Causes of Parturition in Cattle

Causes of Parturition in Cattle1.0 IntroductionParturition in cattle is known to be a abstruse physiological process, where the onset is generally accepted to be initiated by the fetus (Thorburn et al., 1977 Thorburn, 1979). In normal circumstances, this complicated process involving several hormonal interactions and should conclude without any(prenominal) human interference, leaving a healthy cow with a vigorous calf. However, in reality a large proportion of calving require assistant to varying degrees that may result in a stillborn calf (Meijering, 1984). Domestication and breeding programmes in the dairy industry select for oxen that uprise calves that are comparatively larger when compared to their dams a regular occurrence in cattle compared to around other mammals (McClintock, 2004).As dystocia is highly related to the pelvic state (Price and Wiltbank, 1978), being able to measure the pelvic dimensions is beneficial. The process of measuring the internal and impertinen t capacity and diameter of the pelvis is known as pelvimetry (Studdert et al., 2011). This is elucidated in studies which issue that thither is value in employ international pelvimetry as a prognosticateor for the internal pelvic measurements (Murray et al., 2002), while others show that withers height and nerve center girth were the best predictors of internal pelvic surfaces (Kolkman et al., 2012 Coopman et al., 2003). Hence, it would be easier if the fweapon systemer had an alternate method to measure internal pelvic dimensions, such as predicting those dimensions through measurements of external morphometry which could be done directly employ measuring tape. in that locationfore, the ability to accurately determine the possibility of dystocia will allow early and appropriate intervention, which then decreases the unwholesomeness and mortality of the dam and fetus, improving animal welfare and reducing economic losses (Linden et al., 2009).There is a need for information regarding associations surrounded by internal pelvic measurements and external morphometry, which may stick value in determining dams with larger pelvic opening that increases calving ease (Bellows et al., 1971). Currently, no research has been done to bring the association mingled with the intrapelvic measurements and the external morphometric measurements in Friesian cross cattle in Malaysia. Hence, the objective of this study was to determine the relationship amid intrapelvic plain, morphometric measurements, age, system weight and ashes retard tote up in Friesian cross cattle which could be of value in determining dams with larger pelvic openings and thereby reducing the risk of dystocia. It is hypothesized that there is an association between the intrapelvic measurements and external morphometry in Friesian cross cattle. 2.0 Literature Review2.1 DystociaDystocia, defined as delayed or difficult parturition (Mushtaq, 2016), is usually categorise into two main cause s which are direct factors and indirect factors (Meijering, 1984). The former usually being anatomical and physiological factors such as malpresentation of the calf in the fork up shtupal and uterine torsion in the dam. The latter is related to phenotypic effects that are related to the calf such as calf support weight, multiple calvings and perinatal mortality, as healthful as, phenotypic effects associated with the cow such as cow pelvic country, cow body weight at calving, cow body condition score, gestation length and calving assistance. Indirect factors also include non-genetic factors such as cow age, parity of cow, calf sex, nutrition and other disorders, while genetic factors involve cow, bull and calf breeds (Zaborski et al., 2009). The most common cause of dystocia is a somatogenic incompatibility between the size of the foetus and maternal pelvic size, also known as feto-pelvic incompatibility. The pelvic size of the dam is mainly influenced by the stage of maturit y of the cow. As a result, a smaller size of the pelvis contri plainlyes to the higher(prenominal) incidence of dystocia in heifers (Haskell and Barrier, 2014) and vice versa where dams with larger pelvic openings experience less calving difficulty (Barrier et al., 2013).2.2 Breed Comparisons some(prenominal) studies have shown that there are significant differences in pelvic dimensions between breeds of beef and dairy cattle (Ramin et al., 1995 Laster 1974 Meijering and Pastma, 