A cross sectional study was conducted during October and November 2006 on 69 smallholder dairy farms with lactating cows in Mvomero and Njombe districts Tanzania, to determine the prevalence of mastitis and to assess the milk quality on the study farms. Clinical mastitis was investigated using clinical changes of udder and milk at animal level. Cow-side California Mastitis Test (CMT) and microbiological cultures were used to assess subclinical mastitis at quarter level. Milk quality was determined on bulk milk samples at herd level using alcohol and acidity tests, butter fat content, total solids, ash content as well as Delvotest® for antimicrobial residues. Overall prevalence of clinical mastitis at herd level in both districts was 21.7 % (n = 69). Based on CMT, prevalence of subclinical mastitis at animal level was 51.6 % (n = 91). Prevalence of bacterial isolates at animal level was 35.2 % (n = 91) while for fungal it was 16.7 % (n = 90). Based on CMT results, prevalence of subclinical mastitis at quarter level was 30 % (n = 353), while for bacteria and fungi it was 16 % and 6 % respectively. Contamination of milk with antimicrobial residues was 4.5 % (n =67). The milk quality parameters for most of the milk samples were within acceptable levels. Findings in this study have demonstrated high prevalence of subclinical mastitis that may contribute to low productivity of dairy cattle in both districts. About 20 % of CMT subclinical cases had no involvement of microbial pathogens that suggested the need for minimal interventions with antimicrobial agents. These findings call for use of udder disinfectants and improved milking hygiene as intervention strategies to control mastitis on the smallholder dairy farms in Tanzania
In order to understand better the relationship between plant physical structure and rate of intake, twelve plant species were compared: Trifolium repens L., Medicago sativa L., Onobrychis viciifolia Scop., Desmodium intortum (Mill.) Urb., Brassica napus L., Spergula arvensis L., Lolium perenne L., Lolium multifiorum Lam., Festuca arundinacea Schreb., Chlorisgayana Kunth, Cenchrus ciliaris L. and Zea mays L. The effects of early as opposed to late harvesting were compared. Plants were grown in a heated glasshouse in each of 2 years, examined for morphology, anatomy, neutral detergent fibre and digestibility, and fed to sheep for 1-min test periods to record rate of intake.Rate of intake was in the order tropical grasses < temperate grasses < broad-leaved species < S. arvensis. The range was wide: from 4-6 g dry matter/min with C. gayana to 15-6 g with S. arvensis. The lowest rate of intake was associated with the possession of a large number of veins, close together, in parallel lines (tropical grasses); a rather higher rate was associated with fewer veins, further apart, in parallel lines (temperate grasses); the next to the highest rate was associated with broad leaves, which had a network of veins; the highest rate was associated with thin stems containing thin vascular bundles. L. perenne, L. multifiorum, C. gayana and C. ciliaris were similar in the thickness of large and small leaf blade veins and leaf sheath veins. F. arundinacea and Z. mays had rather thicker veins. T. repens, 0. viciifolia. D. intortum and B. napus were similar in the thickness of petiole vascular bundles. Neutral detergent fibre was lowest in B. napus and highest in C. gayana and C. ciliaris. In vitro digestibility was highest in B. napus and lowest in D. intortum.i N T o n n n r T i r i N t n i n v a s c u ' a r bundles and a low proportion of stem I N I K U U U L I I U M occupied by vascular bundles. In the present exAs noted by Mtengeti el al. (1995), the physical periment, in order to reach a better understanding of structure of plants can affect the rate at which they are the relationship between plant physical structure and eaten. A high potential rate of intake may be positively rate of intake, we examined the structure and recorded associated with a high daily voluntary intake (McLeod the rate of intake of twelve species, including the four & Smith 1989; Moseley & Antuna Manendez 1989), examined by Mtengeti et al. (1995). Two temperate which may be advantageous from an animal pro-grasses, two tropical grasses and Zea mays were duction point of view. If given a choice of species, as included for comparison with L. perenne and two when grazing a mixed sward, animals will tend to temperate legumes and one tropical legume were choose plants which can be eaten quickly rather than included for comparison with T. repens. The tropical ones which require much chewing, unless other species would not have grown and survived satfactors, such as taste, dissuade them from choosing isfactorily in field conditions in the UK and so a the former. ...
S U M M A R YFour plant species were compared in each of three harvest periods (in August/September) in 1991 and 1992 at Aberystwyth: white clover {Trifolium repens L.), rape (Brassica napus L.), spurrey (Spergula arvensis L.) and perennial ryegrass (Lolium perenne L.). Plant physical structure was considered in relation to rate of intake by sheep, chewing activity and the effectiveness of chewing in breaking the diet into particles.White clover had a much lower proportion of cell wall than perennial ryegrass, but the rate of intake and the number of chews per min were similar for the two species. White clover petioles broke down into long, thin particles, similar in size and shape to those derived from perennial ryegrass leaf sheaths; many of the clover petioles were not split longitudinally by chewing, in contrast to the ryegrass sheaths. A white clover leaflet was typically broken into about 20 blocky particles, whereas a petiole of similar weight was broken into only about three particles. Veins were close together in ryegrass leaf sheaths and blades, particularly the latter; approximately one in seven strips of weaker tissue between veins was ruptured by chewing leaf sheaths and one in 16 in the case of leaf blades, in each case resulting in particles of c. 2 mm width. Rape had a low proportion of cell wall and a low proportion of vascular tissue in its leaf blades, petioles and stems. Rape leaf blades were eaten quickly, but the stems were eaten slowly. The length and width of particles derived from rape leaf blades were very similar to those of particles derived from white clover leaflets. Spurrey had a high proportion of cell wall and was low in in vitro digestibility, but the rates of intake and chewing were high and relatively few chews were required per g of dry matter ingested. The vascular bundles in the spurrey stems were only half the thickness of the bundles in white clover petioles; pieces of spurrey stem were typically broken at about two places along their length and were not split during eating.The study illustrates the wide variation in plant anatomy among species which can be available to herbivores and some effects of the abundance, thickness and orientation of vascular bundles on rate of intake, chewing activity and the size and shape of particles produced by chewing.
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