Bacteria in the milk of sheep with or without mastitis- mini Review

From a nutritional point of view, sheep milk is more valuable than cow and goat milk and the interest for sheep milk is increasing in many countries. However, sheep milk is easily contaminated during milking, handling, and transport and it is an ideal medium for bacterial propagation. Consequently, sheep milk spoils quite quickly. The proper, clean handling of milk is not only of sanitarian interest, but it also serves the farmers’ interests, because contaminated milk may not be distributed, and is unsuitable for producing good quality products. Following this technological trend, this review addresses the bacterial composition of sheep milk with and without mastitis. Even though sheep milk contains a lot of bacteria, this review article highlighted total plate count, Enterobacteriaceae, coliform, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Campylobacter, Salmonella spp. and Streptococcus spp. Mastitis in sheep is a vital cause of mortality, reduction in milk production and early culling. The reported risk factors for mastitis in sheep were age, a case of mastitis, breed, husbandry systems, and location. The main priority should be implementation of programs to minimize human pathogenic bacteria and mastitis in raw ewe milk.

Data supporting the quality of sheep milk for processing

Although the volume of ingredients in ewe’s milk is substantially higher than in cow’s milk, its hygienic quality is lower. The weak quality of raw ewe’s milk limits the possibilities of processing and results in bad quality products. In our investigation we analysed the state of ewe’s milk processing at a typical medium size dairy firm. We investigated the collection, the amount and the quality of milk and the level of ingredients in milk throughout the purchasing period (lactation period).
The purchasing of ewe’s milk was limited to 5 months (from April to September). Although meat (lamb) provides the major source of income to sheep breeders the extension of the period of ewe’s milk production can be beneficial to shepherds and dairy firms. The amount of ewe’s milk ingredients found corresponded to published findings. However, the hygienic quality of ewe’s milk was varied greatly in the different milk samples and these deviations meant bad quality on average. Physiological factors, the circumstances of sheep breeding and milking, the slow cooling of the milk, the little amount of daily milk and the long storage before transportation to the dairy firm together cause poor hygienic quality. The main problem is the long storage time of milk, but our results raise the question of reconsidering the quality classes. Investigating the effect of the hygienic quality of raw milk on product quality, we can get correct data that can be really authoritative.

Investigation of the milk composition of three Tsigai sheep varieties, and the detection of cazein fractions of sheep milk by Reversed-Phase HPLC

The measurements started in 2005, the author used the milk of 3 types of Tsigai Sheep that are suitable for milking, they examined the milk composition, the possible differences between the milk types, the coagulation characteristics, cheese processing, yielding characteristics and the transfer of solid content into cheese. From the large number of measurements, the results of milk composition examinations are described.
During the research the author examined the milk coagulation property of three types of Tsigai Sheep QTS 25 is a substance investigating instrument, and its primary mission is the analysis of the substance profile. The advantage of this instrument is the representation of the survey graphs from which the part of the substance characteristics could be directly read off. By the help of the applied mathematical and statistical operations we tried to establish connection between the congealment-hardness and the specialty of the different types of Tsigai Sheep.
In 2006 the author began the identification and qualification of the major sheep milk proteins by RP- HPLC method. She used a scientific article written by Bordin et al. The method is able to separate and quantify the seven major proteins. However Bordin’s procedure was developed using bovine milk, the author adapted it to sheep milk.

Upgrading breeding value estimation in beef cattle

This paper gives a summary of the possibility for applying genomic information for breeding value estimation in beef cattle breeding. This process is called genomic prediction and is now widely used in dairy cattle globally as well as in some beef and sheep populations. The advantage of genomic prediction is a more accurate estimate of the genetic merit of an individual at a young age thereby facilitating greater annual genetic gain, predominantly through shorter generation intervals. Genomic predictions are more advantageous for sex-linked (e.g., milk yield), low heritability (e.g., fertility) and difficult-to-measure (e.g., feed intake) traits. The larger the reference population, on average, the more accurate the genomic predictions; additionally, the closer genetically the reference population is to the candidate population, the greater the accuracy of genomic predictions. Research is continuing on strategies to generate accurate genomic predictions using a reference population consisting of multiple breeds (and crossbred). Retrospective analysis of real-life data where genomic predictions have been operation for several years clearly shows a benefit of this technology.

