The objective was to evaluate the maturation time to obtain oocytes in Metaphase II (MII) stages and the rate of division and blastocysts after fertilization in alpacas. For this, the ovaries were obtained from benefited animals. Experiment 1: 441 oocytes were distributed in four times (26, 32, 38 and 42 hours) and matured in TCM-199. At the end of the maturation time, the oocytes were fixed in an ethanol solution: acetic acid (3:1) and stained with aceto-orcein (1%). Experiment 2: 959 oocytes were cultured under the same conditions as experiment 1 and fertilized with sperm obtained by artificial vagina and selected by the Swim Up method. At the end of the fertilization time, the presumed zygotes were cultured in SOFaa medium for 7 days. In experiment 1, 39.6 ± 8.0, 49.1 ± 18.6, 45.9 ± 9.1 and 38.2 ± 9.9% of oocytes were obtained in Metaphase-II for 26, 32, 38 and 42 h of maturation, respectively, without statistical difference (p>0.05). In experiment 2, the cleavage rate was 45.7 ± 3.5, 51.3 ± 10.2, 52.8 ± 5.6 and 50.9 ± 3.1 with no statistical difference between treatments (P>0.05) and the blastocyst rate was 20.5 ± 3.4, 30.5 ± 5.8, 21.2 ± 2.5 and 22.8 ± 3.5 for 26, 32, 38 and 42 hours, respectively, with a statistical difference between 32 hours and 26, 38 and 42 hours (p<0.05). The results obtained suggest that 32 hours of maturation are required to obtain 30.5% of blastocysts

This document is about gene editing mechanisms in animals to enhance certain specific characters in subsequent generations. Gene generation by gene editing is the current revolution in biology. Today it is possible to edit the genome using the CRISPR-Cas tool that allows you to cut and paste very precise DNA sequences like never before. Thus we can improve practically all those characteristics that are determined by a gene, and then completely modify the phenotype of any species.

Proceedings del Primer Simposio Internacional de Reproducción Animal, organizado por el Instituto de Reproducción Animal del Ecuador (IRAE), realizado en el Centro de Convenciones de Guayaquil, 18 y 19 de marzo de 2022.

The aim of the study was to determine the morphological and morphometric characteristics of the vicuña sperm (Vicugna vicugna), looking for possible subpopulations in its structure. Semen was collected by electroejaculation method from three adult male vicuñas weighing 50.33 ± 2.52 kg, once per animal. The volume, color and concentration, sperm morphology and morphometry were determined. The samples for the analysis of sperm morphology and morphometry were stained with Hemacolor®, and analyzed using the CASA-Morph, Integrated Semen Analysis System (ISAS®v1). Five forms of the vicuña sperm head were distinguished: normal, piriform, long, short and rounded. The morphometric parameters determined were the length, width, area, perimeter, ellipticity, elongation, regularity and rugosity of the vicuña sperm head, percentage of acrosome, head gray level, as well as the width, area, distance and angle of insertion of midpiece of the sperm. In relation to morphology, significant differences (P <0.05) were found in the percentage distribution of head shapes, with the normal shape (55.7%) being the majority and different from the other shapes. Significant differences (P <0.05) were found between animals in the morphometric variables of head, percentage of acrosome, ellipticity, rugosity, elongation and gray level; while the variables of the midpiece and regularity did not show differences (P> 0.05). The morphometric variables were distributed in four main components (PCA) called elongation, area, circularity and midpiece width, which explained 84.59% of the total variance. The cluster analysis determined five subpopulations (SP): SP1 grouped small cells of low length, width and area (18.8%); SP2 of sperm of large size, both in area and width of the head (17.38%); SP3 of rounded cells with high values of percentage of acrosome and head gray level (24.04%); SP4 of spermatozoa of intermediate size and elongated, with greater ellipticities and elongation (23.61%); and SP5 of cells of intermediate size and short, with low values of area and length (16.71%).

