2 research outputs found
Lactation length, lactation milk yield and dry off period of exotic and local crossed cows in Cameroon
No full textData on of 403 genetic crossed cows obtained from the database of the Bambui Centre of the Institute of Agricultural Research for Development (IRAD) in the Sudano-guinean altitude zone of West of Cameroon were used to evaluate effect of parity and season on lactation length, lactation milk yield and dry off period. These animals reared between 1985 and 1998 were crosses between imported Jersey (J) and Holstein (H) bull semen with local White Fulani (WF) and Gudali (G) cows. Results obtained revealed that lactation length (LL), lactation milk yield (LMY) and dry off period (DOP) varied significantly between the different genetic crossed groups of cows. Lactation number and season simultaneously affected these traits. Cows with 75% of Holstein exotic blood (75% H x 25% G) recorded the longest LL (265 ± 27.0 days) and the highest LMY (1995 ± 317 kg) being the shortest DOP (82.7 ± 41.3 days) was in 50% H x 50% G genetic crossed group. Genetic crossed group II (75% J x 25% WF) registered the shortest LL (215 ± 6.35 days), lowest LMY (1149 ± 89.7 kg) and longest dry off period (166 ± 10.4 days). Performances obtained for both LL, LMY and DOP with Holstein-Gudali (50% H x 50% G and 75% H x 25% G) crossed as compared to Jersey-White Fulani crossed revealed their high productive potential through their adaptability capacity to harsh conditions of tropics.
Key words: crossed cows, Cameroon, dry off period, exotic and local breeds, lactation length, lactation milk yiel
Effect of different catalase concentrations on chilled Holstein bull’s semen
No full textAbstract
This study aimed to investigate the effect of catalase (CAT)concentrations on the Holstein
bull semen diluted in egg yolk-citrate (EYC) extender and stored at 5oC. Characteristics
evaluated were progressive motility (PM), plasma membrane integrity (PMI), viability and
total abnormal sperm (TAS) percentages. Six ejaculates (each considered a replicate) were
collected from a bull using an artificial vagina method twice a week for 3 weeks. An aliquot
of the semen from each ejaculate was evaluated pre-extension. The remainder semen was
extended in EYC containing 0 U/ml of CAT (T1), 50 U/ml (T2), 100 U/ml (T3), 150 U/ml (T4),
200 U/ml (T5), 250 U/ml (T6), and 300 U/ml (T7) of CAT, and stored at 5oC. Characteristics
were evaluated every day until viability reached zero. The addition of CAT into EYC improved
viability, PM, PMI and decreased the total abnormal sperm cells. Non-significant differences
between T1 and other treatments were observed concerning PM and PMI, but significant
(P< 0.05) differencesexisted between T1 and other treatments for viability, and TAS. Based
on this study, the addition of catalase at an optimal concentration of 200U/ml to the chilled
bull semen diluted in EYC extender and stored at 5oC was advantageous in improving the
semen quality of Holstein bulls. This semen can be satisfactorily used in artificial insemination
programs a week after its collection.
Key words: bull, catalase, extender, semen qualitycharacteristic
