Risk factor analysis for neonatal lamb mortality at an organized farm of arid Rajasthan

Abstract

The comparative neonatal mortality (NM) profile in Magra and Marwari sheep was studied to assess the influence and magnitude of different non-genetic risk factors (odds ratio, OR) using data on 8650 lambs (4768 Marwari and 3882 Magra) born from April, 2000 to March, 2016 at Arid Region Campus (ARC), Bikaner, Rajasthan. Overall annual NM was 1.79%. The NM increased with advancement of age of lambs (0.18% during 0 to1 day-old to 0.52% during 4 to 7 days-old) in
Marwari lambs. Significantly (P<0.001) 2 to 4 times higher NM was observed in Marwari lambs as compared to Magra lambs. In comparison to lambs of >3.50 kg birth weight, theORvaried from 1.3
(3.01 to 3.50 kg birth weight) to 9.5 (up to 2.00 kg birth weight). In comparison to lambs of >3.50 kg birth weight, >30-times higher risk for death due to septicaemia was observed in lambs up to 2.00
kg body weight. Lambs with poor body weight were at 6 times higher risk for enteritis. An inverse relation was observed between magnitude of overall neonatal mortality and age of dam at lambing. Irrespective of breeds, the overall NM was significantly (P<0.001) affected by parity of dam with higher mortality in lambs born to primiparous ewes. Relatively higher risk (2 times) was observed for overall and cause specific NM in lambs born to ewes in their first parity compared to
those in 3 parity. Dam's weight at lambing showed U-pattern for NM with maximum mortality in lambs born to ewes with <28.0 kg body weight particularly during hebdomadal phase. The NM was significantly (P<0.001) 2 times higher in the lamb to dam weight ratio of <0.100 compared to those with ratio of >0.100. Season of lambing generally had non-significant effect on neonatal mortality
in both the breeds. The causes of neonatal lamb mortality were pneumonia (32.90%) in total deaths followed by septicaemia / toxaemia (23.23%), enteritis (14.84%) and tetanus (7.74%). The
study revealed that sheep flocks at ARC, Bikaner had higher neonatal mortality during early phase of life, primarily due to lower birth weight of lamb. Better management should be adopted for proper nursing of lambs with low birth weight particularly born to primiparous ewes.

Full text

RISK FACTOR ANALYSIS FOR NEONATAL LAMB MORTALITY AT AN ORGANIZED FARM OF
ARID RAJASTHAN
C.P. Swarnkar*, H.K. Narula and A. Chopra
1 1
Division of Animal Health
ICAR- Central Sheep and Wool Research Institute (CSWRI), Avikanagar- 304 501, Rajasthan
1Arid Region Campus (ICAR-CSWRI), Bikaner- 334 006, Rajasthan
*E-mail address: swarnkarcp@yahoo.com
Manuscript received on 15.09.2018, accepted on 08.10.2018
DOI: 10.5958/0973-9718.2019.00022.9
ABSTRACT
The comparative neonatal mortality (NM) profile in Magra and Marwari sheep was studied to
assess the influence and magnitude of different non-genetic risk factors (odds ratio, OR) using
data on 8650 lambs (4768 Marwari and 3882 Magra) born from April, 2000 to March, 2016 at Arid
Region Campus (ARC), Bikaner, Rajasthan. Overall annual NM was 1.79%. The NM increased
with advancement of age of lambs (0.18% during 0 to1 day-old to 0.52% during 4 to 7 days-old) in
Marwari lambs. Significantly (P<0.001) 2 to 4 times higher NM was observed in Marwari lambs as
compared to Magra lambs. In comparison to lambs of >3.50 kg birth weight, the OR varied from 1.3
(3.01 to 3.50 kg birth weight) to 9.5 (up to 2.00 kg birth weight). In comparison to lambs of >3.50 kg
birth weight, >30-times higher risk for death due to septicaemia was observed in lambs up to 2.00
kg body weight. Lambs with poor body weight were at 6 times higher risk for enteritis. An inverse
relation was observed between magnitude of overall neonatal mortality and age of dam at
lambing. Irrespective of breeds, the overall NM was significantly (P<0.001) affected by parity of
dam with higher mortality in lambs born to primiparous ewes. Relatively higher risk (2 times) was
observed for overall and cause specific NM in lambs born to ewes in their first parity compared to
those in 3 parity. Dam's weight at lambing showed U-pattern for NM with maximum mortality in
rd
lambs born to ewes with <28.0 kg body weight particularly during hebdomadal phase. The NM was
significantly (P<0.001) 2 times higher in the lamb to dam weight ratio of <0.100 compared to those
with ratio of >0.100. Season of lambing generally had non-significant effect on neonatal mortality
in both the breeds. The causes of neonatal lamb mortality were pneumonia (32.90%) in total
deaths followed by septicaemia / toxaemia (23.23%), enteritis (14.84%) and tetanus (7.74%). The
study revealed that sheep flocks at ARC, Bikaner had higher neonatal mortality during early phase
of life, primarily due to lower birth weight of lamb. Better management should be adopted for
proper nursing of lambs with low birth weight particularly born to primiparous ewes.
Key words: Arid region, Magra, Marwari, Neonatal mortality, Risk factors.
Indian Journal of
Small Ruminants
Indian Journal of Small Ruminants 2019, 25(1): 59-69
In both the arid and semi-arid regions of Rajasthan,
sheep husbandry plays a key role for the sustainable
livelihood of the rural poor and lambs are usually sold at
the age of 3 to 4 months (Swarnkar and Singh, 2010).
Thus, their survival is highly important for the shepherds
to earn more income from sheep rearing. This can only
be achieved by increasing the survival rate of lambs. To
maximise farm profits, it is necessary to understand the
factors that influence mortality of lambs (Piwczynski et
al., 2012) so that appropriate management strategies
can be implemented (Schreurs et al., 2010). In lambs,
neonatal period (birth to first 28 days of life) is the most
critical (Gokce et al., 2014). Neonatal mortality (NM)
includes (a) death during the first week of life
(hebdomadal) and (b) death subsequently to the first
week and until the 28 day of life (post-hebdomadal).
th
Neonatal lamb mortality is a multi-factorial issue and
associated with environment (climate, hygiene, rearing
59

systems), ewe (age / parity, litter size, behaviour, body
condition score, udder health and colostrum yield and
breed) and lamb (birth weight, sex, vigour, colostrum
intake, type of wool coat and breed) (Dwyer et al., 2005;
Vatankhah and Talebi, 2009). Most of the reports on the
lamb mortality in India are generally obtained from a
limited set of data based on a few years' records
(Pachlag et al., 1974; Shrivastava et al., 1983; Malik et
al., 1980), while estimates obtained from large data sets
accumulated over many years may provide more
reliable information on this aspect (Mandal et al., 2007;
Gowane et al., 2018). Thus, long-term farm data over 17
years (2000-2016) were analysed to assess the
comparative neonatal mortality (NM) rate in Magra and
Marwari sheep breed, to determine the influence and
magnitude of different non-genetic factors (odds ratio,
OR) and to ascertain the age-specific causes of death
duringneonatal life.
MATERIALSAND METHODS
Data on 8650 lambs (4768 Marwari and 3882
Magra) born from April, 2000 to March, 2016 at the
Arid Region Campus (ICAR-Central Sheep and
Wool Research Institute), Bikaner in arid Rajasthan
were used for the present study. The flocks were
reared under semi-intensive management system.