1984 McElhenney et al., 1985). There are also differences between herds inside breeds, purebreds and crossbreeds, and small breeds and large breeds. The pelvic height and pelvic largeness increase greatly with advancing age, which shows that the pelvic area is larger in mature cows in comparison to heifers. The specify pelvic heights in beef and dairy heifers can vary from 13.5 cm to 19.3 cm, the pelvic width from 12.6 cm to 18 cm, and the mean pelvic area from 170 cm2 to 290 cm2.2.3 Impact of Dystocia on DamThe occurrence of dystocia has shown to have an adverse effect on the reproductive performance of dairy cows, where the first oestrus, days open and the calving interval were significantly longer (Gaafar et al., 2010). Fertility is further impaired as a result of dystocia as it causes a reduction in conception rate and an increase in the number of serve per conception (Lopez de Maturana et al., 2007). Total draw yield also tends to be lour in cows that have experienced dystocia at calving compared to those that calved normally (Berry et al., 2007). Furthermore, there is a significant increase in the mortality rate of cows experiencing dystocia in comparison to those that calved without assistance and the number is highest in cows that require dear intervention during parturition (Dematawewa and Berger, 1997).2.4 Impact of Dystocia on CalfMajority of stillbirths were account to be a direct result of dystocia (Meyer et al., 2000 Lombard et al., 2007). During parturition, there are several dramatic physiological changes that can have adverse effects on the fetal oxygen concentration (Lombard and Garry, 2013). The foetus can experience neonatal asphyxia during the calving process imputable to hypoxia, decreased blood flow as a result of occlusions of the placenta, or ischaemia. Hypoxia can progress to anoxia, which can be prolonged with instances of dystocia resulting in foetal death (Bluel et al., 2008). The calf can also have hypercapnia, which can cause respiratory acidosis. However, during dystocia the respiratory acidosis will be pronounced and in addition to this, the hypoxia can lead to anaerobic metabolism within the body that results in metabolic acidosis. The acidotic condition of the foetus can negatively affect the central nervous system resulting in lowered vigour, depression and decreased physical activity, which is referred to as weak calf syndrome or dummy calf syndrome (Ravary-Plumion, 2009). The dystocic calves were slower to express most of the neonatal behaviours, particularly those that lead up to reaching the udder, and usually lay recumbent (Barrier et al., 2012). This results in the failure of transfer of passive immunity as the calf is unable to absorb an adequate quantity of colostrum (Johnson et al., 2007 weaver finch et al., 2000). This has been linked with an increase in calf morbidity and mortality and a reduction in the calf growth rate (Robison et al., 1988 Donovan et al., 1998).2.5 Economic ImpactsIn a United Kingdom dairy herd, the total cost of a slightly difficult calving was estimated to be roughly 110, while a more serious difficult calving can range from 350 to 400. This takes into account the labour and veterinary costs, including the cost of caesarean deliveries, the mortality of dams and calves and the culled cows, the losses incurred due to a decreased milk production and poor reproductive performance (McGuirk et al., 2007). In Australian Friesian Holstein herds, the cost of dystocia for a herd can go up to $5100 per year, where 30% of the losses is due to reduced fertility, 20% due to culling or dam death, veterinary costs were about 10% and labour costs were 20%. The cost of dystocia in primiparous cows was about $48.49, while it was $19.15 in mature cows. The overall losses associated with calving difficulties in the Australian dairy industry can be estimated to be in excess of $44 million annually (McClintook, 2004). In a study by Dematewewa Berger (1997), the estimated costs of dystocia were $0.00, $50.45, $96.48, $159.82 and $379.61 for dystocia scores 1 to 5 (1 representing no riddle to 5 representing extreme difficulty). which showed that losses incurred increase as the difficulty of calving increases.2.6 PelvimetryInternal pelvimetry involves the measurement of the pelvic height and the pelvic width, which allows the pelvic area to be determined (Rice and Wiltbank, 1972 Bellows et al., 1971 Morrison et al., 1986 Johnson et al., 1988). The