The present study aimed to compare results for hatchability and growing performance of chicks from 2 biotypes, dual purpose (DP) and brawl (BR), in hipobaric conditions (2718 m above sea level). In experiment 1, a total of 352 hatching eggs were randomly arranged, 176 egg of DP y 176 BR. In experiment 2, a total of 114 one-day-old unsexed chickens were reared for 28 d. The experimental design for hatchability and chick performance variables was completely randomized with 2 treatments (DP and BR). There were no differences between the studied treatments for hatchability results (p>0.05). Hens’ biotype affected chicken performance in the rearing phase (p<0.01), where the DP chickens had better body weight and feed conversion than BR, but BR chickens had lower mortality than DP chickens.

The objective of this research was to evaluate the use of the intravaginal device (CIDR) and estradiol cypionate in synchronization protocols, on oestrus presentation, pregnancy and birth rate in Creole sheep under high altitude conditions. The study was carried out in a non-reproductive season, in the peruvian highlands, using 57 ewes. Four experimental groups were formed: group T1 (n=14) and T3 (n=14), CIDR progesterone device for 7 days and 12 days, respectively; group T2 (n=15) and T4 (n=14), CIDR progesterone device for 7 days and 12 days plus 1 mg of estradiol cypionate, 24 hours after removal of the device in both groups, respectively. Estrous presentation was observed from CIDR removal to 48 hours using vasectomized rams and IATF was performed with fresh semen 48 hours after device removal. The pregnancy rate was determined by ultrasonography at 46 and 90 days after FTAI and the birth rate was recorded. The chi-square test was used for statistical analysis. There was no difference (P>0.05) between groups, for estrous presentation, but there was difference (P<0.05) for pregnancy rate at 46 days between groups with: T1 (42.9%), T3 (38.5%), T4 (21.4%), with respect to T2 (0%) (The difference in results are shown in Table 2). There was a difference (P<0.05) for the pregnancy rate at 90 days: T1 (35.7%) and T3 (30.8%), with respect to T4 (7.1%) and T2 (0 %). The birth rate showed differences (P<0.05) for T1 (28.6%) and T3 (28.6%), with respect to T2 (0%) and T4 (0%). In conclusion, a high pregnancy rate was obtained with CIDR for 7 and 12 days, compared to the use of CIDR plus estradiol cypionate. However, no births were obtained with progesterone plus estradiol cypionate treatment.

The objective was to evaluate the effect of two methods of freezing on seminal quality and effect of seminal plasma as an inducer of ovulation in pregnancy percentages in inseminated alpacas. The semen collection was made post copula. After the collection of the ejaculates, motility and volume were assessed. The ejaculates with volume (≥1 ml) and motility (≥ 60%) were mixed (pool), 80 % was used (3 samples/pool) and 20 % (2 samples/pool) during the experiment. Then and diluted in Tris-base with 20% egg yolk. The samples were cooled 1.5 hours at 5 °C. At that temperature it was combined with the basic dilutor plus glycerol, obtaining a final concentration of 5% glycerol, then they were packed in 0.5 mL (13 x 106 spem/straw) straws to be frozen by horizontal and vertical methods. The seminal (semen + vaginal fluid) quality analysis was performed fresh and after cooling and thawing. Insemination was performed in two groups with thawed semen from two straws of the vertical method, the first group 20 females induced to ovulate with GnRH analog, the second group 20 females induced to ovulate with seminal plasma. When comparing, the results obtained of motility, viability, HOST and acrosomal integrity of fresh sperm, after the freezing process, decreased (p<0.05) compared to fresh and refrigerated samples. On the other hand, when comparing the freezing methods, the sperm values frozen by the vertical method were higher than those obtained by the horizontal method, with (p<0.05) in motility and HOST without (p>0.05) in acrosomal integrity and viability. The vertical semen freezing method can replace the horizontal method to obtain pregnancy.

