关键词: 挪威红牛, 荷斯坦奶牛, 杂交, 繁殖性能, 泌乳性能, 乳品质

Abstract: To evaluate the important economic traits of the hybrid offspring of Norwegian red bulls and Holstein cows，the breeding indexes such as the number of services，first service conception rate，average birth weight of calves，and average interbirth interval and lactation performance indicators such as average lactation day，305‑day milk yield，and peak day average milk yield，as well as milk safety indicators（total bacterial content，heavy metals ions and drug residues）and nutritional indicators（amino acid composition and fatty acid composition）of the hybrid offspring（F₁ and F₂）of Norwegian red bulls and Holstein cows under the same feeding environment were compared.Their reproductive performance，lactation performance and milk quality characteristics were systematically analyzed.The results showed that compared with Holstein cows，the reproductive performance of F₁ and F₂ was significantly improved.The specific performance was that the number of service was significantly reduced，the first service conception rate was significantly increased，the average birth weight of calves was significantly reduced，and the average interbirth interval was significantly shortened.The lactation performance remained stable，and the specific performance was that the 305‑day milk yield and peak day average milk yield of F₁ and F₂ were not significantly different from those of Holstein cattle.The milk quality was significantly improved，which was manifested in the significant increase of average milk fat rate and average milk protein rate，and the decrease of acidity value.Safety standards were met，with all hygiene indicators complying with national standards.The ratio of essential amino acids/total amino acids（41.71%）and essential amino acids/non‑essential amino acids（71.56%）reached the ideal protein standards required by the Food and Agriculture Organization of the United Nations（FAO）and the World Health Organization（WHO）.In conclusion，Norwegian red bull hybridization technology can significantly improve the reproductive efficiency and dairy quality of Holstein cows while maintaining lactation performance.After hybridization，it represents excellent comprehensive production performance and has important application value.

Key words: Norwegian red bull, Holstein cow, Hybridization, Reproductive performance, Lactation performance, Milk quality