TITLE:
Bull Mating Load and Its Effects on Conception Outcomes: A Case of TALIRI Mpwapwa Farm
AUTHORS:
Joel Mahugija Malagira, Mwemezi Lutakyawa Kabululu, Felista Perfect Nicolaus, Deogratias Fidelis Masao, Janeth Frank Nkinda, Neema Vicent Nyoni, Kabuni Thomas Kabuni
KEYWORDS:
Mpwapwa Bull, Mating Load, Conception Rate, Cow-to-Bull Ratio, Reproductive Efficiency
JOURNAL NAME:
Open Access Library Journal,
Vol.13 No.10,
October
30,
2026
ABSTRACT: Cattle production underpins livelihoods, food security, and household income in Tanzania, where the improved Mpwapwa breed—developed for high productivity and tropical adaptation—is widely disseminated to upgrade local herds. However, shared communal use often subjects Mpwapwa and crossbred bulls to extreme mating loads of 40 - 60 cows per season, far exceeding temperate-region recommendations, while locally validated guidelines for optimal cow-to-bull ratios remain absent. This study evaluated how mating load, breed, and age influence conception performance using 10 breeding seasons of secondary farm records (2019-2023) from 33 eligible bulls selected from a population of available bulls, each allocated to one of the breeding groups at different mating loads ranging from 1:16 to 1:77, and retained with their assigned groups for the full three-month duration of each breeding season at the Tanzania Livestock Research Institute Mpwapwa station. Data were analyzed via binomial generalized linear models incorporating interaction terms between mating load, breed, and age. Results showed a significant inverse relationship: conception probability declined as dam numbers per bull increased (OR = 0.985, p = 0.001). Mpwapwa bulls were most resilient to higher loads (OR = 1.012, p