PREVALENCE OF BOVINE MASTITIS AND ITS BACTERIAL CAUSES WITH

THEIR ANTIBIOTIC SENSITIVITY IN A RESEARCH CENTRE FARM IN KENYA

*Ndirangu, P.N.1, Siamba, D.2, Wesonga, H.O.1, Nyongesa, P2 and Mugambi, J.M.1 1KARI, Veterinary Research Centre, P.O. Box, 32 00902, Kikuyu

2Masinde Muliro University of science and technology, P.O. Box 190, Kakamega

Presenter: Dr. Peter N. Ndirangu

INTRODUCTION• Dairy industry is largest agricultural sub-sector

in Kenya contributing 14% of agricultural GDP and 3.5% of total national GDP (GoK, 2008)

• The sector is faced with challenges including bovine mastitis. Mastitis causes economic losses; decreased milk production, veterinary costs, premature culling of cows, cost of replacement as well as discarding and down-grading of milk (Mungube et al., 2005)

• Mastitis refers to inflammation of mammary glands, caused by infectious and non-infectious agents. Main etiological agents are infectious microorganisms, bacteria

• Occurs in two forms: subclinical and clinical

Mastitic milk Normal milk

• Clinical is easily diagnosed via physical examination of udder and milk.

• Subclinical require use of tests like strip cup, California mastitis test (CMT), somatic cell count, culture

Strip cup CMT reagent & paddle

Culture and sensitivity testsSomatic cell analyzer for milk

• What is the treatment for mastitis? Antibiotics are largely applied in mastitis

therapy and Some of those used in Kenya are: penicillin, streptomycin, tetracycline, getamycin, ampicillin and sulphonamides (Ndirangu et al., 2013).

Antibiotics resistance is one reason for low efficacy of antibiotic therapy of mastitis. In Kenya only a few studies have reported the antibiotic sensitivity rates of the bacterial causes of mastitis (Gitau et al. 2011)

• Successful mastitis treatment programs require prior in vitro antibiotic sensitivity testing so as to avoid indiscriminate use of antibiotics. Given systemic or imm.

• What were the big questions?

1. What is the extent of mastitis in the farm?2. Which are the bacterial etiological agents of

the disease and which are the best drugs to use?

OBJECTIVES • To determine the mastitis management

practices and prevalence in cattle. • To determine the bacterial causes of mastitis

and their antibiotic sensitivity rates in the Sahiwal and dairy herds.

MATERIALS AND METHODS 1. Sampling and study herdsStudy design was a cross-sectional study carried

out in two herds of KARI-Naivasha.Sahiwal herd: sahiwal breed, which is a dual-

purpose breed. The herd size was 192 lactating cows where a random sample of 50 cows was selected

Dairy herd: Made up of Friesians & crossbreeds. Herd size was 92 lactating cows and a random sample of 50 cows was selected.

Sahiwal herd Dairy herd

2. Determination of mastitis prevalenceCow details recorded: type of grazing, breed,

stage of lactation, parity, hygiene status, etc. Clinical mastitis diagnosed by physical

examination of cows; visual observation, palpation & stripping to see physical changes in milk before milk sample collection.

Subclinical form was diagnosed by CMT (David et al., 2005). The CMT results were interpreted based on gel formation as -ve (no gel) or +ve (gel) .. scored 1-3

3. Milk sample collection389 milk samples collected from 100 cows in 2

herds since some cows had lost quarters.Collected aseptically. Teats were washed with

warm water, dried with disposable gauze dipped in 70% ethyl alcohol. The first two squirts of milk were discarded.

4. Bacterial isolation and identificationSamples for were selected based on their

mastitis status, clinical mastitis samples were selected and those samples with a CMT score of 2 and 3. In total, 53 samples were selected (32 from sahiwal and 21 dairy herd).

1 ml of milk was streaked on to blood agar with 5% sheep blood and incubated aerobically at 37oC. plates were examined at 24 hours and those with no growth were re-incubated and examined the following day.

