Lameness is a crucial welfare issue in modern dairy husbandry that could result in serious economic losses to dairy producers because of decreased milk yield, reduced fertility, and increased treatment costs and culling rates. Quality of the cow’s claws, especially their hardness, may influence the likelihood that the cow will suffer from claw lesions. Although various factors (i.e., nutrition, genetics, etc.) affect claw quality, the environment in which the cow is housed is very important. Resistance of claw horn to environmental effects likely depends on its hardness because hardness influences rate of horn wear and erosion. Some researchers claim that this relationship puts cows with wet claws at a higher risk of developing claw problems because the horn resistance is diminished. This current study was done in a dairy herd with total of 5800 dairy cows and 2780 milking cows. The average annual daily milk production of the farm recorded as 36 lit/day, cows milked three times a day and housed in free stall barns. Hoof care program were done on the following basis: monthly locomotion scoring, hoof bathing (3-4 days a week), regular hoof trimming at least two times a year by a professional veterinarian hoof trimmer, data recording and analysis. Two groups of cows were selected. Group one on days in milk 120 and group two before drying were referred to trimming chute. Hardness recorded by shore D durometer. Data analyzed in each group and between the groups using two way ANOVA and p values under 0.05 consider significant. Hardness of the solar area in zones one and five (area of toe ulcers and necrosis), four (area of sole ulcer) and three (area of white line disease) were measured. The hardest area of the hoof in group one was located in zone 5 (37.11 ± 6.18) that was significantly harder than area 2-4. And the hardest area in group two was located in zone 5 (49.43 ± 4.94) that didn’t show any significant difference with the other area of the sole. All area of the hooves were significantly harder in group II than group I (P<0.05). Days in milk plays an important role in hoof hardness that may be the reason for more claw horn lesions in 100 days after parturition. This may be a result of negative energy balance, peak production, less comfort, loosing body condition score and so many other problems that may originate in transition period.

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