**3.3.3 Slurry management and claw trimming**

In 72% of the zero-grazing units, manure (slurry) was removed from the alleyway at least once per day and in 18% it was removed more than once per day, while in 10% of the units it remained for more than one day before being removed (Fig. 19). None of the zero-grazing units had claw trimming programmes and none practiced any claw trimming at all. The farmers were completely ignorant of the need for claw trimming.

#### **3.4 Association between risk factors and claw disorders**

The animal-level risk factors found to be significantly associated with chronic laminitis were third or higher parities (χ2 = 11.57, P = 0.009) and lactation stage between 90 to 180 days (χ2

In most of these zero-grazing units, the forage types were mainly mature-wilted or mature non-wilted Napier (*Pennisetum purpureum*), Rhodes (*Cloris gayana*) or mixed wild grasses. Only in one of the units were the cows fed on succulent forages. The Napier grass was fed to the cows in chopped small pieces but the Rhodes and wild grasses in whole lengths without chopping. In addition to forages in 16% of the zero-grazing units, there were

In 81% of the zero-grazing units, concentrate feeding was regular at every milking time which was at least 2-3 times a day and in some there was additional concentrates given to the cows between the intervals from one milking time to the next. In the remaining 19% of the units, concentrate feeding was very occasional and inconsistent, being done mostly for one week in a month only when the farmers had money after they were paid for the milk sales of the previous month. The concentrate feeds used were commercially available and were known as "*Dairy Meal*" (manufactured by *Unga Farmcare Limited, Kenya*). Information provided by the feed milling firm indicated that the average constituents of the concentrate feed were protein (15.5% to 16%), oils (6% to 8%), fibre (9% to 10%) and moisture (12%). The concentrates were in fine ground-grains physical form. In the zero-grazing units that provided regular concentrate feeding, each cow was fed with 6-8 kilograms per day. The zero-grazing units that provided concentrates only occasionally were also inconsistent with the quantities provided per cow. No single zero-grazing unit used any standardized

Cows in 47% of the zero-grazing units were fed regularly (once per day) with 50-100 grams of mineral supplements and in 10% of the units they were fed *ad libitum*. In 40% of the units, they were occasionally (at most 1-2 weeks per month) supplemented with 50 grams of minerals per day. In the remaining 3% of the units, the cows were not given any mineral supplements at all. The mineral supplements given were the locally available commercial mineral mixtures for dairy production such as "*Unga High Phosphorus*" (*Unga Farmcare Limited, Kenya*) or "*Supper Maclick*" (*Cooper Kenya limited*). The standard mineral supplements used in these zero-grazing units averagely consisted of sodium chloride (18% to 20%), calcium (16% to 18%), phosphorus (11% to 12%), magnesium (2.5% to 3%), iron (0.5%), copper (0.16% ), manganese (0.4%), zinc ( 0.5%), sulphur (0.4%), cobalt (0.02%), iodine (0.02%) and selenium (0.0015%). The powdered mineral supplements were fed to the cows

when mixed with concentrates, but the mineral-lick blocks were provided *ad libitum*.

In 72% of the zero-grazing units, manure (slurry) was removed from the alleyway at least once per day and in 18% it was removed more than once per day, while in 10% of the units it remained for more than one day before being removed (Fig. 19). None of the zero-grazing units had claw trimming programmes and none practiced any claw trimming at all. The

The animal-level risk factors found to be significantly associated with chronic laminitis were third or higher parities (χ2 = 11.57, P = 0.009) and lactation stage between 90 to 180 days (χ2

supplementations with succulent maize stover or Napier grass silage.

**3.3.2 Feeding regime** 

concentrate to forage ratios.

**3.3.3 Slurry management and claw trimming** 

farmers were completely ignorant of the need for claw trimming.

**3.4 Association between risk factors and claw disorders** 

Fig. 19. Three different zero-grazing units A, B, and C in the peri-urban areas of Nairobi, Kenya showing slurry that has been left to accumulate for some days and could predispose the claws of cows to develop lesions.

