Effects of Hoof Trimming on Feed Consumption, Milk Yield, Oxidant and Antioxidant System in Dairy Cows with Hoof Deformities

In this study is objectived to reveal the importance of hoof trimming (HT) in cows by determining the changes in feed consumption, milk yield, oxidant, and antioxidant parameters in the days before and after HT in cows with hoof deformities. This research was conducted on 12 female Brown Swiss dairy cows mid to late lactation period that had healthy hooves showing symptoms lameness due to hoof deformities. Daily feed consumption and milk yield ndings were recorded on days the 1,7 (before HT), 13 (on the day of HT), 19,25, and 31 (after HT) of the study. Total oxidant capacity (TOC) and total antioxidant capacity (TAC) tests for determination of oxidative stress index, for the evaluation of antioxidant potential; glutathione peroxidase (GSH-Px), glutathione (GSH), superoxide dismutase (SOD) enzyme, Vitamin E, A, and C levels were measured in blood samples taken on the experiment days. According to the ndings of this study, after HT increased feed consumption and milk yield in cows ( P < 0.05). After HT, TOC decreased ( P < 0.05), TAC ( P < 0.05), GSH-Px ( P < 0.05, P < 0.001), GSH ( P < 0.05, P < 0.001), SOD ( P < 0.05, P < 0.001), Vitamin E ( P < 0.05, P < 0.001) and Vitamin C ( P < 0.05) levels increased signicantly, Vitamin A ( P > 0.05) levels did not change signicantly. Results of this study showed that HT, the oxidant system was suppressed and the antioxidant system was supported in dairy cows with hoof deformities dad healthy hooves. yield after HT was higher than before HT. Subsequently, milk yield was increased after HT. Results of the current study concurred with the ndings of some researchers [33, 41, 42] increased in the milk yield following HT. Increased milk production after HT can be increased feed consumption as a conclusion of having healthier hooves and walking more comfortably and standing because of smooth hoof gure then HT. In the current study, a 0.9 positive relation between feed consumption and daily milk yield was also shown.


Introduction
Hoof deformities and lameness in dairy cows are an increasingly problem in modern dairy farms [1,2].
Various factors such as sheltering environment, high productivity, high herd density, and individual sensitivity make cows prone to claw disorders [3][4][5][6][7]. Lameness causes signi cant economic losses in dairy cattle farms and the most important reason of this economic loss is the decrease in milk production [8][9][10][11][12][13]. After the appearance of lameness, the decrease in milk yield, the cow does not want to go to the manger due to pain, and when it does, barely standing for feed consumption, and therefore feed consumption is reduced. In conclusion, milk yield decreases due to the decrease in feed consumption [14][15][16][17][18]. Additionally to economical losses foot and hoof deformities also adversely in uence the cow's welfare [19][20][21]. Therefore, there is a raising awareness of the importance of HT in cattle in terms of animal health and welfare.
Hoof trimming is done to prevent lesions on the claws and to improve gait by correcting and maintaining foot symmetry and shape, which ensures the correct distribution of weight. Lameness caused by hoof deformities can be treated with correct HT. The correct claw shape helps restore weight-bearing balance and supports recovery from hoof deformities [21][22][23][24][25]. However, the discomfort caused by only deformed hoof structures in the animal and the effect of the correct hoof shape on animal welfare has not been reported. In this study, it was objectived to compare the changes in feed consumption, milk yield, oxidant and antioxidant parameters before and after HT. In addition to previous studies, also with the ndings of this study effects of HT on the economy and animal welfare will be revealed.

