PRE-AND POST-WEANING PHENOTYPIC RELATIONSHIP BETWEEN SOME N'DAMA CATTLE UNEAR MEASUREMENTS IN THE TROPICS

Data collected on 1438 male and 1492 female pure bred N'Dama calves calved between 1948 and 1961 at Fashola Stock farm were used to study the relationship between five N'Dama cattle linear measurements at pre and post Weaning ages. The measurements were Head to Shoulder (HDS); Shoulder to tail drop (STD); Height at withers (HTW); Heart girth (HGT) and Body length (BLT). All measurements had positive values which ranged from 0.2 - 91 except HTW and HDS which had a negative value (-02) in males at yearling age. There was a predominance of positive and highly significant relationship (P<0.01) between height measurement (HTW) and circumference measurement (HGT) which ranged from .04 - .76 with pre weaning measurements having higher values (.69 - .76) in both sexes. High and positive correlation values were also observed between length measurements (HDS, STD and BLT) which therefore shows that only one of such measurements is sufficient for length measurement Generally measurements taken at pre weaning had higher correlation values than those taken at post weaning.

Estimates of phenotypic and genetic trends of growth traits in N'dama herd in Nigeria

Data on birth weight (BTHWT), 205-day adjusted weaning weighi (ADWNWT), and pre-weaning daily gain (ADG) of N'Dama reared at Fasola Stock Farm between 1947 and 1984 were obtained and used to estimate phenotype and genetic trends of these traits. Estimated phenotypic trend was 0.07+0.02 kg/vr, 0.18-0.06kg/yr and -0.005 +0.003kg/yr for BTHWT, ADWNWT and ADG respectively. In contrast, all estimated genetic trends were relatively small and not significantly different from zero. They were 0.02+0.05kg/yr, 0.02+0.05kg/yr and 0.1g/yr for BTHWT, ADWNWT and ADG respectively. The sequential polynomial fitting of the data set indicated that quadratic function adequately described the data with the following regression equation: Y = 9.91 + 0.016 + 0.026 Y = 46.44 - 0.156 + 0.0162 Y = 0.21 - 0.00025 + 1.1862 for BTHWT, ADWNWT and ADG respectively for phenotypic trend curve while for genetic trend curve Y = 0.10 -0.016-0.346' was obtained for BTHWT and ADWNWT and Y = 0.002 - 0.00026' - 70.85b for ADG.

Influence of inbreeding and some environmental factors on calving intervals in N'Dama cattle of Southwest Nigeria

Records of 4184 N'Dama calves born between 1947 and 1984 at Fashola Stock Farm, Oyo State, Nigeria was used to compute inbreeding coefficient and determine its effects on calving intervals of cows. Only 273 of the 4184 calves (6.53%) were inbred with an average inbreeding coefficient of 9.71%, while five out of 293 sires had inbreeding coefficient of 9.25% and 43 out of 1849 dams had inbreeding coefficient of 9.95%. The inbreeding coefficient for the entire population was 0.63%, respectively 0.70% and 0.58% for male and female calves. The average calving interval was 445.34 ± 2.68 days within the herd while year of birth, parity of dam, age of dam and dam's age at first calving all significantly (P<0.05) impacted calving intervals of cows. Season of birth and inbreeding coefficient of dam did not exert statistical (P>0.05) influence on calving intervals of dams. Although the number of inbred animals in the population is relatively low, however the inbreeding level of these animals is high, which may be attributed to the fact that breeding policy on the farm was not strictly adhered to, and lack of proper and adequate registration system coupled with inconsistent animal identification system on the farm may be responsible for the inbreeding observed in the N'Dama population at Fashola Stock Farm.