Polymorphisms in TOX and NCOA2 genes and their associations with reproductive traits in cattle

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

Genetic analysis for gestation length, birth weight, weaning weight, and accumulated productivity in Nellore beef cattle

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

Genome-wide association study of reproductive traits in Nellore heifers using Bayesian inference

An important goal of Zebu breeding programs is to improve reproductive performance. A major problem faced with the genetic improvement of reproductive traits is that recording the time for an animal to reach sexual maturity is costly. Another issue is that accurate estimates of breeding values are obtained only a long time after the young bulls have gone through selection. An alternative to overcome these problems is to use traits that are indicators of the reproductive efficiency of the herd and are easier to measure, such as age at first calving. Another problem is that heifers that have conceived once may fail to conceive in the next breeding season, which increases production costs. Thus, increasing heifer's rebreeding rates should improve the economic efficiency of the herd. Response to selection for these traits tends to be slow, since they have a low heritability and phenotypic information is provided only later in the life of the animal. Genome-wide association studies (GWAS) are useful to investigate the genetic mechanisms that underlie these traits by identifying the genes and metabolic pathways involved. Data from 1853 females belonging to the Agricultural Jacarezinho LTDA were used. Genotyping was performed using the BovineHD BeadChip (777 962 single nucleotide polymorphisms (SNPs)) according to the protocol of Illumina - Infinium Assay II ® Multi-Sample HiScan with the unit SQ ™ System. After quality control, 305 348 SNPs were used for GWAS. Forty-two and 19 SNPs had a Bayes factor greater than 150 for heifer rebreeding and age at first calving, respectively. All significant SNPs for age at first calving were significant for heifer rebreeding. These 42 SNPs were next or within 35 genes that were distributed over 18 chromosomes and comprised 27 protein-encoding genes, six pseudogenes and two miscellaneous noncoding RNAs. The use of Bayes factor to determine the significance of SNPs allowed us to identify two sets of 42 and 19 significant SNPs for heifer rebreeding and age at first calving, respectively, which explain 11.35 % and 6.42 % of their phenotypic variance, respectively. These SNPs provide relevant information to help elucidate which genes affect these traits.

Strategies for genotype imputation in composite beef cattle

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

Caracterização molecular de bovinos de origem Bos indicus e seus cruzados para maciez de carne

O objetivo desse trabalho foi conhecer a variabilidade genética da calpaína e seu potencial como marcador molecular para programas de melhoramento genético, visando auxiliar na seleção de genótipos superiores para maciez de carne zebuína. Para tanto foram analisados 55 animais da raça Nelore, proveniente de outros projetos de pesquisa conduzidos pela equipe técnica do Laboratório de Genética do Instituto de Zootecnia de Nova Odessa. Os animais foram abatidos ao atingirem o acabamento de 4 mm de espessura de gordura e a amostra de carne foi coletada entre a 12ª e 13ª costelas no músculo Longissimus dorsi. A maciez de carne foi avaliada empregando-se a técnica de Warner Bratzler Shear Force em 0 e 14 dias de maturação. O DNA foi extraído a partir das amostras de carne, em seguida foi quantificado e diluído para ser amplificado por PCR. Três polimorfismos foram investigados pelas técnicas de PCR-RFLP e PCR- SSCP, localizados no exon 9, exon 14 e intron 17 do gene calpaína, sendo denominados CPN316, CAPN530, CAPN4751, respectivamente. Os resultados da análise de associação entre os dados de força de cisalhamento (FC) e marcadores moleculares revelaram efeito significativo apenas para o marcador CAPN4751. O alelo C, considerado favorável para maciez de carne, apresentou relação significativa (P>0,05) com valores menores de FC, sugerindo o seu emprego na seleção de genótipos superiores para maciez de carne de bovinos da raça Nelore

Boas práticas de manejo de bezerras leiteiras na fase de cria e potenciais efeitos na recria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo de associação entre polimorfismos de base única com características de eficiência de conversão, consumo e desempenho em bovinos da raça Nelore

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise genética de escores visuais e sua relação com características reprodutivas de animais da raça Nelore

