**5.1 Ruminal acidosis (RA)**

RA is a metabolic disease that settles in the rumen and is produced by the ruminal fermentation of large amounts of nonfibrous carbohydrates, such as starch and sugars, which lead to the production of high amounts of volatile fatty acids (VFAs) and lactate, which accumulate in the rumen and cause an abnormal reduction in rumen pH [58]. Ruminal epithelial cells, not protected by mucus, are vulnerable to chemical acid damage [59], and this decrease in ruminal pH together with high concentrations of VFAs causes ruminitis, erosions, and ulcerations of the ruminal epithelium. In turn, abnormal thickening of the stratum corneum of the mucosa occurs due to accumulation of corneal cells with perturbations in their keratinization resulting in hyper and parakeratosis, observing partially pigmented ruminal mucous membranes [60, 61].

Among the works carried out on the feeding management of the Lidia bull, the one carried out by Bartolomé [26] stands out because he observes 66.2% of the animals studied with ruminal pH values compatible with RA, of which 41.5% chronically (pH = 6.2–5.6) according to the classification of González et al. [62]. In addition, 70.7% of animals presented parakeratosis in the mucosa, and in 26.9%

of bulls sampled, liver lesions were detected. In the same line, Lomillos et al. [27] reported a 43% reduction in the length of the ruminal papilla of bulls subjected to the finishing bait, added to an increase in the thickness of their mucosa, which approximately doubled the value obtained in the group of animals considered control, and maintained in pure extensive regime (**Figures 5** and **6**).

In this context, the decrease in rumen pH predisposes the epithelium to become fragile and loses its ability to act as a barrier between the ruminal environment and the blood, which predisposes the appearance of continuity solutions, which allow the passage of microorganisms toward the bloodstream and the consequent risk of suffering sepsis for the animal [60]. Among others, *Fusobacterium necrophorum* and *Corynebacterium pyogenes*, are bacteria often carried to the liver through the portal vein, and there they begin infection and abscess formation, which compromise their metabolic capacity [5]. From the liver, they can go to the peritoneum, generating peritonitis, and sometimes they can go to the lung, heart valves, kidneys, joints, and so on [63]. In this sense, García et al. [12] recorded abscesses at the liver level in 4% of the studied bulls and hepatic-diaphragmatic adhesions in 21% of cases that extended to the pulmonary pleura, confirming, after culture, *Fusobacterium necrophorum* as the main causative agent of lesions.

At the same time, the intense finishing feeding management based on the use of high amounts of carbohydrates is a predisposing cause of hoof lesions such as the lameness by diffuse aseptic pododermatitis observed in the animals as an excessive growth of the hoof [60] widely described in Lidia cattle [25, 29] and detected with a prevalence of 28% in the fought animals [12].

According to Nocek [64], the relationship between RA and laminitis seems to be associated with hemodynamic alterations of peripheral microcirculation. During acidosis, as a consequence of the decrease in ruminal pH, a process of bacteriolysis takes place in the rumen, releasing vasoactive substances (histamine and endotoxins), which are absorbed through the damaged rumen wall and cause vasoconstriction and dilation, which destroy microcirculation at the level of synovial joints and chorionic tissue of the hoof [65, 66]. The combination of high concentrations of histamine in areas of terminal circulation [67], the increase in digital blood flow and high blood osmolarity induce an increase in blood pressure inside the animal's hoof, producing a serum exudate, which results in edema, internal hemorrhages from thrombosis, and finally, the expansion of the chorion, causes intense pain [60, 64]. The disease presents with signs of lameness, excessive growth of the hooves, and the appearance of dark lines or bands on the surface of the hooves, a consequence of the ischemia generated by vascular damage and

**121**

*The Lidia Breed: Management and Medicine DOI: http://dx.doi.org/10.5772/intechopen.92008*

edema [68]. At present, lameness is treated with anti-inflammatories, and the hoof overgrowth is usually remedied in livestock by a functional cut of the hoof, using

