BILL E. KUNKLE INTERDISCIPLINARY BEEF SYMPOSIUM: Temperament and acclimation to human handling influence growth, health, and reproductive responses in Bos taurus and Bos indicus cattle

Temperament in cattle is defined as the fear-related behavioral responses when exposed to human handling. Our group evaluates cattle temperament using 1) chute score on a 1 to 5 scale that increases according to excitable behavior during restraint in a squeeze chute, 2) exit velocity (speed of an animal exiting the squeeze chute), 3) exit score (dividing cattle according to exit velocity into quintiles using a 1 to 5 scale where 1 = cattle in the slowest quintile and 5 = cattle in the fastest quintile), and 4) temperament score (average of chute and exit scores). Subsequently, cattle are assigned a temperament type of adequate temperament (ADQ; temperament score <= 3) or excitable temperament (EXC; temperament score > 3). To assess the impacts of temperament on various beef production systems, our group associated these evaluation criteria with productive, reproductive, and health characteristics of Bos taurus and Bos indicus-influenced cattle. As expected, EXC cattle had greater plasma cortisol vs. ADQ cattle during handling, independent of breed type (B. indicus x B. taurus, P < 0.01; B. taurus, P < 0.01; B. indicus, P = 0.04) or age (cows, P < 0.01; heifers or steers, P < 0.01). In regards to reproduction, EXC females had reduced annual pregnancy rates vs. ADQ cohorts across breed types (B. taurus, P = 0.03; B. indicus, P = 0.05). Moreover, B. taurus EXC cows also had decreased calving rate (P = 0.04), weaning rate (P = 0.09), and kilograms of calf weaned/cow exposed to breeding (P = 0.08) vs. ADQ cohorts. In regards to feedlot cattle, B. indicus EXC steers had reduced ADG (P = 0.02) and G:F (P = 0.03) during a 109-d finishing period compared with ADQ cohorts. Bos taurus EXC cattle had reduced weaning BW (P = 0.04), greater acute-phase protein response on feedlot entry (P <= 0.05), impaired feedlot receiving ADG (P = 0.05), and reduced carcass weight (P = 0.07) vs. ADQ cohorts. Acclimating B. indicus x B. taurus or B. taurus heifers to human handling improved temperament (P <= 0.02), reduced plasma cortisol (P < 0.01), and hastened puberty attainment (P <= 0.02). However, no benefits were observed when mature cows or feeder cattle were acclimated to human handling. In conclusion, temperament impacts productive, reproductive, and health characteristics of beef cattle independent of breed type. Hence, strategies to improve herd temperament are imperative for optimal production efficiency of beef operations based on B. taurus and B. indicus-influenced cattle.

Ranking of Nellore animals in cattle championships: genetic parameters and correlations with production traits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Finishing precocity visual score and genetic associations with growth traits in Angus beef cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The role of proestrus on fertility and postovulatory uterine function in the cow

Modern protocols to synchronize ovulations for timed artificial insemination and timed embryo transfer that include manipulations in the proestrus period (i.e., between luteolysis and estrus) affect fertility in cattle. Specifically, stimulating pre-ovulatory follicle growth and exposure to estrogens after CL regression increase the proportion of cows pregnant and decrease late embryo mortality. Such effects may be due to both preovulatory actions of estrogens and post-ovulatory actions of progesterone, as concentrations of the later hormone may be changed in response to manipulations conducted during proestrus. In the first portion of this paper we describe strategies used recently to manipulate the proestrus period in protocols for synchronization of ovulation, and to present evidence of their effects on fertility. Manipulations of timing and prominence of sex steroids during the proestrus and early diestrus that affect fertility may act on targets such as the endometrium. This tissue expresses receptors for both estrogens and progesterone and these hormones change endometrial function to support conceptus growth and pregnancy maintenance. However, specific cellular and molecular mechanisms through which fertility is affected via manipulations of the proestrus are poorly understood. In the second portion of this paper we describe a well-defined animal model to study changes in endometrial function induced by manipulations conducted during the proestrus. Such manipulations induced endometrial changes on sex steroid receptors expression, cell proliferation, oxidative metabolism and eicosanoid synthesis in the uterus, but not on glucose transport to uterine lumen. In summary, evidence is accumulating to support a positive role of increasing duration and estrogen availability during the proestrus on fertility to synchronization protocols. Such positive effects may be through changes in endometrial function to stimulate conceptus growth and survival.

