Evaluation of the hygienic quality and associated public health hazards of raw milk marketed by smallholder dairy producers in the Dar es Salaam region, Tanzania

A cross-sectional study was conducted to determine three parameters of the quality of the raw milk marketed by milk selling points (MSPs) in Dar es Salaam region. Total bacterial count (TBC) was used as an indicator of the microbial quality of the milk; antimicrobial residues were determined; and the California mastitis test (CMT) was used to screen for milk somatic cells as an indication of the mastitis level in the cows that provided the milk. Moreover, a water sample at each MSP was taken for bacteriological culturing. Finally, a questionnaire survey was conducted with the milk sellers at the MSPs to identify risk factors for poor milk hygiene. A total of 128 milk samples and corresponding water samples were collected from randomly selected milk selling points in Dar es Salaam region. The mean TBC was (8.2± 1.9) × 10⁶ cfu/ml, and major bacterial isolates from the milk samples were Escherichia coli (6.3%), Bacillus cereus (6.3%), Staphylococcus aureus (6.3%) and Streptococcus agalactiae (6.3%), Enterobacter aerogenes (5.6%) and Enterococcus faecalis (4.7%). In most cases, the organisms identified in milk corresponded to those isolated from the corresponding water samples. Of milk samples, 79.0% were positive to the CMT and 7.0% were positive for antimicrobial residues. TBC was normalized by log-transformation, and the possible predictors of TBC were identified by fitting two linear regression models. In a random effect model, water microbial quality, frequency of cleaning the milk containers, frequency of milk supply, milk storage time and the type of containers, and mixing of fresh and previous milk were significantly (p < 0.05) associated with the mean log TBC. In a fixed effect model, in addition to these indicators, water shortage, water source and the refrigerator condition were significantly (p ≤ 0.01) associated with log TBC. It was concluded that the milk sold in Dar es Salaam region is of poor quality and is of public health significance.     

Factors influencing economic efficiency of milk production among small-scale dairy farms in Mukurweini,Nyeri County,Kenya

Tropical Animal Health and Production - This paper highlights the factors likely to influence the economic efficiency of small-scale dairy farms in Mukurweini, Nyeri County, Kenya. A total of 91...     

Prevalence and antimicrobial resistance of Campylobacter in raw milk in the selected areas of Poland

During the recent years, an immense increase in the number of food poisoning cases in people caused by Campylobacter (C.) species has occurred. Raw milk, next to poultry meat, is considered the most frequent cause of food poisoning in people caused by the subject bacteria, although it is not always possible to isolate Campylobacter cells from the incriminated milk. Most probably this difficulty is caused by low concentration of the pathogen in milk at the level of 2/3 cells/ml although even such low concentration represents risk to human health. The present study was aimed at determining the occurence of Campylobacter bacteria in milk originating from selected regions of Poland. The isolation method applied in this work was effective in recovering as few as 0.1 cell of Campylobacter per g of food. Among 150 bulk milk samples tested, Campylobacter spp. was isolated from 7 (4.6%) ones. The biochemical identification of the isolated strains conducted by means of conventional biochemical tests as well as by applying the API - Campy tests revealed that all the isolates belonged to the C. jejuni species. Determination of resistance to antibiotics was performed by means of the diffusion disks method for the following antibiotics: gentamicin, ciprofloxacin, ampicillin, chloramphenicol, erythromycin, doxycyclin and tetracycline. Among 7 isolates tested, all were susceptible to ampicillin, chloramphenicol, erythromycin and gentamicin, 28.5% to doxycyclin and 14.2% to tetracycline and ciprofloxacin.     

