Production performance of lambs
Fortnightly body weight gain
The overall mean body weight (kg) gain of lambs in G1 group was significantly (P<0.01) higher than lambs reared in G2 and G3 groups (Table 1). In intensive rearing system, the lambs were seldom exposed to harsh climatic conditions such as rain, cold and hot sun and this coupled with good plane of nutrition due to provision of chaffed succulent green forage and concentrate combination resulted in higher body weights as more nutrients were available for formation of muscle mass. In semi-intensive system, the growth rate were higher than extensive system due to supplementation with concentrate mixture apart from grazing.
The results of the present study were similar to the findings of
Karthik et al., (2021) and
Galmessa et al., (2002) who observed that the final body weight gain of lambs in concentrate supplemented group had significant (P<0.05) difference with only grazing animals group in Aged Horro sheep in Ethiopia.
Pankaj (2010) in a study of 90 days on Marwari lambs found that the lambs supplemented with concentrate mixture of 1 per cent body weight had significantly higher body weight than non-supplemented group.
Chaturvedi et al., (2010), Malisetty and Yerradoddi (2013),
Jalajakshi et al., (2016) and
Khanal et al., (2017) have also reported significantly (P<0.01) higher body weight gains with concentrate supplemented ram lambs than solely grazed lambs in extensive production system.
The results of the present study were in contradiction to the findings of
Venkataramanan et al., (2015) who reported that the supplementation of 250 gram concentrate in addition to grazing did not have significant (P<0.05) effect on body weight gain and
Karim et al., (2007) have observed that total body weight gain (kg) was higher in semi-intensive system followed by intensive feeding and extensive range management in Kheri lambs.
There was no significant (P<0.05) difference in the body weight gain of lamb between G1 and G2 groups in the first two fortnights and there was no significant difference in body weight gain in lambs between G2 and G3 group in the first fortnights because of sufficient quantity of lush grasses and forage being available in grazing areas in these months due to sufficient rains in the month of August. From the third fortnight the growth rate of lambs in G1group were significantly (P<0.01) higher as compared to lambs in G2 and G3 groups.
The body weights of lambs in all the three systems of rearing linearly increased from 3 to 9 months age but the weight gain of lambs decreased as the age of the animal advances. Similar results were reported by
Raman et al., (2003), Mishra et al., (2004), Patro et al., (2006), Devendran et al., (2009), Sivakumar et al., (2009), Balasubramanyam et al., (2010), Mondal and Kakati (2010),
Tailor and Yadav (2011),
Panda et al., (2012), Dass et al., (2012) and
Chitra (2017) in different breeds of sheep wherein the growth rate was lowering as the age of the animal increasing.
Average daily gain (ADG)
The mean ADG of lambs in G3 group was lower throughout the study period as compared to lambs in G2 and G1 groups (Table 2), which might be due to inadequately available nutrients in the grasses and forages through grazing which was not sufficient for optimum growth and more energy was spent on locomotion in travelling long distances in search of food and water and exposure to harsh environmental conditions. The results of the present study were in close agreement with the reports of
Porwal et al., (2006), Bharambe and Burte (2012),
Kumar et al., (2018) and
Kochewad et al., (2018) and contrary to the results reported by
Venkataramanan et al., (2015). Karim et al., (2007) and
Arslan et al., (2018) reported higher ADG in grazing lambs with
ad libitum concentrate supplementation followed by intensive feeding and extensive range management.
Chaturvedi et al., (2010), Pankaj (2010),
Malisetty and Yerradoddi (2013),
Jalajakshi et al., (2016), Kumar et al., (2017c) and
Jalajakshi et al., (2018) reported supplementation with concentrate feed along with grazing had higher ADG than only grazing in lambs.
There was no significant (P<0.01) difference in mean ADG of lambs reared in semi-intensive system (G2) and extensive systems (G3) during 10
th, 11
th and 12
th fortnights, which could be due to high parasitic load in the lambs, drinking water from drying water bodies which are potential sources of parasitic ova.
The higher ADG of lambs in the three rearing systems were observed between 3-5 months age as compared to 6-9 months age of the lambs which might be due to better utilization of nutrients between 3-5 months age. These results were similar to the findings of
Patro et al., (2006), Sivakumar et al., (2009), Balasubramanyam et al., (2010), Dass et al., (2016) and
Kumar et al., (2017a).
Cost economics of lambs in different systems of rearing
The cost of animals, labour, water and electricity was same in the three groups. The cost of animals was highest in the three groups followed by cost of labour (Table 3). The cost of concentrate feed was higher in the G1 group than G2 group because in G1 group, the lambs were provided with concentrate @ 1 per cent body weight. The cost of veterinary aid was same in the G2 and G3 groups and higher than G1 group because in G2 and G3 groups deworming was done two times more than G1 group. The cost of recurring expenditure was higher in G1 group followed by G2 and G3 group. These results were in agreement with
Porwal et al., (2006), Devendran et al., (2012) and
Shivakumara and Kiran (2019).
Major part of income is through sale of lambs in all three systems of rearing. The income from sale of manure was higher in G1 group than G2 and G3 group because lambs are in the sheds throughout day. The gross and net income was higher in G1 group followed by G2 and G3 group. Similar results were reported by
Porwal et al., (2006), Pankaj et al., (2010) and
Mahanthesh et al., (2019). The cost of per kg live weight was highest in G1 group than G2 and G3 group because of concentrate and fodder cost.
