Occurrence Of Subclinical Mastitis Research Articles

Effects of environmental modification on mastitis occurrence and hormonal changes in Holstein cows

The purpose of this research was to evaluate the effects of evaporative cooling in freestall on mastitis occurrence, milk production, and composition, as well as cortisol, T3 (triiodothyronine), and T4 (thyroxin) levels in lactating dairy cows. Twenty-eight multiparous cows averaging 70 ± 10 day postpartum were used in four treatments from January to March 2003. The treatments were: Day (cooling from 7:00 a.m. to 7:00 p.m.); Night (cooling from 7:00 p.m. to 7:00 a.m.); 24-hour (cooling 24-hour); and Control (no cooling). Wired cup test was used for clinical mastitis diagnosis, and the California Mastitis Test (CMT) was used to identify subclinical mastitis. Blood and milk samples were taken weekly for microbiological and hormonal analyses. The cortisol levels were higher than normal values in all treatment groups, suggesting stress conditions, but T3 and T4 levels remained normal in all groups. The occurrence of subclinical mastitis was lower in Day and Night groups than in Control and 24-hour groups. Regarding the microbiological analyses, in all groups the isolation of Corynebacterium sp. from milk samples increased while negative coagulase staphylococci (CNS) declined as etiological agents of subclinical mastitis. However, in Day and 24-hour groups, coagulase positive staphylococci (CPS) increased mainly Staphylococcus aureus (49.8% and 47.7% respectively). The Night group showed a decrease in subclinical mastitis occurrences. Our data indicate that all animals subjected to treatments presented high levels of cortisol, indicating a stress condition. The Night treatment presented a reduction in microbial isolation, suggesting a reduced susceptibility to mastitis.

The influence of blood and milk serum zinc concentration on milk somatic cell count in dairy cows

The objective of this study was to evaluate the influence of blood and milk zinc concentration on somatic cell count, milk production and occurrence of subclinical mastitis cases. The study was performed on thirty Holstein cows approximate same body weight, ages 3 to 5 years, with equally milk production. Blood samples were taken after the morning milking from the caudal vein and milk from all four quarters was taken during morning milking. All samples of blood and milk were taken to determined zinc, using inductively coupled plasma mass spectrometry. 37.67% (11/30) cows have blood serum zinc concentration below 7?mol/l, and 63.33% or 19/30 cows have blood serum zinc concentration higher then 13?mol/l. Also 30% (9/30) cows have somatic cell count lower then 400.000/ml which indicate absence of subclinical mastitis, but 70% (21/30) cows have somatic cell count higher then 400.000/ml which indicate subclinical mastitis. According to all results in this research, zinc has very important influence on reducing subclinical mastitis and somatic cell count in milk of dairy cows.

Prevalence and risk factors of subclinical mastitis in lactating dairy cows in north and south regions of Bangladesh

The purpose of the study was to identify the potential risk factors for subclinical mastitis (SCM) in lactating dairy cows in Bangladesh. A cross-sectional study was carried out on randomly selected 212 smallholder dairy farms of Sadar upazilas of Rangpur, Mymensingh, and Satkhira districts of Bangladesh during January to October 2011. The direct interview using a structured questionnaire and physical examination of the cows were done to collect data on 15 variables. Milk samples collected from study cows were subjected to California Mastitis Test (CMT). The diagnosis of SCM was based on the results of CMT and physical examination of udder and milk. The bivariable followed by multivariable analysis was done using SPSS 17.0. Of the total cows examined, 20.2 % had subclinical mastitis. In bivariable analysis, eight risk factors were identified. However, in the final model of multivariable analysis, four potential risk factors were identified. These were history of previous clinical mastitis (odds ratio (OR) 10.51, p<0.001), pendulous type of udder (OR 2.26, p=0.008), no grass feeding (OR 1.84, p=0.039), and body condition score (BCS) 2.5 or less (OR 7.25, p=0.054). Four different factors were significantly associated with the occurrence of subclinical mastitis, which need to be considered in the control of the disease. However, particular emphasis should be given on grass feeding and BCS because these traits can be modified or improved to allow prevention of SCM.

RELATIONSHIP BETWEEN SOMATIC CELL COUNT AND ZINC BLOOD SERUM CONCENTRATION IN DAIRY COWS

The study was conducted on 15 Holstein-Friesian cows aged between 3 and 5 years kept in the free grazing conditions in summer. The samples of milk were taken twice a year for monitoring subclinical mastitis. In addition to milk samples, the blood samples were taken to determine the concentration of zinc in serum. The occurrence of subclinical mastitis in high yielding cows was estimated based on the values of zinc concentration in blood serum and somatic cells of milk. By analyzing the samples of blood serum, a variation in the concentration of zinc in blood serum was noted depending on the season. Somatic cell count in the spring and autumn period in average was over 400.000/ml milk. Based on statistical analysis, the correlation test, it was concluded that the concentration of zinc in blood serum of cows in the experimental group had no significant effect on the somatic cells count in milk.

