Factors Influencing Cattle (Bos Taurus) Use of Streams

Abstract

It is important to establish the reason cattle use streams and surrounding areas so that methods for reducing any damage can be established. The first experiment examined the seasonal effects of cattle behaviour on streams under normal farm management practices and the effectiveness of locating a trough distant (120-160 m) from a stream on the use of the riparian area and remainder of the field. This study was carried our using four similar hill-country fields (on average 1.1 Ha). There were four designated areas in the fields: Top, Middle, Bottom and Stream zones. The Top, Middle and Bottom zones were approximately a third of the field and the Stream zone was a 2 metre wide strip either side of the stream. A trough was placed in the Top zone of half of the fields, and the treatments were alternated over successive seasons over 2 years. Fifteen Angus cows were observed in each field in the Autumn and Winter, and 10 cows with calves were observed in the Spring and Summer, for five days at a time. Observers recorded the location and behaviour of the animals every 10 minutes, and the number of minutes spent drinking in the trough or stream, or spent within 2 m of the stream. Cows spent more time resting in the Middle zone on Day l, and, thereafter, rested most in the Top zone (p<.05). Cows grazed less in the Top zone on Day 1(p<.01), and, thereafter, grazing increased in this zone. There were no significant effects of season on the total time cows spent grazing or resting in the various zones. Both trough and stream were utilised, and there was a tendency for a higher frequency of total drinking when the trough was available, and for the stream to be utilised more frequently than the trough. The presence of an alternative water supply did not alter the distribution of cattle in the field. This study suggested that there are factors other than having water available that may influence the use of stream environments (e.g., feed supply) by cattle. It was thought that if food supply was limiting cattle would not show a strong preference for particular areas of the field or water source. Therefore, the second Experiment examined the effectiveness of a trough at encouraging cattle away from the stream during the summer when cows were grazed at a high pasture allowance. The study was carried out in summer on two pairs of similar hill country fields (on average 1.3 Ha). The fields were divided in the manner described for Experiment 1. A trough was placed in the Top zone of one field of a pair. The study was replicated (using the same fields) in late summer. The treatments alternated between fields on the second replicate. Ten Angus cows and calves were observed in each field. The data were recorded as in Experiment l. There was no significant effect of the trough on the total time cows spent either grazing or resting in the various zones. Grazing increased in the Middle zone from Days 1 to 3. There was no difference in the amount of grazing in the other zones over the days of the trial. Cows grazed more in the Top and Middle zones in the Morning, and in the Bottom plus Stream zones in the Evening, and they rested most in the late Afternoon. Both the trough and stream were utilised, although cattle drank most from the stream. It seemed clear from Experiments 1 and 2 that the stream was attractive to cattle despite the presence of an alternative water source. Therefore, Experiment 3 assessed the relative importance of various resources in the stream area (shade, forage associated with the stream, and the use of stream water for drinking and cooling) on cattle distribution in the field and use of the riparian area. There were four replicates with four fields used in each replicate. The fields varied in size from 0.4 Ha to 1.6 Ha according to topography and availability of pasture. The fields were divided as in Experiment 1. A trough was located next to the stream in all treatments. There were four treatments: Control, where a shade structure was placed next to the stream, and cows had complete stream access; No Shade, where no shade structure was available and there was complete access to the stream; No Paddle, where the shade structure was available, and there was only partial access to the stream whereby the cows could drink but not paddle; No Stream, where the shade structure was available, and there was no stream access. Each field was used for 12 days, which was split into six, 2 day Periods. In Periods 1 and 2 forage was available near the stream and in subsequent Periods this forage was removed. The treatments were allocated to fields in a four by four Latin square design for Periods 3,4,5 and 6. The treatments allocated to Periods 1 and 2 were a repeat of Periods 5 and 6. Ten Angus cows and calves were observed in each field. Pasture availability declined throughout the replicates. Cows grazed most in the early morning and evening, and rested most during the late morning and afternoon, which was similar to the other experiments. There were no significant effects of Treatment alone on the distribution or activities of cattle in the field or near the stream. However, there were a number of interactions between Period, Time of day and Treatment, and these were difficult to interpret. When the trough was located next to the stream and there was complete stream access, cattle used the stream and trough equally. Indeed, cattle used the trough more when it was in close proximity to the stream (Experiment 3) compared to when it was distant from the stream (Experiments 1 and 2). In the No Paddle treatment, cattle spent more time shading under the shade structure, compared to animals with complete access to the shade structure and stream. From this it may be suggested that cooling may be one factor that is implicated in stream use. As yet, it is not possible to establish the relative importance of factors (shade, forage or stream water for drinking or cooling) at the stream. A model based on the combination of the Generalized Matching Law and the Ideal Free Distribution was proposed for predicting cattle choice of resources this still requires validation. In the future, a series of precise experiments with a fewer well defined, measurable variables, may aid in predicting behaviour around waterways, and perhaps also understanding the mechanisms determining cattle choice of water source.