has been successfully used for inducing ovulations at the end of the synchronization protocol Hanlon et al.
Estradiol cypionate EC is another ester of E2 with low water solubility. The use of EC as the ovulatory stimulus given at the time of P4 device removal in the TAI protocol reduces the handling, without reducing fertility. Based on this concept, ovulation resynchronization protocols were developed for females that did not become pregnant. In these reproductive programs, the non-pregnant females from the previous TAI were identified as soon as possible and inseminated again, therefore increasing the proportion of pregnant cows per AI Baruselli et al.
Conventional resynchronization is initiated at the time of pregnancy diagnosis 28 to 32 days after TAI; Marques et al. With this method, it is possible to perform three inseminations with an days interval. Subsequently, early resynchronization was developed, which is initiated in all females independently of the pregnancy diagnosis 22 days after the TAI. With this method, it is possible to perform three inseminations with a days interval. Recently the super-early resynchronization protocol was developed, in which it is possible to perform three inseminations in 48 days.
This resynchronization starts in all females 14 days after TAI. On the 22nd, all the non-pregnant females were diagnosed using Doppler ultrasonography Vieira et al. According to Vieira et al. Thus, super-early resynchronization is based on the use of injectable P4 at the time of insertion of the P4 device 14 after TAI to induce the emergence of a new wave of follicular growth Cavalieri, without impairing the gestation established in the previous AI Rezende et al.
However, recently Motta et al. This information is indicative of conflicting scientific findings and justify further studies to evaluate the effect of treatment with estradiol at the onset of the super-early resynchronization protocol Day IVP: 80, IVP: , These data demonstrate that Brazil was a world leader in the use of this technology. While the IVD embryo production maintained constancy between 46, and 50, , the in vitro embryo production continued enhancing, reaching its peak production in with , IVP embryos IETS, In addition, according to recent data published by the IETS in Viana, , there has been an increase of On the other hand, the number of IVD embryos production had a reduction of In South America, Brazil and Argentina stand out as the largest bovine herds and largest embryos producers Viana et al , In , Brazil wasresponsible for the production of , IVP embryos, which represents
Acesso para assinantes