| 1. |
- Bezerra Lima Verde, Isabel, et al.
(författare)
-
Sperm Quality in Young Bull Semen Can Be Improved by Single Layer Centrifugation
- 2022
-
Ingår i: Animals. - : MDPI AG. - 2076-2615. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Simple Summary Genomic selection enables bulls with desirable genes to be identified early in life. Livestock producers need to use the semen from young bulls as early as possible for efficient milk and meat production with fewer greenhouse gas emissions. However, semen from young bulls is often of lower quality than needed for freezing for commercial artificial insemination. Colloid centrifugation selects spermatozoa with the desirable characteristics needed for fertilization from the rest of the ejaculate. In this study, split ejaculates from young bulls were prepared with or without colloid centrifugation. Using this technique, sperm doses of acceptable quality for artificial insemination could be produced from ejaculates that would otherwise be discarded. Thus, the semen from young bulls would be usable for artificial insemination sooner than is currently the case. Interest in using semen from young bulls is increasing due to identifying promising animals by genomic selection. However, sperm quality in these ejaculates may not reach currently accepted standards for the cattle breeding industry. The purpose of this study was to determine if centrifugation of semen from young bulls through the Bovicoll colloid could improve sperm quality sufficiently for the frozen semen to be acceptable for artificial insemination. Ejaculates from 19 young bulls were split and either processed by Single-Layer Centrifugation (SLC) or not (CON) before freezing. After thawing, sperm quality was evaluated by determination of membrane integrity, mitochondrial membrane potential, DNA integrity, production of reactive oxygen species, sperm morphology and motility. Approximately half of the CON samples reached acceptable post-thaw quality (membrane integrity >= 40%) despite being below the breeding company ' s desired sperm concentration threshold pre-freezing. In the remaining samples, sperm quality was improved by SLC such that 45% of them reached acceptable quality post-thaw. Almost 75% of the young bull sperm samples could have produced usable frozen semen doses by adjusting the breeding company ' s current processing protocols. Since lowering the generation interval has a direct effect on the genetic gain per year, SLC could aid genetic progress in cattle breeding.
|
|
| 2. |
- Deori, Sourabh, et al.
(författare)
-
Fast protein liquid chromatography profiles of seminal plasma proteins in young bulls: A biomarker of sperm maturity?
- 2021
-
Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 250
-
Tidskriftsartikel (refereegranskat)abstract
- Breeding companies want to use semen from bulls as soon as possible to take advantage of their desirable genetics. It takes several weeks for the sperm quality of young bulls to stabilize and for post-thaw sperm quality to become acceptable for artificial insemination. Seminal plasma proteins protect spermatozoa during cryopreservation; it may take some time for the seminal plasma protein profile to stabilize. The purpose of this study was to determine if the seminal plasma protein profile can be used as a marker of likely seminal maturity in young bulls. A comparison was made of the seminal plasma protein profile in the ejaculates of 10 bulls of 9-10 months old (Sample I), with the profiles from ejaculates taken from the same bulls at 13-16 months old (Sample II) using fast protein liquid chromatography. This is a method for separating classes of proteins according to their binding ability. The peak area and peak height of different classes of proteins did not differ significantly between the two samples for each bull, except for peak 5 (heparin-binding proteins) and total peak area (p<0.05). The heparinbinding protein peak height and area were significantly higher (p<0.05) in Sample II than in Sample I. In conclusion, levels of fertility associated heparin-binding proteins increase with age in young bulls and might serve as a biomarker of sperm maturity. .
|
|
| 3. |
|
|
| 4. |
- Hurri, Emma, et al.
(författare)
-
Herd-level prevalence of Mycoplasma bovis in Swedish dairy herds determined by antibody ELISA and PCR on bulk tank milk and herd characteristics associated with seropositivity
- 2022
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 105, s. 7764-7772
-
Tidskriftsartikel (refereegranskat)abstract
- Mycoplasma bovis is an important pathogen causing pneumonia, mastitis, and arthritis in cattle, leading to reduced animal welfare and economic losses worldwide. In this cross-sectional study, we investigated the prevalence of M. bovis in bulk tank milk (BTM) and herd characteristics associated with a positive antibody test result in Swedish dairy herds. Bulk tank milk samples from all Swedish dairy herds (n = 3,144) were collected and analyzed with ID Screen antibody ELISA and PCR. Information on herd characteristics was collected from the national Dairy Herd Improvement database. To identify herd characteristics associated with the presence of antibodies in BTM, logistic regression was used in 4 different models. The apparent herd-level prevalence of M. bovis infection based on antibodies in BTM was 4.8%, with large regional differences ranging from 0 to 20%. None of the BTM samples was positive by PCR. All the antibody-positive herds were situated in the south of Sweden. The logistic regression model showed that larger herds had higher odds of detectable antibodies in BTM (herd size >120 cows, odds ratio = 8.8). An association was also found between antibodies in BTM and both a higher late calf mortality (2–6 mo) and a higher young stock mortality (6–15 mo). This study showed a clear regional difference in the apparent prevalence of M. bovis infection based on antibodies. The relatively low prevalence of M. bovis in Sweden is a strong motivator for the cattle industry to take steps to prevent further spread of the infection. It is essential that the M. bovis status of free herds be known, and the regional differences shown in this study suggest that testing is highly recommended when live cattle from high-prevalence areas are being introduced into herds. We do not recommend using PCR on BTM to detect infected herds, owing to the low detection frequency in this study.
|
|
| 5. |
|
|
| 6. |
- Hurri, Emma, et al.
(författare)
-
Post-thaw semen quality in young bull ejaculates before being accepted for commercial semen doses
- 2022
-
Ingår i: Veterinary Record. - : Wiley. - 0042-4900 .- 2042-7670. ; 191
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Genomic selection enables bulls with desirable characteristics to be identified at a young age, but sperm quality can be poor in the ejaculates of young bulls. Few studies have been done on post-thaw sperm quality in bulls less than 10 months old. The objective of this study was to determine the age at which post-thaw sperm quality was acceptable for artificial insemination.Methods: Semen was collected by artificial vagina; samples containing 100-500 million spermatozoa/ml were frozen for this study. Post-thaw analyses of membrane integrity (MI), mitochondrial membrane potential (MMP), chromatin integrity, morphology, production of reactive oxygen species and sperm kinematics were made.Results: The age at which ejaculates exceeded the breeding company's thresholds of acceptance varied considerably among individuals, with 285 days being the earliest. Morphology (p < 0.003), MI (p = 0.0096), high MMP (p = 0.043) and superoxide production (p = 0.0084) increased between the first and last ejaculates but reached acceptable levels at different ages for individual bulls.Conclusions: It was possible to obtain acceptable post-thaw sperm quality from samples even though sperm concentration was lower than the breeding company's threshold. Therefore, it might be feasible to use ejaculates earlier than is currently considered possible, by modifying semen handling protocols.
|
|
| 7. |
|
|
| 8. |
|
|
