Influence of cow breed and parity on milk productivity and quality indicators

Breed and parity influence milk composition and quality (for example, Holstein cows have higher milk fat and protein content, but their milk composition may vary depending on the parity number) [1]. Somatic cell in milk is influenced by many factors, such as animal species, milk production level, lactation stage, and the individual and environmental factors as well as management practices [2]. This study was conducted to assess the influence of cow breed and lactation number on milk yield, as well as compositional parameters (fat, protein, and lactose content), and somatic cell count. The results obtained may be useful for making informed decisions about herd management and for enhancing the efficiency and quality of milk production. The study was conducted on a commercial dairy farm that maintained more than 900 cows of the Lithuanian Black and White (BW), Lithuanian Red (R), and Holstein (HL) breeds. Animals received a complete ration formulated to meet their physiological needs. The farm operates under a loose housing system and features a 2 × 20 herringbone milking parlour. Herd management was facilitated by DelPro software (DeLaval), from which all data used in this study were obtained. For the analysis of the data, statistical indicators were calculated for each evaluated trait (milk content, percentage of milk fat and milk protein, somatic cell count): arithmetic means, mean error and statistical reliability of the data (P). Lithuanian Black and White cows exhibited the highest overall milk yield, averaging 9325.8 kg (P < 0.05). Lithuanian Red cows produced milk with the highest fat content (4.52 ± 0.10%) and protein content (3.48%; P < 0.05). The highest lactose concentration was found in BW cows (4.45%; P < 0.05). Milk yield increased with lactation number, peaking in cows during their fourth or later lactations, where the average yield reached 9675.5 kg (P < 0.05). Lactose levels decreased with successive lactations, showing the lowest concentration (4.35%) in the oldest group (P < 0.05). Peak daily yields were highest during the 3rd lactation at 47.9 ± 0.55 kg, compared to the lowest yield of 35.8 kg in the 1st lactation (P < 0.05). The highest total milk yield was recorded in BW cows during their 4th lactation, totalling 10 008.5 kg (P < 0.05). In the 1st lactation, Holstein cows achieved the highest single-day yield of 80.0 kg (P < 0.05). Lithuanian Red (LR) cows in their 3rd lactation produced the richest milk in terms of fat content (4.87%), while HL in the 4th lactation had the highest protein content (3.57%). Lithuanian Black and White cows in the 1st lactation had the highest lactose concentration (4.58%, P < 0.05). This breed also exhibited the lowest average somatic cell count (SCC) across all lactations, averaging 351.7 × 10³/mL, with the lowest value observed in 1st lactation cows (171.7 × 10³/mL). The overall lowest SCC (221.8 × 10³/mL) was recorded in 1st lactation cows (P < 0.05). In conclusion, cows tend to reach their highest milk productivity during the 1st and 2nd lactations. However, as cows age, the somatic cell count (SCC) generally increases, while the concentrations of protein and fat in milk typically decline. Observations also indicate that Holstein cows produce the highest milk yield but tend to have a higher SCC.