Prevalence and Etiology of Subclinical Mastitis in Small Ruminants of Tigray Regional State, North Ethiopia

A study was conducted at Kafta Humera and Tanqua Abergelle Districts from April to June, 2011 to assess the prevalence of subclinical mastitis in lactating small ruminants and identify bacterial causative agents. A total of 390 lactating animals comprising 255 goats and 135 sheep were randomly selected from population and screened for evidence of subclinical mastitis. The overall prevalence of subclinical mastitis was found to be 18.03% (46/255) and 28.14% (38/135) in goats and sheep, respectively. California mastitis test (CMT) positive milk samples were subjected to bacteriological examination and the following bacteria were isolated; coagulase negative Staphylococcus (44.7%), Staphylococcus aureus (27.7%), Escherchia coli (17.0%) and streptococci (10.63%). Risk factors; species (p = 0.021), study site (p < 0.001), sheep breed (p = 0.018) and goat breed (p = 0.009) showed statistically significant association with the occurrence of subclinical mastitis in small dairy ruminants. However, there was no statistically significant association between risk factors such as Age (p = 0.779), parity (p = 0.201) and stage of lactation (p = 0.952). Therefore, it can be concluded that mastitis is a significant disease in small ruminants that affects their productivity and measures need to be taken to control the disease.

Antioxidant enzymes and somatic cell count in dairy cows fed with organic source of zinc, copper and selenium

The objectives of this study were to evaluate the effects of dietary organic sources of zinc (Zn), copper (Cu) and selenium (Se) for dairy cows on somatic cell count (SCC), occurrence of subclinical mastitis, number of clinical mastitis cases and concentration of superoxide dismutase (CuZnSOD), glutathione peroxidase (GSH-Px) and ceruloplasmin (CP). Nineteen dairy cows, with confirmed pregnancy, were selected by body weight, body condition score (BCS), number of lactation, and milk yield in previous lactation, and randomly distributed among two groups, one to receive organic ( n = 9) and the other the inorganic ( n = 10) source of Zn, Cu and Se. Diets were formulated to meet the nutritional requirements of animals from 60 days before the expected date of calving up to 80 days of lactation. Blood samples were collected at − 60, − 21, 1, 21, 40 and 80 days in relation to the expected date of calving for analysis of CuZnSOD, GSH-Px and CP concentration. Milk samples for SCC determination were collected weekly after 15 days of lactation, also at day 1 and 7 and when a clinical case was diagnosed for microbiological culture. The number of new and total cases of subclinical mastitis was lower for the group of cows fed with organic sources of Zn, Cu and Se compared to animals receiving inorganic sources. Average SCC during the first 80 days of lactation tended to be lower for the group fed with organic Zn, Cu and Se. Feeding organic Zn, Cu and Se did not alter the concentration of CuZnSOD, GSH-Px and CP.

Caracterização da mastite subclínica em caprinos produzidos em sistema orgânico no Rio Grande do Sul

O leite e derivados são reconhecidos como veículos de patógenos para humanos, secundário a contaminação pós-ordenha ou de infecções do próprio animal, particularmente na mastite. Foi estudada a ocorrência de mastite e aspectos do manejo em cabras de três propriedades criadas em sistema orgânico. O exame clínico da glândula mamária de 64 cabras em diferentes períodos de lactação, não acusou a presença de mastite clínica. Entretanto, o Califórnia Mastitis Test (CMT) identificou 54 (22,7%) metades mamárias reagentes (+ ou ++). Foram colhidas 238 amostras de leite, das quais houve isolamento bacteriano em 37 (15,6%). Em apenas oito amostras houve coincidência entre o isolamento bacteriano e o resultado do CMT, indicando sensibilidade de 21,6% para este teste no diagnóstico de mastite subclínica em caprinos. Staphylococcus coagulase negativa (SCN) foi o microrganismo mais freqüente (83,8%). O teste de sensibilidade microbiana in vitro revelou resistência das linhagens de SCN ao cotrimoxazol (50%), ampicilina (48,1%), nitrofurantoína (7,7%), cefaclor (7,14%) e oxacilina (3,85%). Cefalotina, gentamicina, neomicina, estreptomicina e tetraciclina foram os antimicrobianos mais efetivos frente aos isolados. Não se evidenciou relação entre a ocorrência de mastite subclínica com a raça, a fase de lactação, sistema de ordenha ou qualidade da água utilizada nas propriedades.