• Bacteria were identified microscopically through Gram-staining, morphology and arrangement of the stained bacterial cells, followed by biochemical tests mainly catalase test (used for differentiating Gram-positive cocci and rods) and indole test (for differentiating Gram-negative cocci) as described by Holt et al. (1993).

5. Antibiotic sensitivity testingSensitivity was determined for 19 bacterial

isolates (15 Staph. species & 4 Strep. Species) via Kirb-Bauer disc diffusion method (Quinn et al. ,2000). Isolates selected were those giving a pure culture and a growth score of 3 or 4.

8Antibiotics used: ampicillin, tetracycline, co-trimoxazole, streptomycin, kanamycin, gentamycin, sulphamethoxazole & chloramphenicol. Zones of inhibition were measured.

RESULTS AND DISCUSSIONS

Management practices

Grazing system

Milking method

Milking hygiene

Sahiwal herd Free Hand Poor Dairy herd Semi-zero Machine Good Prevalence Clinical

mastitis Subclinical mastitis

Teat injuries

Sahiwal 3/50 (6%) 27/50(54%) 9/50(18%)Dairy 0 18/50(36%) 3/50 (6%)

• Subclinical mastitis was the most common as reported by others in different parts of Kenya (Ngatia, 1988; Omore et al., 1996; Ondieki et al., 2013). Form of mastitis is an indication of the degrees of udder infection. The 6% clinical mastitis in sahiwal cows is similar to 5.6% prevalence of chronic clinical mastitis reported by Ondieki et al. (2013). However, this was less than the 13.3% reported by Omore et al. (1996) for cows from Kiambu.

Prevalence of subclinical mastitis reported here is similar to those reported by others like Ngatia, 1988; shem et al., 2001

Prevalence of subclinical mastitis in sahiwal cows examined was highest during mid-lactation (4-9 months) of 51.9% and dairy herd was most prevalent in late lactation (66.7%). This finding agrees with the observation made by Ayano et al. (2013).

Bacterial isolates Sahiwal herd: isolation rate was 30/32(93.8%) .

The isolates were Staph. spp 26/30 (86.7%), Strep. spp. 2/30 (6.3%), Corynebacterium 1/30 (3.3%) and E.coli 1/30 (3.3%).

Dairy herd: isolation rate was 18/21 (85.7%). Bacteria were Staph. spp 10/18 (55.6%), Strep. spp. 7/18 (38.9%) and Corynebacterium 1/18 (5.6%).

Similar bacteria have been reported by others like Gitau et al., 2012; Ondiek, et al., 2013

Antibiotic sensitivity Gentamycin and ampicillin showed highest

sensitivity of 18/19(94.7%), kanamycin (79%), co-trimoxazole and chloramphenicol (73.7%), tetracycline (63.2%), streptomycin (52.6%) & sulphamethoxazole (21.1%). Similar findings have been reported by others (Ondiek et al., 2013; Gitau et al., 2011). This may be due to extensive use and misuse of tetracycline, streptomycin and penicillin for many years in Kenya while

• Gentamycin & kanamycin were introduced recently in Kenya thus resistance to the two drugs has not developed extensively.

CONCLUSIONS AND RECOMMENDATIONS 1. Bovine mastitis in KARI-Naivasha was

relatively high, particularly the subclinical form, thus effective control measures needs to be instituted. Such to include; improvement of milking hygiene, teat disinfection, routine testing for mastitis, effective treatment of mastitis cases, among others.

2. Mastitis etiological agents found were Staph. spp., Strept. spp., Corynebacterium and E. coli. Maintenance of environmental hygiene can help to reduce Intrammamary infections with Staphylococci and E. coli.

3. Bacteria isolates were most sensitive to Gentamycin, ampicilin and kanamycin and therefore these are the drugs of choice for mastitis therapy in the study area. However, antibiotic sensitivity testing is a pre-liquisite prior to initiating mastitis therapy.

• Director KARI • This study was funded by Eastern Africa

Agricultural Productivity Project (EAAPP).• Authors are grateful to technical staff of KARI-

VRC and MUUST for their part in sample collection and bacteriological analysis.

• Management and staff of KARI-Naivasha for allowing us to use their cows.

ACKNOWLEDGEMENTS

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