Pós-graduação em Genética e Melhoramento Animal - FCAV

Estudo genômico da produção de leite e seus constituintes em bovinos da raça Guzerá

Pós-graduação em Genética e Melhoramento Animal - FCAV

Efeito da progesterona na expressão do RNAm do receptor de LH e enzimas esteroidogênicas reguladoras do desenvolvimento folicular em células da granulosa de novilhas nelore

Pós-graduação em Zootecnia - FMVZ

O temperamento de bovinos confinados em diferentes disponibilidades de espaço e suas relações com o desempenho e a qualidade da carcaça e da carne

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo genético do escore de condição corporal de vacas Nelore

Pós-graduação em Genética e Melhoramento Animal - FCAV

Termografia digital por infravermelho do escroto e qualidade do sêmen em touros nelore (bos taurus indicus)

Aimed to study the relationship between scrotal temperature on semen quality by use of infrared thermography in Nelore bulls bred extensively. There were scrotal thermography and semen collection. Climatic data were collected by means of globe thermometer. The thermograms of the scrotum were obtained by digital infrared thermography. We carried out ejaculates through electroejaculation for analysis of quantitative and qualitative characteristics. For the data, we used analysis of variance and subsequently applied the Tukey test at 5%. (p <0.05) between animals for sperm vigor, sperm motility between animals and between crops, sperm concentration, total sperm and total viable sperm between groups, between harvests for the scrotum temperatures and climate data. It was concluded that the surface temperatures of the scrotum and climatic factors influence the quality of semen. Thermography is recommended as a complementary test in the evaluation of reproductive bulls.

Diâmetro folicular e taxa de prenhez em protocolo de sincronização com GnRH ou Benzoato de Estradiol no dia 0 em vacas de corte

This work aimed to evaluate the pregnancy rate and follicular diameter using EB or GnRH on the insertion of progesterone implant (D0) in lactating beef cows. Two groups were tested in two experiments. In Exp. 1 were used 61 Nelore cows divided into two groups: G-BE (n = 32) and G-GnRH (n = 29), on D0 was inserted P4 implant (CIDR ) and applied 2 mL of BE (G-BE) or 2.5 mL GnRH (G-GnRH). In D9 was performed ultrasonography (U.S.) to measure the diameter of the dominant follicle (DF) present in the ovary and the implant was removed, with concomitant administration of 2.5 mL of PGF2a and estradiol cypionate (ECP ) followed by calves removal. After 48 hours all the cows were inseminated and the calves returned. In Exp. 2 50 cows were used following the same protocol described above, but the pregnancy was assessed without performing ovarian US. There was no difference (p>0.05) in pregnancy rate between treatments, BE (55%) or GnRH (41%), but the follicular diameter was significantly higher (p<0.05) in pregnant cows treated with EB (10.7 mm vs. 8.5 mm) and in cows treated with GnRH there was no difference (p>0.05) between pregnant and no pregnant cows (11.6 mm vs. 10.2 mm). We concluded the use of GnRH on D0 did not improve the pregnancy rate in lactating beef cows and follicular diameter was greater (p <0.05) in pregnant cows compared to non-pregnant only in G-BE.

Efeito do período pós-parto sobre a taxa de prenhez de vacas de corte submetidas à IATF (Inseminação Artificial em Tempo Fixo)

This work aimed to evaluate the influence of postpartum period (precocious - of 28 to 44 days and late - of 45 to 90 days) on the bovine pregnancy rate using fixed-time AI. For that, 678 cows were divided in two groups: precocious group (G-P, n=151) and late group (G-T, n=527). The animals received CIDR® + 2 mL of estradiol benzoate (BE) in the day zero (D0). After eight days (D8) the dispositive was removed and both groups received 2.5mL PGF2α, concurrent with PGF2α injection, they received either 1.5mL of eCG or temporary calf removal (RTB). In the next day (D9), the cows received 1 mL de BE and 24 hours later, the fixed-time AI was performed with Nelore bovine semen. The calves were returned to their mothers. The pregnancy rate was not different between the groups (p>0.05), G-P=40% and G-T=48%. The results indicate that females with less than 45 days of postpartum are able to hormone protocol of fixed-time IA.