The objective of this study was to analyze equine embryo morphokinetics and whether or not they were indicative of survivability upon successful implantation into the uterus of a recipient female. In equine reproduction, fertility is a lowly heritable trait that has an exceedingly large financial impact on the ability to grow genetic lines. In order to increase pregnancy rates, producers must have access to accurate decision-making tools. Ten (n = 10) fertilized equine embryos collected via flushing by licensed veterinarian, Dr. Gregg Veneklasen, DVM in Canyon, TX. Flushed embryos were filmed for a thirty-five (35) second observation period with an Iolight Microscope and then processed through video motion magnification (VMM) software Lambda Vue, that amplified embryo activity 300x their normal movement. These VMM embryos were then assessed for time specific morphological changes using Image J software. Embryo morphological dimension shifts previously unseen under a simple microscope became humanly perceptible and measurable. For morula stage embryos, measurements of significance were taken on the inner cell mass (ICM), total embryo area, trophoblast to ICM distance, and finally the vertical, diagonal, and horizontal axis of the sub-zonal distance. Protocols were developed for embryos in the blastocyst stages, where measurements were taken on the vertical, diagonal, and horizontal axis of the total embryo, area of the embryo, notation of general ICM location, and trophoblast thickness around the embryo face. All measurements were taken in microns every five seconds for the thirty-five second recording period. Findings presented that embryos with a greater ICM, total embryo area, and sub-zonal vertical, diagonal, and horizontal distance established pregnancies as frequently as embryos with less momentous differences in distance (P < 0.1). This research has shown the relationship between morphokinetics and pregnancy had no significance of determining pregnancy viability. This resulted in enhanced prediction of embryo transfer techniques based on traditional grading, making pregnancy rates more predictable and consistent.
The cloning of beef carcasses that grade USDA Prime – Yield Grade 1 (P1) has produced a sire that ranked well against high performing bulls from multiple breeds. An F1 (P1 x P1) sire would ideally exhibit heterosis and outperform its high performing parents. A terminal sire study was conducted comparing progeny of an F1 (P1 x P1) sire (AxG1) against progeny (heifers and steers) of four high performing sires of varying breeds {P1 (Alpha); Angus; Simmental; Angus x Simmental}. Production traits included morbidity and mortality frequencies, weaning weight, and feedlot arrival weight; carcass traits included edible liver and normal lung frequencies, hot carcass weight, longissimus muscle area, 12th rib fat thickness, and marbling score. A completely randomized experimental design was used; data was analyzed using a mixed model with a fixed effect of sire and random effects of harvest date, sex, and pen. Feedlot arrival weight, frequencies of morbidity and mortality, 12th rib fat thickness, and frequency of grading Certified Angus Beef or USDA Select did not differ (P ≥ 0.16) between sires. Weaning weight and frequency of normal lungs tended (P ≤ 0.08) to differ amongst sires. Differences in hot carcass weight (P < 0.01), longissimus muscle area (P < 0.01), marbling score (P < 0.01), and frequencies of normal lungs (P < 0.01) was detected among sires. Additionally, sire differences in USDA yield grade (P < 0.01), and frequencies of carcasses grading USDA Prime (P < 0.01) and USDA Choice (P < 0.01) were observed. AxG1 progeny exhibited the least 12th rib fat thickness and lowest USDA yield grade in addition to the largest longissimus muscle area, highest marbling score, and greatest frequency of USDA Prime. These data suggest that AxG1 competed extremely well against other high performing industry sires.
Cloning is a technology by which an animal’s tissue can be salvaged and replicated. Carcasses that grade USDA Prime – Yield Grade 1 (P1) represent a rare and antagonistic outcome and are a goal for terminal sire selection in the U.S. A terminal sire progeny test generated offspring for a crossbred bull (14% Zebu, 86% Angus; ALPHA), born in 2012 via somatic cell nuclear transfer (SCNT) from a carcass that graded P1. ALPHA progeny (steers and heifers) were compared against progeny of three purebred (Angus; Charolais; Simmental) reference sires. Live production traits included weaning weight, morbidity, mortality, and days on feed; carcass traits included abscessed liver frequency and lung lesion frequency, individual quality and yield grade parameters, and carcass value. Observed carcass traits for progeny from the Angus, Charolais, and Simmental sires were reflective of the carcass outcomes expected for each sire’s respective breed. Calves sired by the Angus were the earliest maturing indicated by the youngest chronological age at harvest (P ≤0.02) concomitant with the most backfat (P < 0.01), and the greatest marbling scores (P < 0.01). Calves sired by the Charolais had the heaviest carcass weight (P = 0.04), greatest cutability as assessed by USDA calculated yield grade (P < 0.01) and were the heaviest muscled based on longissimus muscle area (P < 0.01). ALPHA-sired calves were the most similar in carcass outcomes to calves sired by the Simmental, combining advantageous quality and yield parameters to produce an intermediate for carcass quality and yield. The economic value of moderate carcass outcomes is reflected in the carcass value per cwt, in which ALPHA-sired steers tended (P = 0.07) to be of greatest value compared to other sire groups. ALPHA progeny performed comparably to high performing reference sires for terminal sire production traits and the P1 genetics in which ALPHA was cloned have economical and biological value in modern U.S. beef production.
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