Risk (Predisposing) Factors for Non-Infectious

χ2 = 5.06, 95% C.I : 1.1 to 2.2, P = 0.0262).

**4. Discussion** 

P = 0.003) enhance occurrence of white line separation

Claw Disorders in Dairy Cows Under Varying Zero-Grazing Systems 415

contributed to the occurrence of chronic laminitis. These factors were: overstocking (O.R. = 1.7, χ2 = 24.29, 95% C.I : 1.3 to 2.2, P = 0.0002), earthen floor (O.R. = 1.5, χ2 = 8.98, 95% C.I:1.2 to 2.0, P = 0.0006), and presence of a curb between walk-alleys and the cubicles (O.R. = 1.5,

The data and statistical analyses indicated that regular (2-4 times per day) concentrate feeding seemed to significantly (β-estimate = 2.187, s.e. = 0.814, P = 0.007) enhance occurrence of sole bruising. Conversely, earthen floor (bare soil) (β-estimate = -1.796, s.e. = 0.835, P<0.001) and regular (at least once per day) mineral supplementation (β-estimate = - 4.59, s.e. = 1.50, P = 0.002) seemed to significantly protect against occurrence of sole bruising. The study also indicated that removal of manure more than once per day significantly (βestimate = -3.58, s.e. = 1.01, P<0.001) protected the claws against occurrence of white line separation, while regular (at least once per day) mineral supplementation was found to significantly (β-estimate = -4.07, s.e. = 2.05, P = 0.048) reduce the frequency of its occurrence. However, regular concentrate feeding seemed to significantly (β-estimate = 3.69, s.e. = 1.24,

Furthermore, good concrete floors (non-slip with no ground defects) seemed significantly (β-estimate = -1.969, s.e. = 0.597, P<0.001) protective against occurrence of heel erosion. There were no statistically significant associations found between the rest of the zerograzing housing-and management-level factors, and the claw disorders. Among the cows with chronic laminitis 89% were zero-grazed and only 11% were pasture-grazed. However,

The strength of this paper is elaborated by the important variations in housing designs, nutritional regimes and management protocol in these smallholder zero-grazing dairy units. The dairy production protocol in these units is so varied to the extent that they can further be subdivided into subunits. It is of paramount importance to note that the prevalent claw disorders affecting cows in these zero-grazing units are non-infective in nature and associated with laminitis syndrome. It is also worth noting that the lesions with high prevalence are mainly non-clinical with the highest proportion being subclinical laminitis. This could be attributed to presence of low-grade but persistent predisposing factors existing in these zero-grazing units that cause insidious claw damage eventually leading to clinical manifestations at an advanced stage that may already have caused irreversible changes in the claws particularly with effects of laminitis (Belge & Bakir, 2005; Nocek, 1997). The significance of high prevalence of subclinical laminitis in these zero-grazing production systems cannot be underrated since it serves as a major contributor to development of other more severe clinical claw lesions with far reaching effects such as sole bruising, heel erosion, white line separation, double soles and eventually chronic laminitis if early remedial measures are not instituted. Such outcomes have been reported previously (Nocek, 1997). A retrospective study carried out on the cases of cattle referred from the same area to the University of Nairobi Large Animal Hospital in the earlier years indicated that previously there was high prevalence of infective claw lesions and negligibly low prevalence of laminitis and associated lesions (Nguhiu-Mwangi, et al., 2008). The pattern of occurrence of claw lesions in the same area has remarkably shifted to high prevalence of non-infective

this difference was found to be statistically significant (χ2 = 11.0, P<0.001)