Animals
This research was conducted on 12 female Brown Swiss dairy cows aged 3 -6 years with a mean bodyweight of 550 ± 600 kg that was in the mid to late lactation period that showing symptoms lameness due to only hoof deformities (without lesion in the living tissue of the foot) at the Agri Ibrahim Cecen University Eleskirt Celal Oruc Academy of Livestock Production, Education, Research and Application Farm, Agri, TR. Data were collected for each cow from the farm registration system: age, the rst calving age of cows, two birth intervals, the mean number of calving, days in lactation, number of lactation, lactation stage, daily milk yield, stay or removal age in the herd.
Feeding and determination of daily feed consumption Cows were fed the same ration during the research. Concentrate (8 kg milk feed) [Cattle Dairy Feed 18%, Birlik Feed Erzurum, Turkey] and roughage (20 kg corn silage, 4 kg clover dry grass, and 3 kg meadow dry grass) were given immediately after morning and evening milking divided into two in a day fed ad libitum. Daily energy needs were computed from the mean weight and daily milk yield to the National Research Council (NRC) requirements [26]. To determine the daily feed consumption of each cow during the study, the animals in the study group were kept in separate compartments on the farm. They were subjected to individual feeding. Daily total feed consumption, morning and evening before feeding was determined by weighing the increased feed in front of the animals (Jadever JWQ-30 Digital precision scale). Daily feed consumption ndings on days the 1,7 (before HT), 13 (on the day of HT), 19, 25, and 31 (after HT) of the study were recorded. The mean feed composition is given in Table 1. Clean drinking water was always kept in front of the animals.

Claw trimming
Twelve cows that dad healthy hooves showing symptoms lameness due to hoof deformities were selected for the study. The health status of the cows was determined by rectal temperature, pulse, and respiration rate 12 hours before HT. Cows showing the values of these 3 parameters outside the physiological range were excluded from the study. On days the 13 th of the study, it was taken to the travail that provided the standing xation of the animal for HT. HT was started from the medial hoof in the hind legs and lateral hoof in the anterior legs. Following the method, the horn hoof was trimmed and corrected by the investigator (SY) and this procedure was completed in approximately 15 min. Claws of the cows were trimmed on different days and checked for hoof disease. The hooves of cows were trimmed following a 1-year interval since the previous trim.

Daily milk yield
Cows that were in the mid to late lactation stage were chosen for the research. The average days in lactation for the cows were 230.4 (inter 124-289 days) and the average number of calvings was 2.06 times (inter 1-4 times) before HT. The milk yield of 12 cows was recorded twice a day (at 6:00 a.m and 6:00 p.m) on days 1,7,13,19,25,31 st of the study using an automatic milking system (milkline® milking). On days the 1, 7, 13, 19, 25, and 31 st of the study, the blood samples taken into glass tubes with and  without anticoagulant were brought to the laboratory as soon as possible and centrifuged at 3000 rpm  for 10 minutes at room temperature and stored  Assay kit] enzyme levels were measured by ELISA using a commercial kit. Plasma vitamin E and A levels, which are antioxidant vitamins, were determined by using commercial test kits accordance to the technique on the HPLC device (Shimadzu UV-1700, Japon) at Agri Ibrahim Cecen University Central Laboratory. Plasma vitamin C levels were determined colorimetrically by the appropriate technique using the phosphotungunstic acid method at Kafkas University Central Laboratory [27].

Statistical Analysis
The one-way analysis of variance (ANOVA) and post hoc Duncan tests were applied to the data to examine the differences among times using the SPSS statistical software package. The ndings are showed as average ± SE. A value of P < 0.05 was accepted signi cantly.

Daily feed consumption (kg)
In the ndings of daily feed consumption on days 1,7,13,19,25 and 31 st  There was a statistically signi cant difference in the comparisons between with the days 19 th , 25 th , and 31 st days (P < 0.05). There was a statistically signi cant difference in the comparisons between the days 25 th and 31 st (P < 0.05). Vitamin E level increased after HT.
In vitamin A measurement results, there was no statistically signi cant difference in comparisons between all time (P > 0.05). Vitamin A level did not change after HT.
Measurement results of oxidant and antioxidant parameters on days 1,7,13,19,25,31 st of the study are given in Table 2.

