Farmers’ socio-demographic characteristics
The respondents in this study had a mean age of 54.5 ± 12.1 SD years and majority (28.4%) was in the age group (57-66) years (Fig.2). Most of the respondents interviewed were male (60%), especially in the dairy farmer group (65%). With regard to education (35.3%) had achieved tertiary education level, 29.3% had secondary education, (33%) primary education and 3(2.6%) informal education.
About 71% of the farmers indicated that livestock production was their main occupation. In addition, 62% of farmers had over six years of livestock rearing or management experience (Table1).
Practices of antimicrobial usage in cattle and poultry
Qualitative antimicrobial use estimate
Of the 116 farms visited 65 (56%) were small-scale dairy farms while 51(44%) poultry farms and all of them used antimicrobials. On personnel that provided farmers with information on drug source, 82.8% (95%CI, 74.9, 88.6) mentioned veterinarians, including 83.1% of the dairy and 82.4% of poultry farmers while 3.4% reported neighbours of whom 3.1% were dairy cattle farmers and 3.9% poultry farmers. Across all the farmer categories, the primary purpose of antimicrobial use was for treatment 83.6% (95%CI, 75.8, 89.3) followed by “treatment and prophylaxis” (13.8%), prophylaxis (1.7%) and growth promotion (0.9%). About 89.2% of the small-scale dairy farmers indicated that treatment was their primary purpose for antimicrobial, compared with 76.5% of the poultry farmers. When asked where they purchased antimicrobials used on cattle and poultry, 44% (95%CI, 35.3, 53.1) of the farmers said veterinary drug shops, 16.4% veterinary clinics while 39.7% patronized individual veterinarians. Notable, 43.1% of the dairy cattle farmers indicated veterinary drug shops while 45.1%of the poultry farmers indicated so. 90.5%(95%CI,83.8,94.6) of the farms signaled that they engaged services of veterinarians/animal health, especially the dairy cattle farmers (90.8%) while 9.5% of the farmers practiced self- administration.
In all the dairy farms visited, antimicrobials were administered through parenteral route while in 98% of the poultry farm orally via drinking water and 2% in feeds. Majority (65.7%) were non-compliant to withdrawal duration, of whom, 63.1% were dairy cattle farmers and 66.7 % were poultry farmers. Most farmers, 66.4% (95%CI, 57.4,74.3) stored their antimicrobials in cupboards, followed by open shelf indoors (24.1%) and shelf direct sunlight (9.5%), with some variations in the different farmer groups (Table 3). Overall, 58.6% of the livestock farmers had favorable practices in accordance to good antimicrobial stewardship based on their responses. Farmers in the age group 27-36 years were four times more likely to have unfavorable antimicrobial use practices than those in the age group 67-76 years (OR = 3.88; 95% CI= 1.71-6.05; p =0.001). Meanwhile, farmers with low educational qualifications (Primary school qualifications and below) were three times more likely to have unfavorable antimicrobial use practices than those with tertiary education (OR = 2.71; 95% CI= 1.44-3.98; p = 0.001) (Table 3).
Table 1. Farmers’ socio-demographic characteristics in Dar es Salaam, Tanzania
Variable
|
Number of farmer categories, n (%)
|
|
Cattle (65)
|
Poultry (51)
|
Overall (116)
|
Confidence interval (95%)
|
Gender
|
M
|
42(64.6)
|
27(52.9)
|
69(59.5)
|
50.4,67.9
|
F
|
23(35.4)
|
24(47.1)
|
47(40.5)
|
32.0,49.6
|
Age (years)
|
27-36
|
2(3.1)
|
11(21.6)
|
13(11.2)
|
6.7,18.2
|
37-46
|
10(15.4)
|
7(13.7)
|
17(14.7)
|
9.4,22.2
|
47-56
|
17(26.2)
|
14(27.4)
|
31(26.7)
|
19.5,35.4
|
57-66
|
19 (29.2)
|
14(27.4)
|
33(28.4)
|
21.0,37.3
|
67-76
|
17(26.2)
|
5(9.8)
|
22(19.0)
|
12.9,27.1
|
Education
|
Informal
|
1(1.5)
|
2(3.9)
|
3(2.6)
|
0.9,7.3
|
Primary
|
21(32.3)
|
17(33.3)
|
38(32.8)
|
24.9,41.7
|
Secondary
|
19(29.2)
|
15(29.4)
|
34(29.3)
|
21.8,38.2
|
Tertiary
|
24(36.9)
|
17(33.3)
|
41(35.3)
|
27.2,44.4
|
Main occupation of respondent
|
Livestock
|
44(67.7)
|
38(74.5)
|
82(70.7)
|
61.9,78.2
|
Others
|
21(32.3)
|
13(25.5)
|
34(29.3)
|
21.8,38.2
|
Experience in livestock rearing (years)
|
|
31(47.7)
|
13(25.5)
|
44(37.9)
|
29.6,47.0
|
|
34(52.3)
|
38(74.5)
|
72(62.1))
|
52.9,70.4
|
Antimicrobials frequently used in poultry and cattle production
A total of 17 antimicrobials were used among the poultry farms, which comprised of 7 classes (Table 4). The most frequently used antimicrobials in poultry production were: enrofloxacin (17.6%), followed by oxytetracycline (13.7%), coridix (13.7%), tylosin (11.8%) and flumequin (5.9) (Fig3). In the small-scale dairy farms, 9 different types of antimicrobials comprising 6 classes were used (Table 5). The frequently used antimicrobials were tetracyclines (20.0%), followed by penicillin (18.5%), sulphonamides (12.3%), tylosin (12.3%), penstrep (10.8%), gentamicin (10.8%), enrofloxacin, 5(7.7%); ampicillin (4.6%) and neomycin (3.1%) (Fig 3).
