Intake Behaviour and Digestive Eff ects of Electronic Identification with Ruminal Bolus in Adult Goats

Abstract

The effect of the ruminal bolus on the intake behaviour and digestive parameters was studied in a group of 12 castrated adult Majorera goats. For the experiment they were housed in a metabolic box for 2 weeks to allow for adaptation and fed either an ad libitum Fibrous Diet (FD) (n = 6) or a Concentrated Diet (CD) (n = 6) offered at 130% of the previous day�s consumption. The animals were subsequently divided into two similar subgroups: bolus (identified with Rumitag Bolus®) and control (simulated application). After one week of feeding with the definitive diet, the measuring period started, which lasted for 12d divided into two sub-periods separated by the application moment (subperiod I: 6d, before bolus application; sub-period II: 6d, after bolus application). Samples of faeces and material refused by the animal were collected daily in order to determine DM, OM, CP, NDF and ADF. For the FD group a significant difference was found due to the period on DMI being higher in sub- period II, but there were no significant statistical differences due to the bolus treatment. For the CD group, DMI increased during sub-period II due to the overall time spent in both sub-groups. Digestibility parameters results were probably conditioned by the stress which was caused by the accumulation of days in the pen. Taking the evolution of daily DM per kg-0.75 live weight intake into account, both groups presented a similar decrease in intake the day after bolus application, to a great extent due to the stress caused by the identification procedure, nevertheless they recovered their DMI level 48 h after application of the bolus. No statistically significant differences in diet intake and digestibility parameters were found due to the application of the ruminal bolus.