Effect of Housing on Lameness, Body Condition Score and Udder Health of Sahiwal Dairy Cattle

Lameness is a huge problem in intensive livestock production and a source of pain and distress for dairy cows (Whay et al., 1997). After fertility and mastitis, lameness ranks third in terms of financial losses in the milk industry (Booth et al., 2004). Zero grazing system is adopted in many parts of the world to adjust cow feed intake according to their production (Van et al., 2008) but now there is an increasing ethical demand for cows to have access to pasture which permits cows to exhibit natural behaviour, which improves the health and welfare of animals and there is a perception that grazing animals are less affected by lameness (Hund et al., 2019). But grazing on slippery grounds can also have harmful consequences like ligament injuries (Webster, 2002).
       
Standing time plays a pivotal role in lameness, in pasture-based dairy systems, cows stand for same time or even longer than housed cattle but the major difference is that, stall fed animals are kept on the concrete floor which have a detrimental effect on claw horn but grazing animals stand and roam on pastures, which is much more comfortable (Navarro et al., 2013).
       
Lameness is less prevalent during the grazing season than during indoor confinement (Gitau et al., 1996). Some digital disorders had a higher prevalence in zero-grazing dairy cows compared to others housing systems (Smits et al., 1992). Navarro et al., (2013) observed that double sole, sole ulcer and infectious diseases like digital dermatitis, interdigital dermatitis and inter digital phlegmon were more frequent in housed animals but white line disease, vertical horn fissures and wall abscesses were more prevalent in cattle on pasture.
       
Sahiwal, an indigenous breed of Zebu cattle of northern India has maximum milk production among indigenous cattle breeds (Nivsarkar et al., 2013) and has many advantages over exotic and crossbred cattle breeds, like high parasite resistance, tolerance to high environmental temperature, drought resistance, good temperament, bloat tolerance, ease of calving and longevity. Sahiwal is also known for its A2 type milk which has medicinal value in human beings (Kalra et al., 2017). Despite of all of its characteristics very little improvement in production traits in this breed had been attempted over the years in our country. Most of the research related directly to mastitis, milk characteristics and lameness has been focused on exotic and crossbred species (Bran et al., 2019; Randhawa et al., 2006 and Singh, 2017). Now, Sahiwal cow is being promoted for milk production in the country. A recent study revealed 43.12 and 18.12 per cent prevalence of subclinical mastitis animal wise and quarter wise, respectively (Singh, 2017). However, not a single study has been witnessed so far on lameness in Sahiwal cows. The objective of this study was to test whether there is a difference in lameness score of cows between stall fed and pasture grazed Sahiwal cows and to determine udder health in both housing systems.
 

The present was conduted at Guru Angad Dev Veterinary and Animal Sciences University (GADVASU) in the year 2020-2021.
 
Selection of animals and management practices
 
204 lactating Sahiwal dairy cows were included in the study from Sahiwal dairy farms at Noormahal, Kaljharani and Abohar in Punjab, India. The animals were stall fed at Noormahal and Kaljharani (n=154) farms which has concrete flooring in feeding area and kacha floor in other half and at Abohar (n=50) animals were pasture grazed with loose housing system in night time. Machine milking was done in one of the organized farm (Noormahal) whereas rest two farms practiced hand milking. Hoof trimming was not practiced in any of the farm. Stall fed animals were fed seasonal fodder and dry roughage. Silage feeding and mineral mixture supplementation were also done in organized farms. Pasture grazed animals were let loose in pastures for grazing and only milking animals were supplemented with concentrate and mineral mixture.
 
Sampling and observations
 
On the day of sampling, each animal was allowed to walk on a flat surface and the gait of each animal was examined using a five-point numerical scoring scale as formulated by Randhawa et al., (2008).
 
Body condition score
 
The body condition score was evaluated on a five-point scale same as described by Ferguson et al., (1994).
 
