RELATIONSHIP BETWEEN CLAWS TREATMENT AND SOMATIC CELL COUNT IN MILK OF SIMMENTAL DAIRY COWS

Abstract

Abstract The relationship between claws treatment and somatic cell count in milk on 45 Simmental cows in age of 3 and 4 years (in the first and the second lactation) with observed claw changes in loose system of rearing and intensive production was analyzed in this paper. The somatic cell count (SCC) was determined by IDF staining and counting method on the day of claws correction and seven and fourteen days afterwards. All statistical analyzes were performed using the statistical program Statgraphics Centurion XV. The results of investigation pointed out that there was very significant difference (P<0.01) regarding SCC values on the day of claw treatment (180 399 cells/ml) and seven days after treatment (87 071 cells/ml), as well as significant difference (P<0.05) between values on days 7 and 14 (162 049 cells/ml) after claws treatment. Value of SCC in milk decreased significantly seven days after claws treatment (P<0.01), but two weeks after treatment it significantly increased (P<0.05). Keywords: dairy cows, Simmental breed, claws correction, somatic cell count

Introduction Good health is “conditio sine qua non” for maximum production of dairy cows. One of the key health aspects is limbs condition, especially claws, enabling ease of movement for the cows, their good welfare and maximal production. Research data (Zlatanović, 2016). revealed that lameness occurrence in dairy farms continuously increase worldwide in last twenty years, even up to more than 50% of the herd in certain farms, at least once a year. Mostly, lameness is caused by disturbed morphological and functional integrity of muscle and bone system of the limbs. The other causes of lameness are mechanical insults in combination with predisposing factors acting for a long time. Concerning lameness occurrence rate, economic losses caused by diverse pathology of the locomotor apparatus

1 Stanković Branislav, PhD, assistant professor, Hristov Slavča, PhD, professor; University of Belgrade, Faculty of Agriculture, Belgrade - Zemun, Serbia 2 Zlatanović Zvonko, PhD, lecturer, College of Agriculture and Food Technology – Prokuplje, Serbia 3 3 Bojkovski Jovan, PhD, professor; University of Belgrade, Faculty of Veterinary Medicine, Belgrade, Serbia 4 Tolimir Nataša, PhD, Institute for Science Application in Agriculture, Belgrade, Serbia
* Corresponding author: Stanković Branislav, baxton@agrif.bg.ac.rs
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are considerable which are reflected in culling cows, decrease of milk production and treatment fees (Clarkson et al., 1996; Shearer and Van Amstel, 2011). The interaction between lameness, lying times, hygiene and the type of surface that the foot is exposed to when cow is standing, is a complex one. Current theories on the pathogenesis of laminitis clearly demonstrate an interaction between events around parturition, diet and the environment (Livesey et al., 1998; Webster, 2001). For instance, there is a growing body of evidence that increased lying times has a beneficial effect on lameness prevalence and claw health. Regarding this, excessive time spent weight bearing may facilitate the breakdown of the dermal-epidermal lamellar connection, initially triggered by the activation of metalloproteinases and other similar enzymes from either hormonal events around calving time (Tarlton et al., 2002), or from the action of Streptococcus bovis exotoxin (Mungall et al., 2001) released during an acidotic event. Increased duration of weight bearing may facilitate the transport of the exotoxin to the capillary beds of the dermal tissues, and also stress the connections between the dermis and epidermis, facilitating sinking of the pedal bone within the horn capsule, subsequently producing clinical signs of laminitis at the sole surface. In addition, rough walking surfaces have been shown to increase lameness prevalence and excessive exposure to concrete may result in excessive wear of the claws (Faye and Lescourret, 1989.).

Besides constitutional compounds, important milk constituents are leucocytes originating from blood and epithelial cells from udder, known as Somatic Cell Count (SCC), whose increased number and changes in composition indices inflammatory tissue reaction (Bramley et al., 1984; Harmon, 1994; Hamman, 1996; Barkema et al., 1999). Quantitative presence of SCC is used to estimate udder health as well as milk yield loses, milk processing traits (Politis and Ng-Kwai-Hang, 1988) and economic loses which are consequence of mastitis (Jones et al., 1984; Brown et al., 1986). The findings of Warnick et al. (2001) revealed decrease in milk production associated with lameness in cows in second or greater lactation and for more severe cases. In their study, in one herd, the decrease in milk production was greater for cows with sole ulcers or foot abscesses than for foot rot or foot warts. Cows with abscesses or foot rot tended to have larger decreases in milk production in the other herd. The authors concluded that inconsistent results between farms may have resulted from differences in the relative frequencies of specific causes of lameness in the two herds and in the way lame cows were identified and defined for the study. Great attention was paid to the causes of lameness, especially in intensive systems of rearing (Green et al., 2002). The aim of this paper is to investigate impact of the lameness on SCC of dairy cows.

