Original
Correlation between ruminal pH and body condition score in cows with subacute ruminal acidosis
Correlación entre el pH ruminal y el índice de condición corporal en vacas con acidosis ruminal subaguda
Correlation between ruminal pH and body condition score in cows with subacute ruminal acidosis
Revista MVZ Córdoba, vol. 22, no. 3, pp. 6215-6224, 2017
Universidad de Córdoba
This work is licensed under Creative Commons Attribution-NonCommercial 4.0 International.
Received: 09 January 2017
Accepted: 08 May 2017
Abstract: Objective. The purposes of this field study were to a) confirm the presence of subacute ruminal acidosis (SARA) in Turkish dairy herds in Aydin region, b) record its regional distribution and c) to determine whether there is a relationship between body condition scoring, ruminal contractions and ruminal pH. Materials and methods. Ruminal fluid samples, via rumenocentesis, were withdrawn from a total of 120 Holstein dairy cows, from 5 herds (n=24 cows per herd). Rumen pH was analyzed on-site with a portable pH-meter for a precise SARA diagnosis. Classical body condition scoring systems (USBCS method) were utilized within 1-5 scale with 0.25 intervals. Results. Out of 120 cows enrolled 13 were (10.83%) classified as affected with SARA (pH<or=5.5), 6.6% were marginal (pH 5.6-5.8) and 82.5% were normal (pH>5.8). There was a significant difference (p<0.01) among farm V and other farms regarding mean ruminal pH. The overall means of BCS were found as 3.45±0.037, 3.43±0.122 and 4.30±0.075 in healthy animals, SARA suspected cows and cows with SARA, respectively with increased BCS in cows with SARA (p<0.01). Inter group comparison of ruminal contractions showed statistical significance (p<0.01). There were correlations among ruminal pH and ruminal contraction (r=0.622, p<0.01), ruminal pH and health status (r=-0.770, p<0.01), rumen contraction and health status (r=0.546, p<0.01). Conclusions. In the present study BCS and ruminal contractions data were used as indicators, in which correlations were found among ruminal pH and ruminal contraction and ruminal pH and BCS, favoring the usage or those parameters as probable biomarkers in cows with SARA.
Keywords: Body condition score, dairy cattle, subacute rumen acidosis.
Resumen: Objetivo. Los objetivos de este estudio de campo fueron a) confirmar la presencia de acidosis ruminal subaguda (SARA) en los rebaños de vacas lecheras turcas en la región de Aydin, b) registrar su distribución regional y c) determinar si existe una relación entre las puntuaciones del estado corporal, ruminal Contracciones y pH ruminal. Materiales y métodos. Se extrajeron muestras de líquido ruminal, a través de rumenocentesis, de un total de 120 vacas lecheras Holstein, de 5 hatos (n = 24 vacas por rebaño). El pH del rumen se analizó en el sitio con un pH-metro portátil para un diagnóstico preciso de SARA. Los sistemas clásicos de clasificación de estado corporal (método USBCS) se utilizaron en escala 1-5 con intervalos de 0,25. Resultados. De las 120 vacas inscritas, 13 fueron (10.83%) clasificadas como SARA (pH =5.5), 6.6% marginales (pH 5.6-5.8) y 82,5% normales (pH>5.8). Hubo una diferencia significativa (p<0.01) entre la finca V y otras fincas con respecto al pH ruminal medio. El promedio global de BCS fue de 3.45±0.037, 3.43±0.122 y 4.30±0.075 en animales sanos, SARA sospechosos de vacas y vacas con SARA, respectivamente con aumento de BCS en vacas con SARA (p<0.01). La comparación intergrupal de contracciones ruminales mostró significación estadística (p<0.01). Hubo correlaciones entre el pH ruminal y la contracción ruminal (r=0.622, p<0.01), pH ruminal y estado de salud (r =-0.770, p<0.01), contracción ruminal y estado de salud (r=0.546, p<0.01). Conclusiones. En el presente estudio se utilizaron indicadores BCS y contracciones ruminal como indicadores, en los que se encontraron correlaciones entre pH ruminal y contracción ruminal y pH ruminal y BCS, favoreciendo el uso o esos parámetros como biomarcadores probables en vacas con SARA.
