Luciana Bava

Effect of cleaning procedure and hygienic condition of milking equipment on bacterial count of bulk tank milk.

The aim of the study was to describe the characteristics of cleaning procedures for milking equipment applied in intensive dairy farms in Lombardy (Italy) and to study their relationships with bacterial count of bulk milk and hygienic condition of milking machine components. A group of 22 dairy farms was visited twice (winter and summer) in order to collect bulk tank milk and post-rinse water samples and swabs from liners and milk receiver. Samples were analysed to determine: standard plate count (SPC), laboratory pasteurization count (LPC), psychrotrophic bacteria count (PBC), coliform count (CC) and Escherichia coli. Cleaning procedures were monitored using electronic milk flow meters with specific software for the measurement of the duration of each cleaning phase, circulating solution temperature and electrical conductivity, turbulence and water filling percentage of pipelines. The results showed that farms classified as high and low milk total bacteria count significantly differed both in terms of liners and receiver bacterial contamination and in terms of water temperature reached during the detergent phase of cleaning milking equipment. Significant positive correlations were found among total bacteria count in milk and bacterial contamination of the liners. Maximum water temperature reached during the cleaning cycle of milking equipment was very low (34.4±8.9°C on average); most of the observations (88.6%) corresponded to water temperatures <45°C. Cleaning temperature was related to psychrotrophic bacteria count of milk and post-rinse water and coliform count in liners. Routine check and regulation of water temperature during the washing phase of the milking machine can be a simple and effective way to control one of the main risk factors for bacteriological quality of bulk tank milk.

How can farming intensification affect the environmental impact of milk production

The intensification process of the livestock sector has been characterized in recent decades by increasing output of product per hectare, increasing stocking rate, including more concentrated feed in the diet, and improving the genetic merit of the breeds. In dairy farming, the effects of intensification on the environmental impact of milk production are not completely clarified. The aim of the current study was to assess the environmental impacts of dairy production by a life cycle approach and to identify relations between farming intensity and environmental performances expressed on milk and land units. A group of 28 dairy farms located in northern Italy was involved in the study; data collected during personal interviews of farmers were analyzed to estimate emissions (global warming potential, acidification, and eutrophication potentials) and nonrenewable source consumption (energy and land use). The environmental impacts of milk production obtained from the life cycle assessment were similar to those of other recent studies and showed high variability among the farms. From a cluster analysis, 3 groups of farms were identified, characterized by different levels of production intensity. Clusters of farms showed similar environmental performances on product basis, despite important differences in terms of intensification level, management, and structural characteristics. Our study pointed out that, from a product perspective, the most environmentally friendly way to produce milk is not clearly identifiable. However, the principal component analysis showed that some characteristics related to farming intensification, such as milk production per cow, dairy efficiency, and stocking density, were negatively related to the impacts per kilogram of product, suggesting a role of these factors in the mitigation strategy of environmental burden of milk production on a global scale. Considering the environmental burden on a local perspective, the impacts per hectare were positively associated with the intensification level.

Effects of season, milking routine and cow cleanliness on bacterial and somatic cell counts of bulk tank milk

The aim of the study was to investigate the effects of season, cow cleanliness and milking routine on bacterial and somatic cell counts of bulk tank milk. A total of 22 dairy farms in Lombardy (Italy) were visited three times in a year in different seasons. During each visit, samples of bulk tank milk were taken for bacterial and somatic cell counts; swabs from the teat surface of a group of cows were collected after teat cleaning and before milking. Cow cleanliness was assessed by scoring udder, flanks and legs of all milking cows using a 4-point scale system. Season affected cow cleanliness with a significantly higher percentage of non-clean (NC) cows during Cold compared with Mild season. Standard plate count (SPC), laboratory pasteurization count (LPC), coliform count (CC) and somatic cell count, expressed as linear score (LS), in milk significantly increased in Hot compared with Cold season. Coagulase-positive staphylococci on teat swabs showed higher counts in Cold season in comparison with the other ones. The effect of cow cleanliness was significant for SPC, psychrotrophic bacterial count (PBC), CC and Escherichia coli in bulk tank milk. Somatic cell count showed a relationship with udder hygiene score. Milking operation routine strongly affected bacterial counts and LS of bulk tank milk: farms that accomplished a comprehensive milking scheme including two or more operations among forestripping, pre-dipping and post-dipping had lower teat contamination and lower milk SPC, PBC, LPC, CC and LS than farms that did not carry out any operation.

Anaerobic digestion and milking frequency as mitigation strategies of the environmental burden in the milk production system.

