Die künstlich Zeugung (Befruchtung) im Tierreich,

Mode of access: Internet.

Die künstliche Bufruchtung der Haustiere.

Translated from the Russian.

Relationship between thirty post-thaw spermatozoal characteristics and the field fertility of 11 high-use Australian dairy AI sires

This study determined the relationship between two measures of field fertility of I I high-use Australian artificial insemination (AI) dairy bulls and thirty standard laboratory assessments of spermatozoal post-thaw viability. The two measures of field fertility used, conception rates (cCR) and non-return rates (cNRR), were both corrected for all major non-bull variables. Sperm viability assessments were conducted on semen collected within the same season as that used to derive the field fertility estimates. These assessments measured sperm concentration, motility, morphology and membrane integrity at thawing, after 2 h incubation and after the swim-up sperm selection procedure. Derivations of these measures and in vitro embryo fertilizing and developmental capacity were also determined. The Genstat Statistical Package [Genstat 5 Release 4.2 Reference Manual, VSN International, Oxford, 20001 was used to conduct an analysis of variance on the viability parameters across semen straws and bulls, and to calculate the strength of correlation between each semen parameter, cNRR and cCR in a correlation matrix. Step forward multiple regression identified the combination of semen parameters that were most highly correlated with cCR and with cNRR. The sperm parameters identified as being most predictive of cCR were the percentage of morphologically normal sperm immediately post-thaw (zeroNorm), the number of morphologically normal sperm after the swim-up procedure (nSuNorm), and the rate of zygote cleavage in vitro (Clv); the predictive equation formed by these parameters accounted for 70% of variance. The predictive equation produced for cNRR contained the variables zeroNorm, the proportion of membrane intact sperm after 2 h incubation at 37 degreesC (twoMem) and Clv and accounted for 76.5% of the variation. ZeroNorm was found to be consistent across straws and semen batches within-bull and the sperm parameter with the strongest individual predictive capacity for both cCR (P = 0.1) and cNRR (P = 0.001). Post-thaw sperm parameters can be used to predict field fertility of Australian dairy sires; the calculated predictive equations are particularly useful for identifying and monitoring bulls of very high and very low potential fertility within a group. (C) 2003 Elsevier B.V. All rights reserved.

Embryonic mortality in buffaloes synchronized and mated by AI during the seasonal decline in reproductive function

The aim was to determine the factors that contribute to embryonic mortality in buffaloes mated by AI during a period of increasing day length which corresponds to a natural decline in reproductive activity. Italian Mediterranean buffalo cows (n = 243) showing regular estrous cycles were synchronized using the Ovsynch-TAI program and mated by AI at 16 and 40 h after the second injection of GnRH. Blood samples were collected on Days 10 and 20 after the first AI and assayed for progesterone (P-4). Pregnancy diagnosis was undertaken on Days 26 and 40 after the first AI using rectal ultrasonography. Buffaloes with a conceptus on Day 26 but not on Day 40 were judged to have undergone embryonic mortality and for these animals uterine fluid was recovered by flushing and analysed for common infectious agents. Estrus synchronization was achieved in 86% of buffaloes and the pregnancy rate on Day 40 was 34%. Embryonic mortality between Days 26 and 40 occurred in 45% of buffaloes and was associated with the presence of significant infectious agents in only 10 buffaloes (8%). Concentrations of P-4 on Day 10 after AI were higher (P < 0.05) in buffaloes that established a pregnancy than in buffaloes that showed embryonic mortality that was not associated with infectious agents. Similarly, on Day 20 after AI P-4 concentrations were higher (P < 0.01) in pregnant buffaloes compared with non-pregnant buffaloes and buffaloes that had embryonic mortality. It is concluded that a reduced capacity for P-4 secretion can explain around 50% of embryonic mortalities in buffaloes synchronised and mated by AI during a period of low reproductive activity and that other as yet unidentified factors also have a significant effect on embryonic survival. (c) 2004 Elsevier Inc. All rights reserved.

Adição de Ácido Linoleico conjugado (CLA) no diluidor de congelação de sémen de touro, recolhido Post-Mortem, das raças Holstein Frísia, Aberdeen Angus, Charolês e Limousine

Dissertação de Mestrado, Engenharia Zootécnica, 7 de Abril de 2016, Universidade dos Açores.