Palabras clave: Condición de la condición corporal, ganado lechero, acidosis ruminal subaguda.
INTRODUCTION
Subacute ruminal acidosis (SARA),a well known digestive disorder, has been characterized by repeated bouts of low ruminal pH (1,2,3). SARA generally results from diets low in digestible fiber or rich in simply fermentable carbohydrates (4,5). Cows with SARA exhibited decreased rumen motility, loss of body condition score (BCS), diarrhea, depression,reduced milk production and laminitis (6,7). Ruminal pH values detected between 5.5 and 6.0 were denoted for cows experiencing SARA or being at risk for SARA (7,8).
The prevalence and the clinical consequences of (SARA) in dairy cows are still poorly understood. Given previous literature connecting SARA to health problems i.e. metabolic diseases of dairy cattle (9), the evidenced proof is relatively weak. SARA has previously been linked to cause systemic inflammation (7) and to participate in BCS loss of affected cows prone to be in poorer condition post calving (10,11). On the other hand regarding SARA detection of pathophysiological route remains difficult because of a) database from field conditions remains insufficient, b)less is known about real consequences, incidence and regional distribution of SARA on the field (11). Furthermore experimental modelling for conceiving SARA in trial animals differ considerably from conditions detected in natural dairy herds. Therefore warranted research regarding the field, is necessary to better understand SARA(11). In the present study the purposes were to a) confirm the presence of SARA in Turkish dairy herds in Aydin region, b) record its regional distribution and c) determine whether there is a relationship between among condition scoring, ruminal contractions and ruminal pH.
MATERIALS AND METHODS
Farm data. The data from 5 dairy farms in Aydin municipality Eagean Region of Turkey, were collected. In an attempt to organize for the dairy herd health management program, one MS Agriculture Engineer [D.A.U. who is the director of Faculty Farm, Faculty of Veterinary, Adnan Menderes University and is specialized (author of many scientific reports on this subject) on BCS] and two Veterinary Surgeons (K.U. and O.Ö.) (from animal hospital, Faculty of Veterinary, Department of Internal Medicine, Adnan Menderes University), visited these farms regularly. During the visits, health status and reproductive performance were checked, at least once a month. The details of feeding management on these farms were similar to a previous study (12). All farms included fed cows on total mixed ration (TMR). In the present study TMR was composed of forages, whole cottonseed, grains, protein, vitamin and mineral supplements mixed together to for a balanced ration
Cow data. A total of 120 cows (n=24 in each farm) with one lactation per cow, were included in the study. The cow data with lactation number, birth date, calving date and general health status were detected and noticed on farm visit. All included cows were examined for physiological reproductive function via rectal palpation 30 days following calving. There was no evidence of postpartum disorders (such as endometritis, displacement of abomasum, ketosis, as beacuse farmers or owners were routinely calling responsible farm veterinarian for examination, diagnosis if necessary).Two groups of 12 cows (13), were selected randomly in each herd. First group consisted of early lactation cows (0-70 days in milk) whereas other relevant composed of mid-lactation cows (70-140 days in milk).
Rumenocentesis and ruminal pH detection. Ruminal fluid collection was carried out via rumenocentesis by experienced researchers (K.U. and O.Ö) 4-8 hours after morning TMR feeding, from 264 selected cows through a period of January to September 2016. Ruminal fluid pH was determined immediately with a portable pH-meter (Edge pH meter, HANNA, Spain) able to detect pH changes from 0 to 14. All cows were checked for number of rumen contraction at the same time.
Body condition scoring. A previously described United States BCS (USBCS) system (14) through visual estimation composed of a 1-5 scale with 0.25 intervals, as was also adopted by some researchers (15,16). After morning milking in farm, BCS data were collected and assessed by one of the present researchers (D.A.U), who is experienced, having MS and PhD degrees in Department of Animal Science, Agricultural Faculty. The latter author assessed BCS on visual observing flowcharts developed and used previously (14) and recently described in a very updated study (15).
