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.     

Bacteriological quality of raw cow's milk from four dairy farms and a milk collection centre in and around Addis Ababa

Bacteriological quality of raw cow's milk taken at different sampling points from four dairy farms and a milk collection centre in and around Addis Ababa was evaluated. Milk samples were aseptically collected from udder, bucket, storage container before and after cooling and upon arrival at the processing plant. A high increase in the mean total aerobic plate count was observed in milk samples taken from the bucket (1.1 x 10(5) cfu/ml), storage container before cooling (4 x 10(6) cfu/ml) and upon arrival at the processing plant (1.9 x 10(8) cfu/ml). The mean coliform counts ranged from 1.3 x 10(4) cfu/ml (storage container before cooling) to 7.1 x 10(4) cfu/ml (upon arrival at the processing plant). The hygienic quality of raw milk from the collection centre was poor with a mean total bacterial count of 1.3 x 10(7) cfu/ml. Milk sampled from the udder contained mainly staphylococci and micrococci as udder-specific bacteria, while samples taken at later stages were additionally contaminated with bacteria of environmental origin (especially Enterobacteriaceae). Lack of knowledge about clean milk production, use of unclean milking equipment and lack of potable water for cleaning purposes were some of the factors which contributed to the poor hygienic quality of raw milk in the study farms.     

Factors influencing production of hygienic raw milk by small scale dairy producers in selected areas of the Jaffna district,Sri Lanka

The objective of the study was to investigate the influence of dairy cow management techniques and milking methods on hygienic quality of raw milk. Total Bacterial Count (TBC) and Total Coliform Colonies (TCC) were studied to determine the effects. Investigations were carried out in fifty dairy farms from August 2007 to December 2007. The mean TBC and TCC for the herds with comparatively good and poor management practices were 0.9 × 10⁵ cfu/ml and 0.2 × 10³/ml and 99 × 10⁵ cfu/ml and >180 × 10³/ml, respectively. The overall mean TBC (22 × 10⁵ cfu/ml) and TCC (47 × 10³/ml) obtained in this study exceeded the internationally recommended levels for TBC (10⁵ cfu/ml) and TCC (<1,000/ml). The overall results obtained suggested that the raw milk tested was of poor hygienic quality with the presence of a great variability among milk samples.     

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.     

Tropical milk production systems and milk quality: a review

We reviewed information on dairy cattle production systems in the tropics, the factors involved, and their influence on milk composition. Genetic factors had greater influence on milk production; specialized breeds produced more milk, and there was an inverse relation between the content of fat, protein, total solids, and the amount of milk produced. Season was related to the availability of forage, and the type of grazing system. Greater pasture area increased individual production, while a greater supply of feed concentrate did not increase milk production. The number of calvings positively affected milk production through the fifth calving, with subsequent declines in production. Milk production increased to a maximum and then declined as lactation progressed. Specialized systems had higher production and better hygienic milk quality; milking and container equipment are critical for maintaining milk sanitary quality. Factor interaction is highly complex, preventing the generation of specific recommendations and general principles applicable to the specific conditions for each system.

     

Effect of cattle management practices on raw milk quality on farms operating in a two-stage dairy chain

In many developing countries, milk production varies greatly according to farm size, cattle breed, and milking practices. However, production systems often are dominated by smallholder farms. Therefore, relatively small volumes of milk are delivered daily from numerous farms to intermediate cooperatives which supply industrial units. This paper argues that in such two-stage dairy chains, milk quality could be improved by focusing on farming practices rather than on the testing of individual deliveries. Indeed, it is difficult to analyze their quality due to technical, economic, and logistic limitations. The objective of this study is to link on-farm practices with milk chemical quality parameters (fat and protein) and hygienic quality criteria (Aerobic Plate Count, APC and Coliforms). Cattle management practices were monitored monthly over one year on 23 farms located on an irrigation scheme in Morocco. 276 milk samples were analyzed. The monthly variability of milk quality parameters was then characterized. Results show that average cow milk chemical parameters vary within a normal range. They remain primarily linked to the genetic type of cows, the lactation stage, and the conversion of feed concentrates’ net energy into milk. Overall milk hygienic quality was poor (APC and Coliforms counts were 100 fold international norms), due essentially to a lack of hygiene and inadequate milking conditions (hands, udder, and teat washing, type of bucket used, dirtiness of cows...). It is suggested that a close monitoring of herd management practices may allow the indirect control of milk quality parameters, thereby avoiding costly analyses of numerous smallholder milk deliveries.     

