Reproduction and production status of dairy cows and associated determinants in military dairy farms of Bangladesh

Abstract

The dairy industry in Bangladesh is essential for food security and the economy, but productivity due to limited by disease, poor management, and genetics. Military dairy farms, though better organized, face similar issues. This cross-sectional study assessed production, reproduction, diseases, host factors, and antibiotic use using secondary data from 113 cows completing their third parity. The mean birth weight was 24.6 kg (median: 25.0 kg; range: 18.0–30.3 kg). Puberty occurred at 27.8 months (median: 28.0; range: 17–43) with a mean body weight of 258.1 kg (median: 260.0 kg; range: 215–332). First conception was achieved at 32.7 months (median: 32.0; range: 23–47), with 1.8 services per conception (median: 1.4; range: 1–10). The calving-to-conception interval averaged 189.7 days (median: 140.0; range: 56–727), calving interval 389.5 days (median: 381.0; range: 282–656), and gestation length 281.6 days (median: 281.0; range: 274–289). Mean lactation yield was 3,093.9 liters (median: 3,051.0; range: 2,240–4,736) over mean lactation length ~280 days (median: 279.0; range: 268–295). Repeat breeding (57.1%) was the most frequent reproductive disorder, followed by dystocia (4.4%) and mastitis (83%). Factor analysis showed milk yield was associated with age at puberty (p=0.09; 95% CI: –0.02 to 0.01) and services per conception (p=0.15; 95% CI: –0.1 to 0.01). Puberty age was linked to farm location (p<0.01; 95% CI: 0.7 to 7.1) and birth weight (p=0.05; 95% CI: –0.01 to 3.6), while body weight at puberty was affected by puberty age (p=0.02; 95% CI: –17.8 to –1.9) and marginally by birth weight (p=0.17; 95% CI: –19.9 to 3.5). Services per conception were influenced by puberty age (p=0.03; 95% CI: 0.03 to 0.06), calving-to-conception interval (p<0.001; 95% CI: 0.2 to 0.9), calving interval (p=0.1; 95% CI: –0.1 to 1.0), lactation length (p=0.1; 95% CI: –0.6 to –0.1), and gestation period (p=0.13; 95% CI: –0.8 to 0.1). The calving-to-conception interval was significantly associated with services per conception (p<0.001; 95% CI: 0.1 to 0.4) and calving interval (p<0.001; 95% CI: 0.2 to 0.6). Logistic regression showed dystocia was influenced by farm location (OR=0.5; 95% CI: 0.07 to 3.1) and calf birthweight (OR=3.7; 95% CI: 0.4 to 37.0). Gentamicin was the sole antimicrobial used, administered intramammarily for mastitis. These findings offer key baseline insights for improving reproductive and productive efficiency in military dairy systems.