Comparative analysis of milk productivity traits of Holstein cows sired by bulls from different countries of origin
Notice bibliographique
Résumé
An assessment of the effect of the countries of origin (CO) of bulls on the indicators of milk productivity of daughter cows during the first and higher lactations was carried out in the conditions of the breeding plant PLAE “Ukraine” of the Lutsk district of the Volyn region. The research material was data on zootechnical and breeding registration of cows, borrowed from the electronic information database of the DFMS “Intesel Orsek” as of September 2024. The CO of the sires was determined by the first two letters of the identification number, as well as the numbers of their fathers and mothers. Based on the CO of the breeding bull from the general population (N = 1275), experimental groups of cows were formed: the first (I) group – descendants of bulls of Canadian origin, the second (II) group – German, the third (III) group – Dutch, and the fourth (IV) group – American (USA) origin. Statistical data processing included a Student’s t-test for independent and paired samples, Pearson’s correlation coefficient, and a one-way ANOVA. A statistically significant effect of the CO of breeding bulls on the milk productivity of primiparous cows was established. The highest level of productivity in quantitative terms was demonstrated by the daughters of Dutch bulls, which significantly exceeded the indicators of the progeny of other groups: in milk yield by 320.0–419.3 kg (P < 0.001), in amount of milk fat by 12.1–16.4 kg (P < 0.001), and in amount of milk protein by 10.0–12.9 kg (P < 0.001). The results obtained partially contradict the data indicating the highest breeding value and transmission ability in American and Canadian bulls, but are consistent with the opinion of other scientists about the significant effect of the environment on the realization of the genetic potential of sires of different CO. During higher lactation, cows of all experimental groups had almost the same level of the milk productivity, which was confirmed by ANOVA. Daughters of Dutch bulls reached peak productivity at the earliest age (1.38), as evidenced by the smallest relative difference between lactations (d = 6.7–6.8 %; P < 0.001) and the highest repeatability (RC = 0.664–0.666; P < 0.001) of productive traits. This may indicate a potentially lower level of their productive longevity. Despite statistical significance (for the first lactation), the effect size of CO on the offspring is not large enough (η2 = 1.16–1.27 %; P < 0.001) to be a key criterion in the selection of a breeding bull. The revealed advantage of the daughters of Dutch sires, in particular NL 520813625 N.Ubrox and NL 447860719 Shirley, allows us to recommend them for widespread use in this herd. Conducting similar studies in other regions using linear mixed models will allow a more accurate assessment of the effect of the bull’s CO on the milk productivity of daughter cows, eliminating the effect of a number of genetic and exogenous factors. This will make it possible to develop more accurate and effective recommendations for domestic breeders, which can be implemented in various farms in Ukraine.
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Comment cette classification a été obtenuedéplier
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Scores du classifieur distillé par catégorie (deux têtes)
| 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 | 0,001 | 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».