Testicular length as an indicator of the onset of sperm production in alpacas under Swedish conditions

Table 3 Model fit (DIC and Delta DIC) and parameter estimates for testicle length of Swedish alpacas

Model	DIC	Delta DIC	α	β	γ	δ
Experiment 1
Null	160.8	0	3.97 (3.8–4.14)
Increment	117.3	43.5	4.96 (4.33–8.445)	0.078 (0.019–0.26)	5.89 (−0.87–29.77)
Increment + BCS	116.7	0.6	4.75 (4.32–6.45)	0.078	5.4 (0.56–10.25)	0.35 (0.10–1.02)
Experiment 2
Null	87.8	0	2.97 (2.55–3.39)
Increment	66.9	20.9	4.43 (3.67–5.95)	0.069 (0.02–0.16)	15.47 (5.17–31.50)

Values are (median 95 % CI in brackets). DIC scores are compared to the null model (including only an intercept parameter). For data from experiment 1, the model including body condition score (BCS) is compared to the increment model. Experiment 1, n = 72. Experiment 2, n = 28
α is the maximum mean testicular length
β and γ are free parameters determining the testicle length increment rate
δ BCS effect on increment rate

ISSN: 1751-0147