Lambing was us ually r estricted to the sp ring
(January–March) and autumn (August–October)
seasons. At lambing, both lambs and dams were
weighed and the lambing date, sex and type of birth
of each lamb were recorded. Each lamb died was
subjected to post-mortem examinations on a daily
basis. The overall NM rate (%) was calculated using
the formula: (Number of lambs died during the first
28 days of life / Number of lambs born alive) x100.
The factors considered in analysis were dam's age,
parity, body weight at lambing, birth weight of lamb
and sex of lamb, year and season of birth and ratio of
lamb's weight to dam's weight at lambing. The data
were analysed by cross-tabulation and tested for
significance by chi-square test Association of factors
influ encin g lamb mo rt ali ty w as ob ta ine d by
odds ratio (OR). A value of OR equal to or more than
1 was considered as presence of an association
between causal facto r and neonatal mo rtality
(Szumilas, 2010).
RESULTSAND DISCUSSION
Overall out of 8650 lambs born, 155 (1.79%) died
during neonatal phase (Table 1). The neonatal mortality
rate was slightly higher during the hebdomadal phase
(0.99%) compared to the post-hebdomadal phase
(0.80%). Significantly (P<0.001) 2 to 4 times higher NM
was observed in Marwari lambs compared to Magra
lambs. The neonatal period is the most vulnerable time
in the life of a lamb, with almost half of all pre-weaning
mortalities occurring on the day of birth (Dwyer, 2008)
and the rate of lamb losses is greatly reduced beyond
the first week of life (Gokce et al., 2014).
An inverse and significant (P<0.001) relationship
was observed between birth weight of lamb and
hebdomadal / overall neonatal mortality. Though sex of
lamb had non-significant (P>0.05) influence on NM in
both the breeds considered separately. However,
irrespective of breeds significantly (P<0.05) higher
mortality occurred in male lambs during post-
hebdomadal and overall neonatal periods. Age of dam
at lambing and season of birth had non-significant
(P>0.05) influence on neonatal mortality. Irrespective of
breeds, the overall NM was significantly (P<0.001)
affected by parity of dam with higher mortality in lambs
born to primiparous ewes. The effect of parity was
evident only in Marwari breed during hebdomadal
phase. The dam's weight at lambing showed U-pattern
for NM with maximum mortality in lambs born to ewes
with <2 8.0 kg body weigh t particularly during
hebdomadal phase. Lamb weight: dam weight had
significant ( P<0.001) influence on over all and
hebdomadal NM with 2 times higher mortality in lambs
with lamb weight: dam weight of <0.100 compared to
those with lamb weight: dam weight of >0.100. Neonatal
mort a lit y r ate w a s infl u enc e d sign i fic a ntl y
(P<0.05/0.001) by year (period) of birth in Marwari
breed. Season of lambing generally had non-significant
(P>0.05) influence on NM in both the breeds. Various
studies have reported how lamb mortality is influenced
by fixed effects such as age of dam, type of birth, sex of
lamb, season and year of birth, birth weight, body weight
of dam and rearing system (Morris et al., 2000; Mandal
et al., 2007; Sawalha et al., 2007). Neonatal mortality
rates ranging from 4 to 20% have been reported from
different countries (Binns et al., 2002; Sawalha et al ,.
2007; Ahmed et al., 2010; Gowane et al., 2018),
representingan important economicloss for farmers.
C.P. Swarnkar et al.
Indian Journal of Small Ruminants 2019, 25(1): 59-69
60

Table 1. Factor-wise neonatal lamb mortality rate in sheep flocks at an organized farm in arid Rajasthan
Factor No. born No. died (%)
Hebdomadal (0-7 days) Post- hebdomadal (8-28 days) Neonatal (0-28 days)
Marwari Magra Total Marwari Magra Total Marwari Magra Total Marwari Magra Total
Overall 4768 3882 62 (1.30) 24 (0.62) 56 (1.17) 13 (0.33) 118 (2.47) 37 (0.95)8650 86 (0.99) 69 (0.80) 155 (1.79)
Birth weight (kg) ** ** NS NS **** NS ** **
Up to 2.00 190 114 13 (6.84) 8 (7.02) 2 (1.05) 1 (0.88) 15 (7.89) 9 (7.89)304 21 (6.91) 3 (0.99) 24 (7.89)
2.01 - 2.50 526 419 14 (2.66) 6 (1.43) 7 (1.33) 2 (0.48) 21 (3.99) 8 (1.91)945 20 (2.12) 9 (0.95) 29 (3.07)
2.51 - 3.00 1352 1200 18 (1.33) 6 (0.50) 23 (1.70) 4 (0.33) 41 (3.03) 10 (0.83)2552 24 (0.94) 27 (1.06) 51 (2.00)
3.01 - 3.50 1653 1365 15 (0.91) 3 (0.22) 15 (0.91) 2 (0.15) 30 (1.81) 5 (0.37)3018 18 (0.60) 17 (0.56) 35 (1.16)
> 3.50 1047 744 2 (0.19) 1 (0.13) 9 (0.86) 4 (0.54) 11 (1.05) 5 (0.67)1791 3 (0.17) 13(0.73) 16 (0.89)
Sex of lamb NS NS NS NS NS NSNS * *
Male 2453 1952 33 (1.35) 14 (0.72) 36 (1.47) 8 (0.41) 69 (2.81) 22 (1.13)4405 47 (1.07) 44 (1.00) 91 (2.07)
Female 2315 1930 29 (1.25) 10 (0.52) 20 (0.86) 5 (0.26) 49 (2.12) 15 (0.78)4245 39 (0.92) 25 (0.59) 64 (1.51)
Dam's age (yr) at lambing NS NS NS NS NS NSNS NS NS
Up to 2 751 729 14 (1.86) 7 (0.96) 7 (0.93) 2 (0.27) 21 (2.80) 9 (1.23)1480 21 (1.42) 9 (0.61) 30 (2.03)
2 - 4 2073 1814 28 (1.35) 12 (0.66) 28 (1.35) 7 (0.39) 56 (2.70) 19 (1.05)3887 40 (1.03) 35 (0.90) 75 (1.93)
4 - 6 1314 1102 17 (1.29) 4 (0.36) 14 (1.07) 3 (0.27) 31 (2.36) 7 (0.64)2416 21 (0.87) 17 (0.70) 38 (1.57)
> 6 630 237 3 (0.48) 1 (0.42) 7 (1.11) 1 (0.42) 10 (1.59) 2 (0.84)867 4 (0.46) 8 (0.92) 12 (1.38)
Parity of dam ** NS NS NS ** NS** NS **
