Bulk tank milk quality data is unlikely to give useful information about dairy cow welfare at herd level.

This research communication explores the value of routinely collected bulk tank milk quality data for estimating dairy cattle welfare at herd level. Selected bulk tank milk quality parameters (somatic cell count, total bacterial count, urea, protein and fat contents) recorded during the years 2014-2016 in 287 Italian dairy farms were compared with the animal welfare data of each farm. The welfare assessment data were extracted from the database of the Italian Reference Centre for Animal Welfare (CReNBA), which includes the outputs of the application of the CReNBA welfare assessment protocol for dairy cows, used at national level for on-farm controls. The statistical analysis was carried out using the correlation coefficient for Kendall's Tau ranks, in order to investigate the presence of a categoric relationship between the selected bulk tank milk quality parameters and the overall animal welfare score or the scores of the single areas A (farm management and staff training), B (housing) and C (animal-based measures). Somatic cell count, total bacterial count, urea and proteins demonstrated only a few statistically significant and very weak correlations with farm animal welfare data, while no significant correlations were obtained for milk fat content. Given the weak correlations found, the selected bulk tank milk parameters seems to be able to provide only limited information about the welfare level of the herd, thus it could be difficult to use them for drawing up a pre-screening model for identifying herds at risk of poor welfare.

Raw donkey milk versus raw cow's milk. A preliminary study to compare the growth of Listeria monocytogenes and Staphylococcus aureus.

Gram-positive foodborne pathogens such as Listeria monocytogenes and Staphylococcus aureus can grow in a wide variety of foods, including raw milk. The aim of the study was to compare the growth of L. monocytogenes and S. aureus inoculated in donkey and cow samples of raw milk during a storage time of 11 days at 8 °C. Moreover, the study aimed to evaluate the influence of lactic acid bacteria (LAB) content on the growth of the two microbiological populations considered. LAB content was lower in raw donkey milk than in raw cow's milk during the entire analyses; on the other hand, pH levels were higher in the donkey milk rather than in the cow's milk, although both values showed a decrease at the day 11. S. aureus showed no significant differences in the two types of milk. From day 0 to 11, L. monocytogenes increased from 3.68 ± 0.02 log CFU/mL to 6.31 ± 0.07 log CFU/mL and from 3.64 ± 0.04 log CFU/mL to 4.59 ± 1.04 log CFU/mL, in donkey milk and in cow's milk, respectively. Our results showed that donkey milk is a more favourable matrix to support the growth of L. monocytogenes than cow's milk.

PCDD/Fs, DL-PCBs, and NDL-PCBs in Dairy Cows: Carryover in Milk from a Controlled Feeding Study.

A feeding study was carried out to investigate the kinetics in cow milk of the 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), the 12 dioxin-like polychlorinated biphenyls (DL-PCBs), and the 6 non-dioxin-like PCBs (NDL-PCBs) regulated by the European (EU) legislation. A fortified ration (ΣPCDD/Fs and DL-PCBs: 24.68 ng TEQ/day/cow; ΣNDL-PCBs: 163.99 µg/day/cow) was given to the animals for 49 days, followed by 42 days on clean feed. EU maximum limit for TEQPCDD/F+DL-PCB was exceeded in milk after 1 week of exposure, while for ΣNDL-PCBs, after 5 weeks. Milk compliance was restored after 1 week on clean feed, but to return to the basal TEQPCDD/F+DL-PCB it took 42 days. At the end of the study, ΣNDL-PCBs had not yet reached the basal level. The carryover rate of ΣNDL-PCBs was 25.4%, while the carryover rate of TEQPCDD/F+DL-PCB was 36.9%. The latter was mainly affected by the 12 congeners contributing most to the toxic equivalent (TEQ) level, explaining the fast overcome of the maximum limit in milk.

Molecular typing of Mycobacterium bovis strains isolated in Italy from 2000 to 2006 and evaluation of variable-number tandem repeats for geographically optimized genotyping.

Spoligotyping and exact tandem repeat (ETR) analysis of Mycobacterium bovis and M. caprae isolated strains has been routinely carried out in Italy since 2000 to obtain a database of genetic profiles and support traditional epidemiological investigations. In this study, we characterized 1,503 M. bovis and 57 M. caprae isolates obtained from 2000 to 2006 in 747 cattle herds mainly located in northern Italy. We identified 81 spoligotypes and 113 ETR profiles, while the combination of spoligotyping/ETR analysis differentiated 228 genotypes, with genotypic diversity indices of 0.70 (spoligotyping), 0.94 (ETR-A to -E typing), and 0.97 (spoligotyping/ETR-A to -E typing), respectively. Despite the high degree of resolution obtained, the spoligotyping/ETR methods were not discriminative enough in the case of genotypes characterized by the combination of SB0120, the predominant spoligotype in Italy, with the most common ETR profiles. To obtain a more informative subset of typing loci, 24 mycobacterial interspersed repetitive unit-variable-number tandem repeat (MIRU-VNTR) markers were evaluated by analyzing a panel of 100 epidemiologically unrelated SB0120 isolates. The panel was differentiated into 89 profiles with an overall genotypic diversity of 0.987 that could be also achieved by using a minimal group of 13 loci: ETR-A, -B, and -E; MIRU 26 and 40; and VNTR 2163a, 2163b, 3155, 1612, 4052, 1895, 3232, and 3336. The allelic diversity index and the stability of single loci was evaluated to provide the most discriminative genotyping method for locally prevalent strains.

Tuberculosis transmission by Mycobacterium bovis in a mixed cattle and goat herd.

A tuberculosis (TB) outbreak caused by Mycobacterium bovis occurred in a mixed herd of three cattle and eighteen goats in Northern Italy in 2005. All the cattle were removed, as opposed to the co-existing goats, who remained in the farm and were not subsequently tested by the official intradermal tuberculin test. At the beginning of May 2006, a 7-day old calf was introduced into the herd from an officially TB-free (OTF) farm. On October 2006, tuberculous lesions were detected at the slaughterhouse in the same animal. The following epidemiological investigation on the herd highlighted a clinical suspicion of TB in one goat out of 35, and visible lesions were found at necropsy in the respiratory and intestinal tracts. Bacteriological culture and molecular tests confirmed the presence of M. bovis in both animals. Spoligotyping and Mycobacterial Interspersed Repetitive Units - Variable Number of Tandem Repeats (MIRU-VNTR) showed the same genomic profile of the previous breakdown occurred in 2005. Since this profile has never been described in Italy, these findings suggest the probable transmission of TB within the farm among cattle and goats. The remaining 34 goats were also tested by single intradermal cervical comparative tuberculin (SICCT) test, Interferon (IFN)-γ assay and ELISA for antibody to M. bovis. The SICCT test and the IFN-γ showed a good concordance with 20 and 19 positive reactors, respectively. By ELISA we found 12Ab-positive animals, seven of which had not been detected by the tests for cell-mediated immunity. Finally, 15 goats were found positive for gross lesions at necropsy. The in vivo tests revealed a total of 27 positive animals out of 35, which highlights the usefulness of the serology in parallel with SICCT and IFN-γ when an advanced stage of infection is suspected. Moreover, our results confirm the necessity for adopting the official tuberculin test on goats co-existing with cattle.