Relationship between Morphometric and Milk Production Characters in Ongole Cattle

Ongole cattle belong to short horn group of zebus, white or light grey in colour with coffin shaped skulls (Joshi and Phillips 1953), massive in size, docile and suitable for steady, heavy draught work. Specific breed characters and virtues evolved over the centuries due to isolation and selection in the home tract contended that the Ongoles are endowed with unique genetic attributes such as superior adaptability to climatic conditions, heat tolerance, ability to subsist on inferior and scarce feed resources and greater resistance to prevailing tropical diseases (Reedy,1925 and Murari, 1956). The conventional wisdom and data on milk production of Ongole cows suggests that, earlier they had good milk yielding potential, which was demonstrated by farmers at several livestock shows and milk yield competitions. Littlewood (1936) summarized the milk yield in Ongole cows and noted highest milk yield recorded 3268 Kgs/ lactation and average milk production was 1603kgs/ lactation of farm bred Ongole cows in Chintaladevi farm.
       
The population of Ongole cattle has been decreasing alarmingly from 2, 58,240 (Livestock Census, 2007) to 1, 15,905 (Breed Survey, 2013) in its native state of Andhra Pradesh due to shifting of the farmers towards buffaloes and crossbreds for milk. Therefore, there is a need for in situ conservation of this breed. Farmers in breeding tract are generally selecting the Ongole cows based on their phenotypic characters like coat colour, stature, external appearance etc. which are poorly correlated to milk production and reproduction. Therefore, in absence of the production records, predicting the association between milk yield and morphometry forms a potential tool for selection of dairy type Ongole cattle. Several researchers found association between morphometric characters like size and shape of udder (Bhuiyan et al., 2004; Dahiya and Rathi 2002; Dahiya 2006; Okan and Ozdal, 2016), chest girth and height at withers (Bardakcioglu et al., 2011) mammary width and milk yield (Prajapati et al., 1995) in cows. Therefore, the present study was carried to find out the relationship of morphometry with milk production which will help in selecting best dairy type of Ongole cows.

The study was taken up from January 2016 to May 2019 in the breeding tract of Ongole cattle viz., Guntur, Prakasam, Nellore, Kurnool, Krishna and West Godavari districts of Andhra Pradesh. The data pertaining to morphometric and milk production characters was recorded in the breeding tract of Andhra Pradesh on 211 elite lactating Ongole cows of different parity, which includes 137 cows maintained at Livestock Research Stations located at Lam (Guuntur district), Mahanandi (Kurnool district) and Chadalawada (Prakasam district) and 74 Ongole cows selected from the farmers holdings.
       
The following Morphometric characters were measured as per the procedures prescribed by Pundir et al., (2011).
 
Body length                   The distance between point of shoulder and the pin bone
Height at withers           The vertical distance between ground and the point of withers
Heart girth                     Circumference of the body behind the base of the hump and just behind the elbows of  the front legs
Abdominal girth             Circumference of the body at flank region                     
Neck length                   Proximal end of cervical region to the distal end of the cranial region
Face length                   The poll of the animal to the end of muzzle                   
Face width                     The distance between front of both the eyes.
Cephalic index                Length of face divided by width of face
Dewlap width                  The widest part of the base of the neck vertically
Ear length                       The base of the ear to the pointed end of the ear
Naval flap width              Widest part from the base of the abdomen vertically
Tail length                       The base of the tail to end of the tail
Tail switch                       The distance between end of tail to tuft of hair
Skin fold thickness         The skins fold thickness at on loose skin of neck region.
Udder length                   The distance from the rear attachment of the udder to the front of the udder  where it blends smoothly with the body.
Udder width                    The distance between two lateral lines of attachment of the udder to abdominal wall, beneath the flank
Udder area                     Length of udder multiplied with width
 
The data on total lactation milk yield (kg), lactation length (days), peak yield (kg), days to reach peak yield (kg), milk yield per lactation (kg) and milk yield per calving interval (kg) was recorded from the available records maintained during the period from 1988 to 2017. at Livestock Research Stations Lam, Mahanandi and Chadalawada.