1 1330 1130 31 (2.33) 11 (0.97) 15 (1.13) 6 (0.53) 46 (3.46) 17 (1.50)2460 42 (1.71) 21 (0.85) 63 (2.56)
2 1130 936 10 (0.88) 5 (0.53) 17 (1.50) 2 (0.21) 27 (2.39) 7 (0.75)2066 15 (0.73) 19 (0.92) 34 (1.65)
3 894 812 7 (0.78) 6 (0.74) 8 (0.89) 3 (0.37) 15 (1.68) 9 (1.11)1706 13 (0.76) 11 (0.64) 24 (1.41)
4 and above 1414 1004 14 (0.99) 2 (0.20) 16 (1.13) 2 (0.20) 30 (2.12) 4 (0.40)2418 16 (0.66) 18 (0.74) 34 (1.41)
Dam wt (kg) at lambing ** ** NS NS ** NS** NS **
Up to 28.0 231 591 9 (3.90) 10 (1.69) 2 (0.87) 3 (0.51) 11 (4.76) 13 (2.20)822 19 (2.31) 5(0.85) 24 (2.92)
28.1 – 32.0 1254 1270 20 (1.59) 9 (0.71) 21 (1.67) 4 (0.31) 41 (3.27) 13 (1.02)2524 29 (1.15) 25 (0.99) 54 (2.14)
32.1 – 36.0 1993 1453 20 (1.00) 1 (0.07) 22 (1.10) 2 (0.14) 42 (2.10) 3 (0.21)3446 21 (0.61) 24 (0.70) 45 (1.31)
>36.1 1290 568 13 (1.01) 4 (0.70) 11 (0.85) 4 (0.70) 24 (1.86) 8 (1.41)1858 17 (2.99) 15 (2.64) 32 (1.72)
Lamb wt : Dam wt ** * NS NS ** NS** NS **
<0.10 3341 2353 58 (1.74) 20 (0.85) 40 (1.20) 7 (0.30) 98 (2.93) 27 (1.15)5694 78 (1.37) 47 (0.83) 125 (2.20)
>0.10 1411 1467 4 (0.28) 4 (0.27) 16 (1.13) 6 (0.41) 20 (1.42) 10 (0.68)2878 8 (0.28) 22 (0.76) 30 (1.04)
Period * NS ** NS ** NS* ** **
P1 (2000-04) 804 801 5 (0.62) 7 (0.87) 4 (0.50) 2 (0.25) 9 (1.12) 9 (1.12)1605 12 (0.75) 6 (0.37) 18 (1.12)
P2 (2004-08) 1019 752 16 (1.57) 6 (0.80) 3 (0.29) 0 (0.00) 19 (1.86) 6 (0.80)1771 22 (1.24) 3 (0.17) 25 (1.41)
P3 (2008-12) 1715 1187 31 (1.81) 8 (0.67) 42 (2.45) 5 (0.42) 73 (4.26) 13 (1.10)2902 39 (1.34) 47 (1.62) 86 (2.96)
P4 (2012-16) 1230 1142 10 (0.81) 3 (0.26) 7 (0.57) 6 (0.53) 17 (1.38) 9 (0.79)2372 13 (0.55) 13 (0.55) 26 (1.10)
Season NS NS NS * NS NSNS NS NS
Jan – Jun 3375 2800 41 (1.21) 21 (0.75) 45 (1.33) 6 (0.21) 86 (2.55) 27 (0.96)6175 62 (1.00) 51 (0.83) 113 (1.83)
Jul - Dec 1393 1082 21 (1.51) 3 (0.28) 11 (0.79) 7 (0.65) 32 (2.30) 10 (0.92)2475 24 (0.97) 18 (0.73) 42 (1.70)
* - Significant (P<0.05); ** - Significant (P<0.001); NS- Non-significant (P>0.05); Difference in number of observations were due to missing record.
Neonatal lamb mortality
Indian Journal of Small Ruminants 2019, 25(1): 59-69 61

Table 2. Stage-wise neonatal lamb mortality rate during hebdomadal phase in sheep flocks at an organized farm in arid Rajasthan
Factor No. born No. died (%)
Immediate (0-1 day) Delayed (2-3 days) Late (4-7 days)
Marwari Magra Total Marwari Magra Total Marwari Magra Total Marwari Magra Total
Overall 4768 3882 8650 11 (0.23) 5 (0.13) 16 (0.18) 14 (0.29) 11 (0.28) z25 (0.29) 37 (0.78) 8 (0.21) 45 (0.52)
Birth weight (kg) ** NS ** ** ** NS** ** **
Up to 2.00 190 114 3 (1.58) 1 (0.88) 6 (3.16) 6 (5.26) 4 (2.11) 1 (0.88)304 4 (1.32) 12 (3.95) 5 (1.64)
2.01 - 2.50 526 419 4 (0.76) 1 (0.24) 0 (0.00) 3 (0.72) 10 (1.90) 2 (0.48)945 5 (0.53) 3 (0.32) 12 (1.27)
2.51 - 3.00 1352 1200 3 (0.22) 2 (0.17) 5 (0.37) 2 (0.17) 10 (0.74) 2 (0.17)2552 5 (0.20) 7 (0.27) 12 (0.47)
3.01 - 3.50 1653 1365 1 (0.06) 1 (0.07) 3 (0.18) 0 (0.00) 11 (0.67) 2 (0.15)3018 2 (0.07) 3 (0.10) 13 (0.43)
> 3.50 1047 744 0 (0.00) 0 (0.00) 0 (0.00) 0 (0.00) 2 (0.19) 1 (0.13)1791 0 (0.00) 0 (0.00) 3 (0.17)
Sex of lamb NS NS NS NS NS *NS NS NS
Male 2453 1952 5 (0.20) 2 (0.10) 7 (0.29) 5 (0.26) 21 (0.86) 7 (0.36)4405 7 (0.16) 12(0.27) 28 (0.64)
Female 2315 1930 6 (0.26) 3 (0.16) 7 (0.30) 6 (0.31) 16 (0.69) 1 (0.05)4245 9 (0.21) 13(0.31) 17 (0.40)
Dam's age (yr) at lambing NS NS NS NS NS NSNS NS NS
Up to 2 751 729 3 (0.40) 1 (0.14) 4 (0.53) 2 (0.27) 7 (0.93) 4 (0.55)1480 4 (0.27) 6 (0.41) 11 (0.74)
2 - 4 2073 1814 5 (0.24) 3 (0.17) 6 (0.29) 6 (0.33) 17 (0.82) 3 (0.17)3887 8 (0.21) 12(0.31) 20 (0.51)
4 - 6 1314 1102 2 (0.15) 1 (0.09) 2 (0.15) 2 (0.18) 13 (0.99) 1 (0.09)2416 3 (0.12) 4 (0.17) 14 (0.58)
> 6 630 237 1 (0.16) 0 (0.00) 2 (0.32) 1 (0.42) 0 (0.00) 0 (0.00)867 1 (0.12) 3 (0.35) 0 (0.00)
Parity of dam NS NS NS NS NS NSNS NS **
1 1330 1130 6 (0.45) 2 (0.18) 8 (0.60) 3 (0.27) 17 (1.28) 6 (0.53)2460 8 (0.33) 11 (0.45) 23 (0.93)
2 1130 936 2 (0.18) 2 (0.21) 2 (0.18) 2 (0.21) 6 (0.53) 1 (0.11)2066 4 (0.19) 4 (0.19) 7 (0.34)
3 894 812 0 (0.00) 1 (0.12) 1 (0.11) 4 (0.49) 6 (0.67) 1 (0.12)1706 1 (0.06) 5 (0.29) 7 (0.41)
4 and above 1414 1004 3 (0.21) 0 (0.00) 3 (0.21) 2 (0.20) 8 (0.57) 0 (0.00)2418 3 (0.12) 5 (0.21) 8 (0.33)
Dam wt (kg) at lambing NS NS ** ** NS NSNS ** NS
Up to 28.0 231 591 1 (0.43) 2 (0.34) 3 (1.30) 7 (1.18) 5 (2.16) 1 (0.17)822 3 (0.36) 10 (1.22) 6 (0.73)
28.1 – 32.0 1254 1270 4 (0.32) 2 (0.16) 6 (0.48) 3 (0.24) 10 (0.80) 4 (0.31)2524 6 (0.24) 9 (0.36) 14 (0.55)
32.1 – 36.0 1993 1453 3 (0.15) 0 (0.00) 3 (0.15) 1 (0.07) 14 (0.70) 0 (0.00)3446 3 (0.09) 4 (0.12) 14 (0.41)
>36.1 1290 568 3 (0.23) 1 (0.18) 2 (0.16) 0 (0.00) 8 (0.62) 3 (0.53)1858 4 (0.22) 2 (0.11) 11 (1.18)
Lamb wt : Dam wt NS NS NS * ** NS* ** **
<0.10 3341 2353 11 (0.33) 4 (0.17) 13 (0.39) 10 (0.42) 34 (1.02) 6 (0.25)5694 15 (0.26) 23 (0.40) 40 (0.70)
>0.10 1411 1467 0 (0.00) 1 (0.07) 1 (0.07) 1 (0.07) 3 (0.21) 2 (0.14)2878 1 (0.03) 2 (0.07) 5 (0.17)
Period NS NS NS NS NS NSNS NS NS
P1 (2000-04) 804 801 0 (0.00) 2 (0.25) 2 (0.25) 3 (0.37) 3 (0.37) 2 (0.25)1605 2 (0.12) 5 (0.31) 5 (0.31)
P2 (2004-08) 1019 752 3 (0.29) 2 (0.27) 2 (0.20) 1 (0.13) 11 (1.08) 3 (0.40)1771 5 (0.28) 3 (0.17) 11 (0.62)
P3 (2008-12) 1715 1187 7 (0.41) 0 (0.00) 7 (0.41) 6 (0.51) 17 (0.99) 2 (0.17)2902 7 (0.24) 13 (0.45) 19 (0.65)