Discussion
Many factors genetics, season, shelter type, herd size, exercise, lying surface, age, pregnancy and lactation, and feeding conditions are effective on foot health. One or more of these factors come together to determine the herd's foot health [28][29][30][31]. Regular hoof trimming is the only way to minimize the effects of these factors [32]. Functional HT, disrupts the vicious circle of excessive mechanical load on the claw, ensuring that the weight is evenly distributed on both claws. Healthy claw tissue production is stimulated as the pressure on keratogenic cells will increase with routine HT in thin bottomed animals [33][34][35][36].
In research by Aoki et al. [37], it has been quantitatively showing that walking characteristics are improved after HT. Phillips et al. [38] have shown that HT body weight is distributed evenly on the foot and therefore on the claws and suggested a corresponding in uence on posture. Nishimori et al. [39] reported a possibility that a change in weight-bearing and posture may affect dry matter intake. They showed that by measuring different blood measurement parameters, cows started eating more roughage after HT. In the present study, each cow included in the study were subjected to individual feeding separate compartment to determine the effect on feed consumption of HT and daily feed consumption was measured on days 1,7,13,19,25, and 31st of the study. Cows' claws were trimmed on days the 13th of the study. Although the day of the HT was not statistically signi cant, the feed consumption of cows decreased temporarily compared to the 1st and 7th days of the study. The slightly reduced in feed consumption on the day of trimming can be attributed to the stress occurring in the animal due to HT, interruption of the daily routine and the fact that it does not yet take the normal shape of the claw and does not press the ground completely and does not adapt to the new claw of the animal, on the days following HT in cows had a decrease in activity for all these reasons feed consumption decreased. In the measurements made on the 19th, 25th, and 31st days after HT feed consumption was found to increase statistically signi cantly. Feed consumption started to increase on days the 6th (on days the 19th of study) after HT may be attributed to the normal shape of the claw and the animal can comfortably step on the ground. Lastly, the increase in feed consumption after HT can be attributed to getting healthy claws of the animals. It was also revealed by the ndings of this study that HT increased feed consumption in cows.
Claw health has a pronounced effect on milk production [2,6,8,9,11,40]. Cows with painful hoof disorders eat less food, are less willing to move, and as a result, they can yield less milk than cows without claw disorders. Likely, the decrease in milk production associated with foot and claw lesions is due to raised energy requirement due to pain, which may also be current without a decrease in feed consumption or a noticeable lameness [2,4,11,27]. Several studies showed the expected decrease in milk production in cows with claw and limb disorders. In a study by Sogstad et al. [41] cows are reported to give more milk after HT than before HT. In another study by Kibar and Caglayan [42] they determined that HT of a one-time hoof increased milk production in dairy cattle with hoof disorders in commercial dairy farms. But in some studies, higher milk yield was not detected after HT. In a study investigated the effects on milk yield of one-time HT by Nishimori et al. [38], demonstrated that milk yield did not change after HT. Taguchi et al. [43] have reported a similar experiment, but no differences in milk production and composition were showed in their research. In another study by Tanaka et al. [33], observed that HT slows down the rate at which milk production reductions in cows in the late lactation period. As many researchers have reported [4,13,23,30], milk yield in the lactation stage is effected by herd factors such as management and nutrition and individual factors as genetics, parity, and disease. Differences in the literature about the in uence of lameness and hoof disorders on milk production are comparatively the conclusion of these complex effects. In the current study, daily milk yield ndings were recorded on days 1,7,13,19,25, and 31st of the research to determine the effect of HT on milk yield in healthy cows. No diversity was showed in milk production in the measurements made on days 1,7 (before HT), 13 (on the day of HT). On the day of HT, the daily milk yield showed not change according to days 1 and 7th, and also the time needed for the complete HT procedure with a mean of 15 minutes was very short. On the 6th day after the HT (days 19th of the study), milk yield was increased, though not statistically signi cant. On the 25 and 31st days of the study (after HT), a statistically signi cant difference was observed in the increase of milk yield. On days 10th after HT on the daily milk yield had recovered to its original value (on days 25th of study) and nal measurements were made on the 31st day of the study.