The aim of the study was to assess, through a cradle to farm gate Life Cycle Assessment, different mitigation strategies of the potential environmental impacts of milk production at farm level. The environmental performances of a conventional intensive dairy farm in Northern Italy (baseline scenario) were compared with the results obtained: from the introduction of the third daily milking and from the adoption of anaerobic digestion (AD) of animal slurry in a consortium AD plant. The AD plant, fed only with animal slurries coming also from nearby farms. Key parameters concerning on-farm activities (forage production, energy consumptions, agricultural machines maintenance, manure and livestock management), off-farm activities (production of fertilizers, pesticides, bedding materials, purchased forages, purchased concentrate feed, replacement animals, agricultural machines manufacturing, electricity, fuel) and transportation were considered. The functional unit was 1kg fat and protein corrected milk (FPCM) leaving the farm gate. The selected environmental impact categories were: global warming potential, acidification, eutrophication, photochemical oxidation and non-renewable energy use. The production of 1kg of FPCM caused, in the baseline scenario, the following environmental impact potentials: global warming potential 1.12kg CO2 eq; acidification 15.5g SO2 eq; eutrophication 5.62g PO4(3-) eq; photochemical oxidation 0.87g C2H4 eq/kg FPCM; energy use 4.66MJeq. The increase of milking frequency improved environmental performances for all impact categories in comparison with the baseline scenario; in particular acidification and eutrophication potentials showed the largest reductions (-11 and -12%, respectively). In anaerobic digestion scenario, compared to the baseline one, most of the impact potentials were strongly reduced. In particular the most important advantages were in terms of acidification (-29%), global warming (-22%) and eutrophication potential (-18%). The AD of cow slurry is confirmed as an effective strategy to mitigate the environmental impact of milk production at farm level.

Management practices and forage quality affecting the contamination of milk with anaerobic spore-forming bacteria

BACKGROUND Anaerobic spore-forming bacteria (ASFB) in milk derive from the farm environment, and the use of silages and management practices are the main responsible of milk ASFB contamination. The aim of this study was to evaluate the relationships between feeding, milking routine and cow hygiene and milk and Grana Padano cheese (produced with and without lysozyme) ASFB contamination. RESULTS The study involved 23 dairy farms. ASFB in corn silage were on average 2.34 ± 0.87 log10 MPN g(-1). For grass, Italian ryegrass and alfalfa, ASFB (log10 MPN g(-1)) were numerically higher for silages (3.22) than hays (2.85). The use of corn silages of high quality (high lactic and acetic acids concentrations) decreased the milk ASFB contamination, whilst the use of herbage silages did not affect it. The presence (>40%) of cows with dirty udders increased the ASFB contamination of milk, while forestripping had a positive effect (-9% ASFB). Ripened Grana Padano had an ASFB count below the analytical limit; Clostridium tyrobutyricum DNA was found only in wheels produced without lysozyme, which also showed late blowing. CONCLUSION The factors increasing milk spore contamination were corn silage quality, cow udder hygiene and inadequate milking routine. Late blowing was present only in cheeses without lysozyme.

Milk flow traits of buffalo cows in intensive farming system

Abstract The particular morphology of buffalo udder is associated to milking difficulties. To better understand the characteristics of milk ejection in buffaloes, a study was conducted in an intensive farm in Lombardy, Italy. A total of 184 milk flow profiles were measured with an electronic flow meter. The results showed that during the first 3 minutes of milking 73% of total milk yield was milked; lag time of milk ejection (1.94 min ± 1.57) was very long and increased significantly with the increasing of lactation stage. The overmilking phase has also a long duration (33% of total milking time, on average). Administration of oxytocin before milking did not significantly affect milk flow parameters and machine on-time. The results suggested that proper pre-milking stimulation and prompt cluster takeoff could improve milking efficiency, ensuring good milk letdown and protecting teat conditions.

Feeding behaviour, digestibility, energy balance and productive performance of lactating goats fed forage-based and forage-free diets

Abstract Six lactating Saanen goats have been used in a Latin Square design to evaluate a grass-based diet (G), a hay-based diet (H) and a nonforage diet (NF). On dry matter, grass and hay contributed for 55% of the diets and had 13.7 and 16.1% CP, 55.4 and 49.4% NDF, 38.0 and 31.6% ADF, respectively. Diet NF had beet pulp, cracked carob beans and whole cottonseed as main ingredients, with more than 75% of the particles greater than 2 mm. Independently of the dietary treatment, the goats spent more time eating than ruminating. Diet NF proved to be effective in stimulating chewing activity, despite a trend for a lower chewing activity for eating (178, 185, 125 min/kg DMI for diets G, H and NF, respectively), but not for ruminating (84, 80, 80 min/kg DMI for diets G, H and NF, respectively). Feed intake did not differ among diets, while regarding digestibility diet NF had the highest values for DM (74.1%), OM (75.7%) and non-fibrous carbohydrates (92.0%), but the lowest for ADF (44.5%). For treatments G, H and NF milk yields were 3011, 3688 and 3212 g/d (P<0.05 between H and G), while milk fat and protein were respectively 3.37, 3.24, 2.96% (P<0.05 between G and NF) and 3.11, 3.32, 3.29%. Milk urea N was lower for diet NF (18.8, 18.6, 12.7 mg/100 ml, P<0.001). Diet NF increased the concentration of the short chain fatty acids of milk fat and decreased the content of C18:0, C18:1 and C18:3 in comparison to the other two diets. No difference among treatments was recorded for CLA. Intake energy was digested to a lesser extent for diet G (68.9, 70.0, 72.7%, P<0.05 between G and NF) due to its poor quality forage. Urinary energy losses reflected the corresponding protein contents of the diets, while no difference was recorded for methane production. ME resulted higher for diet NF (60.0, 60.7, 65.1% of the intake energy, P<0.01), while heat production and milk energy yield were similar in the three treatments. Diet NF had a higher ME content (11.13, 11.26, 11.93 MJ/kg DM, P<0.05), while no significant difference among the diets was recorded in terms of kl (0.64, 0.70, 0.69) and NEl (7.20, 7.93, 8.30 MJ/kg DM). It is concluded from the study that a nonforage diet with an adequate amount of structured fibre could substitute a ration based on poor quality forage in lactating goats; however, good forage seems to enhance milk performance to a greater extent.