P4 (2012-16) 1230 1142 1 (0.08) 1 (0.09) 3 (0.24) 1 (0.09) 6 (0.49) 1 (0.09)2372 2 (0.08) 4 (0.17) 7 (0.30)
Season NS NS NS NS NS NSNS NS NS
Jan – Jun 3375 2800 7 (0.21) 5 (0.18) 10 (0.30) 10 (0.36) 24(0.71) 6 (0.21)6175 12 (0.19) 20 (0.32) 30 (0.49)
Jul - Dec 1393 1082 4 (0.29) 0 (0.00) 4 (0.29) 1 (0.09) 13 (0.93) 2 (0.18)2475 4 (0.16) 5 (0.20) 15 (0.61)
* - Significant (P<0.05); ** - Significant (P<0.001); NS- Non-significant (P>0.05); Difference in number of observations were due to missing record
C.P. Swarnkar et al.
Indian Journal of Small Ruminants 2019, 25(1): 59-69
62

Mandal et al., 2007; Gowane et al., 2018). Birth weight
has been reported as the single greatest contributor to
lamb mortality (Fogarty et al., 2000) with a curvilinear
(U-shaped) relationship (Barazandeh et al., 2012;
Refshauge et al., 2016; Abdelqader et al., 2017).
Extreme-low birth weight lambs are less vigorous at
birth, take longer time to stand and suck successfully,
thereby increasing their risk of infection and have
reduced ability to maintain body temperature
compared to heavier lambs (Dwyer, 2008), whereas
extreme-high birth weight lambs are more likely to die
due to dystocia (Dalton et al., 1980). Therefore,
optimal birth weight, rather than maximum birth
weight, shoul d be the target for survival rate
improvement. The higher mortality in male lambs
compared to female lambs has also been reported in
majority of studies (Vatankhah and Talebi, 2009;
Ahmed et al., 2010; Abdelqader et al., 2017; Gowane
et al., 2018). However, in Ghana Turkson and Sualisu
(2005) reported higher mortality for female lambs. This
di fference has been attribute d to s ex -l in ke d
determinants which according to Mandal et al., (2007)
are yet to be identified. Similar to the earlier reports of
Southey et al. (2001) and Sawalha et al. (2007), this
study also observed an inverse relationship was
observed between magnitude of overall neonatal
mortality and age of dam at lambing. Similar influence
of parity of dam on NM as observed in the present
study has also been reported earlier with higher lamb
mortality in those born to younger ewes (Morris et al.,
2000; Vatankhah and Talebi, 2009; Ahmed et al.,
2010; Mousa-Balabel, 2010). The preponderance of
mortality among lambs from younger ewes may be
due to their poor maternal instinct (Dwyer et al., 2001;
Dwyer and Lawrence, 2005). In the present study,
dam's weight at lambing showed U-pattern for NM with
maximum mortality in lambs born to ewes with <28.0
kg body weight. Ewes with poor body weight usually
deliver lighter lambs with impaired sucking ability,
inadequate lactation or maternal interactions can
prevent the lamb from ingesting sufficient colostrum to
meet its nutritional needs and higher lamb mortality
may be due to inanition (Dwyer et al. 2005). The
significant yearly variation in lamb losses may be
attributed to variation in the environmental conditions,
differences in feed/fodder availability and other
managerial factors (Vatankhah and Talebi, 2009). The
Out of total neonatal mortality, around 55% deaths
were recorded during hebdomadal period. Irrespective
of breeds, mortality revealed 18.6, 29.1 and 52.3%
contribution by immediate (0-1 day -old), delayed (2-3
days-old) and late (4-7 days-old) phase, respectively.
Similar to the present observations, Sharif et al. (2005),
Khan et al. (2006), Mandal et al. (2007), Ahmed et al.
(2010) and Abdelqader et al. (2017) reported 62.1, 82.0,
49.5, 48.8 and 63.5% of lamb mortalities in the first week
of life, respectively. The higher mortality rate within the
first few days of life is a reflection of the transition from a
dependent intrauterine life to an independent extra-
uterine life. On the other hand, Radostits et al. (1994)
reported 3.6% lamb mortality during first week of life in
Peru and attributed to the excellent management
conditions employed under a cooperative system which
provided for high level of health care, nutrition, parasite
control, range management as well as husbandry
among the sheep farmers.
The influence of different factors on phase-wise
mortality during hebdomadal period is presented in
Table 2. The overall mortality rate increased with the
advancement of age (0.18% in 0 to 1 day-old lambs to
0.52% during 4 to 7 days-old lambs) in Marwari lambs.
In Magra lambs, higher mortality was observed in 2 to
3 days-old lambs.
Birth weight of lamb was found to possess significant
(P<0.001) effect in all the phases of hebdomadal period
in Marwari breed. On the other hand, in Magra breed,
though trend was similar but significant (P<0.001) effect
of birth weight was noticed only during 2-3 days-old
lambs. Sex of lamb, age of dam at lambing, period and
season of birth had non-significant (P>0.05) influence
on hebdomadal mortality in both the breeds. In delayed
phase an inverse but significant (P<0.001) relationship
was observed between dam's weight at lambing and
mortality rate. In both the breeds, higher mortality was in
lambs with birth weight less than 1/10 of dam's body
th
weight at lambing. Lamb weight: dam weight ratio had
significant (P<0.05/0.001) influence on mortality during
delayed and late phase in Magra and Marwari breed,
respectively.