影响奶牛泌乳量的因素及高产措施

提高奶牛产奶量、最大限度地增加经济效益是所有养牛户追求的目标。笔者结合近几年章丘市奶牛饲养的实践经验，把影响奶牛泌乳量的因素及高产措施，总结出以下几点：１遗传因素 奶牛的泌乳力首先取决于遗传，它是影响泌乳量的内在因素。主要有品种和个体因素，不同品种牛的产乳量差异很大，一般乳用牛的产乳量高于乳肉役兼用牛，而乳用牛中高度培育品种高于地方品种。在个体因素方面，同一品种的不同个体，在相同的生命时期，相同的饲养管理条件，其泌乳力也会有差别。因此在选择品种时，根据实际情况和经济效益决定是选择乳用型，还是选择…     

Somatic cell counts, mastitis and milk production in selected Ontario dairy herds.

Somatic cell counts were performed monthly on bulk tank milk samples for all producers in the Ontario counties of Hastings, Lennox/Addington and Prince Edward throughout 1978 and 1979. Other data were obtained via a structured questionnaire and from the records of the Ontario Milk Marketing Board. Many producers have not adopted practices that have been advocated for the integrated control of mastitis. For example, 43.3% of producers surveyed used single service paper towels, 63.3% regularly used teat dip and 56.5% dry cow therapy. The mean of the average monthly somatic cell count for all producers for 1978 was 621.1 x 10(3) cells/mL. This latter value was used to divide the producers into case (higher than average) and control (lower than average) groups. Control herds averaged 95.9 liters more shipped milk per cow per month than case herds. Milk from control herds averaged 0.22 percentage points higher than case herds for each of average fat and lactose, and 0.16 percentage points higher for protein. The linear regression of monthly shipped milk on the respective monthly bulk tank somatic cell count indicated a loss of 13.26 L/cow/month for each 100,000 increase in somatic cell count.     

Improvement of small dairy producers in the central coast of Peru

The objective of this study was to characterize a group of small dairy producers in the central coast of Peru and determine the most important limiting factors that affect animal productivity, using Participatory Rural Appraisal methodologies. The information collected during a year included biological and socio-economic characteristics. Inappropriate nutrition, management, health and reproduction were observed in most farms. The average number of animals per family was 17.3, of which 40% were bulls and growing calves. Milk production and net cash income were reduced in the summer. The feeding programme for lactating and growing females of forage exchanged for labour and purchased concentrates did not theoretically or practically meet the cows’ needs. All water was carried to the site on donkeys from one kilometre distance. All cows were negative for a number of potential infectious diseases. By California Mastitis Test of routine samples 7.1% of cows had clinical mastitis and 66.1% subclinical. Taking notional labour and forage costs into account, milk production was at a loss but the farmers considered neither and were satisfied with a net cash income from milk sales three times the average agricultural wage.     

Influence of gastro-intestinal nematodes on the productivity of dairy cattle in the wet highlands of Sri Lanka

Summary To study the response and economics of nematode control in cattle, trials with anthelmintics were carried out in the wet season at New Zealand farm in the highlands of Sri Lanka. Three age groups were used: stall fed yearlings, grazing heifers and lactating cows. Groups were treated with ivermectin or febantel and monitored along with control groups for faecal egg counts, growth and milk production.Treatment reduced the trichostrongylid faecal egg counts in yearlings, heifers and cows for six to 10 weeks, for more than 10 weeks and for 140 days respectively. The growth rate of treated yearlings did not increase significantly while treated heifers did grow significantly faster. Treated cows produced an average of 115 kg more milk over 133 days (P<0.05). The economic gains in reducing the age at first service and in terms of milk yield far outweighed the cost of anthelmintics used.

---

La Influencia De Nematodos Gastrointestinales Sobre La Productividad De Ganado Lechero En Las Tierras Altas Humedas De Sri Lanka