Management Risk Factors for Calf Mortality in Intensive Italian Dairy Farms

High calf mortality is an important factor of economic loss in dairy production. At present, limited data are available on calf rearing practices and calf mortality in Italian dairy farming. The aim of the study was to identify the most important management risk factors for preweaning calf mortality in Italian dairy farms. A group of 28 intensive dairy farms from Lombardy (Italy) were visited to collect information about calf management and calf mortality. Female calf mortality showed high variability among herds and in many cases the percentage of calves dead within the preweaning period was very high. The average perinatal mortality (during calving and within 24 h after birth) was 8.82% of total females born with a maximum value of 30.8%, whereas average early mortality (from 24 h to weaning) was 8.9±7.9%, with a maximum value of 28%. The herd size did not significantly affect calf mortality although the number of calves cared per operator in the big farms was higher than in the small ones. Multivariate logistic analysis showed that feeding first colostrum meal beyond three hours after birth, group housing before 30 d of age and feeding daily less than 5 L of milk or milk replacer per calf multiply the risk to have early mortality higher than 10%. The study showed that early calf mortality could be strongly reduced by paying more attention to a very limited number of operations.

Milk emission and udder health status in primiparous dairy cows during lactation

To investigate the relationships between milk flow traits and udder health status in primiparous cows, 74 primiparous Holstein cows were randomly selected in 5 herds and monitored monthly throughout the whole lactation. A total of 2902 quarter milk samples were collected for bacteriological analyses and the determination of lysozyme, N-acetyl-beta-glucosaminidase (NAGase) and somatic cell count (SCC). Milk flow curves of the whole udder of each cow were registered with continuous electronic milk flow meters. Teat conditions and teat thickness changes during milking were assessed monthly. Quarters, udders and cows were classified as healthy, latent, inflamed and subclinical depending on SCC and the results of bacteriological analyses. Lysozyme in milk, teat apex score and teat thickness change did not vary with udder health status while NAGase in milk significantly increased as udder health status worsened (P<0.001). Milk production (P<0.001) and time of plateau phase (P<0.05) were significantly lower in subclinical cows in comparison with the others. Animals with a high frequency of bimodal curves in the first 100 days in milk showed the worst udder health status during the whole lactation (P<0.01). Moreover, cows classified as subclinical in the first 3 months of lactation had higher peak milk flow than healthy cows (3.81 v. 3.48 kg/min; P<0.05) and shorter duration of plateau phase, expressed both as minutes and as percentage of time of milk flow (pTPL; P<0.001). Multivariate logistic analysis showed udder health status to be associated with duration of plateau phase, time of milk flow, bimodality and duration of overmilking phase. With short time of plateau phase (pTPL <25%), short time of milk flow (<5 min), presence of bimodality and long overmilking phase (>0.8 min) there was an increased risk of poor udder health status. These milk flow traits can be predictive indicators of udder health status; time of plateau phase, expressed as percentage of time of milk flow, can also be a useful parameter for animal selection.

Efficiency of cleaning procedure of milking equipment and bacterial quality of milk

Abstract The cleaning and sanitation of milking equipment could be consider a critical point in the milking procedure because a cleaning failure could influence the level of bacteria contamination of bulk tank milk. Aim of the study is to monitor the cleaning procedures of milking systems in 7 dairy cows farms in Lombardy and to find a relation between efficacy of cleaning system and the bacterial quality of bulk tank milk, remaining washing water through milking equipment and teat cup surface. Cleaning procedures were monitored with Lactocorder, that measured: duration, water temperature, turbulence, percentage of water in pipes, water conductivity of pre- and post-rinse and detergent phases. Results showed that the monitored farms the most of the cleaning parameters were lower than recommendations, in particular maximum water temperature (42.1±9.9°C) and percentage of water during detergent phase (76.1±13.9 %). A maximum temperature of detergent phase <40°C determined a high Standard Plate Count (SPC), thermoduric bacteria and Coliform Count (CC) of bulk tank milk, SPC and CC of teat cup surface. The research indicated that monitoring the efficiency of cleaning milking equipment with proper tools provide useful information about possible sources of contamination of bulk tank milk. Improving cleaning milking efficiency allow to improve milk quality.