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<p>Dairy farming accounts for 16.52% of Bangladesh’s agricultural GDP and supports over 9&#xa0;million people. However, the sector experiences an annual milk deficit of approximately 4.5&#xa0;million metric tons. Understanding lactation dynamics is crucial for improving production and nutritional quality in tropical dairy systems. This study examined the impact of lactation stage on milk yield and composition in Holstein Friesian (HF) and native Bangladeshi Zebu crossbred cows in Patiya Upazila, Chattogram. 20 multiparous cows (2nd-4th parity; 3–5 years; ~400&#xa0;kg) were categorized as early (&lt; 100 DIM), mid (100–200 DIM), and late (&gt; 200 DIM) lactation stages. A calibrated ultrasonic milk analyzer was used to determine the daily yield and composition (fat, protein, lactose, and solids-not-fat [SNF]). Milk yield peaked in early lactation (11.04 ± 0.65&#xa0;Litre [L]/day), reduced 8.7% in mid (10.08 ± 0.69&#xa0;L/day; and dropped 43.9%&#xa0;substantially in late lactation (6.20 ± 0.53&#xa0;L/day) (<i>p</i> &lt; 0.0001). The fat content increased 5.1% from 3.52 ± 0.11% in early to 3.70 ± 0.14% in late lactation with a significant 9.5% rise between mid and late lactation (<i>p</i> &lt; 0.01). SNF had a unimodal pattern, arising in mid-lactation (8.49 ± 0.07%) and showing significant differences across all phases (<i>p</i> &lt; 0.001). Lactose concentration was maximum in mid-lactation (4.68 ± 0.09%), but protein levels remained steady (2.73–2.90%, <i>p</i> &gt; 0.05). Temperature, humidity, Temperature-Humidity Index (THI), parity, body weight, SCC, and season were all found to be non-significant, indicating lactation stage as the principal predictor of variance. These findings give empirical support for stage-specific physiological regulation of milk supply and composition in tropical crossbred cows. Aligning feeding and milking practices with the lactation stage has practical consequences for improving efficiency, product quality, and sustainability in Bangladesh’s developing dairy sector.</p>

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Lactation performance and milk composition trends in Holstein Friesian (HF) crossbred cattle (HF × native Bangladeshi Zebu Cows): insights from a tropical production system

  • 期刊论文

  • 发表日期：

    2026年2月4日

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  • Nusrat Binte Amin,
  • Hasibur Rahman Sakib,
  • Umme Salma Amin

摘要

Dairy farming accounts for 16.52% of Bangladesh’s agricultural GDP and supports over 9 million people. However, the sector experiences an annual milk deficit of approximately 4.5 million metric tons. Understanding lactation dynamics is crucial for improving production and nutritional quality in tropical dairy systems. This study examined the impact of lactation stage on milk yield and composition in Holstein Friesian (HF) and native Bangladeshi Zebu crossbred cows in Patiya Upazila, Chattogram. 20 multiparous cows (2nd-4th parity; 3–5 years; ~400 kg) were categorized as early (< 100 DIM), mid (100–200 DIM), and late (> 200 DIM) lactation stages. A calibrated ultrasonic milk analyzer was used to determine the daily yield and composition (fat, protein, lactose, and solids-not-fat [SNF]). Milk yield peaked in early lactation (11.04 ± 0.65 Litre [L]/day), reduced 8.7% in mid (10.08 ± 0.69 L/day; and dropped 43.9% substantially in late lactation (6.20 ± 0.53 L/day) (p < 0.0001). The fat content increased 5.1% from 3.52 ± 0.11% in early to 3.70 ± 0.14% in late lactation with a significant 9.5% rise between mid and late lactation (p < 0.01). SNF had a unimodal pattern, arising in mid-lactation (8.49 ± 0.07%) and showing significant differences across all phases (p < 0.001). Lactose concentration was maximum in mid-lactation (4.68 ± 0.09%), but protein levels remained steady (2.73–2.90%, p > 0.05). Temperature, humidity, Temperature-Humidity Index (THI), parity, body weight, SCC, and season were all found to be non-significant, indicating lactation stage as the principal predictor of variance. These findings give empirical support for stage-specific physiological regulation of milk supply and composition in tropical crossbred cows. Aligning feeding and milking practices with the lactation stage has practical consequences for improving efficiency, product quality, and sustainability in Bangladesh’s developing dairy sector.