Resumen Se estudió la respuesta económica del control de nemátodos en ganado, mediante el uso de antihelmínticos durante la estación lluviosa, en una granja de altura en Sri Lanka. Se utilizaron tres grupos de edades: animales de un año estabulados, novillas en pastoreo y vacas lactando. Los grupos fueron tratados con Ivermectina o Febantel, estableciéndose seguidamente un control continuado sobre huevos por gramo de heces, crecimiento y producción de leche. Se establecieron grupos controles. Los tratamientos redujeron los conteos de huevos de estrongiloideos en animales de un año estabulados, novillas y vacas por períodos de seis a 10 semanas, por más de 10 semanas y por 140 días respectivamente. La tasa de crecimiento de los animales de un año no se modificó significativamente, mientras que el crecimiento de las novillas fue significativamente mejor. Las vacas tratadas produjeron un promedio de 115 kg de leche más sobre 133 días (P<0.05). Las ganancias económicas en términos de reducir la edad al primer servicio y producción de leche, compensaron satisfactoriamente el costo de los antihelmínticos utilizados.

---

Influence Des Nematodes Gastro-Intestinaux Sur La Productivite Du Betail Laitier Dans Les Hautes Terres Humides De Ski Lanka

Résumé Des essais visant à étudier la réponse et l'économie de la lutte contre les nématodes chez les bovins ont été réalisés en saison humide à la ferme New Zealand dans la région des collines à Sri Lanka. Trois groupes d'âge ont été constitués: éleves de un an nourris à l'auge, génisses au pâturage et vaches en lactation. Les groupes ont été traités à l'ivermectine ou au Febantel et suivis en même temps que le groupe témoin pour ce qui concerne les analyses coprologiques, la croissance et la production laitière. Le traitement a réduit les numérations fécales concernant les trichostrongles chez les élèves, les génisses et les vaches pendant 6 à 10 semaines, pour plus de 10 semaines et pour 140 jours respectivement. Le taux de croissance des élèves traités ne s'est pas accru de manière significative alors que les génisses ont amélioré le leur significativement. Les vaches traitées ont produit en moyenne 115 kg de lait de plus en 133 jours (P<0,05). Le gain économique obtenu par la réduction de l'âge à la première saillie et en terme de rendement laitier contre balançait de loin le coût des anthelminthiques utilisés.

     

Effect of paratuberculosis on culling, milk production, and milk quality in dairy herds

OBJECTIVE: To determine the effect of paratuberculosis on culling, milk production, and milk quality in infected dairy herds. DESIGN: Cross-sectional study. ANIMALS: 689 lactating dairy cows in 9 herds. PROCEDURE: Milk, blood, and fecal samples were obtained from all cows. Fecal samples were evaluated via mycobacterial culture. Serum samples were tested with a commercially available ELISA for antibodies against Mycobacterium avium subsp paratuberculosis, and preserved milk samples were tested with an ELISA for antibodies against M paratuberculosis. Mixed effect and proportional hazards models were used to determine the effect of paratuberculosis on 305-day milk, fat, and protein production; somatic cell count linear score; and the risk of culling. RESULTS: Cows with positive results of bacteriologic culture of feces and milk ELISA produced less milk, fat, and protein, compared with herdmates with negative results. No difference in 305-day milk or fat production was detected in cows with positive results of serum ELISA, compared with seronegative cows. The 3 survival analyses revealed that cows with positive results of each test were at higher risk of being culled than cows with negative results. Paratuberculosis status, as determined by use of all 3 diagnostic tests, was not associated with milk somatic cell count linear score. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for the 9 herds in this study, paratuberculosis significantly decreased milk production and cow longevity.     

Effect of farm characteristics and practices on hygienic quality of ovine raw milk used for artisan cheese production in central Italy

A survey on ovine dairy farms directly transforming own‐produced milk, in the Italian Marche region, was carried out to assess flock and milking practices that may influence milk hygienic‐sanitary conditions. A census survey established that 24 dairy farms were located in this region. Bulk milk samples were collected throughout the milking period in each dairy farm in 2013. Analyzed variables were: (i) chemical parameters such as fat, protein and lactose content, dry matter and pH; and (ii) total bacterial (TBC) and somatic cell counts (SCC). Chemical parameter values were in agreement with published data while, geometric mean (GM) log₁₀ SCC was 5.91 and TBC GM was 57 978 colony forming units/mL, in compliance with Eropean Union criteria. A positive correlation was found between SCC and TBC when GMs of all farm data were considered (Spearman's rho = 0.7925; P = 0.0001). Statistical analysis did not show significant correlation between SCC or TBC GM and dairy farm principal characteristics. Although SCC levels detected in the present study should suggest the need to implement mastitis control programs, Marche's dairy sheep flocks revealed a good hygienic condition level. This is an important aspect in implementing safety for end users of the final product.     

