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Navasota, TX, United States

DeJarnette J.M.,Select Sires Inc. | McCleary C.R.,Sexing Technologies Inc. | Leach M.A.,Select Sires Inc. | Moreno J.F.,Sexing Technologies Inc. | And 2 more authors.
Journal of Dairy Science | Year: 2010

The objective was to compare conceptions rates of Holstein cows and heifers after artificial insemination (AI) with 2.1 or 3.5×106 sex-sorted sperm or 15×106 conventional sperm. Ejaculates collected from 7 Holstein sires were cryopreserved conventionally at 15×106 sperm per dose or sorted to 90% purity for X-chromosome-bearing spermatozoa using flow cytometry and cryopreserved at either 2.1 or 3.5×106 sperm per dose. All treatments were processed in an egg-yolk (20%), Tris, glycerol (7%) extender and packaged in color-coded 0.25-mL French straws. Straws (n=700 straws/dosage per sire) were packaged and distributed in aliquots of 12 (4 straws/sperm dosage) to 69 Holstein herds with an across-herd goal of achieving ∼50% use in heifers and cows. Straw color was recorded in the on-farm recordkeeping system at the time of AI and retrieved by electronic download. Data for cows and heifers were analyzed separately. Among heifers, 6,268 services were retrieved from 45 herds (298±4.2 services/sperm dose per sire; range: 244 to 344). Conception rate of heifers was influenced by the sire by treatment interaction. Conception rate of the 2.1 and 3.5×106 sex-sorted sperm dosages were comparable in 6 of 7 sires. Conception rate of both sex-sorted dosages were less than those of conventional semen for 6 of 7 sires. Across sires, heifer conception rates for 2.1 and 3.5×106 sex-sorted sperm dosages and 15×106 conventional dosages were 44, 46, and 61%, respectively. Among cows, 5,466 services were retrieved from 52 herds (260±3.3 services/sperm dose per sire; range: 236 to 289). Conception rates of cows were influenced by herd, sire, and sperm dosage. Conception rates of the 2.1 and 3.5×106 sex-sorted sperm dosage were comparable for all 7 sires. Conception rates of 2.1×106 sex-sorted sperm dosage were less than those of conventional semen for 4 of 7 sires and conception rates of the 3.5×106 sex-sorted sperm dosage were less than those of conventional semen for 2 of 7 sires. Across sires, conception rates for 2.1 and 3.5×106 sex-sorted sperm dosages and 15×106 conventional dosages in cows were 23, 25, and 32%, respectively. In conclusion, these data could not confirm that a meaningful improvement in conception rates should be expected in cows or heifers from increasing sex-sorted sperm dosage from 2.1 to 3.5×106 sperm per dose. © 2010 American Dairy Science Association. Source


DeJarnette J.M.,Select Sires Inc. | Leach M.A.,Select Sires Inc. | Nebel R.L.,Select Sires Inc. | Marshall C.E.,Select Sires Inc. | And 2 more authors.
Journal of Dairy Science | Year: 2011

The conception rates of Holstein heifers after AI with 2.1 or 10 × 10 6 sperm dosages of sex-sorted or conventionally processed sperm were compared. Ejaculates collected by artificial vagina from 8 Holstein sires were cryopreserved at either 2.1 or 10 × 10 6 sperm per dose with or without sorting to 90% purity for X-chromosome-bearing spermatozoa using flow cytometry. All treatments were processed in an egg-yolk (20%), TRIS, glycerol (7%) extender and packaged in color-coded 0.25-mL French straws. Straws (n=350 straws/treatment per sire) were packaged and distributed in aliquots of 12 (3 straws of each treatment) to 51 herds of Holstein heifers. Straw color was recorded in the on-farm record keeping system at the time of AI and retrieved by electronic download. In total, 9,172 services were recovered, providing a mean sample size of 287±3.5 services/sperm dose per semen type within sire (range: 248 to 318). Conception rates were influenced by the main effects of herd, sire, semen type, sperm dosage, and service number. The herd by sperm dosage interaction was the only interaction determined to be significant and implies that some herds (technicians) are more proficient than others at maintaining high levels of conception with decreased sperm dosages. Across herds and sires, the conception rates of each semen type by sperm dosage combination were as follows: 2.1 × 10 6 sex-sorted, 38%, n=2,319; 10 × 10 6 sex-sorted, 44%, n=2,279; 2.1 × 10 6 conventional, 55%, n=2,282; and 10 × 10 6 conventional, 60%, n=2,292. The observation that conception rates of sex-sorted semen were improved by the 10 × 10 6 sperm dosage is encouraging toward the prospectus of development of a commercially available sex-sorted product with improved conception potential over existing technology. However, the failure of the 10 × 10 6 sex-sorted sperm dosage to achieve conception rates comparable to either dosage of conventional semen is somewhat discouraging toward the plausibility of comparable conception rates to conventional semen in the absence of major technological advances in efficiency of sperm sorting or cryopreservation. © 2011 American Dairy Science Association. Source


Lucena J.A.,University of California at Davis | Kenyon A.G.,University of California at Davis | Reynolds J.P.,Western University of Health Sciences | Moreno J.F.,Sexing Technologies Inc. | And 5 more authors.
Journal of Dairy Science | Year: 2014

The objective of this clinical trial was to compare conception and newborn calf sex ratios among Jersey heifers and lactating cows inseminated with either standard sex-sorted semen (low-dose, high-sort; LDHS) containing 2.1×106 sorted sperm at 90% purity or high-dose, low-sort (HDLS) semen containing 10×106 sorted sperm at 75% purity. After a specified voluntary waiting period (VWP), female subjects, consisting of nulliparous heifers (VWP 10mo of age) and lactating cows (VWP 50d in milk), received their first service and were systematically allocated to each treatment group in the order in which they presented for artificial insemination (AI). Females were bred to the same sire and type of sex-sorted semen for up to 2 additional services. Animals that were not pregnant after 3 breeding attempts were excluded. A total of 1,846 services were performed on 1,011 eligible females (LDHS; n=494, HDLS; n=517), which consisted of 516 nulliparous heifers and 495 lactating cows. Study groups were comparable with respect to the mean age at first AI for nulliparous heifers and the mean days in milk at first AI for parous cows. Insemination with HDLS semen did not result in a higher proportion of pregnancies per AI (P/AI) compared with LDHS semen for either nulliparous heifers (P/AI=43 vs. 38%) or parous cows (P/AI=47 vs. 43%). Insemination of nulliparous heifers using HDLS resulted in a lower proportion of newborn female calves compared with those bred to LDHS (76% vs. 87%). Similarly, lactating cows bred to HDLS gave birth to a lower proportion of newborn female calves compared with those bred to LDHS (79 vs. 90%). The odds ratio for a female calf to be born to an animal inseminated with HDLS compared with LDHS was 0.32 for nulliparous heifers and 0.19 for parous cows. Overall, the use of HDLS resulted in fewer females compared with LDHS, which may be explained by the lower concentration of X-bearing spermatozoa in HDLS compared with LDHS. © 2014 American Dairy Science Association. Source

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