First generation anticoagulant rodenticide persistence in large mammals and implications for wildlife management

Figures & data

Figure 1  Liver concentrations observed in samples biopsied from red deer at set times following a single oral dose of 1.5 mg/kg diphacinone (n = 3, MDL = 0.10–0.20 ug/g). The curve illustrates the fitted values from a mixed effects exponential decay model.

Table 1  Liver concentrations detected in samples biopsied from red deer at set times following a single oral dose of 1.5 mg/kg diphacinone (n = 3, MDL = 0.10–0.20 ug/g) or 8.25 mg/kg coumatetralyl (n = 3, MDL = 0.05–0.20 ug/g).

	Diphacinone			Coumatetralyl
Days after dosing	Deer 1 (ug/g)	Deer 2 (ug/g)	Deer 3 (ug/g)	Deer 4 (ug/g)	Deer 5 (ug/g)	Deer 6 (ug/g)
1	0.58	1.26	0.22	0.39	0.66	0.37
5	0.24	0.40	0.29
8				0.49	0.61	0.41
12	0.41	< MDL	< MDL
15				0.47	0.09	0.09
29	< MDL			0.50	0.09	< MDL
50				0.08	< MDL	0.09
85				< MDL	< MDL	< MDL
Note: A blank cell in the table indicates that a biopsy was not taken at that time.

Figure 2  Liver concentrations detected in samples biopsied from red deer at set times following a single oral dose of 8.25 mg/kg coumatetralyl (n = 3, MDL = 0.05–0.20 ug/g). The curve illustrates the fitted values from a mixed effects exponential decay model.

Figure 3  Liver concentrations detected in samples taken from pairs of pigs euthanised at set times following a single oral dose of 1.5 mg/kg diphacinone (n = 10, MDL = 0.05 ug/g). The curve illustrates the fitted values from a standard exponential decay model.

Table 2  Liver concentrations detected in samples taken from pairs of pigs euthanised at set times following a single oral dose of 1.5 mg/kg diphacinone (n = 10, MDL = 0.05 ug/g).

Days after dosing	Concentration (ug/g) in liver samples	Mean (ug/g)
1	0.57, 0.23	0.40
8	0.26, 0.05	0.16
14	0.13, 0.06	0.10
28	0.05, < MDL	< MDL
43	< MDL, < MDL	< MDL

Table 3  Liver concentrations detected in samples biopsied from cattle at set times following a single oral dose of 1.5 mg/kg diphacinone in trial 1 (n = 2, MDL = 0.10 ug/g) and trial 2 (n = 3, MDL = 0.10–0.20 ug/g).

	Trial 1		Trial 2
Days after dosing	Heifer 1 (ug/g)	Heifer 2 (ug/g)	Steer 1 (ug/g)	Steer 2 (ug/g)	Steer 3 (ug/g)
1	4.6	4.9	5.4	7.6	5.6
8	0.90	1.1	0.89	0.97	1.2
15	0.66	0.82	0.69	0.47	0.53
29	0.53	0.31	0.83	0.62	0.91
43	1.8	0.82
50			0.25	0.49	0.23
75	0.49	0.41
85			0.21	0.13	0.33
117	0.40	< MDL
125			< MDL	< MDL	< MDL
155	< MDL	< MDL

Figure 4  Liver concentrations detected in samples biopsied from cattle at set times following a single oral dose of 1.5 mg/kg diphacinone in trial 1 (n = 2, MDL = 0.10 ug/g). The curve illustrates the fitted values from a mixed effects exponential decay model.

Figure 5  Liver concentrations detected in samples biopsied from cattle at set times following a single oral dose of 1.5 mg/kg diphacinone in trial 2 (n = 3, MDL = 0.10–0.20 ug/g). The curve illustrates the fitted values from a mixed effects exponential decay model.

Table 4  Summary of available hepatic persistence estimates for diphacinone. The estimated time until hepatic concentration is less than MDL is either observed directly from sample analysis (O = observed) or modelled using the hepatic elimination half-life (M = modelled).

Animal	Initial dose (mg/kg)	Method detection limit (MDL)	Mean hepatic elimination half-life (days)	Time until hepatic concentration is less than MDL	Reference
Laboratory rat	1.5	0.1 mg/g	3 days	2 weeks (O)	Fisher et al. (2003)
Red deer	1.5	0.10–0.20 ug/g	6.0 days	29 days (O)	Current study
Pig	12.5	0.02 ug/g	5.43 days Initial (day 1 to 4): 1.30 days; Terminal (day 4 to 15): 14.12 days	104 days (M)	Fisher (2006)
Pig	1.5	0.05 ug/g	12.4 days	43 days (O) 50 days (M)	Current study
Cattle	1.5	0.1 ug/g	Initial (day 0 to 30): 9.4 days: Terminal (day 30 onwards): 25.2 days	155 days (O)	Current study
Cattle	1.5	0.1–0.2 ug/g	Initial(day 0 to 30): 4.1 days; Terminal (day 30 onwards): 35.4 days	125 days (O)	Current study
Cattle	1	0.01 ppm	Not determined	> 90 days (O)	Bullard et al. (1976)

Fisher P , O'Connor C , Wright G , Eason CT 2003 . Persistence of four anticoagulant rodenticides in the livers of laboratory rats . DOC Science Internal Series 139 . Wellington , , New Zealand , DOC . 19 p.

 Google Scholar

Fisher P 2006 . Persistence of residual diphacinone concentrations in pig tissues following sublethal exposure . DOC Research & Development Series 249 . Wellington , , New Zealand , DOC . 19 p.

 Google Scholar

Bullard , RW , Thompson , RD and Holguin , G . 1976 . Diphenadione residues in tissues of cattle . Journal of Agricultural and Food Chemistry , 24 : 261 – 263 . doi: 10.1021/jf60204a010

 PubMed Web of Science ®Google Scholar