Quantitative antimicrobial use estimate
In the poultry farms, oxytetracycline (49%) was the commonly used antimicrobial agent, followed by sulfadimidine (18%), enrofloxacin (9%) and flumequin (6%). ciprofloxacin (5%), tylosin (5%), sulfamethoxypyridazine (3%) and doxycycline (2%). in the small-scale dairy farms, sulphonamide (31.4%) was the most commonly used antimicrobial agent followed by penstrep (17%), gentamicin (13%), neomycin (10%), tetracycline (10%) and tylosin (10%). compounds like penicillin (6%), enrofloxacin (2.3%) and ampicillin (2.4%) were not commonly used.
The averagely applied dosages to poultry and small-scale dairy farms, described as Defined Daily Dose (DDD) and Used Daily Dose (UDD) are presented in Tables 4 and 5, respectively. From the ratio UDD to DDD it can be seen that in the poultry farm, trimethoprim and tylosin were under dosed, neomycin, enrofloxacin and doxycycline slightly over dosed while colistin, sulfadiazine, sulfamerazine, flumequin and sulfadimidine were over dosed. Other compounds were appropriately dosed within the range of 0.8 and 1.2.
In the small-scale dairy farms, the ratio of UDD to DDD indicated that tylosin was the only compound overdosed while the rest were within the dosing range (0.8 -1.2).
Table 2. Practices of antimicrobial usage in livestock production by Farmers in Dar es Salaam, Tanzania
Practice
|
Producer categories, n (%)
|
|
Cattle (65)
|
Poultry (51)
|
Overall (116)
|
Confidence interval (95%)
|
Source of drug information to the farmer
|
Veterinarian
|
54(83.1)
|
42(82.4)
|
96(82.8)
|
74.9,88.6
|
Household experience
|
9(13.8)
|
7(13.7)
|
16(13.8)
|
8.7,21.2
|
Neighbours
|
2(3.1)
|
2(3.9)
|
4(3.5)
|
1.4,8.5
|
Purchasing place for antimicrobials
|
Veterinary drug shops
|
28(43.1)
|
23(45.1)
|
51(44.0)
|
35.3,53.1
|
Veterinary clinic
|
13(20.0)
|
6(11.8)
|
19(16.4)
|
10.7,24.2
|
Individual veterinarian
|
24(36.9)
|
22(43.1)
|
46(39.7)
|
31.2,48.8
|
Purpose for antimicrobial usage
|
Therapeutic
|
58(89.2)
|
39(76.5)
|
97(83.6)
|
75.8, 89.3
|
Prophylaxis
|
1(1.5)
|
1(1.9)
|
2(1.7)
|
0.5,6.1
|
Therapeutic & Prophylaxis
|
6(9.2)
|
10(19.6)
|
16(13.8)
|
8.7,21.2
|
Growth promotion
|
0(0.0)
|
1(1.9)
|
1(0.9)
|
0.2,4.7
|
Drug sellers asking for prescriptions
|
Yes
|
3(4.6)
|
2(3.9)
|
5(4.3)
|
1.9,9.7
|
No
|
58(89.2)
|
45(88.2)
|
103(88.8)
|
81.8,93.3
|
Sometimes
|
4(6.2)
|
4(7.8)
|
8(6.9)
|
3.5,13.0
|
Administration of drug to livestock
|
Veterinarian/Animal health worker
|
59(90.8)
|
46(90.2)
|
105(90.5)
|
83.8,94.6
|
Self
|
6(9.2)
|
5(9.8)
|
11(9.5)
|
5.4,16.2
|
Route of antimicrobial administration
|
Parenteral (Injection)
|
65(100)
|
0(0.0)
|
65(56.0)
|
46.9,64.7
|
Water
|
0(0.0)
|
50(98.0)
|
50(43.1)
|
34.5,52.2
|
Feeds
|
0(0.0)
|
1(2.0)
|
1(0.9)
|
0.2, 4.7
|
Compliance with drug withdrawal period
|
Yes
|
24(36.9)
|
17(33.3)
|
41(35.3)
|
27.2,44.4
|
No
|
41(63.1)
|
34(66.7)
|
75(64.7)
|
55.6,72.8
|
Antimicrobial storage
|
|
|
|
|
Cupboard
|
43(66.2)
|
34(66.7)
|
77
|
57.4,74.3
|
Open shelf indoor