Occurrence of heat waves in Triangulo Mineiro and Alto Paranaiba and their effect on milk yield and feed intake in cattle

The aim of this study was to estimate milk production and food consumption during the occurrence of heat waves in the Triangulo Mineiro and Alto Paranaiba, MG by means of bioclimatic zoning based on the Temperature and Humidity Index (THI). Therefore a history of heat wave occurrence between the years 2000-2010 was compiled. The decline in milk production (DMP) and reduced food consumption (RFC) were simulated in cities where periods of heat waves were identified. Frutal and Ituiutaba had the highest rate of heat wave occurrence per year. The DMP and RFC showed bioclimatic differences between the cities of Uberaba, Ituiutaba and Frutal. The cities with the best bioclimatic conditions were Sacramento and Patrocinio, as they presented a THI classified outside of the emergency range, with a night THI of below 76 and without heat waves. Therefore, the occurrence of heat waves can impair food intake and decrease milk production, thereby most effectively demonstrating the effects of thermal stress on dairy cows in the Triangulo Mineiro and Alto Paranaiba, MG region.

Biotecnologias aplicadas à reprodução de éguas velhas

The acceptance of biotechnology for the most equine breeders association had a significant effect in the horse industry, gaining popularity around the world, because the increasing on the genetic gain, allowing the use of sub fertile mares and stallions with high genetics value on reproduction. The embryos in vitro production of human and cattle has been used with success, however in vitro embryo production is not efficient in the horse, as oocyte transfer (OT) and intracytoplasmatic sperm injection (ICSI). The oocyte transfer has been used especially in subfertile old mares presenting reproductive pathologies as: endometrite, cervical and uterine adhesions, blocked oviduct, perineal laceration and ovulation failures. During oocyte recovery process, the oocytes must be collected from immature follicles that need be matured in vitro or in vivo matured oocytes from pre-ovulatory follicles through the transvaginal aspiration guided by ultrasound. The recovered oocyte is transferred to a previously inseminated recipient mare, through the flank laparotomy. The intracytoplasmatic sperm injection (ICSI) is a procedure of in vitro fertilization that needs only one sperm that is aspirated and injected inside the oocyte. The oocytes used, can be from mature and immature follicles. Fresh, cooled and frozen semen can be used, because the procedure not requires a functional sperm. The use of Piezo drill resulted in a breakthrough the pellucid zone, allowing the vibration per minute provided in the sperm injection pipette, a major result of cleaved oocytes, due to a better sperm injection in the oocyte. The embryo transfer can be straight inside the oviduct, as also transcervical transferred after embryo culture produced in vitro. In conclusion both procedures (OT and ICSI) are effective to be used on equine assisted reproduction, getting results even lower than expected, but satisfactory from animal genetically superior

Influência da adição de fator de crescimento fibroblástico 10 (FGF10), durante a maturação oocitária, na produção in vitro de embriões bovinos

The Brazilian livestock stands out for having the world largest commercial herd of cattle and leads meat exportation and production of bovine embryos. The in vitro production (IVP) of embryos is considered an effective option to overcome problems such as infertility in cows with high economic value and also for genetic improvement of cattle. The in vitro oocyte maturation is an essential step to the success of IVP, but is still considered poor when compared to in vivo maturation. Recent studies have suggeested an important role of Fibroblast Growth Factor 10 (FGF10) on the in vitro maturation of oocytes, which favored the expression of genes related to oocyte maturation and cumulus cell expansion. Aware that maturity stage influences the final production of blastocysts, we aimed study to verify if the addition of FGF10 into the maturation medium is able to affect positively the IVP of bovine embryos. Hence, FGF10 was added to maturation in five different concentrations: 0.5 ng/mL (group 0.5), 2.5 ng/mL (group 2.5), 5 ng/mL (group 5), 10 ng/mL (group 10) and 50 ng/mL (group 50). Additionally, two other maturation groups were used, group BSA (Bovine Serum Albumin, 4 mg/mL) and group FCS (Fetal Calf Serum, 10%). The rates of cleavage, morula and blastocyst were analyzed by Analysis of Variance (ANOVA), differences of P<0.05 were considered significant. Cleavage rates did not differ between the seven groups. On the other hand, morula rate on FCS group was higher than groups BSA, 0.5, 10 and 50 (P<0.05), but did not differ among groups treated with intermediate doses of FGF10 (2.5 and 5). FCS group presented higher blastocyst rate compared to all other groups that were well below the FCS group (P<0.0001). Therefore, the use of FGF10 during oocyte maturation did not affect positively embryo development on the IVP of bovine embryos

Anormalidades fetais e placentárias decorrentes da produção in vitro de embriões bovinos

In vitro production of bovine embryo (IVP) has become a remarkable assisted reproduction biotechnology in Brazil, once it is considered an important tool for the genetic improvement of the herd. However, many abnormalities are associated with IVP technologies, such as higher incidences of embryo loss, abortions, hydrallantois and dystocia, prolonged gestation, increased birth weight and high perinatal mortality. Collectively, these abnormalities are known as “Large Offspring Syndrome”, which has limited the large-scale use of IVP technologies in cattle industry