Ajuste del tiempo de inseminación con semen sexado en vacas superovuladas

En la actualidad los resultados de la combinación del semen sexado y superovulación (SOV) no han sido muy alentadores debido a la baja cantidad de espermatozoides así como a la corta vida media de los mismos. En un trabajo previo realizado en Brasil en vacas Holstein, se demostró que usando el protocolo de SOV P36/Lh60 e inseminando con semen sexado a las 18 y 30 horas de aplicado el inductor de la ovulación (intervalo de 12 hs entre inseminaciones) se obtiene igual cantidad de estructuras transferibles que inseminando a las 12 y 24 horas con semen no sexado. El objetivo de esta investigación fue ajustar las horas de la inseminación artificial (IA) en vacas superovuladas e inseminadas con semen sexado para lograr mejor sincronía con las ovulaciones y así aumentar la cantidad de embriones transferibles. Este ajuste evaluó 2 momentos de IA en los cuales el intervalo entre ambas se disminuyó a 6 hs. Para esto se usaron 30 vacas Holstein en producción superovuladas con el protocolo P36/LH60 y se dividieron en tres grupos en forma aleatoria; en el grupo IA18/30 (control; n=10) las inseminaciones se realizaron a las 18 horas y 30 hs de la aplicación del inductor de la ovulación (GnRh); en el grupo IA18/24 (n=10) sé inseminó a las 18 y 24 hs de la GnRH y al grupo IA24/30 (n=10) se inseminó a las 24 y 30 (se usó 2.1x106 espermatozoides sexados / inseminación). No se encontró diferencia estadística en los tres grupos, sin embargo el grupo IA18/24 mostró ventaja numérica sobre el grupo IA24/30 y el Control (4,1±1,5 vs 1,3±0,4 y 1,9±0,6 respectivamente) en la cantidad de embriones transferibles, con lo que concluimos que el ajuste en las horas de IA con semen sexado en vacas Holstein superovuladas puede ser usado con resultados similares a los trabajos anteriores

Evaluation of breeding strategies for polledness in dairy cattle using a newly developed simulation framework for quantitative and Mendelian traits

Background: Intensified selection of polled individuals has recently gained importance in predominantly horned dairy cattle breeds as an alternative to routine dehorning. The status quo of the current polled breeding pool of genetically-closely related artificial insemination sires with lower breeding values for performance traits raises questions regarding the effects of intensified selection based on this founder pool. Methods: We developed a stochastic simulation framework that combines the stochastic simulation software QMSim and a self-designed R program named QUALsim that acts as an external extension. Two traits were simulated in a dairy cattle population for 25 generations: one quantitative (QMSim) and one qualitative trait with Mendelian inheritance (i.e. polledness, QUALsim). The assignment scheme for qualitative trait genotypes initiated realistic initial breeding situations regarding allele frequencies, true breeding values for the quantitative trait and genetic relatedness. Intensified selection for polled cattle was achieved using an approach that weights estimated breeding values in the animal best linear unbiased prediction model for the quantitative trait depending on genotypes or phenotypes for the polled trait with a user-defined weighting factor. Results: Selection response for the polled trait was highest in the selection scheme based on genotypes. Selection based on phenotypes led to significantly lower allele frequencies for polled. The male selection path played a significantly greater role for a fast dissemination of polled alleles compared to female selection strategies. Fixation of the polled allele implies selection based on polled genotypes among males. In comparison to a base breeding scenario that does not take polledness into account, intensive selection for polled substantially reduced genetic gain for this quantitative trait after 25 generations. Reducing selection intensity for polled males while maintaining strong selection intensity among females, simultaneously decreased losses in genetic gain and achieved a final allele frequency of 0.93 for polled. Conclusions: A fast transition to a completely polled population through intensified selection for polled was in contradiction to the preservation of high genetic gain for the quantitative trait. Selection on male polled genotypes with moderate weighting, and selection on female polled phenotypes with high weighting, could be a suitable compromise regarding all important breeding aspects.

Clínica de animais exóticos

Este relatório de estágio descreve as atividades desenvolvidas no estágio curricular e desenvolve o tema ―Inseminação artificial em Python regius‖. O estágio de seis meses foi realizado na Exoclinic – clínica veterinária de aves e exóticos, permitindo consolidar conhecimentos através da prática clínica e agregar-lhes a área da medicina de animais exóticos, dedicando especial atenção à medicina de répteis. Desenvolvem-se os casos mais frequentes: medicina preventiva nas várias classes de animais, patologia dentária em roedores e lagomorfos, doença do bico e das penas dos psitacídeos e anorexia em répteis. Na monografia aborda-se a anatomofisiologia e o comportamento reprodutivos das cobras e a sua influência no maneio reprodutivo em cativeiro, métodos de avaliação de reprodutores e técnicas de inseminação artificial. Realizou-se um ensaio prático com seis animais, realizando colheitas de sémen, avaliação de alguns parâmetros do sémen, controlo folicular por ecografia e inseminação artificial. Apresentam-se os métodos, os resultados e respetiva discussão; Abstract: Exotic animal medicine This traineeship report describes the activities during the traineeship and develops the theme "Artificial insemination in Python regius." The six-month internship was held in Exoclinic - clínica veterinária de aves e exóticos, consolidating knowledge through clinical practice and adding the medical field of exotic animals, with special attention to reptiles. The most frequent clinical cases are developed: preventive medicine in the various classes of animals, dental pathology in rodents and lagomorphs, Psittacine Beak and Feather Disease in birds and anorexia in reptile. The monograph addresses the anatomy, physiology and reproductive behavior of snakes and their influence on reproductive management in captivity, methods for reproductors selection and evaluation and artificial insemination techniques. Implementation of a field trial with six animals, performing semen crops and evaluation of some of its parameters, follicular monitoring by ultrasound and artificial insemination. Methods and results are presented and discussed.

