Pestic. Sci. 1984, 15, fX0-604

Fenvalerate Residues in Milk Following Topical Treatments to Dairy Cows

Richard F r a n k , Heinz E. Braun, Lloyd A. Miller," and George W. Allan"

Agricultural Laboratory Services Branch, Ontario Ministry of Agriculture and Food, cIo Universig of Guelph, Guelph, Ontario N l G 2 W l , and "Ciba-Geigy Canada Ltd (formerly Shell Canada Ltd), Agriculture Division, 6860 Century Avenue, Mississauga, Ontario L4N 2 W5. Canada

(Revised manuscript received 17 February 1984)

Two mature Holstein cows were treated with 0 . lg of fenvalerate each, in six consecutive topical treatments at intervals of 3 or 4 days. Neither of the diastereoisomers of fenvalerate was detected in the milk 6 h after the application. After 3 days, the mean fenvalerate residue was 0.46pg litre-'; by day 4, this residue had declined below the detection limit of 0.1pg litre-' for each of the diastereoisomers. Two Holstein cows were also treated with 0.5 g of fenvalerate per cow in three consecutive topical treatments at intervals of 14 days. Residues in whole milk were at a maximum 6 h after treatment and declined to less than 0.2pg litre-' over 21 days. Only 0.03 to 0.06% of the applied fenvalerate appeared in the milk as the intact insecticide.

1. Introduction

The synthetic pyrethroids have been shown to be very effective in controlling insect pests on livestock. Gaughan et al.' have reported studies conducted to determine the distribution and metabolism of permethrin in lactating cows, while Wszolek et a1.' have reported on the excretion of fenvalerate into the milk of dairy cows receiving this insecticide in their diet. This present study was undertaken to determine what residues, if any, of fenvalerate [ (RS)-a-cyano-3- phenoxybenzyl (RS)-2-(4-chlorophenyl)-3-methylbutyrate] appear in the milk of dairy cows receiving topical treatments.

2. Experimental methods

2.1. Field procedure Trial A involved two mature Holstein cows (cows 1 and 2) and was performed on a dairy farm near Markham, York County, Ontario. Each cow was treated six times at intervals of 3 or 4 days with a working solution of fenvalerate (2ga.i. litre-'); the solution was prepared from a 10% emulsifiable concentrate of 'Belmark'. The application rate per cow was 50ml of solution, equivalent to 0.1 g a.i. Application was made by hand using a manually operated mister to apply the solution topically all over the animal. Milk samples were collected 6 h before, and 6 h and 3, 4 and 7 days after treatment, to be analysed for fenvalerate residues.

Trial B involved one heifer and one mature Holstein cow (cows 3 and 4, respectively) on a second dairy farm also located near Markham, York County, Ontario. Each cow was treated three times at 14-day intervals with a working solution of fenvalerate (lOga.i. litre-'). The formulation was the same as used in Trial A. The method of application was the same as in Trial A except that the 50ml of solution per cow delivered 0.5g of fenvalerate a.i. Milk samples were collected 6 h before, and 6h and 3, 7, 10 and 14 days after the fenvalerate applications; in addition, samples were taken 21, 28 and 31 days after the third spray application.

600

Fenvalerate residues in milk 601

2.2. Analytical procedures

Samples were subdivided; butterfat determinations were made on one set, while the second set was analysed for fenvalerate residues by gas-liquid chromatography (g.1.c.) according to the procedure described by Braun and Stanek.3

On g.l.c., fenvalerate is resolved into two diastereoisomers; the composition of the two diastereoisomers, in order of elution from the g.1.c. column, has been given as ( R ) ( S ) with (S) (R) (diastereoisomer X), and (R) (R) with (S) (S) (diastereoisomer Y).435

Recoveries were determined by fortification of control milk samples at levels ranging from 1.0 to 1Opg litre-' in whole milk; recoveries averaged 91% for both the diastereoisomers of fenvalerate. The limit of detection for the individual diastereoisomers was 0 . lpg litre-'.