Similar to the present findings, significant effect of
birth weight of lamb on the mortality pattern has also
been reported earlier (Mukasa-Mugerwa et al., 2000;
Neonatal lamb mortality
Indian Journal of Small Ruminants 2019, 25(1): 59-69 63

non-significant effect of season of birth of the lamb on
mortality rate in this study was similar to the reports of
Turkson and Sualisu (2005). However, Berhan and
Van Arendonk (2006) reported mortality rate to be
higher for lambs born in the dry season, compared to
those born during the wet seasons.
Irrespective of the breeds, the probability of risk
for overall NM (Table 3) showed that in comparison
to lambs with >3.50 kg birth weight, OR varied from
1.3 (birth weight 3.01-3.50 kg) to 9.5 (birth weight up
to 2.00 kg). Similar trend with variable magnitudes
Breed variation in magnitude of ORs were also
observed for mortality due to septicaemia and enteritis
(Table 4). Overall male lambs were observed to
possess higher risk for death due to enteritis (OR=2.7)
as compared to female lambs; however in Magra
lambs the risk increased around 7 times. The OR
showed marginally higher risk for NM in lambs born to
younger ewes (<4 yr-old) compared to those from
older (>4 yr of age) ewes except for death due to
enteritis, where lambs from older ewes (>6 yr of age)
had around 3-times higher risk. Breed-wise no definite
(1.8 to 10.0 ) was also observed fo r NM due
pneumonia. Compared to lambs of >3.50 kg birth
weight, >30-times higher risk for death due to
septicaemia was observed in lambs up to 2.00 kg
body weight. Lambs with poor body weight had
around 6-times higher risk for enteritis. The OR was
more or less similar for overall NM in both the breeds;
however for pneumonia it was relatively higher in
Marwari lambs with moderate birth weight (2.01 to
3.00 kg) compared to Magra lambs with low birth
weight (up to 2.00 kg).
pattern was observed for ORs related to overall as well
as cause-specific mortalities. Relatively higher risk
(around 2 times) was estimated for overall and cause
specific NM in lambs born to ewes in their first parity
compared to those in third parity.
In comparison to ewes with 32.1-36.0 kg body
weight at lambing, the probability of risk for overall as
well as cause specific NM was observed to be 1.6 to
2.5-times higher in lambs born to ewes up to 28.0 kg
body weight at lambing.
Table 3. Odds ratio (95% confidence interval) for individual risk factors associated with neonatal lamb mortality at ARC,
Bikaner
Factor Overall Pneumonia Septicaemia Enteritis
Birth wt (kg)
Up to 2.00 9.5 (5.0, 18.1) 10.0 (2.4, 41.9) 30.4 (6.6, 139.6) 6.0 (1.4,25.3)
2.01 - 2.50 3.5 (1.9, 6.5) 8.3 (2.4, 29.2) 4.8 (0.9, 24.6) 1.9 (0.5, 8.0)
2.51 - 3.00 2.3 (1.3, 4.0) 5.4 (1.6, 18.1) 3.2 (0.7, 14.7) 2.8 (1.0, 8.1)
3.01 - 3.50 1.3 (0.7, 2.4) 1.8 (0.5, 6.6) 3.0 (0.7, 13.6) -
> 3.50 - - - 0.0
Sex of lamb 1.4 (1.0, 1.9) 0.9 (0.5, 1.6) 1.2 (0.6, 2.3) 2.7 (1.1, 6.9)
Dam age (yr) at lambing
Up to 2 1.3 (0.8, 2.1) 1.5 (0.6, 3.6) 1.1 (0.5, 2.7) 1.2 (0.3, 5.5)
2 - 4 1.2 (0.8, 1.8) 1.7 (0.8, 3.6) 0.6 (0.3, 1.3) 1.9(0.6, 5.8)
4 - 6 - - - -
> 6 0.9 (0.5, 1.7) 1.1 (0.3, 3.6) 0.2 (0.1, 1.6) 2.8 (0.7, 11.2)
Parity of dam
1 1.8 (1.1, 3.0) 2.3 (1.0, 5.4) 1.9 (0.5, 3.0) 2.3 (0.6, 8.4)
2 1.2 (0.7, 2.0) 1.5 (0.6, 3.9) 0.8 (0.3, 2.4) 1.7 (0.4, 6.6)
3 - - - -
4 and above 1.0 (0.6, 1.7) 0.8 (0.3, 2.2) 1.0 (0.4, 2.7) 0.9 (0.2, 4.2)
Dam weight (kg) at lambing
Up to 28.0 2.3 (1.4, 3.8) 1.6 (0.7, 3.6) 2.4 (0.9, 6.1) 2.5 (0.6, 10.6)
28.1 – 32.0 1.7 (1.1, 2.5) 0.8 (0.4, 1.7) 0.1 (0.0, 0.8) 3.0 (1.0, 8.7)
32.1 – 36.0 - - - -
>36.1 1.3 (0.8, 2.1) 0.8 (0.4, 1.7) 0.7 (0.2, 1.9) 1.5 (0.4, 5.5)
Lamb weight : Dam weight 2.1 (1.4, 3.2) 2.7 (1.3, 5.8) 3.1 (1.2, 8.1) 1.8 (0.7, 4.9)
Period
P1 (2000-04) 0.4 (0.2, 0.6) 0.1 (0.0, 0.6) 0.0 2.9 (1.1, 7.4)
P2 (2004-08) 0.5 (0.3, 0.7) 0.7 (0.4, 1.5) 0.1 (0.0, 0.4) 0.2 (0.0, 1.9)
P3 (2008-12) - - - -
P4 (2012-16) 0.4 (0.2, 0.6) 0.8 (0.4, 1.5) 0.1 (0.0, 0.3) 0.7 (0.2, 2.4)
Season 1.1 (0.8, 1.5) 3.7 (1.5, 9.3) 0.5 (0.3, 1.0) 2.7 (0.8, 9.0)
C.P. Swarnkar et al.