|
16(24.6)
|
12(23.5)
|
28
|
17.3,32.7
|
Shelf direct sunlight
|
6(9.2)
|
5(9.8)
|
11
|
5.4,16.2
|
Table 3: Socio-demographic characteristics of cattle and poultry farmers associated with antimicrobial use practices in Dar es Salaam
Variable
|
Number of respondents n (%)
|
Unfavorable practices n (row %)
|
Odds ratio(OR)
|
95%Confidence Interval
|
P-value
|
Age(in years)
|
67-76
|
22(19.0)
|
4(18.2)
|
1.00
|
|
|
57-66
|
33(28.4)
|
10(30.3)
|
0.33
|
-1.23,1.89
|
0.678
|
47-56
|
31(26.7)
|
13(41.9)
|
1.19
|
-0.33,2.73
|
0.124
|
37-46
|
17(14.7)
|
11(64.7)
|
2.60
|
0.85,4.36
|
0.004
|
27-36
|
13(11.2)
|
10(76.9)
|
3.88
|
1.71,6.05
|
0.001
|
Farmers’ level of Education (Educ2)
|
Primary
|
41(35.3)
|
10(24.4)
|
1.00
|
|
|
Secondary
|
34(29.3)
|
9(26.5)
|
0.23
|
-1.03,1.49
|
0.716
|
Tertiary
|
41(35.3)
|
29(70.7)
|
2.71
|
1.44,3.98
|
0.001
|
Statistically significant at p<0.05
|
Table4. Daily dosages (mg/kg), dosing ratios and total amount of antimicrobials used (g) in surveyed poultry farms in Dar es Salaam
Antimicrobial Class
|
Antimicrobial name
|
DDD (mg/kg)
|
UDD(mg/kg)
|
UDD/DDD
|
Total used [g (%)]
|
Aminoglycosides
|
Neomycin
|
6.3
|
8.5
|
1.3
|
20.4 (0.10)
|
|
|
|
|
|
|
Diaminopyrimidines
|
Trimethoprim
|
10.2
|
6.4
|
0.6
|
12.8 (0.06)
|
|
|
|
|
|
|
Floroquinolones
|
Enrofloxacin
|
10.0
|
12.5
|
1.3
|
1894.5 (9.03)
|
|
Ciprofloxacin
|
15.0
|
17.0
|
1.1
|
1037.5 (4.94)
|
|
Flumequine
|
12.0
|
18.0
|
1.5
|
1260.0 (6.00)
|
|
|
|
|
|
|
Macrolides
|
Tylosin
|
74.2
|
35.0
|
0.5
|
952.0 (4.54)
|
|
|
|
|
|
|
Polymyxins
|
Colistin
|
5.0
|
22.0
|
4.4
|
132.0 (0.63)
|
|
|
|
|
|
|
Sulphonamides
|
Sulfadiazine
|
6.3
|
23.3
|
3.7
|
46.6 (0.22)
|
|
Sulfadimidine
|
30.0
|
42.0
|
1.4
|
3780.0(18.01)
|
|
Sulfamerazine
|
34.0
|
63.2
|
1.9
|
493.0 (2.35)
|
|
Sulfamethoxypyridazine
|
23.0
|
23.0
|
1.0
|
623.3 (2.97)
|
|
|
|
|
|
|
Tetracyclines
|
Oxytetracycline
|
39.8
|
33.3
|
0.8
|
10311.7(49.13)
|
|
Doxycycline
|
20.0
|
25.0
|
1.3
|
425.0 (2.02)
|
Defined Daily Dose (DDD), Used Daily Dose (UDD), Total used = Total volumes of antimicrobial used (grams).
Table 5. Daily dosages (mg/kg), dosing ratios and total amount of antimicrobials used (g) in surveyed dairy farms in Dar es Salaam
Antimicrobial Class
|
Antimicrobial name
|
DDD (mg/kg)
|
UDD(mg/kg)
|
UDD/DDD
|
Total used [g(%)]
|
Beta-lactamase
|
Penicillin
|
8.0
|
8.2
|
1.0
|
502.7 (4.51)
|
|
Penstrep
|
12.5
|
13.0
|
1.0
|
1886.5 (16.93)
|
|
Ampicillin
|
10.0
|
11.0
|
1.1
|
275.2(2.47)
|
|
|
|
|
|
|
Aminoglycosides
|
Gentamicin
|
9.0
|
8.4
|
0.9
|
1471.2 (13.2)
|
|
Neomycin
|
21.0
|
21.0
|
1.0
|
1094.6 (9.83)
|
|
|
|
|
|
|
Floroquinolones
|
Enrofloxacin
|
4.5
|
4.2
|
0.9
|
262.7(2.34)
|
|
|
|
|
|
|
Macrolides
|
Tylosin
|
6.0
|
10.0
|
1.7
|
1063.4 (9.55)
|
|
|
|
|
|
|
Sulphonamides
|
Sulphonamides
|
21.0
|
24.0
|
1.1
|
3502.8 (31.44)
|
|
|
|
|
|
|
Tetracycline
|
Oxytetracycline
|
11.7
|
10.0
|
0.9
|
1084.2 (9.73)
|
Defined Daily Dose (DDD), Used Daily Dose (UDD), Total used = Total volumes of antimicrobial used (grams).