Accordingly, milk yield after HT was higher than before HT. Subsequently, milk yield was increased after HT. Results of the current study concurred with the ndings of some researchers [33,41,42] increased in the milk yield following HT. Increased milk production after HT can be increased feed consumption as a conclusion of having healthier hooves and walking more comfortably and standing because of smooth hoof gure then HT. In the current study, a 0.9 positive relation between feed consumption and daily milk yield was also shown.
Claw disorders can be responsible for the deterioration of animal welfare by causing pain and stress in cattle [44][45][46][47]. Oxidant and antioxidant parameters are often used to assess pain and stress in animals [36]. However, in the literature searches, no publication investigating the effect on the oxidant and antioxidant system of HT to evaluate the pain and stress caused by claw disorder in cattle. For this reason, this study also aimed to determine the effect on oxidant and antioxidant systems of HT in cows.
Under normal conditions, oxidants and antioxidants are in balance in the organism. However, in situations such as in ammation, infection, pain, and stress, this balance is disrupted in favor of oxidants, and free radicals occur, which can cause damage to cells or tissues [48].
It is recommended to measure TOC and TAC to determine the oxidant and antioxidant status in the organism and their balance. In this study, a signi cant decrease in TOC values was observed in the measurement results after the HT. In TAC measurements, the day of HT decreased signi cantly and showed a signi cant increase in measurement days after HT. GSH-Px is the most effective of antioxidant enzymes. It is responsible for the destruction of intracellular hydroperoxides. By converting H 2 O 2 to water, prevents the formation of methemoglobin and protects the membrane lipids against peroxide anion, and protects the integrity of the cell membrane. GSH-Px values were signi cantly lower before and on the days of HT, there was a signi cant increase in the measurements made after HT. GSH is an important intracellular nonenzymatic antioxidant. Its oxidized form is involved in the inhibition of free radicals, stabilization of reduced sulfhydryl groups, and regeneration of tocopherol and ascorbate. It also acts as the cofactor of GSH-Px. GSH values were signi cantly lower before HT and on the days of HT, there was a signi cant increase in the measurements made after HT. SOD is the rst enzyme to act in the antioxidative system, which is found in the mitochondria matrix of hepatocytes, erythrocytes, and brain cells. It has a stable structure. It catalyzes the reaction that converts O 2 -to H 2 O 2 . SOD values were signi cantly lower before HT and on the days of HT, there was a signi cant increase in the measurements made after HT. The low levels of GSH-Px, GSH, SOD before HT are thought to be due to their use in order to neutralize the radicals that occur due to oxidative stress developing during lameness.
The synergism between Vitamin C and E in preventing lipid peroxidation is well known. While Vitamin C increases the antioxidant effect of Vitamin E, it also reduces its consumption. Under normal conditions, Vitamin C is synthesized by the liver of adult cattle and this synthesis is su cient for physiological needs. However, ruminants are susceptible to de ciencies due to the destruction of Vitamin C by the rumen micro ora. Vitamin C de ciency also reduces the body's defense power against infections. In the present study, it is noteworthy that after HT, Vitamin E and C levels were signi cantly increased in cattle compared to before. It is thought that the reason for this situation is the decrease in feed consumption due to lameness and the increasing use due to developing oxidative stress. On the other hand, in Vitamin A levels, no signi cant change was observed in concentrations at study through. This may be related to the use of vitamins such as E and C primarily during oxidative stress.
This study showed that after HT, the oxidant system was suppressed and the antioxidant system was supported in dairy cows. In this study, it has been shown with the ndings of the oxidant and antioxidant defense system that HT increases animal welfare in cattle.

Conclusions
In this study, an increase in feed consumption and milk yield was observed after HT. At the same time, in this study where the effects of HT on the oxidant and antioxidant system were investigated, it was observed that the oxidant system was suppressed and the antioxidant system was supported after the HT. In light of all this information, the hypothesis that HT the necessity of regular claw trimming to ensure healthy claws and prevent lameness is clear, and it is, therefore, an integral part of improving the welfare of cattle was con rmed.