Comparison of diurnal and seasonal patterns of feeding behaviour of cows and calves at Neudamm Farm in Namibia

Abstract

This paper aims to compare the seasonal and diurnal feeding behaviour of cows and calves at Neudamm Farm in central Namibia. Seasonal bite rates of cows, diurnal bites of cows and calves, and diet composition and preference were assessed and compared. Ten cows and ten calves were followed and observed from a distance, in the morning and in the afternoon. The observations were done on the same cows during the wet and dry seasons while calves were only observed during the wet season. The number of bites taken by each animal within a continuous period of 5 minutes was recorded. Herbaceous plant inventory was done in the foraging area using a step-point method. Each herbaceous plant intercepted was assessed for evidence of grazing and its life form was recorded. Bite rates were compared between morning and afternoon, and between seasons using a two-sample t-test. Preference for life forms and species were tested using a Chi-Square test. The morning bite rate of 38 bites/minute of cows during the wet season was significantly higher than that of the morning dry season of 34.9 bites/minute. This is attributed to the high abundance of nutritious forage resources during the wet season when animals did not have to do much searching compared to the dry season. Afternoon bite rates of cows did not significantly differ between seasons. Morning bite rates were significantly lower in the mornings than in the afternoons in winter. This was because cold morning temperatures slowed down animal feeding rates but increased with the progression of the day. Bite rates of calves did not significantly differ between morning and afternoon during the wet season because they were still learning to forage while being dependent on the mothers for milk. Cattle preferred Schmidtia pappophoroides, Eragrostis trichophora, Heteropogon contortus and Eragrostis nindensis due to their palatability and high grazing value. Nidorella resedifolia, despite being very abundant, was avoided because it contains a toxic alkaloid.