|
|
Relationship between photoperiod and melatonin level at growth stages of buffalo heifers
|
|
Abstract: This work was carried out at Mehalet Moussa Experimental Station, Animal Production Research Institute. The experiment was conducted to determine the effect of day light length on melatonin level at different ages of buffalo heifers. Fourteen buffalo heifers were assigned into two similar groups (7 animals each). The heifers weighted 111.1±2.1 as well as 4.5±0.8 month aged. The first group (G I) exposed daily to artificial light during october to end of March (16 hr. light VS 8 hr dark). The second group (G2) exposed to ( 8 hr light VS 16 hr dark) during the same seasons, after that all animals exposed to natural day light. The two groups fed the same ration according to Animal Production Research Institute allowances. Results revealed that melatonin (MLT) concentration raised (P<0.05) in the heifer of G2 than that of G 1. On the other hand, progesterone concentration (P4) were increased (P<0.05) in G 1 than that heifers exposed to 8 light and 16 dark during all stages of growth. Daily fed intake increased significantly in G 1 than that in G2. Daily growth and relative growth rate were equal of both treatments groups at the first stage of the experiment. But, significant (P<0.05) increase at stage of growth 2, 3 and 4, respectively. Long day light increased (P<0.05) thyroxin concentration at stage of growth I and 2 and decreased at stage 3 after that increased at stage 4. Concentration of thyroxin were significant (P<0.05) between both groups. The opposite relation between MLT and P4 and T4 recommended that increased day light length during autumn and winter seasons to increase of growth and induce improvement in reproductive traits in the ruminant. Heifers in G I reached at puberty age faster and with larger body weight than in G2. The same trend was observed at the age and weight at conception. Heifers in both groups not affected by thermal humidity index (THI) at test time. Animals within a normal (THI) at the same time.
Keywords: Photoperiod, Melatonin, Growth, Buffalo, Heifers
|
| Publication year |
2008
|
| Pages |
437-450
|
| Availability location |
معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى- الجيزة
|
| Availability number |
|
| Organization Name |
|
| serial title |
Egyptian Journal of Basic Applied Physiology
|
| Author(s) from ARC |
|
| Agris Categories |
Animal physiology - Nutrition
|
AGROVOC
TERMS |
Growth.
Heifers.
Melatonin.
Photoperiodicity.
Water buffaloes.
|
| Publication Type |
Journal
|