Milk sampling
 
Milk samples were collected after properly disinfection of the teat surface with 70% ethanol. Samples of milk were collected during evening milking time.  About 10 mL to 20 mL of quarter foremilk were collected aseptically in separate sterile containers after squirting a few initial streams in all cows and cow composite sample were collected form individual buckets after full milking. The milk samples were placed in an ice box and carried to the laboratory where they were kept at 4°C in a refrigerator for further laboratory testing.
 
Analytical milk processing
 
The California Mastitis Test was conducted and interpreted as per the standard method (Pandit and Mehta, 1969) as cow side test with laboratory prepared CMT reagent. The somatic cell count in composite milk was analysed by a flow cytometry based automatic analyser (Somascope, Delta Instruments, Netherlands) and the results were expressed in×10³ cells/mL. Electrical conductivity was recorded with the help of digital conductivity meter (Eutech Instruments, CON 700) and the results were expressed in milli Siemens per cm (mS/cm) at 25°C. The pH was recorded by electrical pH recorder (Systronics, µpH system 361). Milk composition, in terms of fat, SNF, protein and lactose, was estimated by a milk analyzer (Lactoscan, Bulgaria) in percentages.
 
Statistical analysis
 
Data were analysed using MINITAB statistical software to analyse the relationship of lameness and milk quality. Cows having healthy and/or latent quarter health status were categorized in the healthy group. However, cows having at least one quarter with specific or non-specific mastitis were considered as the mastitis group. Cows with a locomotion score ‘0’ were grouped as non-lame and cows having locomotion scores 1 (mild), 2 (moderate) or 3 (severe) were considered as the lame group. Pearson chi-square test was applied to analyse relation between lameness and body condition score and lameness and mastitis. Data pertaining to somatic cell count (SCC) was log transformed (LnSCC) to obtain normal distribution and descriptive statistics (mean, standard error) were calculated using the general linear method. SCC log, TP, SNF, Lactose, Fat, EC and pH in different housing were also analysed by Pearson chi-square test. The results were expressed as statistically significant at P<0.05.
 

The prevalence of clinical lameness was quite low in Sahiwal cows i.e. 6 per cent (in this overall study), which could be due to comparatively more innate immunity of these cows due to indigenous nature. Low milk production in Sahiwal cows in comparison to crossbred and exotic cows may lessen their demand for concentrates, thereby leading to lesser chances of sub-acute ruminal acidosis and associated laminitis. Moreover, Sahiwal cow’s hooves were observed much harder undertaking claw trimming, in contrast to cross bred cow hooves (personal observation) and severity of lesions progresses much rapidly in soft hooves.
       
All the Sahiwal cows had black hooves and it was observed that black hooves are less prone to claw lesions than white hooves (Randhawa, 2006). Sahiwal cows were also observed to have more subcutaneous fat, as the majority of cows had BCS ≥3, more fat in body means they must be having more fat in digital cushion also, which must have provided cushioning effect to a great extent. Hence the animals were non lame on visual examination even though claw lesions were present.
 
Lameness score in relation to management system (free stall vs. pasture grazing)
 
Lameness score was not significantly affected (P>0.05) by housing management of the cows (Table 1). Cows in the pasture grazing system were equally prone to lameness odds as in free stalls. Overall, low prevalence of clinical lameness can contribute to this finding. The findings of present study are similar to Laven and Lawrence (2006) who stated that grazing is not relevant for decreasing lameness prevalence. Haufe et al., (2012) also reported that beneficial effects of seasonal grazing on lesions such as sole haemorrhages, sole ulcer and heel-horn erosion are not necessarily verifiable and similarly, Bergsten et al., (2015) reported that longer periods of access to pasture during seasonal grazing do not generally improve claw health. In his study, Hund et al., (2019) also noticed that lameness (severe) problems continue to occur in pasture-based herds as in stall fed herds.