internal dimension s are metric using a sliding calliper device that is referred to as a Rice pelvimeter. Other instruments have also been positive such as the Krautmann-Litton Bovine pelvic meter and the EquiBov Bovine pelvimeter (Deutscher, 1987). The external pelvimetry is mostly done in correlation to the internal pelvic dimensions where the measurements are taken on the external body of the animal for example, the pin width, snarf width, rump length and hook to pin length (Bellows et al., 1971 Johnson et al., 1988 Coopman et al., 2003). Pelvimetry is a relatively simple and reliable method to determine pelvic parameters of cows with the basis that the larger the pelvic area, the lower the calving difficulty. However, a farmer would require the services of a veterinarian with the skills and knowledge to peform this technique, which would increase costs to the farm (Kolkman et al., 2012).2.7 Welfare The measurement of internal pelvic parameters is invasive and carries a risk of trauma to the rec tal mucosa. It has been recommended to administer epidural anaesthesia which allows the cow to stand normally without arching her back or attempting to strain. However, the administration of the epidural anaesthesia requires specialised veterinary nurture (Murray et al., 2002). Despite the risk for injury, if the internal pelvimetry is done properly and gently with the use of adequate quantities of lubrication, damage to the rectal mucosa can be prevented (Hiew and Constable, 2015).3.0 Materials and Methods data was placid from 50 Friesian cross dairy cattle (23 from Ladang 16, Taman Pertanian Universiti (TPU), Universiti Putra Malaysia (UPM) and 27 others from two dairy cattle farms in Bangi, Selangor and Lenggeng, Negeri Sembilan that were part of the Ladang Angkat Programme) within a period of 2 weeks using convenience sampling. All of the cows were between 2-14 historic period of age and weighed between 200-750 kg. The ages of the cows at TPU were taken from recrodsm, whereas the ages of the other cattle were determined using teeth (Lawrence et al., 2001). This study was approved by the Institutional Animal Care and Use Committee (IACUC), with the reference number UPM/IACUC/FYP.2016/FPV.71The external morphometry that was measured was the pectoral circumference, abdominal circumference, hook width and pin width. Thoracic circumference (Figure 1) was determined using a measuring tape (tailor fibreglass measuring tape) set(p) immediately caudal to the scapula and forelimbs. The abdominal circumference (Figure 2) was determined by placing the same tape tape cranial to the hind limbs, genus Tuber coxae and udder, and was measured in centimetres (West, 1997) (Figure 3). The hook width (Figure 4) was measured using the linear surmount between the most lateral surfaces of the wings of the ileum or genus Tuber coxae. The pin width (Figure 5) is the linear distance between the most lateral surfaces of the tuber ischium (Singh et al., 1984) (Figure 6). These distances were measured in centimetres using straight rulers and a tape measure whereby one straight metal ruler was placed vertically at the lateral aspect of the tuber coxarum or tuber ischium and the other straight metal ruler was placed vertically at the lateral aspect of the opposite tuberosity with the measuring tape stretched tautly between the two rulers (Craig, 1941). The body condition score was measured using a 5-point scoring method with quarter-point increments from an established scoring system from Elanco Animal Health (1997). The body weight was determined by measuring the thoracic circumference using a calibrated heart girth tapeMH1, in kilograms.Figure 3 External morphometry a. Thoracic circumference, b. ab circumference (Elanco Animal Health, 1997)Figure 4 beat the distance between the tuber coxaeFigure 5 measuring the distance between the tuber ischiiFigure 6 External morphometry a. The distance between tuber coxae, b. The distance between tuber ischii (Elanco Animal Health, 1997)The internal pelvimetry was measured using a Rice pelvimeter (Lane Manufacturing Inc., Colorado, U.S.A.) (Figure 3) that provides measurements in centimetres with a gradient of 0.25 cm. Faeces were manually evacuated from the rectum and the pelvimeter was well lubricated using an aqueous based lubricant (BOVIVET Gel granulate). The closed pelvimeter was gently and slowly introduced into the rectum in a closed position by the hand, with the arm of