The objective of this prospective field study was to evaluate the effects of extending the lactation period on various reproductive measurements of high-yielding Holstein cows. On 40 d in milk (DIM), cows were gynecologically examined (transrectal palpation, sonography, vaginoscopy). Cows without signs of clinical endometritis were blocked by parity and were randomly allocated to 1 of 3 experimental groups with a voluntary waiting period (VWP) of 40, 120, and 180 d, respectively (G40, n = 135; G120, n = 141; G180, n = 139). Cows of G120 and G180 were reexamined at the end of the VWP. If natural estrus was detected within 46 d after the end of the VWP, an artificial insemination was performed. If no estrus was detected, the respective cows were synchronized by applying the classical Ovsynch protocol. We found no difference in the proportion of cows in which estrus was detected between 40 to 86 DIM or in the days to first estrus between the 3 groups. Estrus detection in this period was lower in cows with body condition score <3 on 90 DIM compared with body condition score ≥3 (61.5 vs. 76.0%) and in cows with high energy-corrected milk production (ECM) on 92 DIM [58.6 vs. 70.1%, for cows with higher and lower than the median (39.9 kg) ECM, respectively]. The proportion of cows that estrus was detected within 46 d after the VWP was greater in G120 (88.9%) and G180 (90.8%) compared with G40 (70.4%). These effects were more apparent in cows with high ECM. The rate of estrus detection and of becoming pregnant in this period was greater for G120 (hazard ratio = 2.2 and 1.6, respectively) and for G180 (hazard ratio = 2.4 and 1.8) compared with G40. Cows in both groups with extended lactation had greater overall first service conception rates (G120 = 48.9%; G180 = 49.6%) and a lower number of services per pregnant cow (G120 = 1.56 ± 0.1; G180 = 1.51 ± 0.1) compared with G40 (36.6%; 1.77 ± 0.1). We observed no difference in pregnancy loss or in the proportion of cows culled up to 305 d of lactation between the 3 groups. The number of Ovsynch protocols per 1,000,000 kg of ECM was reduced by 75% in G180 and by 74% in G120 compared with G40 (5.9 vs. 7.1 vs. 25.1). In conclusion, extending the lactation of dairy cows can improve main reproductive measurements in high-yielding cows.
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http://dx.doi.org/10.3168/jds.2018-15115 | DOI Listing |
CRISPR J
January 2025
Department of Animal Science, University of California, Davis, California, USA.
In mice, naturally occurring and induced mutations in the suppressor of cytokine signaling-2 () gene are associated with a high growth phenotype characterized by rapid post-weaning weight gain and 30-50% heavier mature body weight. In this work, we demonstrate an electroporation-based method of producing knock-out (KO) sheep. Electroporation of dual-guide CRISPR-Cas9 ribonucleoprotein complexes targeting was performed 6 h post-fertilization in sheep zygotes.
View Article and Find Full Text PDFTheriogenology
January 2025
Department of Animal Sciences, University of Florida, Gainesville, FL, USA. Electronic address:
Implementing accelerometer technologies in beef operations is an alternative to increase precision in estrous detection. We hypothesized that (1) the accelerometer algorithm has similar accuracy in detecting behavioral estrus as does visual observation of pressure-sensitive sensors (estrus patches) in grazing beef cows; (2) variables measured by the accelerometer, such as estrus intensity, are associated with hormonal, ovarian, and uterine variables monitored before, during, and after estrus; and (3) the accelerometer variables are associated with the probability of pregnancy in grazing beef cows submitted to embryo transfer (ET). Fifty cows were fitted with accelerometer and patches to detect estrus after a synchronization protocol in eight subsequent rounds.
View Article and Find Full Text PDFAnim Reprod
December 2024
Department of Animal Science, South Dakota State University, Brookings, SD, U.S.A.
Early puberty is associated with improved long-term reproductive performance. Predicting who will achieve early puberty is limited to intensive, invasive serial blood collections for measurement of reproductive hormones. The vaginal genome during pubertal development has potential as biomarkers of early estrus in the pre-pubertal period.
View Article and Find Full Text PDFPol J Vet Sci
June 2024
İstanbul University-Cerrahpaşa, Department of Industrial Engineering, Faculty of Engineering, Istanbul, 34320, Türkiye.
The aim of this study was to evaluate the changes in calcium, phosphorus and some biochemical parameters in dogs with open and closed cervix pyometra, which was then compared with a control group. A total of 62 bitches of age group 5-10 years old irrespective of breed were enrolled into the study. Control group consisted of 22 bitches which were clinically healthy and in luteal phase of the estrus cycle.
View Article and Find Full Text PDFBiosens Bioelectron
March 2025
Nanobiointeractions&Nanodiagnostics, Istituto Italiano di Tecnologia (IIT), Via Morego, 30, 16163, Genova, Italy. Electronic address:
Lateral flow assays (LFA) are widely adopted in point-of-care diagnostics across a spectrum of applications, due to their simplicity of use and cost-effectiveness. However, in complex biological matrices (e.g.
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