Material and Methods The relationship between claws treatment and somatic cell count in milk on 45 Simmental cows in age of 3 and 4 years (in the first and the second lactation) with observed claw changes in loose system of rearing and intensive production was analyzed in this paper. The average amount of milk in the first and second lactation was 4900 and 5300 kg of milk per cow, respectively. Cows consumed water ad libitum and were fed with total mix ration regarding milk production.
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The samples for somatic cell count were taken at the time of milking on the day of correction of claws, and then after seven and fourteen days from the correction for determination of somatic cells count. The number of somatic cells in 1 mL of milk was determined IDF staining and counting method. The method for determining the number of somatic cells in milk is given in the Rulebook on methods of microbiological analyzes and super analyzes of foodstuffs (Official gazette SFRJ, no. 25/80). Counting was performed on the day of claws correction and seven and fourteen days afterwards. All statistical analyzes were performed using the statistical program Statgraphics Centurion XV.

Results and Discussion Results related to SCC and statistical parameters were presented in table 1. Table 1 Descriptive statistic parameters regarding SCC in cow’s milk
Number X SD CV (%) Xmin Xmax Range Standard asymmetry of cows
On correction day 45 180,399 125,983 69.83 27,550 633,650 606,100 5.28 7 days after correction 45 87,071 78,749 90.44 18,367 428,000 409,633 7.87 14 days after correction 45 162,049 203,624 125.65 27,550 826,500 798,950 7.06 According data in table 1, it could be observed that SCC was decreased from 180399 to 87071 cells/mL on day 7th after correction, but increased to 162049 cells 14 days after correction. Standard deviation was large and in range from 78,749 on 7th day to 203,624 on day 14th after correction. The coefficient of variation was the lowest on the day of correction and amounted to 69.83%. Seven days later its value was 90.44%, and 14 days after treatment amounted to 125.65%. Somatic cell count ranged from a minimum of 18,367 seven days after correction, to a maximum of 826,500 fourteen days after correction of claws. The range of values was 606,100 on the day of correction, after seven days had a value of 409,633, and fourteen days later, it was 798,950. In table 2 were presented results of statistical analysis of significance of SCC differences on correction day, 7 days after correction and 14 days after correction. Table 2 Significance of SCC differences on correction day, 7 days after correction and 14 days after correction
Source of variation Σ x2 Degrees of freedom Mean square F-value P-value Between treatment 2.20028E11 2 1.10014E11 5.19 0.0067** Inside the treatment 2.79558E12 132 2.11787E10 - - Σ 3.01561E12 134 - - - **P<0.01
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According table 2, it could be noticed that there were very significant difference between SCC of treatments - periods of SCC evaluation. In table 3 were presented results of homogeneity of treatments testing and analyzed possible influence of extreme values on statistical significance of the results. Testing revealed the homogeneity of the examined groups, so nonparametric tests were not performed. The drastic drop of somatic cell count seven days after claws treatment might be understand through decrease of the stress and pain relief, while fourteen days after treatment numerous previously mentioned factors took over (Faye and Lescourret, 1989; Livesey et al., 1998; Webster, 2001; Mungall et al., 2001; Tarlton et al., 2002).

Table 3 Test of homogeneity of treatments
Number Mean value Homogeneity of treatments On correction day 45 180.399 Homogeneous 7 days after correction 45 87.071 Homogeneous 14 days after correction 45 162.049 Homogeneous