= 9.75, P = 0.021). But lactation stage between 1 to 90 days was significantly (χ2 = 9.06, P = 0.028) associated with subclinical laminitis. Failure to remove manure (more than one day) from the walk-alleys (r = 0.215, χ2 = 13.85, P<0.001), regular (2-4 times per day) concentrate feeding (r = 0.135, χ2 = 5.45, P = 0.0196) and lack of or inadequate mineral supplementation (r = 0.172, χ2 = 8.9, P = 0.0307) were all found to significantly have unconditional association with subclinical laminitis (Table 2). However stepwise logistic regression analysis (screening interactions of floor types, type of cubicle bedding, manure removal, concentrate feeding, type of forage and mineral supplementation) revealed that the most significant zero-grazing housing-and management-level contributor to the occurrence of subclinical laminitis was regular concentrate feeding ( O.R. = 2.08, χ2 = 5.5, 95% C.I: 1.1 to 3.9, P = 0.0212).


Table 2. Association of subclinical laminitis with possible risk factors in a study carried out in 300 dairy cows from 32 smallholder zero-grazing units to evaluate digital characteristics of laminitis and related claw lesions in Nairobi and its environs

Zero-grazing housing- and management-level risk factors that had unconditional association with chronic laminitis were revealed by descriptive statistics. These were overstocking (fewer cubicles than the number of cows) (r = 0.36, χ2 = 38.87, P<0.0001), presence or absence of cubicle bedding (r = 0.312, χ2 = 29.13, P = 0.0003), earthen floor (r = 0.203, χ2 = 12.33, P = 0.0151), presence of a high curb between walk-alley and the cubicles (r = 0.157, χ2 = 7.43, P = 0.0244), leaving manure (more than one day) in the walk-alleys (r = 0. 279, χ2 = 23.33, P<0.0001), regular (2-4 times per day) feeding with concentrates (r = 0.218, χ2 = 14.25, P = 0.0002), and regular (once per day) mineral supplementation (r = 0.321, χ2 = 30.85, P<0.0001) (Table 3).


Table 3. Association of chronic laminitis with possible risk factors in a study carried out in 300 dairy cows from 32 smallholder zero-grazing units to evaluate digital characteristics of laminitis and related claw lesions in Nairobi and its environs

Furthermore, stepwise logistic regression analysis (testing interactions of all these unconditionally associated factors) pointed out the farm-level factors that most significantly contributed to the occurrence of chronic laminitis. These factors were: overstocking (O.R. = 1.7, χ2 = 24.29, 95% C.I : 1.3 to 2.2, P = 0.0002), earthen floor (O.R. = 1.5, χ2 = 8.98, 95% C.I:1.2 to 2.0, P = 0.0006), and presence of a curb between walk-alleys and the cubicles (O.R. = 1.5, χ2 = 5.06, 95% C.I : 1.1 to 2.2, P = 0.0262).

The data and statistical analyses indicated that regular (2-4 times per day) concentrate feeding seemed to significantly (β-estimate = 2.187, s.e. = 0.814, P = 0.007) enhance occurrence of sole bruising. Conversely, earthen floor (bare soil) (β-estimate = -1.796, s.e. = 0.835, P<0.001) and regular (at least once per day) mineral supplementation (β-estimate = - 4.59, s.e. = 1.50, P = 0.002) seemed to significantly protect against occurrence of sole bruising. The study also indicated that removal of manure more than once per day significantly (βestimate = -3.58, s.e. = 1.01, P<0.001) protected the claws against occurrence of white line separation, while regular (at least once per day) mineral supplementation was found to significantly (β-estimate = -4.07, s.e. = 2.05, P = 0.048) reduce the frequency of its occurrence. However, regular concentrate feeding seemed to significantly (β-estimate = 3.69, s.e. = 1.24, P = 0.003) enhance occurrence of white line separation

Furthermore, good concrete floors (non-slip with no ground defects) seemed significantly (β-estimate = -1.969, s.e. = 0.597, P<0.001) protective against occurrence of heel erosion. There were no statistically significant associations found between the rest of the zerograzing housing-and management-level factors, and the claw disorders. Among the cows with chronic laminitis 89% were zero-grazed and only 11% were pasture-grazed. However, this difference was found to be statistically significant (χ2 = 11.0, P<0.001)