提高原料奶卫生指标的三种方法

提高原料奶的卫生指标根源在奶牛场,但大多数奶农并没有意识到奶牛场规范挤奶程序,保护牛舍环境舒适、干净,维护和清洁挤奶设备是生产优质原料奶的关键,是奶牛场中提高牛奶卫生质量的重要途径。     

Food safety in raw milk production: risk factors associated to bacterial DNA contamination

While human illness from milkborne pathogens may be linked to contamination of the product after pasteurization or improper pasteurization, such diseases are usually associated with consumption of raw milk or its by-products. Molecular biology tools were applied to investigate contamination by Listeria monocytogenes, Salmonella spp., some pathogenic strains of Escherichia coli, and Campylobacter jejuni in 548 raw milk samples from 125 dairy farms established in two regions from southern Brazil. Moreover, 15 variables were evaluated for their association with raw milk contamination levels, and the risk factors were determined by multiple regression analysis. Salmonella spp. were more frequently detected, followed by pathogenic E. coli. There was difference in contamination index between the regions, in which risk factors such as temporary cattle confinement, low milk production, low milking machine cleaning frequency, and milk storage area without tile walls were identified. The risk factors were specific to each region studied. Nevertheless, the data can be used to improve milk quality of dairy farms/herds with similar management practices.     

Microbiological quality of goat's milk obtained under different production systems

In order to determine the safety of milk produced by smallholder dairy goat farms, a farm-based research study was conducted on commercial dairy goat farms to compare the microbiological quality of milk produced using 3 different types of dairy goat production systems (intensive, semi-intensive and extensive). A survey of dairy goat farms in and around Pretoria carried out by means of a questionnaire revealed that most of the smallholder dairy goat farms surveyed used an extensive type of production system. The method of milking varied with the type of production system, i.e. machine milking; bucket system machine milking and hand-milking, respectively. Udder half milk samples (n=270) were analysed, of which 31.1% were infected with bacteria. The lowest intra-mammary infection was found amongst goats in the herd under the extensive system (13.3%), compared with 43.3% and 36.7% infection rates under the intensive and semi-intensive production systems, respectively. Staphylococcus intermedius (coagulase positive), Staphylococcus epidermidis and Staphylococcus simulans (both coagulase negative), were the most common cause of intramammary infection with a prevalence of 85.7% of the infected udder halves. The remaining 14.3% of the infection was due to Staphylococcus aureus. Bacteriology of bulk milk samples on the other hand, showed that raw milk obtained by the bucket system milking machine had the lowest total bacterial count (16,450 colony forming units (CFU)/ml) compared to that by pipeline milking machine (36,300 CFU/ml) or hand-milking (48,000 CFU/ml). No significant relationship was found between the somatic cell counts (SCC) and presence of bacterial infection in goat milk In comparison with the herds under the other 2 production systems, it was shown that dairy goat farming under the extensive production system, where hand-milking was used, can be adequate for the production of safe raw goat milk.     

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.     

Contamination of raw milk by Listeria monocytogenes on dairy farms

Possible sources of exogenous contamination of raw milk by Listeria monocytogenes were examined on four dairy farms of different size and type of animal housing during morning milking. Feeds, including hay and concentrates, were found to be major sources of both pathogenic and nonpathogenic species of Listeria on the barns. L. innocua was the only species isolated from the grass silage, which was of good quality on all the farms. The numbers of Listeria were below 10(2)/g in all feed samples. Fecal shedding of listeriae was detected in 11.9% of the cows and the prevalences of L. monocytogenes among farms ranged from no detections to 8.7%. The number of Listeria isolations from constructions inside the barns and from the milking environment varied between the farms. Listeriae were detected almost everywhere on one of the farms whereas on another farm the only isolations were from feed passages and floors. 13.6% of the swab samples taken from the teats before washing and drying were Listeria positive, whereas no isolations were made after cleaning the udder. Good milking and barn hygiene is considered important for diminishing the risks of exogenous contamination of raw milk by listeriae.     

Milk producers’ awareness of milk-borne zoonoses in selected smallholder and commercial dairy farms of Zimbabwe

A cross-sectional questionnaire-based study was conducted to assess milk producers’ awareness of milk-borne zoonoses in selected smallholder and commercial dairy farms of Zimbabwe. The questionnaire was designed to obtain information on dairy breeds, milk production, dairy farmers’ knowledge and awareness of zoonoses with particular emphasis on milk-borne zoonoses and farmers’ behavioural practices that may lead to increased risk of milk-borne zoonoses transmission. A total of 119 dairy farmers were interviewed, and 41.5% were aware of milk-borne zoonoses with a significantly (P < 0.01) higher percentage of commercial dairy farmers (65.0%) being aware compared to smallholder dairy farmers (36.7%). The behavioural practices of dairy farmers observed to increase the risk of milk-borne zoonoses transmission were; consumption of raw milk (68.1%), sale of raw milk to the local public (25.2%), lack of cooling facilities by smallholder farmers (98%), and no routine testing (84.9%) and medical check-ups (89.1%) for milk-borne zoonoses. General hygienic and disease control practices need to be integrated in the milk production process particularly at the smallholder level. Awareness, teaching and training programmes for smallholder dairy farmers can improve disease control in animals and reduce the public health risk of milk-borne zoonoses.     

