Pregnancy loss is a major contributing factor to reproductive inefficiency in both the beef and dairy industries. Sires can have a significant influence on the amount of pregnancy loss; however, this relationship is still poorly investigated. The primary objective of this study was to identify sires associated with high or low incidence of pregnancy loss (between d 30 and 100 of gestation) and investigate their effect on concentration of circulating pregnancy-associated glycoproteins (PAGs). Postpartum multiparous Nelore cows were inseminated artificially at a fixed time (FTAI, d 0) after synchronization of ovulation. A total of 736 cows were assigned randomly to be inseminated with semen from either of 6 Angus sires, whereas a separate subset of 492 cows were inseminated randomly with semen from either of 3 Nelore (n = 235) or either of 2 Angus sires (n = 257). Estrus expression was evaluated on d 0 using Estrotect Heat Detector patches. Blood samples were collected on d 30 of gestation for quantification of PAGs and pregnancy diagnosis was performed by ultrasound on d 30 and 100 after FTAI. Cows diagnosed pregnant at the first examination but not pregnant at the second were defined to have pregnancy loss. Overall pregnancy rate at d 30 was 54% (660/1,228) and pregnancy loss was 6.21% (41/660). Cows receiving semen from Nelore sires had greater (P < 0.001) pregnancy rate, greater (P = 0.014) pregnancy loss, and lesser (P = 0.002) PAG concentrations at d 30 of gestation compared with cows receiving Angus semen. Circulating PAG concentrations were lower (P = 0.008) in cows that had pregnancy loss (9.76 ± 0.25 vs. 7.41 ± 1.02 ng/mL). Angus sires were retrospectively classified according to percentage of pregnancy loss as either high pregnancy loss (mean of 7.25% or 67% of total) or low pregnancy loss (mean of 3.93% or 33% of total). Cows receiving semen from high pregnancy loss sires had 1.9 times greater (P = 0.123) rate of pregnancy loss and had lower (P = 0.059) PAG concentrations at d 30 of gestation compared with cows mated to low pregnancy loss sires. In summary, PAG concentrations reflected probability of pregnancy maintenance and were influenced by both sire and sire breed used at FTAI. Variation in the incidence of pregnancy loss was detected among sires that could not be predicted with standard semen fertility evaluations. Exploring the relationship of sire and PAG production might be promising to improve sire selection with regard to pregnancy loss.

No abstract

No abstract

ResumoA eficiência reprodutiva é um dos principais fatores envolvidos na viabilidade econômica do setor de criação de bovinos. Objetivou-se realizar a avaliação ginecológica e citológica em vacas Holandesas com mais de três repetições de cio. O experimento foi desenvolvido em seis propriedades leiteiras comerciais, com manejos sanitários e reprodutivos semelhantes e assistidas por médicos veterinários. Foram incluídas apenas vacas da raça Holandesa, até cinco parições e mais de três repetições de cio consecutivas. Na propriedade, os animais foram identificados e procedidos o exame ginecológico e citologia endometrial. No presente estudo foram avaliadas 77 vacas e as causas reprodutivas encontradas em vacas Holandesas sujeitas ao descarte involuntário foram: endometrite clínica com secreção vaginal purulenta e mais que 3% de neutrófilos (7,79%), endometrite clínica com secreção vaginal purulenta e menos que 3% de neutrófilos (2,6%), endometrite subclínica (10,4%), urovagina (1,3%) e 77,9% que não se sabe a causa, porém não está associado aos distúrbios reprodutivos avaliados. Concluiu-se que: a) o índice de vacas que não apresentaram a causa diagnosticada é muito alto e isto interfere diretamente na eficiência reprodutiva; b) o exame proposto diagnosticou 22,1% de distúrbios clínicos que poderiam ser evitados ou tratados e desta forma reduzindo o descarte involuntário. Palavras-chave: Bovinos, endometrite clínica, endometrite subclínica, urovagina AbstractThe objective of this study was to evaluate the gynecological examination and endometrial cytology in Holstein cows with more than three repetitions of estrus. The experiment was conducted in six commercial dairy herds both with similar reproductive and sanitary managements and assisted by veterinarians. It was included only Holstein cows up to five calving and more than three consecutive repetitions of estrus. Seventy-seven cows were identified and carried gynecological examination and endometrial cytology. The reproductive causes found in this study, subject to involuntary culling, were: clinical endometritis 1 Médicos Veterinários autônomos, Uberlândia, MG.

This study compared two frequently employed techniques for the collection of endometrial and inflammatory cells and characterized postpartum endometrial cytology (EC) of clinically normal postpartum crossbred dairy cows in dairy farming system in Southwestern Brazil. Thirty-four crossbred, clinically healthy dairy cows with normal delivery and puerperium, complete uterine involution and without any treatment were monitored until 42 days in milk (DIM). All cows were evaluated by complete clinical and gynecological examinations at days 0, 7, 14, 21, 28, and 42 DIM. The gynecological examinations were done by transrectal palpation, ultrasonography, vaginoscopy, evaluation of the vaginal mucus and EC by using the cytobrush (CB) and low-volume uterine flush (LVF) techniques. The agreement (Kappa statistic) between the two technicians was good for CB (86%) and LVF (80.3%) for the counting of the percentage of neutrophils. The average number of neutrophils was significantly higher throughout the experiment for LVF, but a reduced percentage of neutrophils were observed during the postpartum period for both techniques. The amount of macrophages, lymphocytes, and eosinophils were not affected during postpartum and there was no significant difference relative to these cells when the two techniques were compared. There were significant differences in the percentage of cows with subclinical endometritis only at d28 by CB (22.2%) and LVF (59.3%). Key words: Uterine diseases, clinical pathology, diagnostic cytology, cattle ResumoObjetivou-se comparar duas técnicas frequentemente usadas na colheita de células endometriais e inflamatórias e caracterizar a citologia endometrial (CE) de vacas leiteiras mestiças no pós-parto fisiológico, criadas em sistemas de fazendas leiteiras do sudoeste do Brasil. Foram utilizadas 34 vacas clinicamente sadias com parto e puerpério fisiológico, completa involução uterina e sem qualquer tratamento até os 42 dias pós-parto (dpp). Realizou-se o exame clínico e ginecológico no parto e aos 7, 14, 21, 28 e 42 dpp. O exame ginecológico foi executado pela palpação retal, ultrassonografia, vaginoscopia, avaliação de muco vaginal e CE realizada com escova citológica (CB) ou por lavado uterino de baixo volume (LVF). A concordância (Kappa statistic) entre os técnicos na contagem da porcentagem de neutrófilos foi boa para CB (86%) e para LVF (80,3%). A média de neutrófilos foi maior em todos os momentos na técnica de LVF, porém a redução de neutrófilos foi observada durante o pós-parto nas duas técnicas de citologia. A contagem de macrófagos, linfócitos e eosinófilos não variou durante o pós-parto e não houve diferença entre as técnicas CB e LVF. Houve diferença apenas aos 28 dpp, na porcentagem de vacas com endometrite subclínica, entre as técnicas CB (22.2%) e LVF (59.3%).