Criopreservação de embriões bovino produzidos in vitro: estado da arte

In the last years, the embryo in vitro production for every domestic species and mainly for bovine has attained a notorius status. This reproductive biotechnical procedure associate with ultrasound-guided ovum pick up (OPU) has been more and more incorporated and spread in our cattle herds, ranking up Brazil already at the top of the list in number of in vitro embryo produced. Some significant advantages provided, such as the possibility of using the premature or pregnant animals oocytes, without necessarily requiring the use of hormonal treatment, to make it possible to generate pregnancy at a shorter period of time, the rationalization in the use of semen and optimization in the use of sexed semen were determinant factors for OPU/IVP to reach this outstanding position. Nevertheless, right now the possibility of IVP embryo cryopreservation, just now is the biggest impediment for maximizing the use of this biotechnology, due to both lack of efficient methods and low laboratory produced embryo cryotolerance. Nowadays, the most used methods of IVP embryo cryopreservation are: slow freezing and vitrification. Traditionally, slow freezing is still the most used methods for in vivo and in vitro produced embryo cryopreservation. However, more recently vitrification - although still not commercially used in large scale - has been presenting satisfactory results in IVP embryo cryopreservation, according to searches

Dinâmica folicular ovariana e bases para a aplicação das biotécnicas da reprodução em bovinos

In the last years Brazil has achieved a leading position in worldwide cattle breeding. This country is consolidating the practice of an intensive and technical level cattle breeding, due to greater emphasis on reproductive efficiency and genetic improvement. The attention given to reproductive efficiency became to enhance the genetic improvement process, by exploiting the full reproductive potential of the animals. The biotechniques applied to reproduction arised to expand the reproductive potential for greater economic return. Are the most important reproductive biotechniques the FTAI and in vivo and in vitro embryo production for embryo transfer. Different hormonal treatments are consolidating to interfere with normal physiology in order to achieve the desired goals. The FTAI works to increase the reproductive rates of cattle through pre-booked artificial insemination in all the females in reproduction, without the need for estrous detection. The in vivo and in vitro embryo production aims to distribute the genetics of males and females genetically improved by transferring their embryos to genetically inferior females. Superovulation treatments designed to prevent the mechanism of dominance, which results in many follicles ovulating simultaneously for in vivo embryo production. To the in vitro embryo production, the technique of ovarian puncture guided by transvaginal ultrasound allows to aspirate a number of quality oocytes. The application of biotech is based on knowledge of the female and ovarian reproductive physiology and knowledge of their acting in different breeds and environments.

Indução de parto em bovinos: Princípios e aplicações

Currently, Brazil has one of the largest cattle herds worldwide. In order to keep that milk and meat were introduced reproductive biotechnologies such as artificial insemination, embryo transfer and in vitro fertilization. In certain situations the technique may have undesired effect, for example, the production of calve calves due to the very large increase in the gestation period when performed in vitro fertilization. To avoid this problem we perform the induction of labor in order to prevent the product is longer the womb. This induction can also be made in case of diseases that compromise the life of the mother, twin pregnancy an abnormal size calf. The administration of short acting steroids, prostaglandins, association of short acting steroids and prostaglandins and association of short acting steroids, prostaglandins and long-acting corticosteroids are some of the possibilities of induction

Molecular investigation of zoonotic genotypes of Giardia intestinalis isolates in humans, dogs and cats, sheep, goats and cattle in Araçatuba (Sãoo Paulo State, Brazil) by the analysis of beta-giardin gene fragments

In the period from July 2009 to October 2010, fecal samples from 61 animals and 154 humans from the municipality of Aracatuba (São Paulo State, Brazil) were studied. Fecal samples from animals were collected in the Municipal Animal Shelter and the Veterinary Hospital of the Universidade Estadual Paulista. Human fecal specimens were collected in playschools in the outskirts of the city by the private network of clinical analysis laboratories of the municipal. Diagnosis was done by optical microscopy using the Faust and Hoffmann, Pons and Janer techniques. The genotypes of Giardia intestinalis were characterized by PCR-RFLP and confirmed by sequencing the ß-giardin gene. Human specimens were positive in 25.3% (39/154) of the cases with 26.8% (36/134) of the specimens from children and 15% (3/20) from adults being positive. The frequency of G. intestinalis among the animals was 23.0% (14/61). A total of 32 isolates of G. intestinalis obtained from human feces and six from dogs and cats were characteristic of the A genotype (AI and AII/AIII). The results of this study in respect to frequency of giardiasis are similar to reported in most studies in Brazil. The prevalence observed in animal populations conforms to worldwide infection rates. G. intestinalis genotypes considered zoonotic were detected in both pets and humans from the city of Aractuba, suggesting a possible zoonotic transmission of the parasite in the northwestern region of São Paulo State. The absence of these genotypes in farm animals may imply that they are not involved in the chain of transmission to humans in this region.

Efeitos de diferentes inibidores da meiose sobre a maturação in vitro de oócitos bovinos e subsequente tolerância dos embriões a vitrificação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crude glycerin in the supplement for beef cattle on pasture

Pós-graduação em Zootecnia - FCAV

Different sources of forage with crude glycerin in diets with higher percentage of concentrate to beef cattle

Pós-graduação em Zootecnia - FCAV