Coagulase-negative staphylococci in ewe udder surface and raw milk samples

Coagulase-negative staphylococci (CNS) are among the major causes of subclinical mastitis in dairy ewe flocks. This has a financially significant impact on the ewe dairy sector and consumer health. The determination of the bacterial count, particularly CNS, is critical in terms of the quantity and quality of ovine milk. Thus, the purpose of this study was to quantify the CNS count in the udder surface and raw milk samples of the ewe, in addition to identifying CNS strains (n=8) collected from udder surface and individual raw milk samples by 16S rRNA gene sequencing. A total of 164 samples of udder surface and raw milk originated from four sheep farms were tested. The obtained values were compared between the different farms. Furthermore, values during 2018 and 2019 in the case of Farm I were compared. Significantly higher (p<0.05) average count was observed in udder surface samples taken from Farm I (2.8±1.0 lg CFU/cm2) than that of Farm III samples (2.3±0.6 lg CFU/cm2). In the case of individual raw milk, the higher value was observed in samples derived from Farm III (3.5±0.9 lg CFU/mL), while the obtained value was significantly lower (p<0.05) in samples originated from Farm IV (1.8±0.4 lg CFU/mL). In the bulk tank milk samples, the highest mean value was 5.3±0.4 CFU/mL, and there was no significant (p>0.05) variation between farms. Coagulase-negative staphylococci counts were decreased to a certain extent in both sample types tested during 2019 except for individual raw milk derived from the Tsigai breed. The correlation between the mean CNS counts of udder surface and individual raw milk was very weak (r=0.048). Staphylococcus simulans, Staphylococcus auricularis, and Staphylococcus equorum were identified by molecular sequencing and Staphylococcus simulans were the most frequently identified CNS species. A higher CNS count of bulk tank milk than individual raw milk indicates possible contamination during milking and storage. Therefore, further studies are required to investigate the other sources of bulk tank milk contamination to improve the hygienic quality of milk.

Some Aspects of the Relationship Between the Quality of Sheep Milk and Dairy Products

The correlation between the quality of raw milk and the quality of milk products is evident. In spite of this fact we can find only a few references contained exact data related sheep milk. In recent paper we investigated the effect of SCC of sheep milk on the cheese yield (semi hard traditional cheese) and certain texture parameters of yoghurt from sheep milk. We wanted to know the relevant limit values of these properties for dairy applications.
In our opinion – in the case of the cheese yield – that the strong negative effect can be experienced when SCC is above 700.000-1 million/cm3.
In the case of yoghurt from sheep milk the limit values of SCC can be 1 million/cm3 for Adhesivity and Whey draining and 500.000/cm3 for Hardness. Considering these limit values in the selection of milk become materialise the highest quality of products and the economical production.

Changes in the Composition of the Milk of Racka Sheep During Lactation

We examined the changes in the composition of the milk of 36 Racka sheep during lactation. As milking of Racka sheep is not performed anywhere in the country, the test was restricted to the examination of milk components. However, quantity could not be measured. We analysed the fat, protein, lactose, carbamide and somatic cell count content of the milk from sampling. By means of correlation analysis, milk components were compared to the age of ewes, then the number of lactation days. With the advancing of the lactation and by analysing the milk components, we found differences between the two colour-variants of Racka sheep. Additional trials are required to decide whether the differences between the two colour-variants may be considered as constants, or can be attributable to the relatively small number of samples.

Impact of lameness on the milk production of ewes

The aim of this study was assessing the impact of lameness on the milk production, somatic cells count and component of milk. We assess also impact of lameness on the order of entry into the milking parlour.

The experiment was carried at the farm, located in northern Slovakia. The farm keeps sheep Improved Valachian. Samples of milk were taken during two periods: May, July. It was taken 428 samples together. We recorded three groups by lameness- strong lame, slightly lame, non-lame ewes. We recorded also the order of entry of ewes into the milking parlour in milking row. The results were mathematically processed using the Microsoft Excel program and statistically evaluated by SAS.

We found significant statistical differences between months (P<0.0001) in all the above mentioned indicators. In July we recorded 26 ewes with slightly lameness and 18 ewes with strong lameness. Other ewes were non-lame. Non-lame sheep had in July the highest milk yield (356±148 ml) and the lowest decrease in milk yield from May to July (-206±131 ml) compared with slightly (317±116 ml, -223±163) and strong (319±122 ml, -219±151 ml) lame ewes. However, these differences were not statistically significant. We have not identified statistically significant differences between groups in somatic cells count (logxSCC for non-lame: 4.83±0.608 in ml, slightly lame: 4.76±0.653 in ml, strong lame 4.71±0.787 in ml). Milk composition (fat, proteins, lactose) nor changes in the composition of milk that occurred between May and July were not affected by lameness of ewes. But lameness in July affected the change the order of entry of ewes in the milking parlour in July compared with the order of entry recorded in May.

