Invited review: Abomasal damage in veal calves

Abstract

Within all cattle production systems, veal calves are the most severely affected by abomasal damage, with current prevalence at slaughter ranging from 70 to 93% of all animals affected. Although most damage is found in the pyloric region of the abomasum, fundic lesions are also found. Despite past research into the etiology of abomasal damage and the many risk factors that have been proposed, consensus on the causal factors of abomasal damage in veal calves has not yet been reached. The aim of this review was to integrate and analyze available information on the etiology of, and possible risk factors for, abomasal damage in veal calves. We describe various proposed pathways through which risk factors may contribute to damage formation and conclude that the etiology of abomasal damage is most likely multifactorial, with diet being a main contributor. Pyloric lesions, the most common type of damage in veal calves, are likely the result of large and infrequent milk and solid feed meals, whereas fundic lesions may be caused by stress, although the evidence for this is inconclusive. Providing calves with multiple smaller milk and solid feed meals (or ad libitum provision) may decrease abomasal damage. In future research, ulcers, erosions, and scars as well as fundic and pyloric lesions should be recorded separately, because etiologies of these may differ. Further research is required to understand the exact pathway(s) by which milk replacer causes abomasal damage in veal calves; that is, whether low abomasal pH, overloading, or composition are important. Further research is also required to elucidate whether rapid intake of milk replacer and solid feed, which is influenced by restricted amounts fed, inter-calf competition, and calf breed, increases abomasal damage. Research is also needed into the effect of medication and nutrient deficiencies other than iron. The types of experimental designs that can be used for future research could be enhanced if a means to assess abomasal damage antemortem is developed. We conclude that it is unlikely that abomasal or ruminal hairballs, iron deficiency, water provision, and various infections and diseases are significant contributors to abomasal damage in veal calves.

Perspectives on the Management of Surplus Dairy Calves in the United States and Canada

“…An additional concern with certain specialfed veal calves, specifically for milk-fed veal calves, is the contribution of feeding strategies to abomasal damage, which has a prevalence at harvest ranging from 70 to 100% (65,66). Abomasal damage is multifactorial in origin and could be due to inaccessibility to the outdoors and water, limited forms of roughage, bucket feeding, large and infrequent milk meals, and limited space allowance [reviewed by (13)]. Feeding calves low volumes of milk reduces productivity and health and leads to negative affective states, and it is unclear why the practice persists.…”

“…Historically, surplus calf production systems, including veal farms, have struggled with negative stigma, including societal concerns about animal welfare (9). Calves are removed from dairy farms as neonates (10), and are often transported longdistances with one or more stops at auction markets or assembly stations (11,12) before arriving to calf raisers where they are housed individually and fed low planes of nutrition (13). Poor care surplus calves receive during the first few weeks of early life contributes to high rates of morbidity and mortality.…”

Association between gastrointestinal tract, claw disorders, on-farm mortality and feeding management in veal calves

“…Although there are several hypotheses on the aetiology of abomasal lesions in veal calves (Bus et al 2019), also their high prevalence recorded in this study might be mainly related to the amount and the type of solid feeding provided to calves. Support to this assumption comes from previous studies showing that the consumption of large amounts of corn grain alone (Prevedello et al 2012) or of 80:20 of concentrate and roughage diets (as-fed basis) (Berends et al 2014) by veal calves worsen their abomasal damage.…”

Welfare Assessment in Calves Fattened According to the “Outdoor Veal Calf” Concept and in Conventional Veal Fattening Operations in Switzerland

“…The occurrence of abomasal pyloric lesions found in our study (65% (IF)–72% (CF) of examined abomasa) is similar to the findings of other authors [ 31 , 32 ]. Abomasal ulcers have a multifactorial etiology, whereby stress and feeding techniques play important roles [ 31 , 33 ]. A study in foals, where, in contrast to calves, a survey in living animals can be performed via endoscopy, showed gastric lesion prevalences between 47 and 57% in foals without signs of gastric disease.…”

“…In our study, all IF calves were fed twice daily, whereas automatic feeders allowing more meals per day were present in all CF. The impact of abomasal lesions on calf welfare is difficult to quantify as a diagnosis in vivo is not possible in ruminants (except for bleeding and perforating ulcers) [ 33 ]. Nevertheless, gastric lesions are known to be painful in monogastric species, and perforating ulcers are an important reason for death in calves [ 31 , 33 , 38 ], and an impact on animal welfare must, therefore, be considered.…”