In table 4 were presented significances of SCC differences between treatments using LSD test. Table 4 Significance of differences of SCC between treatments
Tested treatments Difference +/- Limit (range) Significance Correction day – 7 days after correction 93.328,0 60688,5 * Correction day – 14 days after correction 18.350,0 60688,5 - 7 days after correction - 14 days after correction -74.978,0 60688,5 * ns = p>0,05; * = p<0,05; ** = p<0,01
SCC evaluation in milk was carried out on the day of correction of claws, seven and fourteen days after the correction. Mean values of SCC in 1 mL of milk in three periods studied had the following results: 180,399 on the day of correction, after seven days 87,071 and 14 days after correction 162,049. Large standard deviation which had a value of 78,749 seventh day after correction to 203,624 (125.65% CV) on the fourteenth day after the correction of claws was noticeable. Analysis of variance confirmed the significance of differences in SCC between the values obtained at three time periods studied (P<0.01; F=5.19). Homogeneity tests confirmed the homogeneity of the group. Significant differences in SCC were between the values at the correction claw and seven days later, as well as between the values of the seventh and fourteenth days. Average somatic cell count was significantly lower for seven days after the correction of the feet, and later rose again. Average SCC in 1 mL milk healthy udder amounts 70 000 – 90 000, and in the most cases it is smaller than 150 000 in 1 mL. The count and population of somatic cells composition depends on many factors, such as season, parity, lactation phase, external factors and technological procedures on farm, udder health and activity (Bodoh et al., 1976; Kennedy et al, 1982; Barkema et al., 1998, 1998a; Hristov, 2002a; Hristov et al., 2002b; Schukken
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et al., 2003;). Increase of SCC values is related to the type of pathogen as well (Schepers et al., 1997). The value of SCC is significantly higher in colostrum than in milk. In the first days after calving in first lactation, SCC is more than 1000000 in 1 mL of milk, and after two weeks, about 500000 in 1 mL (Boboš and Vidić, 2005). At the end of lactation SCC again increases. It must be taken into account the variation in SCC in the morning or evening milking as well as during the same milking. Generally, the SCC is the greatest at the end of milking, and the lowest immediately before milking. It was found that SCC increases in the elderly cow’s milk, as well as with the increase in days of the milking. The increase in SCC and increasing the number of lactation animals can be explained by the fact that the risk of infection increases with age, probably because the immune system of older cows is not efficient enough or because the udder is already exhibited many unfavorable factors in early lactation, which facilitates the penetration of bacteria in mammary gland (Detilleux et al., 1997). In addition, SCC can also be a characteristic of the breed, which may be used in the selection with the aim of reducing the incidence of subclinical and clinical mastitis (Mrod and Swanson, 1996). Morphological characteristics of the udder as a hereditary trait influence the SCC (Boettcher et al., 1998). Different stressors also influence SCC (Dohoo and Meek, 1982). The effect of season on the SCC has also been the subject of numerous studies. Besides a significant increase in SCC in milk, heat stress reduces milk production up to 10-20%. The number of somatic cells is the lowest during winter and highest during summer (Dohoo and Meek, 1982; Wells and Ott, 1998), which is in accordance with high occurring rate of cow’s mastitis during hot season and high rate of infection in summer caused by environmental pathogens (Smith et al., 1985). In addition to all the above factors, the most significant factor influencing the increase of SCC in milk is an infection of the mammary gland (Dohoo and Meek, 1982; Djabri et al., 2002). This refers to the SCC in milk of individual udder quarter, milk cows in general and milk in a pooled sample of the herd. Generally, SCC in aggregate herd milk should be determined after milking, while in particular quarters on high-capacity farms in countries with developed dairy production it is done usually once a month in different ways. This is in accordance with results of Warnick et al. (2001) and Green et al. (2002), who concluded that type and severity of clinical lameness has a significant impact on milk production and important information for assessing the economic impact of clinical lameness and its impact on cow health, pointing out the importance of early identification of clinical lameness and the urgency of techniques to improve the definition of this highly subjective diagnosis. Accurate determination of SCC, mostly in bulk milk samples, is performed by Fossomatic which use a method of automatic counting cell nuclei on the principle of fluorescence microscopy (Sandholm et al., 1995). Considering that for subclinical mastitis there are no visible changes in the udder and the milk SCC determining the aggregate sample of milk used to assess the health status of the herd, and possible losses in production. Maximum limit of SCC is being used as a factor to determine the suitability of milk for processing, whereby the value of the upper limit of SCC varies in different countries (for us is 400,000 cells/mL pooled sample of milk). It is also accepted as an international standard for determining the quality of milk, both in developed and in developing countries. These results indicate that the positive effect of the correction claw reflected in the reduction of the number of somatic cells in milk, even though many factors, such as breakdown of the dermal-epidermal lamellar connection, acidosis, rough walking surfaces,
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took over afterwards. Nevertheless, for more specific results and conclusions further and much more extensive investigations should be performed.

Conclusions According presented data, it could be concluded that there was very significant difference (P<0.01) between SCC values on day of correction and 7 days after correction, as well as significant difference (P<0.05) between SCC values seven and fourteen days after claws correction. The number of somatic cells in milk was significantly reduced week after correction of claws, then, fourteen days after the correction claw increased significantly (P <0.05). This indicates that the positive effect of the correction claw reflected in the reduction of the number of somatic cells in milk, even though numerous factors, such as breakdown of the dermal-epidermal lamellar connection, acidosis, rough walking surfaces, took over later. Even if it is so, for more specific results and conclusions further and much more extensive investigations should be performed. Acknowledgement. This paper was financed by Project of Ministry of Science of Republic of Serbia “Optimization of technological procedures and zootechnical resources on farms with the goal to upgrade sustainability of milk production” TR 3108