The morphometric and milk production data collected was analysed by fitting into linear models to find of the effects, calculated correlation coefficients and regression coefficients in SPSS 16 software.

The mean length, height, heart girth, abdominal girth, tail length, tail switch length, face length, face width, cephalic index, dewlap length, naval flap length, ear length, neck length, udder length, udder width, udder area, teat length, teat diameter and skin fold thickness of Ongole cows are presented in Table 1. The length, height, heart girth, abdominal girth, neck length and udder length were significantly (P<0.01) higher in Ongole cattle maintained at individual farmers compared to herds maintained at Livestock Research Stations. This might be due to phenotypic selection of cows by the farmers for size since several decades due to increased demand for large sized males for use in “stone pulling sport” which is very popular in Andhra Pradesh state. Due to this, the individual care and management of the cows by the farmers may be good compared to the cows maintained at Livestock Research Stations.Themorphometric values reported in the present study were comparable with studies of Murari (1956) and Ngadiyono et al., (2017) in Ongole cattle.
 

 
The mean lactation milk yield (kg), milk yield per day of lactation (kg), milk yield per day of calving interval (kg),peak yield (kg) and lactation length (days) was 918.76±45.57, 2.98±0.02, 1.55±0.04, 4.25 ± 0.15, 65.68 ± 0.89 and 241.34 ± 2.01, respectively. The data pertaining to milk production performance reported in the present study was mostly collected from Livestock Research Stations since the availability of the data at the farmers level was scarce. The production performance of Ongole cows recorded in the present study was in accordance with the findings of Vinoo et al., (2005) and Sai Reddy (2010).
       
The analysis of the morphometric and milk production data revealed that lactation milk yield and lactation length were positively and significantly (P<0.01) correlated with udder area, udder length, face length and cephalic index in Ongole cattle (Table 2). Bhuiyan et al., (2004) and Rana et al., (2010) found that the udder measurements had significant positive correlation with milk yield in cows of Bangladeshi and Vrindavani cattle, respectively. Patel et al., (2016) also confirmed it in crossbred cows and Modh et al., (2017) in Gir cows.
 

       
However, lactation milk yield and lactation length were negatively correlated with skin fold thickness and tail length. Prabhakar et al., (2018) in Tharparker cattle and Dhillod et al., (2017) in Murrah buffaloes reported similar negative correlations between lactation milk yield and skin thickness.
       
The present study observed positive (P<0.05) correlations between peak yield and dewlap length and negative (P<0.05) correlation between peak yield and skin fold thickness (-0.156).  Positive (P<0.05) correlations were also observed between days to reach peak yield with heart girth (0.182) and abdominal girth (0.145) and non-significant correlations were found between days to reach peak yield and other morphometric characters.
       
The regression coefficients of udder area, skin fold thickness, face length and tail length for lactation milk yield and lactation length were 0.296, -0.195, 0.267 and -0.186 and 0.144, -0.145, 0.271 and -0.163, respectively and these coefficients were found to be significant (P<0.01).
       
The significant association of the morphometric characters with the total lactation milk yield and lactation length from the regression analysis were considered for construction and fit into  multiple linear prediction equations based on the intercept, regression coefficients and coefficients of determinations (R² values) obtained in this study.
       
The regression coefficients and R² values of the different equations and ranking of different prediction equations based on R²values are presented in Table 3 and 4 and the scattered plots are presented in Fig 1 and 2. On regression analysis, the morphometric characters such as udder area, skin fold thickness, face length and tail length found to be significantly (P<0.01)  associated with the total lactation milk yield and lactation length. Hence, these four morphometric characters were fit into a multiple linear equation and was computed based on the intercept, regression coefficients to predict the total lactation milk yield and lactation length. The results revealed that the udder area, skin fold thickness, face length and tail length may be given more weightage in selecting dairy type Ongoles.