the investigator protected using a disposable rectal sleeve (KRUTEX super sensitive disposable examination gloves) The pelvic height (Figure 4) was measured by opening the device within the pelvic canal and recording the distance between the dorsal aspect of the pubic symphysis on the floor of the pelvis and the ventral aspect of the sacral vertebrae. The pelvimeter was then closed and rotated 90 to measure the pelvic width, (Figure 5) which is defined as the horizontal distance at the widest point between the left and right ileal shafts at right angle to where the height was measured (Bellows et al., 1971). One limitation of the Rice pelvimeter is that it has a maximum reading of 20 cm, but in this study none of the cows had pelvic measurements that exceeded 20 cm. The intrapelvic area was calculated as the area of a rectangle by multiplying the pelvic width and the pelvic height (Gaines et al., 1993 Ramin et al., 1995 Green et al., 1988). The intrapelvic area can also be measured as an ellipse with the equation PA = PH - PW - /4 (David, 1960). Despite the higher degree of accuracy offered by the ellipsoidal equation, the rectangle equation was used for calculation because the ellipsoidal equation offered no advantage of predicting the risk of dystocia and did not differ when be pelvic size (Rice and Wiltbank, 1972).All measurements taken were measured three times consecutively by the same person and the resulting mean values were used for analyses.Data was placed on a data capture sheet for eac h farm, and transferred to an Excel spread sheet (Microsoft Office Excel, 2016). The data was then analysed using IBM SPSS Statistics interpretation 22. Data was expressed as mean standard deviation. Shapiro-Wilk test was used as a numerical means of assessing normality, and the output of a normal Q-Q darn was used to determine this graphically. A one-way analysis of variance (ANOVA) was conducted to examine the relationship of age categories (2 3 years, 3 4 years, 4 5 years, 5 6 years and 6 years) on the external morphometry and internal pelvic measurements. Pearson product-moment correlation coefficient (r) was used to determine the association between internal pelvic dimensions and external morphometry, age, body weight and body condition score. Regression analysis was performed to determine the ability of external morphometry, age, body weight and body condition score to predict internal pelvic dimensions. The data collected were used to develop multiple regression equat ions that estimate the inner pelvic sizes from the external measurements.4.0 ResultsThe descriptive statistics for age, body weight, body condition score, external morphometry and internal pelvic measurements for the 50 Friesian cross cows are given in parry 1.Table 1 Age, body condition score, body weight, external morphometry and internal pelvic measurements for 50 Friesian cross cattle.TraitMinimumMaximumMeanS.E.S.D.MedianAge (months)24.00165.0060.164.1729.1654.00Body condition score (1-5)2.504.003.210.050.363.25Body weight (kg)277.3722.7456.914.098.7437.8Thoracic circumference (cm)151.5206.2177.01.812.4175.9Abdominal circumference (cm)152.0227.8189.22.215.8189.4Distance between tuber coxae (cm)38.357.247.50.64.447.7Distance between tuber ischae (cm)20.045.631.50.85.731.8pelvic height (cm)12.4219.5016.640.221.5917.13Pelvic width (cm)11.6719.0815.640.241.6915.50Pelvic area (cm2)158.31398.86263.287.2151.02262.43There was no significant difference between the mean pelvic area of th e cows sampled and the minimum pelvic size of Friesian-Holsteins that was determined to have a low incidence of dystocia, where cows which had pelvic sizes greater than the determined value of 260 cm2 would have a reduced risk of dystocia (Hoffman et al., 1996). The mean pelvic size of the sampled cows was 3.28 cm2 larger than the determined value of 260 cm2. In this sample, 24 cows out of the 50 (48%) had pelvic areas below 260 cm2, with the smallest pelvic area being 158.31 cm2.4.1 Analysis of variance (ANOVA)The analysis of variance showed that there was a statistically significant difference between the age and thoracic circumference (P = 0.008), abdominal circumference (P = 0.046), distance between tuber coxae (P = 0.046) and distance between tuber ischii (P = 0.009). However, there was no difference when it came to pelvic height, pelvic width and pelvic area (P 0.05) amongst the age categories. The post-hoc comparisons using the Tukey HSD