Seasonal changes in nutritional status and reproductive performance of Zebu cows kept under a traditional agro-pastoral system in Tanzania
| Autor: | M.N. Mgasa, R. Nkya, N.L. Kanuya, S. B. P. Bittegeko, E. Ropstad, Olav Reksen, M. K. Matiko |
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| Rok vydání: | 2006 |
| Předmět: |
Time Factors
Pregnancy Rate Rain Nutritional Status Ice calving Estrous Cycle Tanzania Animal science Food Animals Pregnancy medicine Animals biology Reproduction Postpartum Period Nutritional status biology.organism_classification Zebu medicine.disease Circumference Shorthorn Herd Body Constitution Animal Nutritional Physiological Phenomena Cattle Female Animal Science and Zoology Seasons |
| Zdroj: | Tropical Animal Health and Production. 38:511-519 |
| ISSN: | 1573-7438 0049-4747 |
| Popis: | The objectives of this study were to assess changes in nutritional status/body condition score, percentage pregnancy and calving rate in Zebu cows and to establish the relationship between body condition score loss and postpartum interval to resumption of ovarian activity. A total of 198 cows and postpubertal heifers of the Tanzanian Shorthorn Zebu kept under a traditional management system were randomly selected from 200 smallholder herds. Factors investigated during bi-weekly visits include body condition score (BCS), heart-girth circumference, milk yield and reproductive status of the animals, pregnancy/non-pregnancy and cyclicity/non-cyclicity. Local weather conditions and dates of occurrence of other reproductive events such as calving were also recorded. Calvings occurred all year round but with a strong seasonal distribution characterized by annual peaks observed between April and July. The annual calving pattern was closely related to rainfall, with peak precipitation occurring a few months before peak calving. The overall percentage pregnancy varied from 30% to 50% throughout the year. Postpartum cows exhibited minimum mean BCS and heart-girth circumference 12–14 weeks after calving, and cows with BCS loss >1 point exhibited the longest time interval from calving to onset of ovarian activity. |
| Databáze: | OpenAIRE |
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