3 Animal Protein-Free Semen Extender for Fixed-Time Insemination of Beef Cows
Notice bibliographique
Résumé
Current semen cryopreservation protocols include the use of animal products, such as egg yolk, in semen extenders, which raises important biosecurity concerns related to the transmission of infectious agents. Therefore, there is a need for alternatives to animal proteins in semen extenders. Cholesterol-cyclodextrin (CC) has been used as an adjunct in semen extenders to facilitate the delivery of exogenous cholesterol into sperm plasma membranes. The purpose of this study was to determine the fertility potential of semen extended with cholesterol of plant origin (PhytoChol, Wilshire Technologies, NJ, USA) in a fixed-time insemination program for beef cows. Semen was collected by electroejaculation from mature Simmentals bulls (n = 4 bulls, 4 replicates/bull) and analysed using computer-assisted semen analysis (CASA). Ejaculates from different bulls with =200 × 106 sperm mL-1 and =60% total motility were pooled. The pooled ejaculates were distributed into 3 treatments and diluted to 50 × 106 mL-1 in Tris-citric-acid base extenders containing either egg yolk (20% vol/vol egg yolk, control), 0.5 mg of CC per mL of semen, or 1.0 mg of CC per mL of semen. Glycerol (7% vol/vol) was added to each extender. Extended semen was loaded into 0.5-mL straws and frozen to –196°C. Post-thaw sperm motility was analysed using CASA. Ovulation was synchronized among multiparous beef cows using 1 of 3 protocols: (1) 5-day intravaginal progesterone-releasing device (PRID) and prostaglandin F2a PGF2a) treatment on the day of PRID removal (n = 37 on random days of cycle); (2) oestradiol + progesterone treatment and 7-day PRID followed by PGF2a on the day of PRID removal (n = 37 on random days of cycle); or (3) PGF2a alone (n = 19 on Day 7 to 9 from ovulation). Cows were treated with gonadotropin-releasing hormone (GnRH) and assigned randomly to be inseminated with 1 of the 3 semen treatments 72 h after PGF2a treatment. Ovulations were confirmed and pregnancies were diagnosed 28 to 35 days after insemination by ultrasonography. Post-thaw sperm motility was compared among extenders by analysis of variance. Pregnancy rates were compared among groups by generalized linear mixed model. Total motility (52 ± 3%, 59 ± 3%, and 62 ± 7%) and progressive motility (47 ± 3%, 54 ± 3%, and 58 ± 6%) did not differ among the egg yolk, 0.5 mg CC, and 1.0 mg CC extenders, respectively. There were no differences in pregnancy rates among synchronization groups; therefore, data were combined to compare the effects of semen extender. Four cows were excluded due to improper synchronization treatment. Pregnancy rates of cows inseminated with egg yolk (n = 31), 0.5 mg CC (n = 31), and 1.0 mg CC (n = 27) semen were 32, 74, and 52%, respectively (P < 0.05). Fertility in cattle inseminated using semen extended with cholesterol of plant origin has not been previously reported. We conclude that plant cholesterol may be used to replace animal proteins (egg yolk or milk origin) in bovine semen cryopreservation. Research supported by grants from the Saskatchewan Agricultural Development Fund, Agriculture and Agri-Food Canada, and Alberta Livestock and Meat Agency.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».