3. Results

3.1. Trial A Neither diastereoisomer of fenvalerate was detected (to a limit of 0.1 pg litre-') in the milk drawn from two cows, 6 h after receiving topical treatments of 0.1 g per cow. At day 3 after application, the total fenvalerate residue ranged from <0.20 to 1.14pg litre-' in the whole milk of the two cows (Table 1); roughly equal quantitites of the two diastereoisomers were found. There was a strong indication that, with 0 . lg fenvalerate per cow, residues at day 3 declined with each successive treatment, as indicated by a residue of 1.14 and 0.44pg litre-' after the first spray, in

Table 1. Fenvalerate residues in milk taken from two Holstein cows treated with 0.1 ga.i. per cow in six consecutive topical treatments over a 26-day period in 1982 (Trial A)

Treatment date

Time from spray application

to milk sampling

20 July (pre-spray) 20 July (after-spray)

23 July 26 July 30 July 2 August 6 August

-6 hours + 6 hours 3 days 3 days 4 days 3 days 4 days 3 days 7 days

~~

Fenvalerate in whole milk &g litre-')"

Cow 1 (9 years old) Cow 2 (6 years old)

Diastereoisomefi Diastereoisomep

X Y Total X Y Total

co.10 co.10 <0.20 <0.10 co.10 <0.20 co.10 <0.10 <0.20 co.10 <0.10 co.20

0.41 0.73 1.14 0.20 0.24 0.44 0.28 0.60 0.88 CO.10 <0.10 <0.20 0.10 0.42 0.22 <0.10 <0.10 <0.20 0.24 0.29 0.53 0.12 0.14 0.26

co.10 c0.10 c0.20 co.10 co.10 c0.20 0.11 0.10 0.21 <0.10 co.10 <0.20

co.10 <0.10 <0.20 <0.10 co.10 <0.20

Mean residues: 6h , C0.20; 3 days, 0.46 (f0.33); 4 days, 0.20; and 7 days, <0.20pg fenvalerate litre-'. The composition of diastereoisomers X and Y of fenvalerate is given in section 2.2.

Table 2. Milk production and the removal of fenvalerate in the milk from the four cows subjected to all the sprays described in sections 2.1 and 2.2

(Trials A and B)

Fenvalerate Production of milk ~

~ Removed in milk

Weight Butterfat Applied Trial Animal (kg) content (76) (mg) 0%) ("/.I

A Cow 1 714 3.5 600 385 0.06 Cow 2 628 3.8 600 186 0.03

B Cow 3 820 4.2 1500 970 0.06 Cow 4 1154 3.8 1500 172 0.05

602 R. Frank el d.

cows 1 and 2, respectively, while after six sprays, the comparable residues were respectively 0.21 and <0.20,ug litre-'. By day 4, residues were at or below the detection limit in the milk of both cows (Table 1). The total milk production over the 26-day study contained 385 and 166pg, respectively, of intact fenvalerate from the two cows. This represented 0.03 and 0.06%, respectively, of the 600mg applied topically to each cow (Table 2).

3.2. Trial B The highest residues of fenvalerate in milk, from the 0.5 g per cow application rate, occurred 6 h after treatment and declined below the limit of detection in 14-21 days (Table 3). Consecutive applications produced the highest residues in milk after the second treatment; residues after the third treatment were lower than after the second, but higher than after the first treatment (Table 4 and Figure 1). The two diastereoisomers appeared to remain in the ratio of 1 : 1 as the residue in milk declined over the 14-day period. Regression analysis of the data from Trial B appears in Table 4 and reveals a half-residue disappearance time from milk of 5.4 to 8.1 days. Over the 59-day study period, the milk produced contained 970 and 772,ug of intact fenvalerate, respectively (Table 2). This represented 0.06 and 0.05%, respectively, of the 1500mg applied topically to each cow.

Table 3. Fenvalerate residues in milk taken from one heifer and one mature Holstein cow, treated with 0.5ga.i. per cow in each of three consecutive topical applications over a 59-day period (Trial B)

Fenvalerate in whole milk (pg litre-')

Cow 3 (2-5 yean old) Cow 4 ( 5 years old)

Time from spray Diastereoisomerb Diastereoisomef' application to Mean residue of milk samulina Treatment' X Y Total X Y Total three treatments

-6 hours Prespray <0.10 10.10 <0.20 <0.10 <0.10 <0.20 <0.20 +6 hours First 0.39 0.59 0.98 0.63 0.48 1.11

Second 3.70 3.10 6.80 0.83 0.74 1.57 2.43 (k2.21) Third 1.30 1.20 2.50 0.92 0.70 1.62

3 days First 0.30 0.49 0.79 0.47 0.57 1.04 Second 1.30 1.60 2.90 0.25 0.23 0.48 1.17 (f0.88) Third 0.27 0.44 0.71 0.60 0.51 1.11

7 days First 0.21 0.28 0.49 0.14 0.23 0.37 1.02 (f0.86) Second 0.70 0.70 1.40 <0.10 <0.10 <0.20 Third 1.30 1.20 2.50 0.63 0.41 1.14

