MAXIMIZING IN VITRO EMBRYO PRODUCTION IN CATTLE

In vitro embryo production (IVEP) is used to develop high-quality genetics associated with intergenerational genetic gain. It is characterized by acquisition (in vivo or post-mortem) and maturation (MIV) of oocytes from donors, followed by fertilization (FIV) of matured oocytes and culture (IVC) of embryos, which are then sent to transferred or cryopreserved. Even with extensive knowledge on IVEP, some biochemical and hormonal regulations that involve embryonic development are still unknown, leading to a low overall efficiency of the biotechnological process. Although in vitro developed embryos have a lower quality than that produced in vivo, in terms of resistance to challenging events, IVEP presents itself as a potential biotechnology. In cattle breeding, reproductive biotechnologies are key to increase and improve the genetic improvement of the herd, associated with productive and reproductive efficiency. In this article, the steps and strategies of IVEP and its contribution to reproduction in the cattle sector are discussed.

Efficiency of tick biotherapic on the control of infestation by Rhipicephalus (Boophilus) microplus in Dutch dairy cows.

Background: cattle tick Rhipicephalus (Boophilus) microplus poses serious problems for farmers in Brazil, especially because the parasite easily develops resistance to pesticide agents. For this reason, together with other factors including environmental, human and animal contamination and costs, alternative approaches have been sought for. Aims: this study sough to evaluate the efficiency of a tick biotherapic on tick-infested cows. Methods: 34 dairy Dutch cows were divided in 2 groups: one group received 100g/day of mineral salt supplement impregnated with tick biotherapic 12cH for 6 months, and then in alternate days with tick biotherapic 30cH to complete 28 months of treatment; the other group (control) received only the mineral salt supplement. After 28 months of treatment, engorged Rhipicephalus (boophilus) microplus females were collected in both groups, counted and weighed; in vitro tests were carried out to assess mass of ticks; egg mass; egg-hatching rate; and reproductive efficiency. Results: There was significant difference between both groups for all parameters evaluated; tick-mass (p = 0.0008); egg mass (p=0.0044); egg-hatching rate (p= 0.0017); and reproductive efficiency (p = 0.0044). Conclusion: treatment with tick biotherapic significantly decreased the mass of engorged females, deposition and hatching rate of eggs, resulting consequently in the decrease of the reproductive efficiency of ticks.

The Relationship Between Coat Color and Reproductive Performance of Dairy Cows in Algeria

The objective of the current study was to analyze the reproduction parameters of 48 dairy cows (29 Montbeliardes and 19 Normandes) and their relationship to coat color. Cows were imported from European countries and raised in the semi-arid region of Sétif in Algeria. The findings showed that the cows of the Montbéliarde breed were more fertile and of greater reproduction efficiency, compared to Normandes. Regarding the Montbéliarde breed, the intervals between calving and calving to conception were respectively 378.34 and 98.65 days, which were shorter than those of the Normandes breed (67 and 22 days, respectively). Normandes cows registered a higher number of services per conception (1.54 ± 0.9), compared to Montbeliarde cows (1.34 ± 0.55). Calving to the first service interval of the Normandes (76 days) was longer by 5 days than that of the Montbéliarde breed. The coats of Montbéliarde cows (51%) were whiter than those of Normandes (48%). A darker hair coat probably assured protectivity against thermal stress and greater efficiency of reproduction. The interval between calving in Montbéliarde cows was significantly affected by coat color; the interval between calving of cows with a colored coat was shorter (358 days) than whiter cows (400 days). For Normandes, cows with a colorful coat required fewer services per conception number (1.44). Hair works as a temperature regulator and may affect reproduction performances. The results of the current study suggest the possibility of integrating coat color into animal selection. It can be assumed that colored coats for Montbéliarde and Normande breeds appear to be related to their reproductive efficiency (interval between calving and number of services per conception, respectively).

