ARSF and tuberculosis: By indirect immunofluorescence, we observed that the protein arylsulfatase F (ARSF) was expressed at a higher proportion at the acrosome, mid-, and principal piece in sperm (Pattern I) from fertile TB stallions than in sperm from subfertile TB stallions (mean ± SD: 57 ± 8% vs. 17 ± 5%, respectively; P < 0.05), while at a lower proportion at the midpiece and principal piece (Pattern II) in sperm from fertile TB stallions than in sperm from subfertile TB stallions (mean ± SD: 16 ± 7% vs. 49 ± 3%, respectively; P < 0.05).