Schmallenberg virus epidemic: Impact on milk production,reproductive performance and mortality in dairy cattle in the Netherlands and Kleve district,Germany

Schmallenberg virus (SBV), a novel orthobunyavirus that rapidly spread throughout north-western Europe in 2011, caused congenital malformations in lambs and goat kids (Van den Brom et al., 2012) and newborn calves (Hoffmann et al., 2012). The impact of the SBV epidemic seemed limited however, in terms of the number of affected herds with malformed offspring (European Food Safety Authority, 2012b). Nevertheless, little is known with regard to the overall within-herd impact of SBV infection. The objective of the current study was to quantify the impact of the 2011 SBV epidemic on the productivity of dairy cattle in the Netherlands and the district of Kleve, Germany.     

The associations between milk production, milk composition and Salmonella in the bulk milk supplies of dairy farms in Ontario.

The purpose of this study was to assess changes in dairy herd milk production and milk composition associated with changes in Salmonella contamination of bulk milk on dairy farms in southwestern Ontario. Twenty-three dairy farms that had submitted milk filters for culture from which Salmonella were isolated (cases) and 23 farms that submitted Salmonella-negative milk filters (controls) were included in the study. The rolling herd averages for milk and fat of case and control farms for the months of December 1985, December 1986 and April 1987 were compared and no significant differences were detected. Case and control farms were divided into three groups (A,B,C) on the basis of Salmonella culture results of milk filters submitted at various time periods throughout the study. Daily and monthly changes in milk production and composition parameters that reflected the time periods of milk filter culture were compared. The following unconditional associations between a changing Salmonella infection status on dairy farms and changes in milk production or composition variables were significant (p less than or equal to 0.05): group A: case farms had higher plate loop counts than control farms; group B: case farms had younger cows than control farms; group C: case farms had cows with longer average days in lactation than control farms. After analytical control of confounding variables, the disappearance of Salmonella from bulk milk supplies of dairy farms was associated with a decrease in percent fat and in somatic cell count.     

Effects of dairy husbandry practices and farm types on raw milk quality collected by different categories of dairy processors in the Peruvian Andes

In developing countries, milk quality is often mismanaged in relation to husbandry practices, collection logistics, and the production of small batches. This paper investigates how the management of milk quality from farm to dairy processor impacts on both chemical and hygienic indicators, in a context characterized by farm scale diversity, the co-existence of formal and informal markets, and high milk demand. It is based on an analysis of the chemical and hygienic quality of milk samples collected over a 12-month period from 20 farms and three dairy processors. Data from the farmers’ husbandry practices and the logistics of milk collection were also collected. A large range of quality profiles and farming practices were observed. This diversity is explained by rainfall and temperature pattern, farm size which affects hygienic quality, and lack of efficient logistics between farms and dairy processors. The findings indicate that in a context of high demand for milk and poor private and public regulations, milk quality is impacted upon by poor stakeholders’ management practices.     

Factors influencing the content of urea in the milk of ewes

In total records of 363 East Friesian breed of sheep and 15 Lacaunes from 15 flocks located in Lower Austria, Upper Austria and Styria were available to investigate the influences on milk urea content. In one flock different groups of ewes were fed with low, medium and high amounts of energy and protein, but constant protein and energy ratio. The milk urea levels exhibited to statistically significant differences but the tendency of the feeding effect could be confirmed. Additional parameters influencing the urea content of milk of ewes are: herd specific factors, stage of lactation, mastitis, preservation and different analytical methods. The content of urea in milk is not suitable for assessment of the energy/protein-ratio of ewes with mastitis problems. Due to the special composition of sheep milk it is important to take account of the analytical method for determination of urea. Thus milk urea of one flock should be evaluated but not of individual sheep. In spite of these influence factors the determination of milk urea is a valuable tool for assessment of the energy and protein intake.     