Second 0.11 0.29 0.40 0.18 0.14 0.32 Third 0.72 0.47 1.19 0.26 0.29 0.55

Second 0.12 0.23 0.35 0.60 0.61 1.21 Third 0.12 0.19 0.31 0.63 0.64 1.27

10 days First <0.10 0.23 0.33 0.10 <0.10 0.20 0.50 (f0.36)

14 days First 0.13 0.19 0.32 <0.10 <0.10 <0.20 0.61 (k0.49)

21, 28 and 31 days Third co.10 <0.10 <o.m <0.10 <0.10 <0.20 <0.20

a Pre-spray and first application, 23 July; second application, 5 August; third application, 20 August 1982. The composition of diastereoisomers X and Y of fenvalerate is given in section 2.2.

Table 4. Rate of disappearance of fenvalerate from the milk of cows 3 and 4 (Trial B)

Spray treatment Mean fenvalerate Half-residue after which milk residue (6h to 14 days) disappearance time

was sampled (pg litre-') Regression equation R= (days)

First 0.58 (f0.36) Log Y=-0.030-0.037 x 0.86 8.1 Second 1.56 (f2.00) Y=2.800-2.097 log x 0.96 5.4 Third 1.29 (k0.74) Log Y=+0.328-0.042 x 0.76 7.2 All 1.15 (f1.29) Y=1.766-1.113 logx 0.97 6.4

Fenvalerate mM~es in milk

140

120

100

80

60

603

-

-

-

-

-

1'

c 0 - .- r E .- C

0) c

- E 0

C

9 0

\ h/lo-o -- 0- -

I I I I I I I - - I

40p,

2 0

2

Time (days)

Figure 1. Daily secretion of fenvalerate in the milk of two cows (cows 3 and 4) following three topical treatments (0.5g of fenvalerate per cow at each treatment) over a 59-day period. The arrows indicate treatments 1. 2 and 3.

4. Discussion

Wszolek et a1.' reported on two Holstein cows fed daily for 4 days with rations containing 5 and 15mg of fenvalerate litre-'; the total dose fed in 22.7kg of diet per day represented 0.454 and 1.362g, respectively. The concentrations of fenvalerate in the whole milk increased to a maximum of 0.048 and 0.250pg litre-', respectively, on the fourth experimental day. Residues declined to non-detectable levels by day 7 and day 10, respectively. The total secretion of fenvalerate in the milk amounted to 0.44 and 0.64% of the total dose fed in the diet.

In the present Trial A, six consecutive topical treatments, 3 and 4 days apart, of 0.1 g per cow, resulted in residues declining to <0.2mg litre-' in the milk by day 7; the highest residues were present 3 days after treatment. In Trial B, three consecutive topical treatments, 14 days apart, of 0.5 g per cow, resulted in residues declining to c0.2 mg litre-' in the milk by day 21; the highest residues were present 6 h after treatment. No explanation can be offered for the different times that the peak concentrations were seen in the milk. The total secretion of intact fenvalerate varied from 0.03 to 0.06% of that applied.

Gaughen et al.' reported that ( l R S , 3RS)- and (lRS, 3SR)-permethrins, diastereoisomers of another pyrethroid, were largely eliminated from the body of lactating Jersey cows in 12 to 13

604 R. Frank cf al.

days after an initial feeding at a rate of about 1.0mg litre-' on 3 consecutive days. The milk and fat contained higher residues of the (lRS, 3RS)- than the ( l R S , 3SR)-diastereoisomer, and the residue was almost entirely present as the unmetabolised compound. In this present study, the two diastereoisomers of fenvalerate were found to be present in approximately equal quantities.

References

1. 2. 3. 4. 5 .

Gaughan. L. E.; Ackerman, M. E.; Unai, T.; Cassida, J. E. J. Agric. Food Chem. 1978, 26, 61S616. Wszolek, P. C.; Lein, D. H.; Lisk. D. J. Bull. Environ. Contam. Toxicol. 1980, 24, 296-298. Braun, H. E.; Stanek, J . 1. Assoc. Off. Anal. Chem. 1982, 65, 685689. Horiba. M.; Kitahara, H.; Takahashi, K.; Yamamoto. S.; Murano, A. Agric. Biol. Chem. 1980, 44, 1197-1199 Lee, Y. W.; Westcott. N . D.; Reichle, R. A. 1. Assoc. Off. Anal. Chem. 1978, 61, 869-871.