Rapid Detection of Somatic Cell Count Based on Hybrid Variable Selection Method

Somatic cell count detection is the daily work of dairy farms to monitor the health of cows.The feasibility of applying near-infrared spectroscopy to somatic cell count detection was researched in this paper.Milk samples with different somatic cell counts were collected and preprocessing methods were studied.Variable selection algorithm based on hybrid strategy and modelling method based on ensemble learning were explored for somatic cell count detection.Detection model was used to diagnose subclinical mastitis and the results showed that near-infrared spectroscopy could be a tool to realize rapid detection of somatic cell count in milk.

Udder Health Status of First Parity Dairy Cows in Early-Lactation Based on Somatic Cell Count Categories

The main aim of this study was to investigate the prevalence of intramammary infection (IMI) in early-lactation of primiparous cows using milk recording cow composite somatic cell count (CSCC) categories (combining the first 2 milk recording results after calving). Another aim was to evaluate the milk urea (MU) content as a potential supplementary indicator to SCC or CSCC for the identification of IMI in primiparous cows after calving. This retrospective observational study was conducted on records of test-day of primiparous cows over a period of 6 years (January 2016 to December 2021. The SCC data for 158 Holstein Friesian primiparous cows, with their first milk recording 5 to 35 days after calving and their second milk recording 28 to 56 days in milk (DIM), were identified. Each primiparous cow was assigned a CSCC category (low-low, low-high, high-low or high-high) based on the CSCC at the first 2 milking recordings using the following cut-offs: ≤150,000 cells/ml (low), >150,000 cells/ml (high). The association between CSCC categories and MV content was analyzed using correlation models. At the first milk recording, a proportion of 63.29% was in the low SCC category, and the rest (36.71%) was in the high SCC category. At the second milk recording, a proportion of primiparous cows in CSCC categories was 59.49%, 3.80%, 27.85% and 8.86% in low-low, low-high, high-low and high-high, respectively. At the second milk recording, a proportion of 12.66% of primiparous cows was in the high CSCC category and a proportion of 87.34% of primiparous cows was in the low CSCC category, indicating a poor and a good udder health, respectively. The association of SCC with MU content in low and in high SCC categories at the first milk recording was positive and moderate (+0.49) and negative and strong (-0.97), respectively. The association of CSCC categories with MU contents at the second milk recording was inconclusive. We concluded that CSCC categories may be a useful tool for identifying success and problems regarding the udder health of primiparous cows in early lactation.

Relationship of Somatic Cell Count with Milk Yield and Composition in Chinese Holstein Population

The objective of this study was to analyze the relationship of somatic cell count （SCC） with milk yield, fat and protein percentage, fat and protein yield using analysis of variance and correlation analysis in Chinese Holstein population. The 10 524 test-day records of 568 Chinese Holstein Cattle were obtained from 2 commercial herds in Xi＇an region of China during February 2002 to March 2009. Milk yield, fat percentage, fat and protein yield initially increased and then dropped down with parity, whereas protein percentage decreased and SCC increased. Analysis of variance showed highly significant effects of different subclasses SCC on milk yield and composition （P〈 0.01）. Compared with milk yield with SCC ≤ 200 000 cells mL-1, milk yield losses with SCC of 200 000-500 000 cells mL-1, 501000-1 000 000 cells mL-1, ≥ 1 000 000 cells mL-1 were 0.387, 0.961 and 2.351 kg, respectively. The highly significant negative correlation coefficient between somatic cell score （SCS） and milk and protein yield, milk yield and fat and protein percentage, protein percentage and fat yield were -0.084, -0.037, -0.061, -0.168, and -0.088, respectively （P〈 0.01）. The highly significant positive correlation coefficients between SCS and fat yield and fat and protein percentage, milk yield and fat and protein yield, fat percentage and protein percentage and fat yield, protein yield and protein percentage and fat yield were 0.041, 0.177, 0.105, 0.771, 0.865, 0.122, 0.568, 0.318, and 0.695, respectively （P〈 0.01）. There was no significant relationship between fat percentage and protein yield （P 〉 0.05）. The results of the present study first time provide the relevant base-line data for assessing milk production at Xi＇an region of China.

