Serum Nerve Growth Factor Levels as a Predictor of Bull Candidate Semen Quality of Madura Cattle

Table 4

Regression equation among significantly correlated variables.

No	Predictor	Parameters	Regression equation	r	R^2	value
1	NGF levels	Testosterone levels	Tes = 6.75 + 8.91NGF	0.70	0.49	0.0004
2		Sperm concentration	Con = 0.86 + 0.28NGF	0.45	0.20	0.0002
3		Sperm Viability	Via = 52.15 + 12.47NGF	0.48	0.23	0.0008
4		Sperm motility	Mot = 40.55 + 13.87NGF	0.52	0.27	0.001
5	Testosterone levels	Sperm concentration	Con = 0.71 + 0.03Tes	0.71	0.50	0.00003
6		Sperm viability	Via = 41.41 + 1.41Tes	0.75	0.56	0.00003
7	Sperm viability	Sperm motility	Mot = −16.59 + 1.10Via	0.94	0.88	0.00002

R: coefficient of determination; r: coefficient correlation; : significance of probability; NGF: nerve growth factor; Tes: testosterone; Con: sperm concentration; Via: sperm viability; Mot: sperm motility; r: correlation coefficient; R²: determinant coefficient.