Is lack of antibiotic usage affecting udder health status of organic dairy cattle?

Abstract

This research communication aimed to compare somatic cell count (SCC), the main marker of udder health status, in organic farms not using antibiotics (O, n = 6), organic farms using antibiotics (OA, n = 7) and conventional farms (CA, n = 5) using antibiotic treatments, all of them at pasture. SCC was statistically significantly higher in O (173780) compared to CA (93325) and OA (107152). Milk yield had a significant diluting effect on SCC and differences between groups increased with parities. Stratified analysis of SCC depending on lactation number and % of monthly SCC test with different linear scores (LS) indicated that there is no difference in udder health in the primiparous heifers from the three groups of farms, but it deteriorates in older cows because of chronic infections in O (possibly due to lack of antibiotic use). Our results suggest that the non-use of antibiotics had an effect in udder health leading to higher occurrence of clinical and subclinical mastitis. Therefore, preventive management practices for mastitis control are essential in organic farms.

Short communication: The main factors affecting somatic cell count in organic dairy farming

“…1). Previous studies in Spain have indicated poorer udder health status on organic farms that favour the use of alternative therapies over use of antibiotics, especially in older cows (Orjales et al, 2016); indeed, the same study concluded that although organic farming aims to reduce the use of antibiotics, treatment must be used in older cows to maintain udder health status. As already mentioned, older cows on organic farms are at a greater risk of suffering chronic subclinical mastitis, which is very difficult to control unless antibiotic therapy is used.…”

“…1). The SCC has been reported to increase significantly with lactation number on organic dairy farms in northern Spain, particularly farms on which antibiotic therapy is not used (Orjales et al, 2016) and has been related to chronic infection after several lactation periods (Villar & López-Alonso, 2015).…”

“…In fact without hygiene or without an adequate maintenance of milking machine, antibiotic dry therapy and teat dipping are insufficient measures to prevent mammary infections and to achieve low SCC. Recent studies in northern Spain have indicated higher SCC in organically reared herds than in conventionally reared herds (Villar & López-alonso, 2015;Orjales et al, 2016). This is mainly associated with a higher prevalence of chronic subclinical mastitis in organic herds , although the higher SCC may be partly explained by the higher number of parturitions and the lower production rates on organic farms.…”

Breed performance in organic dairy farming in Northern Spain

“…As was expected, in the present study LS and percentage of SCC surpassing >200,000 somatic cells increased with lactation number in all breed groups (Reneau, ). These increases become more evident when cows survive during many lactations (Tancin, ) as in organic systems (Orjales Galdo et al, ; Orjales et al, ). Studies carried out in organic and pasture‐based systems to evaluate the effect of breed on SCC, LS or udder health produce inconclusive results, although only broad comparisons can be made.…”

Organic Dairy Cattle: Do European Union Regulations Promote Animal Welfare?

“…However, this result is clearly dependent of whether or not organic farmers chose to keep using antibiotics at all. Organic farms that chose to abolish the use of antibiotics had higher somatic cell counts (a proxy measure of poor udder health and of subclinical mastitis) compared to conventional farms, but no differences were found between Spanish organic farms that use antibiotics (when needed) and conventional farms [ 182 ]. These results confirm previous work showing either no differences in mastitis prevalence or treatments between both systems [ 171 , 183 ] or reduced prevalence of mastitis in organic herds [ 175 , 184 ].…”