Effects of ear corn silage supplementation on milk production and milk fatty acid profiles in grazing dairy farms

This study investigated the effects of substituting ear corn silage (ECS) for commercial formula feed on milk production and milk fatty acid profiles in grazing dairy farms during the summer season. A field survey was conducted on five grazing dairy farms in every summer month of 2017, 2018, and 2019. Three of the five farms substituted fresh ECS for the commercial formula feed at a ratio of 2:1 from July of each year (ECS farms). Other farms maintained the same feeding management as before (non‐ECS farms). An interview survey was conducted on each farm to calculate feed intake and milk yield per cow. Feed and milk samples were collected in each survey. Milk compositions and milk fatty acid profiles were determined. The substitution of ECS for the commercial formula feed did not affect milk yield or milk composition, but ECS farms maintained low levels of milk urea compared with non‐ECS farms (p < .01). The ECS substitution also influenced some of the milk fatty acid proportions; C16:0 and C16:1 increased, and trans‐11 C18:1, cis‐9,trans‐11 C18:2, and the sum of polyunsaturated fatty acids decreased, while these fatty acid proportions were maintained in non‐ECS farms throughout the summer season (p < .05).     

Evaluation of Tunisian milk quality in dairy herds: Inter‐relationship between chemical,physical and hygienic criteria

The objective of this paper was to evaluate the global milk quality in Tunisian dairy herds. Samples of milk were analyzed for chemical, physical and hygienic parameters. Milk total solids, fat content and density were consistently correlated and one of them can be used as a chemical indicator of milk quality. The somatic cell count value of 689 × 10³/mL was higher than the recommended threshold. All milk samples were positive for the major pathogen Staphylococcus aureus. These hygienic parameters were related more closely with chloride content, minerals and electrical conductivity, which allows them to be used as indicators of mammary gland infection. It was concluded that milk producers have at hand rapid and easy tools for assessing the overall quality of milk.     

Risk factors for persistent presence of salmonella antibodies in bulk tank milk

Given bulk milk serology, salmonellosis is present on a restricted number of Dutch dairy farms. The affected farms are clustered in some regions of the country. This study was designed to find risk factors for having persistent positive bulk milk serology for salmonella within the regions with the highest prevalence. With that knowledge, a reduction of persistent infected farms may be achieved. To this end, we performed a rather small matched case-control study with two groups of 24 farms each. Case herds were characterized by having a positive bulk milk serology for salmonella for all three samplings during one year, whereas control farms were located near the positive farms and were negative in all these three samplings. Several risk factors were found not significant, while the significant risk factors concerned general on farm hygiene practices. Significant risk factors in the multivariate analyses were less hygienic calf facilities (OR = 6.1, p = 0.04), lower cleaning frequency of alleys (OR = 5.7, p = 0.08), and a higher frequency of claw trimmers visiting the farm (OR = 5.9, p = 0.07). We concluded that these risk factors are similar to those found outside the regions with a high number of farms with a positive bulk milk serology for salmonella.     

我国规模牛场奶牛个体生鲜乳乳蛋白水平及影响因素探析

本研究旨在探析我国规模奶牛场奶牛个体乳蛋白的水平、分布和影响因素。利用SAS9．0的GLM过程,统计分析覆盖16省（市、区）,33个规模奶牛场,23351头中国荷斯坦牛,从2007年至2009年连续3年的237430个奶牛个体生鲜乳的乳蛋白率检测记录。分析表明,我国规模奶牛场奶牛个体生鲜乳的乳蛋白率平均3．28±0．22％。其中,乳蛋白率大于等于2．95％的奶牛个体占80．2％,所提供乳蛋白量占群体混合样生鲜乳总蛋白量的79．3％。奶牛的胎次、产奶阶段、产奶量、乳脂率、体细胞数、泌乳季节、泌乳月份都极显著影响奶牛个体生鲜乳的乳蛋白率（P〈0．01）;饲养区域、奶牛场和年度总体显著影响奶牛个体生鲜乳的乳蛋白率（P〈0．05）。我国规模奶牛场奶牛个体生鲜乳的乳蛋白率主要处于2．95％以上（〉80％）,合理调控各种影响因素,可有效提高生鲜乳的乳蛋白率。     

