Relationship of fertility to ovarian follicular waves before breeding in dairy cows

Cows with two waves of follicular growth during the estrous cycle yield follicles that are older and larger at ovulation compared with cows having three waves. The objectives of the current research were 1) to compare fertility in cows with two or three follicular waves and 2) to examine associations between luteal function, follicular development, and fertility after breeding. Follicular waves were monitored by ultrasonography during the estrous cycle before insemination in 106 dairy cows. Fewer cows had three follicular waves before next estrus and ovulation than two waves (P \u3c 0.01; 30% vs 68%, respectively), but pregnancy rate was higher (P = 0.058; 81 vs 63%, respectively). Cows with two waves had shorter estrous cycles (P \u3c 0.01), with the ovulatory follicle being both larger (P \u3c 0.05) and older (P \u3c 0.01). In cows with three waves, luteal function was extended (P \u3c 0.05) and the peak in plasma progesterone occurred later (P \u3c 0.05) in the estrous cycle compared to two wave cows. Considering cows that became pregnant, luteal phase length was shorter (P \u3c 0.05) during the estrous cycle preceding insemination than for nonpregnant cows. In conclusion, fertility was greater in lactating cows inseminated after ovulation of the third-wave follicle that had developed for fewer days of the estrous cycle as compared with two-wave cows

Descrição de dois anos de atuação da Comissão de Ética no Uso de Animais do Setor de Ciências Agrárias da Universidade Federal do Paraná Two years description of the Animal Use Ethic Committee of the Agrarian Science Sector of the Federal University of Paraná

A Comissão de Ética no Uso de Animais do Setor de Ciências Agrárias (CEUA-SCA) da Universidade Federal do Paraná (UFPR) foi criada em 2005. Este artigo teve por objetivo estudar os dois primeiros anos do trabalho dessa Comissão, principalmente quanto à redução do sofrimento animal. Foram avaliadas a composição e a metodologia de trabalho da CEUA-SCA, além da efetividade na redução do sofrimento animal, pela razão emissão de certificados por projetos protocolados (C:P) e pelo estudo dos projetos que receberam ofícios. Foram avaliados 42 protocolos de pesquisa de 2006 e 24 de 2007. Animais vertebrados foram os mais usados, submetidos com maior frequência a procedimentos grau B de invasividade. Os resultados sugerem que a CEUA-SCA, no período estudado, colaborou para o controle do uso de animais nas pesquisas sob a responsabilidade do SCA-UFPR. Destaca-se a necessidade do preenchimento adequado dos formulários pelos proponentes, o aumento da pluralidade na composição da Comissão e a importância de um órgão federal que centralize informações relativas à atuação das CEUAs no Brasil.<br>The Animal Use Ethic Committee of the Agrarian Sciences Sector (CEUA-SCA) of the Federal University of Paraná (UFPR) was created in 2005. The objective of this research was to describe the first two years of CEUA-SCA's work, mainly regarding to the reduction of the animal suffering. The CEUA-SCA's composition and work methodology were studied, as well as the effectiveness to reduce the animal suffering, evaluated by the ratio of certificates emitted and projects registered (C:P) and by the observation of projects that received official letters. Forty two research protocols in 2006 and 24 in 2007 were evaluated. Animals used were mostly vertebrates being submitted more frequently to procedures considered B for invasiveness degree. The results show that the CEUA-SCA, in the studied period, collaborated to the control of the animal use under the responsibility of the SCA-UFPR. Further improvement relates to the need for proper formularies fulfilment by the proposers, the increase of plurality in the Committee composition and the importance of a federal agency centralizing the Brazilian CEUAs information