Feeding of Dairy Cattle in the Forest-Garden Farms of Kandy,Sri Lanka

A survey on feeding practices was conducted with 60 farmers belonging to four categories (15 farmers in each): male farmers without off-farm income (M^–), male farmers with off-farm income (M⁺), female farmers without off-farm income (W^–), and female farmers with off-farm income (W⁺). Data on herd size, feeds offered, milk production, chest girth, reproduction and management were collected monthly over a period of 1 year. In addition, samples of fodder and concentrates were collected monthly and analysed for dry matter (DM), organic matter (OM), crude protein (CP) and in vitro organic matter digestibility (OMD). Of the 550 rations analysed, grass was included in 99.8% of all rations, followed by gliricidia (65%), creepers (50%) and jak leaves (32%). Consequently, the rations were high in OMD (47–59%) and CP (7.8–23.5%). High-protein forage or coconut cake or both were also included as a supplement in 92% of the rations. Both M^– and W^– farmers had larger (p<0.001) herds (mean 1.8 animal units (AU) per household) than their counterparts with off-farm income (mean 1.44 AU/household), but only the male farmers without off-farm income achieved higher feeding levels (84.4 vs 65.6–72.1 g digestible organic matter (DOM)/kg^0.75 per day) and milk production (6.4 vs 5.3–5.7 L/lactating cow). The lower production of animals kept by female and M⁺ farmers was related to lower feeding levels. M^– farmers realized higher feeding levels than their M⁺ counterparts. W^– farmers did not collect extra feed in response to higher levels of production. It was concluded that dairy farming in the mid-country of Sri Lanka is particularly important for poorer households without income from off-farm employment.     

Surveillance of dairy production holdings supplying raw milk to the farmhouse cheese sector for Escherichia coli O157, O26 and O111

Clinically healthy domestic animals can harbour Escherichia coli O157 and other verocytotoxigenic E. coli (VTEC) strains in their faeces. Milk filters can be used to microbiologically monitor direct milk secretion and environmental contamination for these pathogens. The aim of this study was to establish baseline data on the prevalence and characteristics of VTEC organisms in lactating animals (bovine, ovine and caprine) supplying milk to the farmhouse cheese sector, with particular emphasis on serogroups O157, O111 and O26. Fifty-six bovine, 13 caprine and 5 ovine herds/flocks, the majority of which supplying milk for farmhouse cheese production, were surveyed from May 2004 to July 2005. Milk filters were analysed by immunomagnetic separation followed by PCR, on a serogroup-specific basis for E. coli O157, O26 and O111. Positive isolates were examined using a multiplex PCR protocol, for their potential to produce verocytotoxins (vt1/vt2), the haemolysin-encoding gene (hlyA) and the gene encoding attaching and effacement (eae). Five verocytotoxigenic and 22 non-virulent E. coli O157 isolates were detected. Seventeen E. coli O26 isolates were also detected, four of which were verocytotoxigenic, seven isolates contained the eae gene only and six isolates were devoid of any of the virulence factors. The VTEC O157 and O26 isolates contained the hlyA and eae genes along with the verocytotoxin genes. No E. coli O111 isolates were detected. Some of the herds were positive on more than one occasion and multiple E. coli serogroups were isolated from the same milk filter sample. Although all food products tested were VTEC negative, routine surveillance for such pathogens in raw milk/raw milk products is of public health importance. Herd-level surveillance along with subsequent risk management action may be a cost-effective component of risk reduction strategies for food production, drinking water supplies and the protection of public health.     

