Genotype has a significant effect on biological efficiencies of dairy cows. Environmental changes affect differently between different genotypes of animals. A biometrical study was conducted on reproductive organs of dairy cows (n = 100) of different genotypes (Local, Local×Holstein Friesian, Local×Jersey and Local×Sahiwal) available in Bangladesh. Reproductive tracts of cows were collected immediately after slaughter from different slaughter houses in Rajshahi, Bangladesh. The comparison of morphometric values of most of the parameters of reproductive tract observed in different genotypic cows showed significant differences (p<0.05). Local×Holstein Friesian had significantly higher values (p<0.05) on the most of parameters of genitalia measured, followed by the Local×Jersey, Local×Sahiwal and Local. Local×Holstein Friesian had the longest uterine horn (29.20±1.65 cm for right and 29.87±1.75 cm for left), uterine body (3.42±0.20 cm length and 2.83±1.40 cm width), cervix (5.64±0.24 cm length and 4.89±0.23 cm width) and vagina (24.66±0.64 cm length and 6.08±0.36 cm width). The right ovary was wider in diameter, larger in length and heavier in weight as compared to left one in all genotypes. This confirms the fact of right ovary being more active than the left one. Moreover, the biometry of ovary and tubular parts of genitalia in Local×Holstein Friesian and Local×Jersey cows are suggestive for selection of crossbred dairy cows to get maximum benefits from crossbreeding in respect of productive and reproductive performance and also for genetic improvement.

The study was designed to determine the effects of breed, age, parity, feeding practice, Body Condition Score (BCS), timing of insemination, postpartum insemination interval and milk yield on first service pregnancy rates in cows (n = 308). The demographic factors were recorded by interviewing the farmers. All cows were examined for pregnancy diagnosis by rectal palpation of genital tract at 60-80 days post Artificial Insemination (AI). The pregnancy rate of different groups was compared and analyzed by Z test using SPSS software version 17. The overall pregnancy rate in cows was 52.6%. Though the age and parity of cows and milk yield did not affect significantly on pregnancy rate, the pregnancy rate was the highest in cows of 3-5 years of age (56.1%), in cows of parity 1-2 (57.4%) and in moderate yielding (2-5 liters milk/day) cows (62.1%). Balanced feeding and timing of insemination had a profound impact on the pregnancy rate of cows. The pregnancy rate in cows fed with combination of green grass, straw and concentrate was significantly (p<0.05) higher (63.5%) than cows fed only straw (38.5%). The pregnancy rate in cows with BCS 3-4 was significantly (p<0.05) higher (58.0%) than that of BCS 1.5-2 cows (35.0%). The pregnancy rate in cows inseminated at 6-12 h after the start of standing estrus was significantly (p<0.05) higher (58.8%) than those inseminated 13-24 h after start of standing estrus (40.4%). Cows with good BCS and AI at 6-12 h after the start of standing estrus are the best choice of selection for getting the best result in the first service pregnancy rate in cows.

No abstract

No abstract

A biometrical study of female reproductive organs of dairy cows (n=100) of different age (A, B, C= <3, 3 to ≤5, >5 years) and body weight (X, Y, Z = <200, 200 to 300, >300 kg) groups respectively was conducted to find out age and body weight depended changes in biometry of reproductive organs. The