| Abstrakt: |
Two experiments were conducted to determine appropriateness of conditions in a method being developed for evaluating efficacy of different electric fence additions to cattle barb wire fence for goat containment. In Experiment 1, two 6×6 Latin squares (LS), each with 24 yearling Boer goat doelings previously exposed to electric fence, were conducted. After overnight fasting, groups of four doelings were placed in 2.4×2.4 m pens without forage. One pen side was five strands of four-point barb wire (non-electrified) at 31, 56, 81, 107 and 132 cm from the ground adjacent to a pasture with abundant vegetation. One LS had periods 2–3 days in length and the other 7 days. Electric fence treatments for each square were addition to barb wire fence of four electric fence strands 15, 28, 43 and 58 cm from the ground at low voltage of 4–4.5 kV (4S-LV); two strands at 15 and 43 cm and high voltage of 8.5–9 kV (2S-HV); two strands at 15 and 43 cm and low voltage (2S-LV); one strand at 15 cm and low voltage (1S-LH-LV); one strand at 43 cm and low voltage (1S-HH-LV) and one strand at 23 cm and high voltage (1S-MH-HV). Percentages of doelings exiting (6% and 4%) and shocked in 2 h (15% and 16% for 7 and 2–3 days, respectively) were low and did not differ between period lengths. The percentage of doelings exiting in 2 h was not affected by fence treatment. Period of squares affected (p<0.05) the percentage of doelings shocked (54%, 25%, 4%, 6%, 0% and 4% for periods 1, 2, 3, 4, 5 and 6, respectively). Experiment 2 was with 30 Boer and 30 Spanish growing doelings in the same study area. Because of less than anticipated shock and exit in Experiment 1, some conditions were changed, including a defined period of exposure to electric fence, training for pen exit before the experiment and longer fasting (24 or 36 h). Fence treatments were those of Experiment 1 but without 4S-LV and with slightly lower voltage. Doelings were divided into three sets of 20 and used in a completely randomised design (CRD), and one set continued repeated exposure to the different fence treatments in a 5×5 LS. Thereafter, period 1 was repeated in period 6. For the CRD approach, the percentage of doelings exiting in 1 h was >90%. With the LS method the percentage of doelings exiting also was similar among fence treatments but was 75%, 70%, 40%, 70% and 75% for 2S-HV, 2S-LV, 1S-LH-LV, 1S-HH-LV and 1S-MH-HV, respectively. With a comparison involving doeling sets used in the LS, the percentage of doelings shocked was lower (p<0.05) in period 6 vs. 1 (5% vs. 50%), although there was no difference with doelings not used in the LS. In conclusion, results were not promising for successful use of an LS approach, and large differences between experiments in levels of shock and exit indicate need for further change in conditions. |
