Type traits, teat end hyperkeratosis and dirtiness score of holstein-friesian and red-holstein cows and their relations with milk yield and quality

Milk plays a great role in human nutrition and its quantity and quality is influenced by so many factors. The determination and evaluation of those factors is very crucial. This study aimed to determine the relationships between linear and non-linear type traits, teat end hyperkeratosis (TEH), body dirtiness score (BDS), and milk yield and quality in Holstein-Friesian (HF) and Red-Holstein (RH) cattle. A total of 120 first-lactation cows, including 58 HF and 62 RH, imported from Hungary as pregnant heifers in 2023, were used in Cincin Village, Aydın Province, Türkiye. The farm was visited once a month during morning milking, and the BDS and TEH of the cows were determined during milking and the milk quality characteristics were determined by analyzing the milk samples representing the milking. The study was conducted between November 2023 and January 2025. 18 linear type trait (LTT) scores were determined using a 1 to 9 scale. These traits are; stature (ST), chest width (CW), body depth (BD), rump angle (RA), rump width (RW), body condition score (BCS), rear legs rear view (RLV), rear legs set angle (RLA), hock structure (HS), foot angle (FA), fore udder attachment (FUA), rear udder width (RUW), rear udder height (RUH), central ligament (CL), udder depth (UD), rear teat placement (RTP), fore teat length (FTL) and mammary acuity (MA). The least square means of these traits were 6.53 ± 0.10, 5.15 ± 0.14, 5.63 ± 0.10, 6.82 ± 0.16, 4.29 ± 0.08, 4.85 ± 0.09, 4.91 ± 0.08, 6.47 ± 0.10, 5.09 ± 0.09, 4.31 ± 0.06, 4.52 ± 0.08, 5.77 ± 0.09, 4.77 ± 0.04, 5.29 ± 0.07, 8.31 ± 0.08, 6.06 ± 0.17, 5.36 ± 0.08 and 7.44 ± 0.18 scores, respectively. In the non-linear (100 points) method, which is another evaluation method based on type traits, the dairy strength (DS), frame, feet and legs (FL), udder and total score (TS) were determined and the least square means were 82.30 ± 0.17, 82.97 ± 0.13, 81.76 ± 0.18, 83.98 ± 0.09 and 82.98 ± 0.06 scores, respectively. As for the TEH and BDS, scales of 1 to 4 and 1 to 5 were used, respectively and their overall means were found to be 2.52 ± 0.03 and 2.43 ± 0.03 scores, respectively. The milk yield and quality traits considered here were the morning milk yield (MMY), average dairy milk yield (ADMY), 305 days milk yield (305-dMY), milk fat content (FC), non-fat dry matter (NFDM) content and somatic cell count (Log10SCC) and their least square means were 12.65 ± 0.12 kg, 26.54 ± 0.81 kg, 8350.02 ± 282.97 kg, 3.24 ± 0.02%, 9.57 ± 0.05% and 5.28 ± 0.01 (190,546 cells/ml), respectively. While breed effects on most linear and non-linear type traits were not significant (P > 0.05), higher values were obtained in HF than RH cows. With the stepwise regression analysis performed, the RW, RLA, FUA and HS traits from the LTTs were used for the 305-gMY; RW, RLA and DS from the nonlinear 100-point method were used for the ADMY; BCS and RW traits from the linear type traits were used for the MMY. As for Log10SCC, only the FTL trait was prominent. Therefore, these type traits were included in the statistical analysis model along with environmental factors in the analysis of the relevant trait, and their effects were investigated. Correlations coefficients between milk yield and type traits were also determined and there was a significant moderate correlation for the RW with ADMY and 305-dMY (r = 0.33, r = 0.31, respectively). On the other hand, only the milk FC was found to be significantly positively correlating with the BD (r = 0.20); other calculated correlation coefficients were ranging between -0.34 and 0.33. Regarding the first calving age (FCA) as a reproductive trait, both the breed and birth season effects were found significant (P < 0.01) and the overall mean was found to be 27.00 ± 0.14 months. The FCA was also significantly positively correlating with the RA (r = 0.20, P < 0.05) and all correlations with type traits ranged between -0.27 and 0.20. In conclusion, although significant differences were observed in favor of the HF breed regarding the type traits, including udder characteristics, dairy strength and total score, no differences were found between the breeds in terms of milk yield; however, it was determined that the RH breed had higher milk components (FC and NFDM) in addition to lower SCC levels.