Cirurgia e clínica de espécies pecuárias

Neste relatório são, primeiramente, descritas as atividades desenvolvidas durante o Estágio Curricular do Mestrado Integrado em Medicina Veterinária da Universidade de Évora, no âmbito de clínica e cirurgia de espécies pecuárias. Pretendeu-se, depois, determinar se a suplementação de bovinos de aptidão leiteira com β-caroteno injetável contribui para reduzir o número de inseminações artificiais necessárias para uma gestação. Por outro lado avaliou-se a influência que podem ter algumas variáveis, como sejam a estação do ano ou o número de partos da vaca. Procurou-se, ainda, estudar a evolução dos teores séricos de β-caroteno nos animais suplementados e não suplementados com Dalmafertyl®, utilizando a técnica de cromatografia líquida de alta eficácia ultravioleta. A suplementação parenteral de β-caroteno, nomeadamente com Dalmafertyl®, na Primavera, mostra resultados benéficos na reprodução de vacas e novilhas de aptidão leiteira, aumentando a produtividade e diminuindo custos; ABSTRACT: LARGE ANIMAL SURGERY AND CLINICS On the following report are described the activities that took place during the Curricular Externship as part of the Veterinary Medicine Integrated Masters from University of Évora, in large animal surgery and clinics. Also, it was intended to determine if injectable β-carotene supplementation on dairy cattle can be a decreasing factor on the artificial insemination number needed to result in pregnancy. On the other hand, it was assessed its influence on some variables that can affect pregnancy, such as seasons and calving number. It has been studied the evolution of β-carotene serum levels on Dalmafertyl® supplemented and non-supplemented animals using the high-performance liquid chromatography ultraviolet detection method, as well. β-carotene parenteral supplementation using Dalmafertyl® seems to have benefic results on dairy cattle reproduction when it comes to Spring, which leads to productivity increase and cost decrease

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Due to economical and scientific limitations, sheep embryo reproductive technologies are less commercially applied than in other animal species. However, it is very clear that, in the near future, those techniques are expected to have a central role in animal production as a consequence of genetic and reproductive demands. One drawback is that results obtained after sheep embryo cryopreservation are unattractive for commercial purposes. It is expected that a successful cryopreservation of sheep embryos can push forward all other reproductive biotechnologies in this species, such as multiple ovulation and embryo transfer (MOET), artificial insemination, or in vitro production of embryos. This paper tries to discuss the current and future perspectives of cryopreservation of in vivo- and in vitro-produced sheep embryos concerning advantages and limitations for its practical use and possible solutions for improving methods to allow a higher survival rate of cryopreserved embryos.

Route of Oxytocin administration and nonsurgical embryo recovery in Santa Inês ewes after induction synchronous estrus.

Oxytocin has been used to promote cervical dilation with the objective to access uterus both in artificial insemination and transcervical embryo recovery in sheep and goats. The objective of this study was to test the effect of two routes of oxytocin administration on nonsurgical embryo recovery efficiency in Santa Inês ewes after induction of synchronous estrus. Results of this study showed that nonsurgical transcervical embryo recovery can be efficiently done in some ewes; a higher number of individuals is needed to conclude that transcervical embryo recovery can be efficiently done in ewes and surgery embryo collections can be avoided in near to 60% of pluriparous Santa Inês ewes; and that the route of oxytocin administration did not affect the parameters evaluated.

Update and overview on assisted reproductive technologies (ARTs) in Brazil.

2016

Embryo transfer as a tool to disseminate k-casein BB genotype and improve milk clotting properties

Dairy industries are asked to be increasingly competitive and efficient. Despite the increasing trend in milk yield and protein content during the last decade genetic selection, milk coagulation ability has diminished and even if the absolute amount of cheese produced has increased, the relative cheese yield from a set amount of milk, has decreased. As casein content and variants, along with milk clotting properties (MCP) are determined to a large extent at DNA level, genetic selection and embryo transfer can provide efficacious tools to reverse this trend and achieve improvements. The aim of the proposed research was to determine how rapidly and to what extent milk coagulation properties could be improved by using embryo transfer (ET) as a tool to increase the frequency of k-casein BB genotype cattle and reducing A and E variants in an Italian Holstein herd with a low prevalence of the favourable genotype. In the effort to optimize superovulation protocols and results, synchronization of wave emergence was performed through manual transrectal ablation of the largest (dominant) ovarian follicle on days 7 or 8 of the cycle (estrus = day 0); different drugs and dosage for the superstimulation protocol were experimented trying to overcome the negative effects of stress and the perturbance of LH secretion in superovulated highly producing lactating cows and the use of SexedULTRA™ sex-sorted semen, for artificial insemination of superovulated cows was reported for the first time. The selection program carried out in this research, gave evidence and gathered empirical data of feasible genetic improvements in cheesemaking ability of milk by means of k-casein BB selection. In conclusion, in this project, selection of k-casein BB genotype markedly enhanced cheese-making properties of milk, providing an impetus to include milk coagulation traits in genetic selection and breeding programs for dairy cattle.