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The aim of this article was to compare plasma estrone sulfate (E1SO4), clinical biochemistry, and milk yield of dairy cows carrying a female fetus from a bull (BULL) or from its clone (CLONE), evaluating also the relationship between the former variables and the birth weight of the newborn. Sixteen recipient dairy Friesian heifers (10 BULL and 7 CLONE) received a female embryo, obtained by in vitro embryo production and sexing by polymerase chain reaction with the semen of the BULL or the CLONE. Blood samples on all cows were obtained before feed distribution in the morning from jugular vein from 4 weeks before to 4 weeks after calving, to be analyzed for metabolic profile. The samples from late gestation were also analyzed for E1SO4 concentration. To separately assess the effect of calf birth weight (CBW), data were categorized as follows: low (<39 kg; BWT-A), mid (39-46 kg; BWT-B), and high (>46 kg; BWT-C). The plasma concentrations of β-hydroxybutyric acid (BHB, P=0.019), Na (P=0.002), Cl (P=0.026), strong cation-anion balance (P=0.020), total bilirubin (P=0.054), and α1-globulin (P=0.044) were higher in prepartum BULL recipients than those in CLONE, whereas BHB (P=0.021) and Mg (P=0.090) were higher in postpartum BULL recipients, while no differences were recorded in the remaining postpartum parameters. The CBW class had significant interaction with week of gestation on antepartum plasma estrone sulfate (P=0.021), whereas CBW per se affected antepartum plasma BHB (P=0.021), and nonesterified fatty acids (NEFA; P=0.011) being higher in BWT-C which also had the lower NEFA concentration during postpartum. Milk yield was unaffected by the sire used, both for quantitative and qualitative aspects. Cows carrying heavier fetus (BWT-C) had a different lactation affected by month compared with the other 2 CBW groups. From these results, there were no differences between BULL and CLONE recipients. Estrone sulfate, BHB, and NEFA may be used to predict CBW and provide different nutritional management during gestation., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Assisted reproductive techniques developed for cattle in the last 25 years, like ovum pick up (OPU), intracytoplasmic sperm injection (ICSI), and somatic cell nuclear transfer, have been transferred and adapted to buffalo and horses. The successful clinical applications of these techniques require both the clinical skills specific to each animal species and an experienced laboratory team to support the in vitro phase of the work. In cattle, OPU can be considered a consolidated technology that is rapidly outpacing conventional superovulation for embryo transfer. In buffalo, OPU represents the only possibility for embryo production to advance the implementation of embryo-based biotechnologies in that industry, although it is still mainly in the developmental phase. In the horse, OPU is now an established procedure for breeding from infertile and sporting mares throughout the year. It requires ICSI that in the horse, contrary to what happens in cattle and buffalo, is very efficient and the only option because conventional IVF does not work. Somatic cell nuclear transfer is destined to fill a very small niche for generating animals of extremely high commercial value. The efficiency is low, but because normal animals can be generated it is likely that advancing our knowledge in that field might improve the technology and reduce its cost., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Nuclear transfer (NT) is a complex procedure that requires considerable technical skills. Over the years attempts have been made to simplify the micromanipulations involved and to make the procedure more user-friendly. A significant step forwards has been the development of the zona-free NT methods. We have used zona-free NT with mechanical aspiration of the metaphase plate as a mean of enucleation, in a comparative approach with the conventional nuclear transfer zona-enclosed method in cattle, horse, sheep and pig. The absence of the zona considerably facilitates the enucleation step and significantly increases cell fusion success. On the other hand, the culture of zona-free NT embryos requires the embryos to be cultured individually or anyway separated from each other to avoid aggregation and also requires to prolong the in vitro culture up to the blastocyst stage before transfer. Blastocyst rate is equal or higher with zona-free method as compared to zona-enclosed method while survival after cryopreservation and development to term is comparable. In conclusion, our findings, together with published data, demonstrate that the zona-free system described in this paper can significantly increase the output of NT blastocysts over the conventional zona-enclosed system.