Statistical analysis. In an attempt to perform analysis, determination of the effects of the factors on ruminal pH in the models were carried out using a General Linear Model (GLM) procedure of the SPSS Release 18.0. According to evaluation predicated on 5 traits (farm, lactation period, health status, BCS and ruminal contraction), it was stated that those characters had effect on ruminal pH. The model of this purpose was shown below. The differences between subclass means were determined by Duncan’s multiple range test (17). The statistical model used for the analysis is as follows:
Yijklm = μ + si + lpj + hsk + VKPl + byx. Xijklm + byx+ eijklm
Where; Yijkl: i. farm, j. lactation period, k. health status, l. body condition score, m. cow’s 305-day lactation milk yield,
μ :population mean,
si : i. farm’s effect (i: 1, 2, 2, 4, 5),
lpj : j. lactation period’s effect (j: 1, 2),
hsk: k. health status’s effect (k: 1, 2, 3),
VKPl: l. body condition score’s effect (l: 1, 2, 3)
Xijklm : i. farm, j. lactation period, k. health status, l. body condition score , m. cow’s ruminal contraction,
byx : partial regression coefficient with regard to ruminal contraction of ruminal pH,
eijklm: residual error.
The relations between traits and ruminal pH were investigated by Pearson Correlation Test (SPSS, 2009).
RESULTS
Lactation data. In each herd 2 groups of 12 cows were enrolled randomly in each herd. To those of an overall 120 animals included 13 were (10.83 %) classified as affected with SARA (pH< or=5.5) whereas 8 other cows (6.6%) were marginal (pH=5.6-5.8). To those of cows with SARA were detected in 1 out of 5 farms, in farm V. Out of those 13 cows, 7 were in early lactation and 6 were in midlactation period.
Ruminal contractions. Regarding health status (SARA, SARA suspected or healthy controls) of animals,group comparison showed statistical significance (p<0.01) for ruminal contractions.
Ruminal pH analysis. It was possible to draw a ruminal fluid from all initially selected 120 animals (60 in early lactation and 60 in midlactation period). Overall, 13 cows (10.83%) had a ruminal pH≤5.5 at the time of rumenocentesis. In farm V mean (st. dev) ruminal pH was 5.55±0.087, presenting statistical significance in contrast to other 4 farms without SARA positive animals. The minimum and maximum pH values were found to be 5.06 and 6.79, respectively. On the other side on farm V, marginal pH values, between 5.6 and 5.8, were found in 8 cows (6.6%) out of all cows, 4 (12%) early lactation and 4 (23.9%) mid-lactation cows.
BCS anaysis. In healthy animals mean (st. error) BCS were detected as 3.45±0.037, whereas in SARA suspected cows and in cows with SARA were deemed 3.43±0.122 and 4.30±0.075, respectively with a statistically significance (p<0.01). Overall interpretation revealed increased BCS in cows with SARA (Table 1).
| Groups | BCS | |||
| N | Min | Max | ||
| Healthy | 99 | 3.45a± 0.037 | 2.75 | 4.25 |
| SARA Suspected | 8 | 3.43a± 0.122 | 2.75 | 3.75 |
| SARA | 13 | 4.30b± 0.075 | 4.00 | 4.75 |
| Ruminal Contraction | ||||
| Healthy | 99 | 9.48a± 0.123 | 7 | 12 |
| SARA Suspected | 8 | 8.63a± 0.324 | 7 | 10 |
| SARA | 13 | 6.85b± 0.154 | 6 | 8 |
| a, b, c, d: Least square means on the same columnwithin each factor, followed by the different letter are significantly (p<0.01), ** p<0.01. NS: Nonsignificant, BCS: Body condition score | ||||
Descriptive statistics. The descriptive statistics of all type traits according to lactation number for farms were calculated and were shown in Table 2. The effects of farms on ruminal pH were found statistically significant (p<0.01). The means of ruminal pH were found similarly at lactation period and the effects of lactation period were found non-significant (p>0.05). The mean values of ruminal pH were found 5.26, 5.68 and 6.57 according to health status (respectively, SARA, SARA suspected and healthy) (Table 2). Finally, the means for BCS were ranged from 5.90 to 6.55 (Table 2). The effects of health status and BCS on ruminal pH were found significant (p<0.01). The effects of ruminal contraction on ruminal pH were found significant (p<0.05).
