This causes an extension of the
calving interval. In order to obtain an effective breeding plan for water buffalo, the estimates of heritability, repeatability and correlations are determined.
Kenyan farmers are estimated to lose 500 million litres of milk worth S billion annually from the long
calving interval.The study also found that the two reproductive diseases, bovine viral diarrhoea (BVD) and neospora caninum (neosporosis), were present in cattle in all the three counties.
Calving Interval Gestation length n x [s.sub.x] n x [s.sub.x] 47 411.01 9.80 64 284.92 (a) 1.02 222 402.59 5.13 261 282.04 (b) 0.57 BREED 12 393.09 17.99 10 263.65 (e) 2.31 28 410.26 12.00 31 280.01 (d) 1.34 43 419.63 9.69 49 283.24 (d) 1.07 58 401.54 8.48 74 286.51 (c) 0.87 CALVING MONTH 78 415.59 7.33 97 288.05 (bc) 0.77 42 408.82 10.49 52 289.47 (ab) 1.10 8 398.66 21.77 12 293.45 (a) 2.12 269 406.80 6.03 325 283.48 0.64 OVERALL N.S.
Also, mean of
calving interval was 415.99 days ([+ or -] 79.62).
As well as age at first calving, calving spread has a huge impact on
calving interval. Fixed calving periods aid significantly in hitting that elusive 365 days; anything that does not calve within the allotted period should be culled.
Calving interval is affected by a number of factors, including herd health, nutrition, body condition score, sire choice and general management strategy.
In order to maintain an adequate interval from calving to pregnancy and a large proportion of the herd with a
calving interval inferior to 13 months, the voluntary waiting period must be limited to the first 60 to 70 d postpartum and, once insemination starts, service rate should be 100%, first AI pregnancy rate greater than 35%, and pregnancy rate for every 21-d estrous cycle above 20%.
Genetic variability for
calving interval and growth traits in Mertolenga cattle.
In order for the operation to maintain a 12-month
calving interval, the postpartum interval must be kept to no longer than about 80 days.
During the 1980s a female's
calving interval was three years, yet at present it is five.
CI, preceding
calving interval (in days), MDM, mean daily milk yield for the previous complete lactation (in kg), PCALV2 or PCALV3, preceding calving difficulty (difficult vs easy or difficult, moderate and easy, respectively), MAST, mastitis during pregnancy (healthy vs mastitic).
Kenyan dairy cows have long
calving intervals. Ideally, a cow should produce a calf once a year but the average
calving interval is about 600 days.