test gave indications that the means for thoracic circumference was lower for the age categories 2 3 years (170.1 10.7 cm, P = 0.021), 3 4 years (172.4 12.4 cm, P = 0.017) compared to the category 6 years (189.4 12.9 cm). There was a significant difference (P = 0.034) for abdominal circumference when comparing age category 4 5 years (180 13.3 cm) to 6 years (201.6 15.3 cm).4.2 Pearsons Product-Moment CorrelationTable 2 illustrates the correlations between the external morphometry and internal pelvic dimensions, using Pearsons Product-Moment Correlation. This reveals that the external morphometric parameters of thoracic circumference, abdominal circumference, distance between tuber coxae, and distance between tuber ischii have a moderately, positive correlation with the internal pelvic measurements of pelvic height, pelvic width and pelvic area that were statistically significant (P = 0.01). Age in months had a weak and positive correlation with pelvic height (r = 0.35) and pelvic area (r = 0.29) at the level of P = 0.05. However, there was no correlation between age and pelvic width (r = 0.25, P = 0.86).Table 2 Correlations between the external morphometry and internal pelvic parameters.TraitsPelvic HeightPelvic WidthPelvic AreaThoracic circumference0.50**0.53**0.48**Abdominal circumference0.60**0.52**0.52**Distance between tuber coxae0.46**0.49**0.43**Distance between tuber ischae0.47**0.54**0.50**** Correlation coefficient (r) is significant at the 0.01 level (2-tailed)Body weight (kg) showed a moderate positive correlation with pelvic height (r = 0.40), pelvic width (r = 0.50) and pelvic area (r = 0.44) at a level of P = 0.01. Body weight also displayed a very strong positive correlation with thoracic circumference (r = 0.99), abdominal circumference (r = 0.76), distance between tuber coxae (r = 0.77) and the distance between tuber ischae (r = 0.73) at a level of P = 0.01. There were no correlations between the intrapelvic height (r = 0.11, P = 0.55), intrapelvic width (r = -0.10, P = 0.47) and intrapelvic area (r = -0.08, P = 0.60)and the body condition score (-0.104 .There were positive correlations between age in months and thoracic circumference, abdominal circumference, distance between the tuber coxae and distance between tuber ischii, all of which are significant at the level of P = 0.01 (Table 3). There is also a significant correlation between age in months and the body weight (r = 0.58, P Table 3 Correlations between the age (months) and external morphometry in 50 Friesian cross cattle.Age (months) withCorrelationP-valueThoracic circumference0.56Abdominal circumference0.48Distance between tuber coxae0.45Distance between tuber ischae0.63The correlations between the external morphometry measurements are given in Table 4. There is significant, strong and positive correlation between each of the external morphometric measurements that were taken, where P Table 4 Correlations between the external morphometry of 50 Friesian cross cattle.TraitsThoracic circu mferenceAbdominal circumferenceDistance between tuber coxaeThoracic circumferenceAbdominal circumference0.76**Distance between tuber coxae0.78**0.72**Distance between tuber ischae0.72**0.64**0.77**** Correlation coefficient (r) is significant at the 0.01 level (2-tailed)4.3 Regression analysisSeveral models were developed using linear and multiple regression analyses, which can be used to predict internal pelvic parameters using the external morphometric measurements that are given in Table 5. The best predictors for pelvic height would be body weight and the external parameters of thoracic circumference and abdominal circumference, where these parameters explain 58% of the variability of pelvic height. For pelvic width, the ideal predictor would be the distance between the tuber ischii which explains 29% of the variability of the pelvic width. Body weight, thoracic circumference and the distance between tuber ischii were the best predictors for pelvic area where they explain 40% of the variability of the pelvic area.Table 5 Models to predict inner pelvic sizes from easily neighborly external morphometryYModelR2S.E.Pelvic HeightY = -50.57 0.06 - BW + 0.47 - Th + 0.05 - Abd0.581.13Y = -48.90 0.05 - BW + 0.52 - Th0.401.25Y = 5.13 + 0.06 - Abd0.371.38Pelvic WidthY = 6.74 + 0.19 - TcTc0.241.49Y = 10.61 + 0.16 - TiTi0.291.45Pelvic AreaY = -1549.01 1.54 - BW + 14.22 - Th0.3342.51Y = 1585.33 1.56 - BW + 13.22 - Th + 1.17 - Abd0.3941.15