The correlations between factors and ruminal pH were presented in Table 3. The highest correlations among ruminal pH and ruminal contraction were found (0.622) and statistically significant (p<0.01). The lowest and negative correlations were found between ruminal pH and health status (r=-0.770) and was found significant (p<0.01). Also, correlations between rumen contraction and health status were found positive (r=0.546) and significant (p<0.01).
| Factors | N | Ruminal pH | Min | Max |
| Farms | ** | |||
| I | 24 | 6.51ab ± 0.079 | 5.69 | 7.13 |
| II | 24 | 6.75c ± 0.085 | 6.27 | 7.67 |
| III | 24 | 6.35a ± 0.066 | 5.72 | 6.77 |
| IV | 24 | 6.71bc ± 0.069 | 5.96 | 7.21 |
| V | 24 | 5.55d ± 0.087 | 5.06 | 6.79 |
| Lactation period | NS | |||
| 0-70. day | 60 | 6.36 ± 0.067 | 5.40 | 7.67 |
| 70-140. day | 60 | 6.38 ± 0.629 | 5.06 | 7.21 |
| Health status | ** | |||
| Healthy | 99 | 6.57a ± 0.039 | 5.69 | 7.67 |
| SARA suspected | 8 | 5.68b ± 0.088 | 5.52 | 5.80 |
| SARA | 13 | 5.26c ± 0.143 | 5.06 | 5.47 |
| BCS | ** | |||
| 2 | 22 | 6.32a ± 0.084 | 5.69 | 7.02 |
| 3 | 73 | 6.55a ± 0.053 | 5.52 | 7.67 |
| 4≤BCS | 25 | 5.90b ± 0.743 | 5.06 | 7.13 |
| a, b, c, d: Least square means on the same columnwithin each factor, followed by the different letter are significantly (p<0.01), ** p<0.01, NS: Nonsignificant, BCS: Body condition score | ||||
| Factors | Ruminal pH | Health Status | BCS | Rumen Contraction |
| Ruminal Ph | 1 | |||
| Health Status | -0.770** | 1 | ||
| BCS | 0.622** | -0.582** | 1 | |
| Rumen contraction | -0.226 | 0.546** | -0.175 | 1 |
| ** p<0.01 | ||||
DISCUSSION
Altough there has been several literature regarding SARA, an uncertainty is still evident for interpretation of ruminal pH values truly to diagnose SARA (7,18). In practice by ruminocentesis manuplation, ruminal pH analysis was recommended for evaluation of SARA incidence in dairy farms (10). In the present study all 5 farms participated were employed within 24 cows per each.For the herd level, analysis of ruminal pH in a sample of 5–19 cows per herd might be of beneficial specifically at the postpartum period (10,19). Most Turkish dairy cows are raised in small-medium sized farms [herd size ranges from 25 to 100 milking cows].All forages, protein supplements, minerals, vitamins and grains are thoroughly mixed in TMR, in which the cows were fed in the present study.
In the present study as was also aformentioned above at the time of rumenocentesis, 7 early lactation cows in and 6 other relevant mid-lactation cows in farm V were found to be experiencing SARA (cows with a ruminal pH ≤5.5). Similarly on that farm 4 early lactation cows and 4 other relevant mid-lactation cows were marginally acidotic.Interestingly out of 5 different farms enrolled, solely the farm V were composed of 21 (out of 24) SARA positive or SARA risk animals. At herd level if 1/3 or more of the cow population present rumen pH between 5.6-5.8, the animals were detected as marginally acidotic (13). Both SARA positive and SARA risk animals were located on the same farm, in which whole animals were fed TMR ration, similar to other farms (I to IV) involved where all cows were healthy. The difference might be briefly explained with either errors in ration formulation or inappropriate TMR particle size (20). Similar findings were previously reported by Morgante et al. (19) detected that feeds chopped extremely fine were in association with SARA, in which could be the key factor in our study. The farm ration was formulized by the owner who has no sicentific education.Ration formulation and mixing errors were reported as foremost risk factors related to existence of SARA (21). Lastly regular interpretation of both ration formulation and feed particle size has growing interest (20).