The Fattening and Slaughtering Examination at the Hungarian Racka Sheep

Fattening and slaughtering characteristics of both types (black and white) of the Hungarian racka sheep were investigated at the site of the National Institute for Agricultural Quality Control in Atkár. The Hungarian merino, the dairy cigaja and the British milksheep were applied as control groups. 10 animals were examined from both sexes in each genotype. The examination was carried out according to the principles set in the Codex for sheep breeding. During the test acute diarrhoea occurred in each control group. However, only few lambs were excluded from the test from the British milksheep and the Hungarian merino groups because of significant changes in their condition. Consequently, the results obtained were not significantly influenced. No symptoms of any illness could be recognised in the Hungarian racka sheep, though. The significance of the difference between the average of the examined groups were checked by T-tests.
Daily gain was significantly less compared to the control groups, except for the white racka males. The lambs starving for 24 hours before slaughtering weighed 25.3-30.0 kgs on average. The black and white racka females weighed the least while the Hungarian merino females weighed the most. The quantity of abdominal and kidney fat was significant in the case of our native females. The quantity of abdominal fat was significantly bigger compared to each control group. On comparing the investigated groups it turned out that the white racka males had the biggest skin weight while the white Hungarian racka females had the smallest, that is the two extremes were recognised in the same colour (white) of one bred. On qualifying the slaughtered animals females had better results than males in each bred; the racka sheep were better than the dairy cigaja but were worse than the Hungarian merino and British sheep groups.
The huge differences in the carcasses of the groups were seen clearly when chopping. Examining the leg, it was noticed that the native groups proved to be smaller than the control groups, except for the black racka males. As for the short loin, the Hungarian racka and the Hungarian merino sheep proved to be the best, whereas the dairy cigaja and the British milk males had much smaller ones. The results gained when investigating the rack were similar to those of the short loin. As far as the rib and shoulder are concerned, the black racka females and the dairy cigaja females had the worst results. After chopping, the right side was also boned in every group. The small proportion of bone in the case of racka sheep was easily noticeable that resulted in the fact that the white racka females had the highest quantity of short loin compared to the other groups. When examining the back quarter, the bone proportions of the 4 racka groups proved to be significantly less than those of the control groups but it was not true for the meat proportions. As for the front quarter meat, the racka males were prominent in the great shoulder meat and in the small proportion of bone. The quantity of the first quarter bone was the least in the case of racka sheep and was the biggest for dairy cigajas. This difference proved to be significant in most cases.
In short, the Hungarian racka groups had the best results in meat quantity, which was especially significant compared to the dairy cigaja sheep. However, the quantity of external fat increased.

The results of the investigation of the β-casein gene polymorphism in sheep breed – Review

β-casein is the most abundant protein fraction in sheep milk, and has at least six different alleles (A, B, C, G, X, Y). The alleles of the β-casein gene may influence on the quality and quantity of milk. Knowing the gene polymorphism has an important role in the process of milk production. The properties of milk could be positively influenced by themolecular genetic methods.

Livestock production development in AP Vojvodina

The aim of this paper is to present the effects of breeding program implementation on the development of animal breeding in Vojvodina since 2010. Data from the Main breeding organization (controlled population) and data from the Statistical Office of the Republic of Serbia (total population) were used as a basis for this research. The main breeding organization is the Departmant of
Animal Science, Faculty of Agriculture, University of Novi Sad that implemented the main breeding programs in cattle, pig, sheep, goat, horse and poultry production. The milk yield in a recorded population of Holstein Friesian and Simmental cows shows evident phenotypic increasing trend as opposed to a population that is not controlled. The results of the selection measures in Vojvodina show that pig breeding has an upward trend and that we have an increasing number of small and medium (family) farms. Interest in sheep and goat production is increasing primarily because of the high demand for products made from sheep meat and goat milk and meat. In the recent decades, Vojvodina has been faced with a decrease in the number of horses. At the same time, there is an increasing interest in sports horses and recreation. According to poultry production results of parental flocks, an increasing tendency was  observed in the production of controlled flocks recently, while the number of breeding stock breeders was reduced.