Indian Journal of Small Ruminants 2019, 25(1): 59-69
64

Table 4. Breed-wise odds ratio (95% CI) for individual risk factors associated with neonatal lamb mortality at ARC, Bikaner
Factor Overall Pneumonia Septicaemia Enteritis
Marwari Magra Marwari Magra Marwari Magra Marwari Magra
Birth wt (kg)
Up to 2.00 8.1 (3.7, 17.9) 12.7 (4.2, 38.5) 5.5 (0.3,88.9) 13.5 (2.4, 74.5) 23.0 (4.8, 109.0) 12.2 (1.7, 87.2) 8.8 (1.7, 44.0) 0.0
2.01 - 2.50 3.9 (1.9, 8.2) 2.9 (0.9, 8.9) 16.2 (2.0, 129.5) 2.7 (0.4, 16.1) 4.0 (0.7, 21.9) 1.6 (0.1, 18.0) 2.1(0.3, 12.6) 1.6 (0.1, 18.0)
2.51 - 3.00 3.0 (1.5, 5.8) 1.2 (0.4, 3.65) 15.7 (2.1, 117.2) 0.9 (0.2, 5.6) 3.1 (0.7, 14.7) 0.6 (0.1, 6.3) 2.9 (0.7, 11.1) 2.9 (0.6, 14.7)
3.01 - 3.50 1.7 (0.9, 3.5) 0.5 (0.2, 1.9) 5.7 (0.7, 45.3) 0.0 2.5 (0.5, 12.0) - - -
> 3.50 0.0 0.0 0.0- - - - -
Sex of lamb 1.3 (0.9, 1.9) 1.5 (0.8, 2.8) 0.9 (0.5, 1.7) 1.0 (0.3, 3.1) 1.1 (0.5, 2.2) 2.0 (0.4, 10.8) 1.89 (0.6, 5.5) 6.9 (0.9, 56.5)
Dam age (yr) at lambing
Up to 2 1.2 (0.7, 2.1) 2.0 (0.7, 5.3) 1.5 (0.6, 4.3) 1.5 (0.2, 10.8) 1.4 (0.6, 3.6) 0.5 (0.1, 4.8) 0.4 (0.1, 3.9) 0.8 (0.2, 4.1)
2 - 4 1.2 (0.7, 1.8) 1.7 (0.7, 4.0) 1.6 (0.7, 3.6) 2.4 (0.5, 11.5) 0.8 (0.3, 1.8) 0.2 (0.1, 1.9) 1.0 (0.3, 3.4) -
4 - 6 - - - - - - - 0.0
> 6 0.7 (0.3, 1.4) 1.3 (0.3, 6.4) 1.0 (0.3, 3.5) 0.0 0.0 1.6 (0.2, 15.0) 2.1 (0.5, 8.4) 0.0
Parity of dam
1 2.1 (1.2, 3.8) 1.4 (0.6, 3.1) 2.3 (0.8, 6.3) 2.2 (0.4, 10.7) 1.7 (0.5, 5.4) 0.5 (0.1, 2.9) 3.4 (0.4, 28.9) 1.8 (0.3, 9.3)
2 1.4 (0.8, 2.7) 0.7 (0.2, 1.8) 1.4 (0.5, 4.3) 1.7 (0.3, 9.5) 1.4 (0.4, 4.8) 0.0 4.0 (0.5, 34.0) 0.4 (0.1, 4.8)
3 - - - - - - - -
4 and above 1.3 (0.7, 2.4) 0.4 (0.1, 1.2) 1.0 (0.3, 3.1) 0.0 1.4 (0.4, 4.6) 0.3 (0.1, 2.6) 2.5 (0.3, 22.7) 0.0
Dam weight (kg) at lambing
Up to 28.0 2.3 (1.2, 4.6) 10.0 (2.8, 35.7) 1.8 (0.6, 5.4) 4.9 (0.9, 27.1) 5.3 (1.9, 14.7) 1.0 (0.1, 6.8) 0.00 2.9 (0.3, 27.9)
28.1 – 32.0 1.6 (1.0, 2.4) 5.0 (1.4, 17.6) 0.8 (0.4, 1.8) 1.7 (0.3, 10.3) 1.8 (0.7, 4.1) 0.4 (0.1, 3.2) 2.2 (0.7, 7.0) 1.8 (0.2, 16.1)
32.1 – 36.0 - - - - - 0.0 - 0.0
>36.1 0.9 (0.5, 1.5) 6.9 (1.8, 26.1) 0.5 (0.2, 1.2) 3.9 (0.6, 23.1) 0.5 (0.1, 1.7) - 0.9 (0.2, 3.9) -
Lamb weight : Dam weight 2.1 (1.3, 3.4) 1.7 (0.8, 3.5) 2.3 (1.0, 5.6) 3.1 (0.7, 14.3) 2.8 (1.0, 7.9) 3.1 (0.4, 26.7) 5.9 (0.8, 45.2) 0.6 (0.2, 2.5)
Period
P1 (2000-04) 0.3 (0.1, 0.5) 1.0 (0.4, 2.4) 0.1 (0.1, 0.6) 0.0 0.0 0.0 1.5 (0.5, 4.8) 4.3 (0.9, 21.4)
P2 (2004-08) 0.4 (0.3, 0.7) 0.7 (0.3, 1.9) 0.6 (0.2, 1.2) 0.5 (0.1, 1.9) 0.1 (0.1, 0.5) 0.0 0.2 (0.1, 2.0) 0.0
P3 (2008-12) - - - 0.0 - - - 0.0
P4 (2012-16) 0.3 (0.2, 0.5) 0.7 (0.3, 1.7) 0.4 (0.1, 0.8) - 0.1 (0.1, 0.4) 0.2 (0.1, 1.8) 0.4 (0.1, 1.9) -
Season 1.1 (0.7, 1.7) 1.0 (0.5, 2.2) 3.6 (1.3, 10.3) 4.3 (0.5, 33.1) 2.3 (1.3, 4.2) 0.4 (0.1, 1.9) 2.7 (0.6, 11.9) 2.7 (0.3, 22.0)
Neonatal lamb mortality
Indian Journal of Small Ruminants 2019, 25(1): 59-69 65

In Magra breed, the lambs born to ewes with higher
body weight (>36.1 kg) at lambing had 6.9 and 3.9 times
higher risk for death due to overall and pneumonia
specific mortality compared to those born to ewes with
32.1-36.0 kg body weight at lambing. The OR for lamb
weight: dam weight ratio suggested 1.8 (enteritis) to 3.1
(septicaemia) times more risk for NM in <0.100 lambs
compared to >0.100 lambs. The OR for death due to
enteritis increased to 5.9 in Marwari lambs for lamb
weight: dam weight ratio of <0.100. The lambs born
during January to June were at higher risk of pneumonia
(3.7 times) and enteritis (2.7 times) as compared to
lambs born during July to December.
The overall responsible causes for neonatal lamb
mortality showed predominance of pneumonia with
32.90% contribution in total deaths followed by
septicaemia / toxaemia (23.23%), enteritis (14.84%)
and tetanus (7.74%). Among different phases of
neonatal period, pneumonia and septicaemia /
toxaemia were major contributors for mortality during 0
to 1 day-old lambs. The predominant causes of mortality
in decreasing orders were septicaemia / toxaemia,
pneumonia and enteritis in 2 to 7 days-old lambs and
pneumonia, septicaemia / toxaemia, enteritis and tetanus
during8 to 28 days-old lambs(Table5). Breed-wise profile
showed almost comparable contribution of pneumonia in
both the breeds. However, there was predominance of
septicaemia / toxaemia in all the stages of hebdomadal
phase in Marwari breed and enteritis in 0 to 1 and 4 to 7
days-old lambs of Magra breed. Death due to tetanus was
observed only in Marwari lambs particularly during post-
hebdomadalphase.
The analysis for predominant causes of NM
revealed significant influence of birth weight on
mortality due to pneumonia, septicaemia (P<0.001)
and enteritis (P<0.05); however, non-significant
effect was observed for mortality due to tetanus
(Table 6). In Marwari compared to the lambs with
>3.5 kg birth weight, lambs with <2.0 kg birth weight
h a d c o n s i d e r a b l y h i g h e r m o r t a l i t y d u e t o
septicaemia (4.21% v/s 0.19%) and enteritis (1.58%
v/s 0.00%).