BCS possess significance during different lactation stages (fresh cows, early lactation, mid-lactation, late lactation and dry period). BCS frequently exists as 3 (5-point scale) in mid-lactation stage. If cows present over-form throughout mid-lactation, BCS varies from 3.5 to 4.0 (5-point scale) (22). In a very recent study a total of 50 head Holstein-Friesian cows in mid-lactation (at 1st-4rd parity), located in Aydin, Turkey were scored comperatively by use of the primary systems utilized within the US (1-5 scale with 0.25 intervals) and to those of Bayer Health Care Animal Health’s BCS Cowdition Smartphone App. In the latter study overall mean values of BCS were found as 3.37±0.068 and 3.45±0.060 for BCS Cowdition and USBCS, respectively. There was a positive correlation (r=0.81, p=0.01) among BCS Cowdition and USBCS systems with a positive linear relationship (r=0.66, p=0.001) (15).
Ruminal pH was detected lower in cows with extensive loss in BCS after calving. The reason for the poor BCS in low ruminal pH cows might be similar to a dairy cow study (10) in which metabolic acidosis resulted with elevated protein catabolism accompanied by growth impairment. In general during the postpartum period a cow loses BCS because of negative energy balance in an attempt to achieve a peak milk production (23). In the present study mean BCS were detected as 3.45±0.037, whereas in SARA suspected cows and in cows with SARA were deemed 3.43±0.122 and 4.30±0.075, respectively with a statistically significance (p<0.01). Overall interpretation revealed increased BCS in cows with SARA. In addition there was a significant (p<0.01) correlation (r=0.622) between BCS and ruminal pH, observed in this study. The alterations of BCS could be related to several reasons i.e. appropriate level of nutrition and a well designed ration could affect body weight of cows along with conversion of tissues for increased productivity (24,25,26).
Decreased number of ruminal contractions were previously denoted as a clinical finding in relation with SARA (27). In a prior study in Iran, there were no significant differences between cows experiencing SARA and other cows in number of rumen contractions (in 2 min, p=0.592). Furthermore no significant difference was either detected between animals with SARA and those with marginal pH values and the rest of the cows regarding number of ruminal contractions (in 2 min, p=0.455) (13). In the present study taking into account health status (SARA, SARA suspected or healthy controls) of animals, group comparison showed statistical significance (p<0.01) for ruminal contractions.
The correlation between factors and ruminal pH were investigated in the present study. The highest correlations was found between ruminal pH and ruminal contraction (0.622) with a statistical significance (p<0.01). The lowest correlation was evident between ruminal pH and health status (r=-0.770, p<0.01). Between rumen contraction and health status a positive (r=0.546, p<0.01) correlation was detected.
In conclusion in the present study an attempt is made to establish the regional distribution of SARA in selected dairy herds in Aydin mucipality of Eagean Region based on the ruminal pH determination. Consequences of SARA on individual health, production level and metabolic status for both individual and herd level were established. Therefore BCS and ruminal contractions data were used as indicators, in which correlations were found among ruminal pH and ruminal contraction and ruminal pH and BCS, favoring the usage or those parameters as probable biomarkers in cows with SARA.
In a small to middle sized farms, the problem solely in 1 cow might affect the farmer’s income. Hence at the cow level, quick determination of ruminal pH in early lactation may have helped prevention and reduce economic loss (28). Given the current and different feeding management conditions in Turkish dairy farms, and the association between ruminal pH and the incidence of postpartum disorders remains unclear, the interpretation of ruminal pH might provide useful and applicable information to improve the health and milk production of dairy cows(28).Furthermore this study and previous one (29) also demonstrated the presence of SARA in this region, which may be taken into account with possible preventative measurements.
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