Effect of brewer's grain on rumen fermentation, milk production and milk composition in lactating dairy cows

Six lactating Holstein cows were divided into two groups (n = 3) and used in a double reversal trial with three periods of 14 days each to evaluate the rumen fermentation, milk production and milk composition of cows fed brewer's grain (BG). The control diets contained 14% chopped Sudangrass hay, 24% corn silage, 18% alfalfa hay cube, 34% concentrate mixture‐1 and 10% concentrate mixture‐2 (wheat bran, soybean meal and cottonseed). In the experimental diet, wet BG replaced the concentrate mixture‐2. The protozoal population, concentration of ammonia‐N and volatile fatty acids in the ruminal fluid did not differ between the control and BG diets. The molar percentage of acetic acid was significantly higher (P < 0.05) with the BG diet at 5 h after feeding. The milk yield, the percentage of protein, lactose, solids not‐fat and somatic cell counts of milk did not differ between the two diets. The percentage of milk fat tended to increase with the BG diet. The BG diet significantly increased the proportions of C18:0 and C18:1 in milk fat (P < 0.01, P < 0.05, respectively) and tended to increase that of conjugated linoleic acid.     

Effects of flaxseed supplementation on milk production, milk fatty acid composition and nutrient utilization by lactating dairy cows.

Twelve multiparous Holstein cows at 72 +/- 20 days in milk were used in a switch-back design with 14-d periods to determine the effect of replacing barley grain into a dairy total mixed ration with micronized or raw flaxseed on nutrient digestibility, milk yield, milk composition. Total mixed diets were (DM basis) 50% barley silage, 50% concentrate mix mainly rolled barley grain and canola meal. Diets were supplemented with 1 kg raw (RF) or micronized (MF) flaxseed to substitute 1 kg of rolled barley grain (C). Neutral detergent fibre, ADF and CP digestibility of the diets were not significantly affected by supplementation; however, calcium digestibility was reduced by 62% and 46% when raw and micronized flax were fed, respectively. Milk yield (38.3, 39.6, and 38.4 kg/d for diets C, RF and MF, respectively) was similar for all diets. Milk fat (3.50, 3.48, and 3.52%) and protein (3.31, 3.34, and 3.31%) for diets C, RF and MF, respectively, were not affected by treatment diets. Concentrations of c9, t11 conjugated linoleic acid (CLA; 0.51, 0.72 and 0.76 g/100 g fatty acids) in milk fat increased (P<0.05) similarly among the two flaxseed supplemented diets. The RF and MF diets significantly increased the C18:1, C18:1 trans-11, C18:2 cis-9, cis-12 and C18:3 in milk fat however, C12:0, C14:0 and C16:0 were significantly reduced compared with control. Replacing barley grain with flaxseed in the diet of lactating cows increased the beneficial fatty acids in milk without depressing nutrient digestibility. Micronization of flaxseed did not reveal any advantage over raw flaxseed.     

在发展乳业时乳肉并举的意见

一个世纪以来 ,国外流行所谓“向奶牛要肉”的提法 ,就是发展、生产“奶肉牛”或“奶牛肉”。这是发展牛肉生产的一个好途径。奶牛是利用植物性饲料来生产动物蛋白质和脂肪 (奶油 )效率最高的家畜 ,因而它在总牛数中占有较大的比例 ,而全球可繁母牛在全世界平均占成年总牛数 70 % (欧洲最高 ,占 90 %以上 ) ,不少国家平均每十人就有一头奶牛。另外 ,在目前世界上畜牧业总产值中 ,牛奶一项占30 % ,牛肉占 2 7% ,两者合计占 57%。说明奶牛是当代畜牧业生产的主力和核心。1　奶用牛产肉的理论依据从生物学观点来看 ,要把肉用牛充作产奶使用是根…     

Effect of pre-partum feed supplementation on post-partum ovarian activity,milk production and calf growth of small holder dairy Cattle in Cameroon

Tropical Animal Health and Production - Seventy-two cows were selected for an on-farm study on the effect of feed supplementation before calving on milk production, ovarian activity and calf growth...