The Effect of Herbage Availability and Season of Year on the Rate of Liveweight Loss during Weighing of Fasting Ewe Lambs

Jimmy Semakula,Hugh T Blair,Rene A Corner-Thomas,Stephen T Morris,Paul R Kenyon

doi:10.3390/agriculture11020150

Jimmy Semakula, Hugh T Blair + Show 3 more

Open Access

https://doi.org/10.3390/agriculture11020150

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Abstract

Sheep (Ovis aries) liveweight and liveweight change can contain errors when collection procedures are not standardized, or when there are varying time delays between removal from grazing and weighing. A two-stage study was conducted to determine the effect of herbage availability and season of year on the rate of liveweight loss during fasting and to develop and validate correction equations applied to sets of delayed liveweights collected under commercial conditions. Results showed that ewe lambs offered the Low herbage availability lost up to 1.7 kg and those offered the Medium or High herbage availability lost 2.4 kg during 8 h of delayed weighing without access to feed or drinking water. The rate of liveweight loss varied by season, herbage availability and farm (p < 0.05). Applying correction equations on matching liveweight data collected under similar conditions, provided more accurate estimates (33–55%) of without delay liveweight than using the delayed liveweight. In conclusion, a short-term delay prior to weighing commonly associated with practical handling operations significantly reduced the liveweight recorded for individual sheep. Using delayed liveweights on commercial farms and in research can have significant consequences for management practices and research results globally, therefore, liveweight data should be collected without delay. However, when this is not feasible delayed liveweights should be corrected, and in the absence of locally formulated correction equations, the ones presented in this paper could be used.

Highlights

Liveweight (LW) is an indicator of the physical state of an animal, and change in LW is a useful tool to assess how an animal is responding to its current environment [1,2]
Agriculture 2021, 11, 150 evaluated liveweight loss correction equations developed from stage one, on different ewe lambs
The present study showed that ewe lambs lose a significant amount of liveweight while feed and drinking water are restricted

Summary

Introduction

Liveweight (LW) is an indicator of the physical state of an animal, and change in LW is a useful tool to assess how an animal is responding to its current environment [1,2]. Advances in technology have led to commercially available automated weighing systems which combine electronic scales and use of radio frequency identification (RFID). These automated systems make it easier to regularly collect and utilize liveweight data of individuals over time [3]. Liveweight fluctuations due to gut-fill in ruminants can be affected by factors influencing feed intake such as age and size of the animal, time of day relative to sunrise, ambient temperature, and differences in grazing behavior, and time since last meal [2,4,6,8,9,10,11]

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