Prevalence of the Staphylococcal Enterotoxins Genes in Raw and Milk Products along the Value Chain in Mbeya and Mbozi Districts, Tanzania

The study determined the prevalence of genes coding for Staphylococcal enterotoxins (SEs) from Staphylococcus aureus isolates in milk produced and sold in Mbeya and Mbozi districts in Tanzania. Samples of raw milk (n=300), boiled hot (ready-to-consume) milk (n=72) and sour milk (n=72) were randomly collected from smallholder dairy farmers, milk collection points (MCP) and milk shops. Laboratory analysis showed that 59.7% of the milk samples contained Staphylococcus species. Biochemical tests showed that 12.4% of the isolates were positive for S. aureus, of which 5.6, 2.5 and 4.3% were from samples collected from farmer’s herd milk, MCP and milk shops, respectively. Furthermore, multiplex Polymerase Chain Reaction (mPCR) results showed that 36.4% of the total S. aureus isolates (n=55) had SEs genes. Frequently observed gene was Sea (32.6%) while Sej was not detected in any of the isolates. The distribution of the SEs genes along the milk market channel showed 35, 15 and 50% of the genes came from isolates samples collected at farm level, MCP and milk shops, respectively. Moreover, no statistical difference were observed for SE coding gene between the districts and seasons, though higher (65%) prevalence of S. aureus isolates carrying SEs genes were observed in dry than wet season (35%). The prevalence of SE coding gene in raw, boiled hot and sour milk were 4.3, 5.6 and 4.2%, respectively. The results obtained show that milk produced and marketed in the two districts contained S. aureus isolates expressing gene for enterotoxins production which pose a potential public health risk. Hence, the results indicate the need to institute proper hygienic measures by all milk stakeholders in order to avoid contamination of milk with S. aureus. Further studies on the diversity and distribution of enterotoxins producing S. aureus in the Southern highlands and other areas in the country are recommended. Keywords: Boiled hot milk, sour milk, enterotoxins, Staphylococcus aureus, Multiplex PC

Evaluation of current performance of dairy cattle in ASAS and kitulo farms in the southern highlands of Tanzania .

This study was carried out to evaluate the current performance of dairy cattle at ASAS and Kitulo farms in the Southern Highlands of Tanzania. The objective was to assess the effects of genetic and non-genetic factors on lactation and reproductive performance, calf mortality rate, longevity traits and constraints affecting performance of dairy animals. Ayrshire and Friesian cows were involved in the study. Data were analysed using General Linear Models procedure of Statistical Analysis System (SAS). Average ages at first calving (AFC) at ASAS farm were 1059.5±19.41 and 1105.7±12.99 days for Ayrshires and Friesians, respectively. Breed and calving period significantly (P < 0.05) influenced AFC. At Kitulo farm AFC was 1151.7±9.63 days. Both parity and period of calving significantly (P < 0.001) influenced CI. Mean calving intervals (CI) at ASAS farms were 410.8±8.1 and 423.4±6.8 days for Ayrshire and Friesian cows, respectively. At Kitulo farm mean CI was 421.6±1.43 days. Mean lactation milk yields (LMY), lactation lengths (LL) and dry periods (DP) at the ASAS farm were 2696.8±75.4kg, 305.8±5.7 and 92.9±2.6 days, and 3000.1±62.9kg, 318.7±4.8 and 96.3±2.2 days for Ayrshires and Friesians, respectively. Breed (P < 0.001), parity (P < 0.001) and period of calving (P < 0.05) significantly influenced LMY and DP. At Kitulo farm mean LMY, LL and DP were 2608.3±24.0 kg, 322.3±1.4 and 91.2±0.52 days. Only period had a significant (P < 0.01) effect on LL. Overall abortion, stillbirth, pre-weaning and post- weaning mortality rates were 4.8, 3.7, 6.5 and 11.0% for ASAS farm. Corresponding rates at Kitulo farm were 11.2, 7.6, 12.1 and 13.0%. Mean lifetime milk production at ASAS farm for Ayrshires and Friesians were 11 303.6 and 13 517.5 kg while at Kitulo farm it was 13 481.2 kg. Management improvement including testing andiii vaccination of heifers against brucellosis and rehabilitation of infrastructures is therefore recommended

Evaluation of current performance of dairy cattle in ASAS and kitulo farms in the southern highlands of Tanzania .

This study was carried out to evaluate the current performance of dairy cattle at ASAS and Kitulo farms in the Southern Highlands of Tanzania. The objective was to assess the effects of genetic and non-genetic factors on lactation and reproductive performance, calf mortality rate, longevity traits and constraints affecting performance of dairy animals. Ayrshire and Friesian cows were involved in the study. Data were analysed using General Linear Models procedure of Statistical Analysis System (SAS). Average ages at first calving (AFC) at ASAS farm were 1059.5±19.41 and 1105.7±12.99 days for Ayrshires and Friesians, respectively. Breed and calving period significantly (P < 0.05) influenced AFC. At Kitulo farm AFC was 1151.7±9.63 days. Both parity and period of calving significantly (P < 0.001) influenced CI. Mean calving intervals (CI) at ASAS farms were 410.8±8.1 and 423.4±6.8 days for Ayrshire and Friesian cows, respectively. At Kitulo farm mean CI was 421.6±1.43 days. Mean lactation milk yields (LMY), lactation lengths (LL) and dry periods (DP) at the ASAS farm were 2696.8±75.4kg, 305.8±5.7 and 92.9±2.6 days, and 3000.1±62.9kg, 318.7±4.8 and 96.3±2.2 days for Ayrshires and Friesians, respectively. Breed (P < 0.001), parity (P < 0.001) and period of calving (P < 0.05) significantly influenced LMY and DP. At Kitulo farm mean LMY, LL and DP were 2608.3±24.0 kg, 322.3±1.4 and 91.2±0.52 days. Only period had a significant (P < 0.01) effect on LL. Overall abortion, stillbirth, pre-weaning and post- weaning mortality rates were 4.8, 3.7, 6.5 and 11.0% for ASAS farm. Corresponding rates at Kitulo farm were 11.2, 7.6, 12.1 and 13.0%. Mean lifetime milk production at ASAS farm for Ayrshires and Friesians were 11 303.6 and 13 517.5 kg while at Kitulo farm it was 13 481.2 kg. Management improvement including testing andiii vaccination of heifers against brucellosis and rehabilitation of infrastructures is therefore recommended