对云南省不同来源生鲜乳品质的比较分析

本试验旨在通过对不同来源生鲜乳的相关指标进行测定和比较分析,评价其品质,为地方奶牛养殖业的发展提供参考依据.采集2017-2020年云南省养殖专业合作社、乳品公司养殖场、收购站和机械化挤奶站4种来源的生鲜乳共661个样品,采用国家标准方法测定其相关指标,用SPSS 22.0统计软件做单因素方差分析.结果显示,2017-...     

A bulk tank milk survey of Ostertagia ostertagi antibodies in dairy herds in Prince Edward Island and their relationship with herd management factors and milk yield

The objective of this study was to quantify the relationship of the levels of antibodies to Ostertagia ostertagi in bulk-tank milk samples from Prince Edward Island (PEI) dairy farms to milk production and to herd-management practices potentially related to gastrointestinal nematode infections. The milk samples were obtained from 289 to 322 dairy farms during 2000; production and management data were available from 197 and 200 farms, respectively. Cow exposure to pasture and whole-herd anthelmintic treatment were the only herd management variables significantly associated with antibody levels in the fall of 2000. An increase in antibody levels from the observed 25th percentile to the 75th percentile (interquartile range) was associated with a drop in milk production of 1.2 kg/cow/day. The results of this study indicate that the enzyme-linked immunosorbent assay for O. ostertagi antibody is a potentially useful technique to measure parasite exposure in adult dairy cows and that parasite burdens in lactating cattle in PEI have an important impact on milk production.     

Ensiling characteristics of total mixed ration prepared with local feed resources in Mozambique and their effects on nutrition value and milk production in Jersey dairy cattle

To effectively utilize total mixed ration (TMR) prepared with locally available feed resources, we studied the nutritional value and milk production in Jersey dairy cattle fed a local general diet (LGD) and fermented TMR in Mozambique. Ten head of Jersey dairy cattle with 337 ± 19.8 kg body weight, aged 3–4 years in mid location were used in this study. The LGD diet was designed following the general feeding method of local smallholding farms; it contained native grass, Napier grass, wheat bran, and mineral–vitamin mix. Fermented TMR was prepared using Napier grass, corn bran, wheat bran, formula feed, and mineral–vitamin mix. Fermented TMR was preserved as good quality, with a relatively low pH and high lactic acid content. Compared to LGD, fermented TMR significantly improved the dry matter intake and digestibility in dairy cattle. Milk yield was significantly higher in dairy cattle fed with TMR than in those fed with LGD, by 3.75 L/d; milk quality was not significantly different between treatments. The results confirmed that LGD had a low dry matter intake and milk yield, and fermented TMR prepared with local feed resources can attain good quality and improve milk yield in dairy cattle in Mozambique.     

我国规模牛场奶牛个体生鲜乳体细胞数水平及影响因素探析

本研究旨在探析我国规模奶牛场奶牛个体生鲜乳体细胞数（SCC）的水平、分布和影响因素。利用SAS9.0的GLM模型,统计分析覆盖16个省（市、区）,33个规模奶牛场,23 351头中国荷斯坦牛,从2007年至2009年连续3年的225 775条奶牛个体生鲜乳SCC检测记录。结果表明：奶牛个体生鲜乳SCC的总体均值为48×104cell/mL,标准差为117×104cell/mL,个体生鲜乳SCC波动范围较大;其中,77.9%的奶牛个体,其生鲜乳SCC小于50×104cell/mL,对群体混合样生鲜乳SCC的影响系数为0.26;11.3%的奶牛个体,其生鲜乳SCC介于50×104～100×104cell/mL之间,乳房处于隐性感染状态,对群体混合样生鲜乳SCC的影响系数为0.16;10.8%的奶牛个体,生鲜乳SCC大于100×104cell/mL,理论上乳房处于临床感染状态,对群体混合样生鲜乳SCC的影响系数为0.58。奶牛个体生鲜乳体细胞数评分（SCS）呈正态分布,与奶牛个体因素（产奶量、乳脂率、乳蛋白含量、胎次和泌乳阶段）和环境因素（泌乳月份、泌乳季节）差异极显著（P〈0.01）,与奶牛养殖区域、奶牛场差异不显著（P〉0.05）。我国规模奶牛场奶牛个体生鲜乳SCC主要在50×104cell/mL以下,依据影响参数能实现对生鲜乳SCC水平的调控。