Table 5. Causes (% contribution) of neonatal lamb mortality at an organized farm in arid Rajasthan
Cause Breed No. died (% contribution)
Hebdomadal (0-7 days) Post- Grand Total
Immediate Delayed Late Total hebdomadal (0-28 days)
(0-1 day) (2-3 days) (4-7 days) (8-28 days)
No. died Marwari 11 14 37 62 56 118
Magra 5 11 8 24 13 37
Total 16 25 45 86 69 155
Heat stroke Marwari - 1 (7.14) 1 (2.70) 2 (3.23) - 2(1.69)
Magra - - - - - -
Total - 1 (4.00) 1 (2.22) 2 (2.33) - 2 (1.29)
Exposure Marwari 1 (9.09) - 2 (5.41) 3 (4.84) - 3 (2.54)
Magra - 2 (18.18) - 2 (8.33) - 2 (5.41)
Total 1 (6.25) 2 (8.00) 2 (4.44) 5 (5.81) - 5 (3.23)
Septicaemia / Marwari 3 (27.27) 7 (50.00) 11 (29.73) 21 (33.87) 9 (16.07) 30 (25.42)
Toxaemia Magra 1 (20.00) 3 (27.27) - 4 (16.67) 2 (15.38) 6 (16.22)
Total 4 (25.00) 10 (40.00) 11 (24.44) 25 (29.07) 11(15.94) 36 (23.23)
Enteritis Marwari 1 (9.09) 2 (14.28) 6 (16.21) 9 (14.52) 6 (10.71) 15 (12.71)
Magra 2 (40.00) - 4 (50.00) 6 (25.00) 2 (15.38) 8 (21.62)
Total 3 (18.75) 2 (8.00) 10 (22.22) 15 (17.44) 8 (11.59) 23 (14.84)
Hepatitis Marwari - - 2 (5.41) 2 (3.23) - 2 (1.69)
Magra - - - - - -
Total - - 2 (4.44) 2 (2.33) - 2 (1.29)
Pneumonia Marwari 4 (36.36) 4 (28.57) 8 (21.62) 16 (25.81) 23 (41.07) 39 (33.05)
Magra 1 (20.00) 4 (36.36) 2 (25.00) 7 (29.17) 5 (38.46) 12 (32.43)
Total 5 (31.25) 8 (32.00) 10 (22.22) 23 (26.74) 28 (40.58) 51 (32.90)
Tetanus Marwari - - 1 (2.70) 1 (1.61) 11 (19.64) 12 (10.17)
Magra - - - - - -
Total - - 1 (2.22) 1 (1.16) 11 (15.84) 12 (7.74)
Miscellaneous Marwari 2 (18.18) - 6 (16.21) 8 (12.90) 7 (12.50) 15 (11.71)
Magra 1 (20.00) 2 (18.18) 2 (25.00) 5 (20.83) 4 (30.77) 9 (24.32)
Total 3 (18.75) 2 (8.00) 8 (17.78) 13 (15.12) 11 (15.94) 24 (15.48)
C.P. Swarnkar et al.
Indian Journal of Small Ruminants 2019, 25(1): 59-69
66

Table 6. Factor-wise magnitude for predominant causes of neonatal mortality (%) in sheep at an organized farm in arid Rajasthan
Factor No. died (%)Number born
Pneumonia Septicaemia Enteritis
Marwari Magra Total Marwari Magra Total Marwari Magra Total Marwari Magra Total
Overall 4768 3882 8650 39 (0.82) 12 (0.31) 51 (0.59) 30 (0.63) 6 (0.15) 36 (0.42) 15 (0.31) 8 (0.21) 23 (0.27)
Birth weight (kg) ** ** ** ** * NS** ** *
Up to 2.00 190 114 1 (0.53) 4 (3.51) 8 (4.21) 2 (1.75) 3 (1.58) -304 5 (1.64) 10 (3.29) 3 (0.99)
2.01 - 2.50 526 419 8 (1.52) 3 (0.72) 4 (0.76) 1 (0.24) 2 (0.38) 1 (0.24)945 13 (1.38) 5 (0.53) 3 (0.32)
2.51 - 3.00 1352 1200 20 (1.48) 3 (0.25) 8 (0.52) 1 (0.08) 7 (0.52) 5 (0.42)2552 23 (0.90) 9 (0.35) 12 (0.47)
3.01 - 3.50 1653 1365 9 (0.54) - 8(0.18) 2 (0.15) 3 (0.18) 2 (0.15)3018 9 (0.30) 10 (0.33) 5 (0.17)
> 3.50 1047 744 1 (0.10) 2 (0.27) 2 (0.19) - 0 (0.00) -1791 3 (0.17) 2 (0.11) -
Sex of lamb NS NS NS NS NS *NS NS *
Male 2453 1952 19 (0.77) 6 (0.31) 16 (0.65) 4 (0.20) 10 (0.41) 7 (0.36)4405 25 (0.57) 20 (0.45) 17 (0.38)
Female 2315 1930 20 (0.86) 6 (0.31) 14 (0.60) 2 (0.10) 5 (0.22) 1 (0.05)4245 26 (0.61) 16 (0.38) 6 (0.14)
Dam age (yr) at lambing NS NS NS NS NS NSNS NS NS
Up to 2 751 729 7 (0.93) 2 (0.27) 8 (1.07) 1 (0.14) 1 (0.13) 2 (0.27)1480 9 (0.61) 9 (0.61) 3 (0.20)
2 - 4 2073 1814 20 (0.96) 8 (0.44) 12 (0.58) 1 (0.06) 6 (0.29) 6 (0.33)3887 28 (0.72) 13 (0.33) 12 (0.31)
4 - 6 1314 1102 8 (0.61) 2 (0.18) 10 (0.76) 3 (0.27) 4 (0.30) -2416 10 (0.41) 13 (0.54) 4 (0.17)
> 6 630 237 4 (0.63) - 0(0.00) 1 (0.42) 4 (0.63) -867 4 (0.46) 1 (0.12) 4 (0.46)
Parity of dam NS NS NS NS NS NS* NS NS
1 1330 1130 17 (1.28) 6 (0.53) 10 (0.75) 2 (0.18) 5 (0.38) 5 (0.44)2460 23 (0.93) 12 (0.49) 10 (0.41)
2 1130 936 9 (0.80) 4 (0.43) 7 (0.62) - 5 (0.44) 1 (0.11)2066 13 (0.63) 7(0.34) 6 (0.29)
3 894 812 5 (0.56) 2 (0.25) 4 (0.45) 3 (0.37) 1 (0.11) 2 (0.25)1706 7 (0.41) 7 (0.41) 3 (0.18)
4 and above 1414 1004 8 (0.57) - 9(0.64) 1 (0.10) 4 (0.28) -2418 8 (0.33) 10 (0.41) 4 (0.17)
Dam weight (kg) at lambing NS NS NS NS NSNS ** * NS
Up to 28.0 231 591 4 (1.73) 4 (0.68) 6 (2.60) 2 (0.34) 0 (0.00) 3 (0.51)822 8 (0.97) 8 (0.97) 3 (0.36)
28.1 – 32.0 1254 1270 10 (0.80) 3 (0.24) 11 (0.88) 2 (0.16) 7 (0.56) 4 (0.31)2524 13 (0.52) 13 (0.52) 11 (0.44)
32.1 – 36.0 1993 1453 19 (0.95) 2 (0.14) 10 (0.50) - 5 (0.25) -3446 21 (0.61) 10 (0.29) 5 (0.15)
>36.1 1290 568 6 (0.47) 3 (0.53) 3 (0.23) 2 (0.35) 3 (0.23) 1 (0.18)1858 9 (0.48) 5 (0.27) 4 (0.22)
Lamb weight : Dam weight * NS * NS * NS** * NS
<0.10 1411 2353 33 (0.99) 10 (0.42) 26 (0.78) 5 (0.21) 14 (0.42) 4 (0.17)5694 43 (0.76) 31 (0.54) 18 (0.32)
>0.10 3341 1467 6 (0.43) 2 (0.14) 4 (0.28) 1 (0.07) 1 (0.07) 4 (0.27)2878 8 (0.28) 5 (0.17) 5 (0.17)
Period ** * ** NS NS *** ** **
P1 (2000-04) 804 801 1 (0.12) - 0 (0.00) - 5 (0.62) 6 (0.75)1605 1 (0.06) - 11 (0.69)
P2 (2004-08) 1019 752 8 (0.79) 3 (0.40) 2 (0.20) - 1 (0.10) -1771 11 (0.62) 2(0.11) 1 (0.06)
P3 (2008-12) 1715 1187 24 (1.40) - 27 (1.57) 5 (0.42) 7 (0.41) -2902 24 (0.83) 32 (1.10) 7 (0.24)
P4 (2012-16) 1230 1142 6 (0.49) 9 (0.79) 1 (0.08) 1 (0.09) 2 (0.16) 2 (0.18)2372 15 (0.63) 2 (0.08) 4 (0.17)
Season ** NS NS NS NS NS** * NS
Jan – Jun 3375 2800 35 (1.04) 11 (0.39) 17 (0.50) 3 (0.11) 13 (0.39) 7 (0.25)6175 46 (0.74) 20 (0.32) 20 (0.32)
Jul - Dec 1393 1082 4 (0.29) 1 (0.09) 13 (0.93) 3 (0.28) 2 (0.14) 1 (0.09)2475 5 (0.20) 16 (0.65) 3 (0.12)
* - Significant (P<0.05); ** - Significant (P<0.001); NS- Non-significant (P>0.05); Difference in number of observations were due to missing record.