Significance and Relevance of Spermatozoal RNAs to Male Fertility in Livestock

Livestock production contributes to a significant part of the economy in developing countries. Although artificial insemination techniques brought substantial improvements in reproductive efficiency, male infertility remains a leading challenge in livestock. Current strategies for the diagnosis of male infertility largely depend on the evaluation of semen parameters and fail to diagnose idiopathic infertility in most cases. Recent evidences show that spermatozoa contains a suit of RNA population whose profile differs between fertile and infertile males. Studies have also demonstrated the crucial roles of spermatozoal RNA (spRNA) in spermatogenesis, fertilization, and early embryonic development. Thus, the spRNA profile may serve as unique molecular signatures of fertile sperm and may play pivotal roles in the diagnosis and treatment of male fertility. This manuscript provides an update on various spRNA populations, including protein-coding and non-coding RNAs, in livestock species and their potential role in semen quality, particularly sperm motility, freezability, and fertility. The contribution of seminal plasma to the spRNA population is also discussed. Furthermore, we discussed the significance of rare non-coding RNAs (ncRNAs) such as long ncRNAs (lncRNAs) and circular RNAs (circRNAs) in spermatogenic events.

Effect of Inseminator on Reproductive Performance in Dairy Cattle

The reproductive efficiency of dairy cattle is critical to the economic success and sustainability of the enterprise. Due to its many advantages, artificial insemination has inevitably taken its place in herd management today and different artificial insemination methods have been developed until today. At the same time, artificial insemination is carried out by commercial artificial insemination operators or do-it-yourself operators in cattle farms. One of the factors affecting the success of artificial insemination is inseminators. The aim of this study is to determine the effect of inseminators on conception rates in reproductive challenges and to reveal the differences between the success rates of inseminators. A total of 227297 artificial insemination acts carried out by 35 inseminators for four years belonging to the Konya Cattle Breeders' Association in Turkey were assessed for this purpose. In the study, the insemination success rate was determined as 41.36%. In addition, the percentage of inseminators with a total insemination success rate of more than 50% is very low, such as 2.9% and the percentage of those who achieved 35.9% and below was 9.3%. As a result, it can be stated that the inseminators having a lower success rate than the overall should be retrained to avoid some costs or losses in farms.

Development of Poly-NIsopropylacrylamide Surfaces for the Selection of Swine Sperm

The reproductive efficiency of pig farms is directly correlated with the fertility of the boars. The aim of this work was to develop polymeric materials that can be used as a platform to select a subpopulation of sperm with better cell physiological parameters. Polymeric hydrogels composed of Poly-N-isopropylacrylamide with different positive charges given by copolymerization with (3-acrylamidopropyl) trimethylammonium chloride (APTA, 5-10-15%), were synthesized. Subsequently, the interaction between the sperm cells and the polymeric surfaces was analyzed in TALP medium. Release of the spermatozoa from the polymeric surfaces was induced by changing to Ca2+ free media. Sperm motility, cell viability, plasma membrane and acrosome integrity were evaluated. The results indicated that a higher percentage of swine sperm attached to PNIPAM co-15% APTA hydrogels (62.86±3.33%). Ninety seven percent (97.19±1.45 %) of the sperm released from the PNIPAM co-15%APTA surfaces were viable (p<0.05 vs unbound population and raw semen), with acceptable motility (58.89±1.28%) and with intact plasma and acrosomal membranes (69±1.2% and 98.5±0.65% respectively). These results indicate that hydrogels can be used to select boar sperm with high viability and mobility for use in assisted reproductive techniques.

THE EFFECT OF THE DOE WEIGHT ON HER REPRODUCTIVE EFFICIENY

Thirty-six local dose have been used and were divided in to three groups sacording to weight, in each group twelve dose. In the first group the weights of the dose were higher than ( 2.5 kgs) and less than (3 kgs). The second groups was higher than 3 kgs) and less than (3.5 kgs). The third group was higher than (3.5 kgs) and less than (4 kgs). The aim of this study was to obtain the effect of doe weight on her reproductive efficiency (gestation period, litter size, litter weight at birth and weaning, growth rate of offspring preweaning, conception rate and preweaning mortility). The weight of the doe had no significant effect upon the gestation period and this period was 30.9, 31.2, 31.3 days for the three groups respectively, on the other hand the litter size was affected significantly by doe weight and litter size was at birth and preaweaning (5.1 , 5.8 and 6.2), (4.5, 5.3 and 5.7) for the three groups respectively. The offspring weight at birth and weaning was affected significantly by doe weight and this weight was (40.1 , 48.2 and 53.3 gms), (203.6, 227.5 and 233.8 gms) for the three groups respectively while the conception rate was not affected by doe weight. The mortility percentage in the prewaning period was not significantly by doe weight