       
In contrast, Gitau et al., (1996) observed that the lameness incidence was significantly higher in zero-grazing i.e. housed cows compared to cows on pasture. Hernadez-Mendo et al. (2007) observed that even as brief time as 4 weeks continuously on pasture can improve the gait of lame cows significantly, particularly reluctance to bear weight and tracking up is improved. It was not determined if the effect was due to an improvement in claw health, increased exercise at pasture, or decreased joint stiffness, which causes less lameness incidences in grazing animals (Van der et al. 2005). Likewise Olmos et al., (2009) observed that the continuously grazing cows exhibited less abnormal locomotion and clinical lameness compared housed cows.   
 
Body condition score in different management systems
 
Grazing animals had significantly lower (P<0.05) BCS than stall fed animals (Table 2). Feeding of TMR to stall-fed animals could be a reason for this finding as grass in pasture has lower nutrient content than TMR. More exercise in grazing animals than stall fed animals stall-fed animals could be another factor responsible for this finding.


       
Further, lactating cows on pasture might lose body weight by metabolizing their fat reserves to meet their energy requirement for lactation Hernadez-Mendo et al. (2007). Similar, findings were observed by Mbugua et al., (1999) and Washburn et al., (2002) that stall-fed animals were of higher body weight and better condition than the grazed animals, throughout the lactation. However, Rust et al., (1995) did not observe body condition score differences in confinement cows and pastured cows.
 
Prevalence of claw lesions in different management systems
 
More lesions were present in the stall fed animals than pasture grazed animals (Table 3). White line lesions and double soles were prevalent equally in both the systems whereas all other lesions were found significantly more in stall-fed animals (P<0.05). Concrete flooring in stalls could be a precipitating factor for higher prevalence of lesions in stall fed animals as there is more wearing of horn on concrete flooring. The loose horn of the hooves gets flacked away in pasture grazing animals due to friction during walking, thus the mild lesions will get trimmed naturally but the stall fed animals have limited walking area that too hard abrasive concrete floor which aggravates the horn injury. Surprisingly, beside the presence of lesions animals in both groups were not lame clinically this reveals their higher threshold for pain perception and adaptation to local condition. This finding was supported by the observations of Smits et al. (1992) and Somers et al., (2003), who recorded that claw disorders have a higher prevalence in zero-grazing dairy cows exposed to concrete flooring than others.


       
In the contrast Bergsten et al., (2015) observed more claw disorders after pasture grazing in seasonally grazing animals. Navarro et al., (2013) also noticed that white line disease, vertical horn fissures and wall abscesses were more frequently found in lame cattle on pasture as compared to housed animals.
 
Incidence of mastitis in Sahiwal cows in different management systems
 
In present study, higher CMT scores (Table 4), SCC and EC (Table 5) revealed that significantly more (P<0.05) number of quarters of stall fed animals were having mastitis in comparison to the grazing animals (Table 6). This could be attributed to presence of underfoot slurry in the stall fed animals which acts as a source of infection for ascending infection in the udder. These finding are identical to the findings of Washburn et al., (2002) who recorded a decreased incidence of mastitis in loose-housed, pasture grazed cows when compared to tied, zero-grazing cows. On the contrary, Rust et al., (1995) did not found any difference of SCC and mastitis in grazing and stalled animals. Reason for non-significant change in milk fat percentage and other factors could be that, the milk composition was assessed in the composite milk in which fat is usually low and other factors could have got diluted.






 

The frequency of clinical lameness in Sahiwal cows was relatively low, at just 6 percent and housing management had no noticeable impact on lameness score. Compared to stall fed cattle, grazing animals had considerably lower BCS. White line lesions and double soles were similarly common in both systems, however all other foot lesions were observed considerably more prevalent in stall-fed animals than in pasture-grazed animals. Higher CMT scores, SCC and EC results in the current investigation showed that considerably more stall-fed animals’ quarters had mastitis than did grazing animals.

None.