It seems clear that the RA generated after the intensive bait and the pathological processes to which it predisposes or directly causes, affects the performance of the bull in the arena in the form of physical decline of the animal that hinders its ethological and physical performance [12, 20, 26, 69]. Therefore, it is of great importance to explore possible solutions or prevention strategies by designing a

To control the process, in principle, it would be enough to reduce the amount of nonfibrous carbohydrates provided with the diet, but this measure would lead to a decrease in the rations' energy level, with the consequent delay in the fattening of

In the case of the final bull bait, improved rationing and feeding management could have a considerable impact on rumen pH stability. Adapting the ruminal environment by slowly and gradually changing from one forage feed ration to another concentrate would stimulate the development of the rumen papillae and the growth of the lactic acid transforming flora [5], in such a way so that a greater amount is metabolized and the mucosa of the rumen can absorb a greater amount of generated VFAs. This adaptation of the mucosa to concentrated rations takes approximately 4–6 weeks [64] and changes in microflora about 3 weeks [70]. The adoption of the mixed total ration type feeding system, better known as "unifeed" carriage (**Figure 7**), widely used in dairy cattle, ensures a balanced consumption of concentrate and forage, which is a very important advantage. In this way, it is possible to increase the energy density of the rations by reducing the risk of digestive problems [71]. In fact, in recent years, this type of food management has begun to be incorporated into the Lidia farms, mainly in farms located in the south of the peninsula, later extending through Madrid and Salamanca [72].

In this sense, the contribution of compensated and high fiber rations through the use of "unifeed" mixer cart during the bull bait does not generate a pH decrease below the physiological limits, as shown in Graph 1 that describes the pH ruminal of bulls fed following this pattern of food management for a month [31]. However, it is not clear that this handling is the solution to the RA of the bull since the use of these mixing machines during the entire bait period, which usually lasts between 3 and 9 months, can generate lesions in the morphology of the papilla ruminal (decrease in length and thickening of the mucosa) similar to those found in animals

the cattle crush facilities to immobilize the animal.

*Thickened and shortened papilla of finished bulls [27].*

the bull and the consequent economic losses.

new food management.

**Figure 6.**

**Figure 5.** *Normal papilla of extensive animal.*

*The Lidia Breed: Management and Medicine DOI: http://dx.doi.org/10.5772/intechopen.92008*

*Animal Reproduction in Veterinary Medicine*

of bulls sampled, liver lesions were detected. In the same line, Lomillos et al. [27] reported a 43% reduction in the length of the ruminal papilla of bulls subjected to the finishing bait, added to an increase in the thickness of their mucosa, which approximately doubled the value obtained in the group of animals considered

In this context, the decrease in rumen pH predisposes the epithelium to become fragile and loses its ability to act as a barrier between the ruminal environment and the blood, which predisposes the appearance of continuity solutions, which allow the passage of microorganisms toward the bloodstream and the consequent risk of suffering sepsis for the animal [60]. Among others, *Fusobacterium necrophorum* and *Corynebacterium pyogenes*, are bacteria often carried to the liver through the portal vein, and there they begin infection and abscess formation, which compromise their metabolic capacity [5]. From the liver, they can go to the peritoneum, generating peritonitis, and sometimes they can go to the lung, heart valves, kidneys, joints, and so on [63]. In this sense, García et al. [12] recorded abscesses at the liver level in 4% of the studied bulls and hepatic-diaphragmatic adhesions in 21% of cases that extended to the pulmonary pleura, confirming, after culture, *Fusobacterium* 

At the same time, the intense finishing feeding management based on the use of high amounts of carbohydrates is a predisposing cause of hoof lesions such as the lameness by diffuse aseptic pododermatitis observed in the animals as an excessive growth of the hoof [60] widely described in Lidia cattle [25, 29] and detected with a

