What is the fine-grained topic of the following text: The offspring of Definite Article and Alderbrook have fared well in bumpers, hurdles and chases when asked to wear first-time blinkers or a visor, while Giant's Causeway may have been a horse who loved to eyeball his rivals, but is producing offspring who are responding well to some types of headgear; the record of Giant's Causeway's progeny fitted with first-time blinkers over hurdles is two winners from six runners. Only return the topic.
Performance of certain horses' offspring with first-time blinkers or visor in racing.