Interactions between bacteria type, proteolysis of casein and physico-chemical properties of bovine milk

The effects of separate infection with four major pathogens frequently associated with the occurrence of subclinical mastitis in cows (Staphylococcus aureus, S. chromogenes, Escherichia coli and Streptococcus dysgalactiae) on milk quality for cheese production were studied for quarters of the same animal. Infection increased somatic cell count (SCC), modified leucocyte distribution, decreased lactose concentration and increased proteolysis of casein. Regardless of bacteria type, the plasmin activity in milk from the infected glands increased ∼2 fold compared with uninfected quarters. These changes were associated with increased rennet clotting time and decreased curd firmness for milk from infected glands, indicating that milk quality for cheese production was negatively affected by infection. Although the general pattern of bacterial invasion was similar, each type of bacteria elicited the above-described responses in a specific manner. SCC, commonly used by the dairy industry as a measure of milk hygienic quality, provided the poorest prediction of milk quality for cheese production in comparison to indices of proteolysis of casein.

Period prevalence and etiology of subclinical mastitis in Awassi sheep in southern Jordan

To investigate the period prevalence, etiology and some epidemiological features of subclinical mastitis in Awassi ewes from the southern part of Jordan, milk samples from 318 lactating ewes were aseptically collected for bacterial and somatic cell counts (SCC) tests. Milk samples were collected at monthly intervals. The period prevalence of subclinical mastitis was 18.3% and the prevalence within each flock remained relatively constant throughout the study period. A significant association ( P<0.001) was observed between the occurrence of subclinical mastitis and the age of ewe. Presence of teat lesions has no impact on the prevalence of subclinical mastitis. The prevalent bacterial species isolated from mammary glands with subclinical mastitis were Staphylococcus aureus (39%), Streptococci (25%), Escherichia coli (19.6%) and coagulase-negative Staphylococci (17.9%). Coagulase-negative Staphylococci were the most prevailing isolates from samples that showed negative SCC results.

Study on risk factors and their association with subclinical mastitis in lactating dairy cows in Trinidad.

A cross-sectional study was conducted on dairy farms in eight milking centres in Trinidad to determine the prevalence of risk factors for mastitis and to assess their relationship to occurrence of subclinical mastitis. The California mastitis test (CMT) was used to determine the prevalence of subclinical mastitis by estimating the somatic cell counts in bulk and composite milk. Of a total of 177 dairy farms studied, 121 (68.4%), 39 (22.0%) and 17 (9.6%) practised semi-intensive, extensive and intensive management systems, respectively. A total of 129 (72.9%), 37 (20.9%) and 11 (6.2%) farms milked cows in parlours, stanchions and pasture/out-on-field, respectively. Based on sanitary practices, 40 (22.6%), 123 (69.5%), and 14 (7.9%) farms were classified as good, fair, and poor, respectively, while 76 (42.9%) and 60 (33.9%) farms reported to rarely experience and frequently experience water shortages, respectively. Amongst the 177 farms, only seven (4.0%) used machine-milking primarily, 152 (85.9%) screened for mastitis as a routine, 18 (10.2%) teat dipped, and 49 (27.7%) practised dry cow therapy. To detect mastitis, of 152 farms involved, 20 (13.2%) used the strip cup while only two (1.3%) employed the CMT. Pipe-borne water delivered directly from the hose was the only source of water to 91 (51.4%) farms while seven (4.0%) and eight (4.5%) farms used only well and surface water (ponds and rivers), respectively. Based on bulk milk samples, the farm prevalence of subclinical mastitis was 60.5% (107 of 177) with a range from 33.3% (centre 5H) to 100.0% (centre 2B). The difference was statistically significant (P < 0.01; chi 2). However, using composite milk, the farm prevalence of subclinical mastitis was 52.5% (93 of 177) with a range from 21.2% (centre 5H) to 92.9% (centre 2B) and again, the difference in prevalence was statistically significant (P < 0.001; chi 2). Subclinical mastitis was detected in 150 (45.0%) of 333 lactating cows screened and the range of prevalence was from 17.9% (centre 5H) to 56.3% (centre 1C). The difference was statistically significant (P < 0.001; chi 2). Of a total of 14 risk factors for mastitis studied which were related to animal husbandry, personnel, mastitis control and water, only two, the herd size and practice of dry cow therapy were significantly (P < 0.05; chi 2) associated with subclinical mastitis. It was concluded that the high prevalence of subclinical mastitis in Trinidad dairy herds could significantly reduce milk production with associated economic loss. Although a majority of the risk factors studied were not found to be significantly associated with the occurrence of subclinical mastitis possibly due to confounding factors, the need to eliminate or reduce these risk factors cannot be over-emphasized.