According to Nocek [64], the relationship between RA and laminitis seems to be associated with hemodynamic alterations of peripheral microcirculation. During acidosis, as a consequence of the decrease in ruminal pH, a process of bacteriolysis takes place in the rumen, releasing vasoactive substances (histamine and endotoxins), which are absorbed through the damaged rumen wall and cause vasoconstriction and dilation, which destroy microcirculation at the level of synovial joints and chorionic tissue of the hoof [65, 66]. The combination of high concentrations of histamine in areas of terminal circulation [67], the increase in digital blood flow and high blood osmolarity induce an increase in blood pressure inside the animal's hoof, producing a serum exudate, which results in edema, internal hemorrhages from thrombosis, and finally, the expansion of the chorion, causes intense pain [60, 64]. The disease presents with signs of lameness, excessive growth of the hooves, and the appearance of dark lines or bands on the surface of the hooves, a consequence of the ischemia generated by vascular damage and

control, and maintained in pure extensive regime (**Figures 5** and **6**).

*necrophorum* as the main causative agent of lesions.

prevalence of 28% in the fought animals [12].

**120**

**Figure 5.**

*Normal papilla of extensive animal.*

**Figure 6.** *Thickened and shortened papilla of finished bulls [27].*

edema [68]. At present, lameness is treated with anti-inflammatories, and the hoof overgrowth is usually remedied in livestock by a functional cut of the hoof, using the cattle crush facilities to immobilize the animal.

It seems clear that the RA generated after the intensive bait and the pathological processes to which it predisposes or directly causes, affects the performance of the bull in the arena in the form of physical decline of the animal that hinders its ethological and physical performance [12, 20, 26, 69]. Therefore, it is of great importance to explore possible solutions or prevention strategies by designing a new food management.

To control the process, in principle, it would be enough to reduce the amount of nonfibrous carbohydrates provided with the diet, but this measure would lead to a decrease in the rations' energy level, with the consequent delay in the fattening of the bull and the consequent economic losses.

In the case of the final bull bait, improved rationing and feeding management could have a considerable impact on rumen pH stability. Adapting the ruminal environment by slowly and gradually changing from one forage feed ration to another concentrate would stimulate the development of the rumen papillae and the growth of the lactic acid transforming flora [5], in such a way so that a greater amount is metabolized and the mucosa of the rumen can absorb a greater amount of generated VFAs. This adaptation of the mucosa to concentrated rations takes approximately 4–6 weeks [64] and changes in microflora about 3 weeks [70].

The adoption of the mixed total ration type feeding system, better known as "unifeed" carriage (**Figure 7**), widely used in dairy cattle, ensures a balanced consumption of concentrate and forage, which is a very important advantage. In this way, it is possible to increase the energy density of the rations by reducing the risk of digestive problems [71]. In fact, in recent years, this type of food management has begun to be incorporated into the Lidia farms, mainly in farms located in the south of the peninsula, later extending through Madrid and Salamanca [72].

In this sense, the contribution of compensated and high fiber rations through the use of "unifeed" mixer cart during the bull bait does not generate a pH decrease below the physiological limits, as shown in Graph 1 that describes the pH ruminal of bulls fed following this pattern of food management for a month [31]. However, it is not clear that this handling is the solution to the RA of the bull since the use of these mixing machines during the entire bait period, which usually lasts between 3 and 9 months, can generate lesions in the morphology of the papilla ruminal (decrease in length and thickening of the mucosa) similar to those found in animals

**Figure 7.** *Small format "unifeed" mixer truck, adapted to Lidia cattle (BIGA).*

fed through traditional feeding management. In addition, the feeding time generates a negative effect on the severity of the lesions, with the animals fed for more than 6 months being the ones with the greatest lesions at the level of the rumen mucosa [27].

Another strategy to prevent RA is the use of additives both chemical and microbial. Among the first are buffer substances such as bicarbonate, alkalizing agents such as magnesium oxide, or adjuvants such as bentonite, which can help fight RA because it absorbs part of the volatile fatty acids at the ruminal level [5, 65, 73, 74]. The most commonly used microbial additives to combat RA are yeast extracts and live yeasts. These microorganisms help maintain ruminal pH by stimulating the growth of cellulolytic bacteria and lactic acid users, preventing their accumulation in the rumen [75].
