Tall fescue sward structure affects the grazing process of sheep

Leonardo Silvestri Szymczak,Delma Fabiola Ferreira Da Silva,Reuben Mark Sulc,Paulo César De Faccio Carvalho,Carolina Bremm,Anibal De Moraes,Renata Francieli Moraes,Alda Lucia Gomes Monteiro,Claudete R Lang

doi:10.1038/s41598-020-68827-0

Abstract

The study of factors influencing animal intake can provide a better understanding of the dynamics of the pasture ecosystem and serve as a basis for managing livestock in a more efficient way. We measured different sward surface heights of tall fescue in the process of short-term intake rate of sheep. There was a significant effect of sward surface height on herbage mass (P < 0.001), leaf lamina mass (P < 0.001), other species mass (P = 0.02), bite mass (P = 0.01) and short-term intake rate (P = 0.03) of sheep. There was a quadratic fit between time per bite and bite mass (P = 0.006). Multivariate analysis showed that the short-term intake rate and bite mass were positively correlated (r = 0.97), bite rate and total jaw movement rate were positively correlated but both were negatively correlated with time per bite. The sward surface height of tall fescue corresponding to the maximum short-term herbage intake rate was 22.3 cm. The underlying processes were driven by the bite mass, which was influenced by the leaf lamina bulk density and its consequences upon time per bite. This sward surface height can be adopted as a pre-grazing target for rotational stocking systems to optimize sheep nutrition on pastures.

Highlights

The study of factors influencing animal intake can provide a better understanding of the dynamics of the pasture ecosystem and serve as a basis for managing livestock in a more efficient way
There was no significant difference between pre- and post-grazing sward surface height (SSH) for each treatment (P = 0.19 for 14 cm, P = 0.29 for 17 cm, P = 0.15 for 20 cm, P = 0.10 for 23 cm and P = 0.78 for 26 cm) with each grazing test period, so the average values between pre- and post-grazing were used for forage variables
There was a significant effect of SSH treatment on herbage mass (HM) (P < 0.001), leaf lamina mass (LLM) (P < 0.001) and other species mass (OSM) (P = 0.02) (Table 1)

Summary

Introduction

The study of factors influencing animal intake can provide a better understanding of the dynamics of the pasture ecosystem and serve as a basis for managing livestock in a more efficient way. The underlying processes were driven by the bite mass, which was influenced by the leaf lamina bulk density and its consequences upon time per bite This sward surface height can be adopted as a pre-grazing target for rotational stocking systems to optimize sheep nutrition on pastures. The intake rate represents the consumption of forage per unit of time and is considered a fundamental component of the ingestive behaviour of grazing animals, being the product of bite mass and bite rate In this context, the bite can be considered as the first scale of the grazing p rocess[11,12,13,14] and is under direct influence of the sward structure[8]. In the context of competition strategy at the plant–animal interface, the animals adapt to changes found in the pasture at the time of grazing, which promote behavioural changes, such as altering the pattern of displacement, food selection, the ratio of mass acquired and rate of harvest by animals, and mandibular and non-mandibular m ovements[25,26,27,28]

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