Blood neutrophil extracellular traps:a novel target for the assessment of mammary health in transition dairy cows

Background:Mammary health is important for transition dairy cows and has been well recognized to exert decisive effects on animal welfare.However,the factors influencing mammary health are still unclear.Differential somatic cell count(DSCC)could reflect the mastitis risk since it is the percentage of neutrophils plus lymphocytes in total somatic cells and could be reflective of mammary health of dairy cows.This work aimed to investigate the assessment and prognosis of the health of transition cows based on blood neutrophil extracellular traps(NETs).Results:Eighty-four transition Holstein dairy cows were selected.The serum was sampled in all the animals at week 1 pre-and postpartum,and milk was sampled at week 1 postpartum.Based on the DSCC in milk at week 1,cows with lower(7.4%±4.07%,n=15)and higher(83.3%±1.21%,n=15)DSCCs were selected.High DSCC cows had higher levels of red blood cell counts(P<0.05),hemoglobin(P=0.07),and hematocrit(P=0.05),higher concentrations of serum oxidative variables[reactive oxygen species(P<0.05),malondialdehyde(P<0.05),protein carbonyl(P<0.05),and 8-hydroxy-2-deoxyguanosine(P=0.07)],higher levels of serum and milk NETs(P<0.05)and blood-milk barrier indicators,including serumβ-casein(P=0.05)and milk immunoglobulin G2(P=0.09),than those of low DSCC cows.In addition,lower concentrations of serum nutrient metabolites(cholesterol and albumin)(P<0.05)and a lower level of serum deoxyribonuclease I(P=0.09)were observed in high DSCC cows than in low DSCC cows.Among the assessments performed using levels of the three prepartum serum parameters(NETs,deoxyribonuclease I andβ-casein),the area under the curve(0.973)of NETs was the highest.In addition,the sensitivity(1.00)and specificity(0.93)were observed for the discrimination of these cows using NETs levels with a critical value of 32.2 ng/mL(P<0.05).Conclusions:The formation of NETs in blood in transition dairy cows may damage the integrity of the blood-milk barrier and thereby increase the risk for mastitis in postpartum cows.

An Interconnection between Elevated SCC Levels in Milk around the First Artificial Insemination and Pregnancy Rate in Dairy Cows

The aim of this study was to evaluate the impact of the somatic cell count (SCC) levels measured at 28-test-day intervals or pregnancy rate at the first artificial insemination of Holstein Friesian cows. All necessary information was taken from test day and farm records. Levels of SCC in milk, 30 days before, and 30 days after the first artificial insemination (FAI) date were divided into 4 categories and their interconnection with pregnancy rate (PR) at FAI was evaluated by applying logistic models. A SCC threshold of 150.000 cells/ml of milk was used to differentiate uninfected udders and infected udders of Holstein Friesian cows. A level of SCC > 150.000 cells/ml in milk, and a level of SCC < 150.000 cells/ml before and after FAI respectively were considered udders with new infections. A level of SCC > 150.000 cells/ml in milk before FAI as well as after FAI, was considered chronically infected udders or subclinical intramammary infections (IMI). Data from 792 FAIs from farm and test day records over a 4-year period (2019-2022) were evaluated. The outcome of this study revealed that the risk for low PR at the first AI was increased in cows with infected udders (OR = 1.33, CI 0.99 - 1.78), compared with uninfected udders. Increased levels of SCC after FAI had a negative effect on PR, while before FAI was not affected. To achieve a good PR, mastitis control measures must be fully adopted to a large extent around the first AI.

Genetic Polymorphism of TLR4 Gene and Correlation with Mastitis in Cattle

Toll-like receptor 4 （TLR4） recognizes pathogen ligands and mediates signaling to initiate innate and adaptive immune responses. In this experiment, a 316 bp and 382 bp fragments of TLR4 gene named T4CRBR1 and T4CRBR2, of Chinese Holstein, Sanhe cattle, and Chinese Simmental was amplified by polymerase chain reaction （PCR）, respectively. The genetic polymorphisms in the three populations were detected by Single-Strand Conformational Polymorphism （SSCP） in the first locus and by digesting the fragments with restriction endonuclease Alu I in the second one. Results showed that both alleles （A and B） of two loci were found in all the three populations and the value of polymorphism information content （PIC） indicated that these were a moderate polymorphism. Statistical results of X^2 test indicated that two polymorphism sites in the three populations fitted with Hardy-Weinberg equilibrium （P 〉 0.05）. After sequencing, A-G single nucleotide polymorphism （SNP） was identified at nucleotide 4,525 in intron 1 of TLR4 gene and C-T SNP was identified at nucleotide 1,397 in exon 3 of TLR4 gene. Meanwhile, the effect of polymorphism of TLR4 gene on somatic cell score （SCS） was analyzed, the results indicated that the cattle with allele A in T4CRBR1 showed lower somatic cell score than that of allele B （P 〈 0.05）. In short, the allele A might play an important role in mastiffs resistance in bovine.