The objective of this study was to compare the uterine health between fertile, sub-fertile alpacas and tuis using transrectal ultrasonography, endometrial cytology and bacterial isolation. A total 10 tuis (young mature females without breeding with average age of 1.5 years) and 20 adult alpacas of the Suri breed were used. In turn, the adult females were divided into two groups of 10 animals each according to their reproductive history: fertile group (parturition every year) and sub-fertile group (1 to 2 years without pregnancy). In all females, the thickness of the cervix and uterine horns was determined by transrectal ultrasonography. On the other hand, endometrial cytology and bacterial isolation were performed from samples obtained by uterine flushing. A Kruskal-Wallis and a Chi-square tests were used to compare ultrasonography and cytology groups. A greater thickness of the cervix and both uterine horns (p˂0,05) was observed in the fertile alpacas with respect to the sub-fertile and tuis. The percentage of PMN in tuis and sub-fertile alpacas was < 2%, while in fertile alpacas the percentage of PMN were: 6 animals with < 2% PMN, 2 animals with 2-5% PMN and two other alpacas with > 5% PMN. The bacteria isolated were: Bacillus lechiniformis and Escherichia coli in the three groups studied, Staphylococcus saprophyticus and Bacillus cereus in tuis and fertile alpacas, Staphylococcus aureus in tuis and sub-fertile, Bacillus spp. and Micrococcus spp. in fertile and sub-fertile alpacas, Bacillus lactic acid, Staphylococcus epidermidis and Citrobacter spp. in fertile alpacas, Enterococcus spp., Bacillus subtilis and Klebsiella spp. in sub-fertile and Enterobacter spp. in tuis. The low percentage of PMN in endometrial cytology in sub-fertile alpacas would indicate the absence of endometritis at the time of the study. However, the lower thickness of the cervix and uterine horns observed in sub-fertile alpacas suggest that it would be necessary to perform uterine biopsies in order to evaluate if there is any association between the thickness of the uterine wall and the presence of degenerative and/or inflammatory changes observed on histopathological examination.

The objective of this work was to evaluate the relationship of uterine health with mineral profile, hematological values and leukocyte form in dairy cows in grazing systems. During the months of March 2017 to July 2019, a total of 249 primiparous and multiparous Holstein cows belonging to dairy establishments in the southern basin of the province of Santa Fe - Argentina were reviewed in the postpartum period. The results showed that of the 249 (100%) cows at the first review, 111 (44.6%) were healthy and 138 (55.4%) had some degree of clinical endometritis. Of which 63 (45.6%) presented G1, 60 (43.5%) presented G2 and 15 (10.9%) cows presented G3. The Ca2+ and Mg2+ values did not show significant differences (p≥0.05) between both groups of cows. Significant differences (p <0.05) were found between the two groups, for the White Blood Cell values, being smaller in the group of animals with clinical endometritis. The red series values found not showing significant differences (p≥0.05) between both groups of cows. It is concluded that for this group of cows analyzed no relationship of uterine health with the mineral profile and values of the red series has been found. However, in the leukocyte form, cows with clinical endometritis had lower white blood cell values than healthy cows.

The use of reproductive technologies in the reproduction of the domestic animals has different objectives, between the most important uses are the prevention of diseases transmitted via natural mating, the optimization of the reproductive management, the more economic interchange of genetic material, the development of more efficient animal production systems, the generation of offspring with predetermined sex and genetic composition according to market requirements, the conservation of genetic resources and the increment of the rate of genetic gain in the animal populations; being this last application the one that has the most frequent and important usage and the most significant impact in the animal production industry. The importance of the reproductive technologies in animal improvement is because it allows us to achieve a significant increment in the reproductive rate of selected individuals (to get the maximum number of offspring per breeding animal), this makes possible to obtain high intensity and precision of selection and at the earliest age possible (reducing generation interval) resulting in the highest genetic gain per unit of time. From all the reproductive technologies developed, the artificial insemination (AI) in cattle is the most widely used technology globally and at national level in Peru, followed by the embryo transfer (ET) in cattle and by the AI and ET in sheep. From the design and usage of the in vitro embryo production and methodologies for the embryo micromanipulation it has started the development of a series of advanced reproductive technologies from a simple embryo bisection up to cloning of individuals, reproduction using stem cells and production of quimeras with cells genetically modified. In Peru is only in the last decade that the research and development and commercial application of reproductive technologies in the livestock reproduction has started with some advances in in vitro embryo production, embryo transfer, animal cloning, etc. with visible impact in the animal production industry and generating many challenges in order to increase its efficiencies and achieve its commercial use.