Evaluation of Mastitis Related Measures ＆ Their Applications to Classify Buffalo Milk in Chitwan, Nepal

A study was performed to evaluate the epidemiological aspects of buffalo mastitis in the District Chitwan, Nepal for characterizing the California mastitis test （CMT）, somatic cell count （SCC）, electrical conductivity （EC） values and bacteriological analysis for defining buffalo milk. The CMT was performed by mixing equal volume of milk and 3% sodium lauryl sulphate. The SCC was determined by staining milk film with New Man’s Lampert Stain and EC values were measured by manual digital mastitis detector and expressed as mS/cm. Bacteriological analysis was done on the basis of Gram’s stain, morphological findings, colony characteristics and biochemical tests. The maximum number （16%） of clinical cases of mastitis was observed in the month of July and lowest in the month of April （1.6%）. When the temperature and humidity increased, it indicates that there is need for better care of lactating buffaloes during this month. On a quarter basis, 16% of the foremilk samples in buffaloes were diagnosed as having subclinical mastitis and 11% were diagnosed as having clinical mastitis. The results of CMT scores and SCC showed the evidence that subclinical and clinical mastitic milk was having CMT positive scores （＋1~＋3） with ≥ 200 × 103 cells/mL. The mean pH of clinically normal buffalo milk was 6.75 （range 6.39 to 7.08） and subclinical mastitic and clinical mastitic milk was 6.85 （range 6.37 to 7.10） and 6.88 （range 6.41 to 7.20）, respectively. Analysis of EC value in the milk revealed the presence of mastitis in buffaloes and the cut-off values was 3.7 mS/cm. The coagulase negative Staphylococcus （CNS）, such as S. albus and S. epidermidis were the predominant organisms associated with subclinical mastitis, and CNS and coliforms in clinical mastitis. This information suggests that environmental mastitis was prevalent in buffaloes of Chitwan District. In this study, 9.5% of the quarters were having bacterial count （BC） more than 250 cfu/mL. The proposed criteria for normal milk are absence of clinical signs, CMT negative, SCC 〈 200 × 10^3 cells/mL, EC 〈 3.7 mS/cm and 〈 250 cfu/mL bacteria. The parameters for defining subclinically mastitic milk are absence of clinical signs, CMT positive, SCC ≥ 200 × 10^3 cells/mL, EC 〉 3.7 mS/cm and 〉 250 cfu/mL bacteria. Similarly, clinical mastitic milk was defined as milk having presence of clinical signs, CMT positive, SCC ≥ 200 × 10^3 cells /mL, EC 〉 3.7 mS/cm and BC 〉 250 cfu/mL.

Evaluation of Milk Compositional Quality and Mammary Gland Health of Dairy Herds in the Southwestern Brazilian Amazon

Samples of raw milk from bulk cooling tanks were collected in five municipalities of the Southwestern Brazilian Amazon to establish the prevalence of Staphylococcus aueus and Streptococcus agalactiae, as well as to evaluate the milk composition and its correlation with the bulk tank somatic cell count (BTSCC). A total of 250 samples were collected to investigate the causal agents of bovine mastitis in whole milk, from 50 bulk milk tanks in each municipality. Under laboratory conditions, the samples were diluted to 1/10 and 1/100, and samples of 0.1 ml from each dilution were plated in triplicate on selective media for Staphylococcus aureus and Streptococcus agalactiae. To evaluate the correlation between the major milk components (fat, protein and lactose) and the BTSCC, samples were collected for 18 months from 73 dairy herds. The presence of the above-mentioned contagious mastitis pathogens was detected in 97.2% (243/250) of refrigerated raw milk samples evaluated. Analysis of the major milk components and BTSCC demonstrated that during the study period, fat compo-nent showed the largest variance, followed by protein and lactose, which also showed significant variances.

Economic Impacts of Clinical and Sub Clinical Mastitis on Dairy Farms

Studies have reported on the economic impacts of clinical and subclinical mastitis on dairy farms.Bovine mastitis is a disorder that affects dairy farms and has a major economic impact.Most of the economic losses are the result of mastitis.Mastitis is an invasive infection that is among the most numerous and highly complicated infections in the dairy sector.Mastitis is one of the most expensive diseases in terms of production losses among animal diseases.Mastitis reduces milk production,changes milk composition,and shortens the productive life of infected cows.Farmers must concentrate on avoiding mastitis infection whilst putting in place and following a mastitis control programed.Bovine mastitis,the most significant disease of dairy herds,has huge effects on farm economics.Mastitis losses are due to reduced milk production,the cost of treatments,and culling.Major factors related to low milk yield could be low genetic potential as well as poor nutritional and managerial approaches.Most of the losses are related to somatic cell count(SCC),which is characterised by an increase in the percentage of milk.Culling costs are the costs of rearing or buying a replacement animal,mostly heifers.Overhead impacts include the replacement animals'lower milk supply effectiveness.The expense of replacing animals prematurely due to mastitis is one of the most significant areas of economic loss.