Neonatal lamb mortality
Indian Journal of Small Ruminants 2019, 25(1): 59-69 67

A non-consistent p attern was observed for
pneumonia; however, magnitude of mortality to
tetanus had an inverse relation with birth weight of
lambs. Sex of lambs had non-significant variations for
all the major cause specific mortality rates. The dam's
age at lambing had significant (P<0.001) effect only on
mortality due to tetanus and restricted to lambs born to
>4 year old ewes. Parity of dam had non-significant
influence on all the major cause specific deaths in
neonatal lambs. Dam's weight at lambing had
si gn if icant (P<0.05) influe nc e on N M du e to
septicaemia with maximum of 1.47% mortality in
lambs born to ewes with 25.1-30.0 kg body weight.
However, analysis of data as per lamb weight: dam's
weight showed significant (P<0.05) influence on
mortality due to pneumonia, septicaemia and enteritis
with 2 to6 times higher mortality in lambs possessing
<0.100 lamb weight: dam weight ratio compared to
those with >0.100. Year of birth (periods) had
significant (P<0.001) influence on pneumonia and
septicaemia related mortality with maximum during
2008-2012. Significantly higher mortality due to
pneumonia (P<0.05) and tetanus (P<0.001) was
observed in December – March and August –
November born lambs.
In accordance with the present observations on
causes of neonatal lamb mortality, pneumonia was
reported as the most widespread cause of mortality
(Mukasa-Mugerwa et al., 2000; Mandal et al., 2007)
followed by digestive disorders. However, Ahmad et
al. (2000) and Sharif et al. (2005) reported diarrhoea
as major cause of neonatal lamb mortality. Higher
mortality due to septicaemia and enteritis in lambs with
<2.0 kg birth weight could be attributed to low vigour,
insufficient colostrum intake (Dwyer and Morgan,
2006) and ingestion of soil. The study revealed that in
sheep flocks at ARC, Bikaner higher neonatal
mortality during early phase of life was primarily
influenced by birth weight of lamb. Strategies should
be adopted for better feeding of pregnant ewes during
late gestation and proper nursing of lambs (with low
birth weight particularly born to primiparous ewes.
ACKNOWLEDGEMENTS
The authors acknowledge the support and facility
provided by the Director, ICAR-Central Sheep and Wool
Research Institute, Avikanagar and Head, Arid Research
Campus, Bikaner. All India Network Programme on
Neonatal Mortal ity in Farm A nimals (ICAR) is duly
acknowledged for funding support. The authors also
acknowledge all the staff involved in the management of the
sheep flocks since inception of the projects.
REFERENCES
Abdelqader, A., Irshaid, R., Tabbaa, M.J., Abuajamieh, M.,
Titi, H. and Al-Fataftah, A.R. 2017. Factors influencing
Awa ssi lambs survivorship under field co nditions.
Livestock Science 199: 1-6.
Ahmad, R., Khan, A., Javed, M.T. and Hussain, I. 2000. The
level of immunoglobulins in relation to neonatal lamb
mortality in Pak-Karakul sheep. Veterinarski Arhiv 70:
129-139.
Ahmed, A., Egwu, G.O., Garba, H.S. and Magaji, A.A. 2010.
Studies on risk factors of mortality in lambs in Sokoto,
Nigeria. Nigerian Veterinary Journal 31: 56-65.
Barazandeh, A., Moghbeli, S.M., Vatankhah, M. and
Hossein-Zadeh, N.G. 2012. Lamb survival analysis from
birth to weaning in Iranian Kermani sheep. Tropical
Animal Health and Production 44: 929-934.
Berhan, A. and Van Arendonk, J. 2006. Reproductive
performance and mortality rate in Menz and Horro sheep
following controlled breeding in Ethiopia. Small Ruminant
Research 63: 297-303.
Binns, S.H., Cox, I.J., Rizvi, S. and Greena, L.E. 2002. Risk
factors for lamb mortality on UK sheep farms. Preventive
Veterinary Medicine 52: 287-303.
Dalton, D.C., Knight, T.W. and Johnson, D.L. 1980. Lamb
survival in sheep breeds in New Zealand hill country. New
Zealand Journal of Agricultural Research 23: 167-173.
Dwyer, C.M. 2008. The welfare of the neonatal lamb. Small
Ruminant Research 76: 31-41.
Dwyer, C.M. and Lawrence, A.B. 2005. A review of the
behavioral and physiological adaptations of extensively
managed breeds of sheep that favour lamb survival.
Applied Animal Behaviour Science 92: 235-260.
Dwyer, C.M. and Morgan, C.A. 2006. Maintenance of body
temperature in the neonatal lamb: effects of breed, birth
weight and litter size. Journal of Animal Science 84: 1093-
1101.
Dwyer, C.M., Calvert, S.K., Farish, M., Donbavand, J. and
Pickup, H.E. 2005. Breed, litter and parity differences in
the morphology of the ovine placenta and developmental
consequences for the lamb. Theriogenology 63: 1092-
1110.
C.P. Swarnkar et al.
Indian Journal of Small Ruminants 2019, 25(1): 59-69
68

Dwyer, C.M., Lawrence, A.B. and Bishop, S.C. 2001. The
effects of selection for lean tissue content on maternal and
neonatal lamb behaviours in Scottish Blackface sheep.
Animal Science 72: 555-571.
Fogarty, N.M., Hopkins, D.L. and van de Ven, R. 2000. Lamb
production from diverse genotypes. 1. Lamb growth and
survival and ewe performance. Animal Science 70: 135-
145.
Gokce, E., Atakisi, O., Kirmizigul, A.H., Unver, A. and
Erdogan, H.M. 2014. Passive immunity in lambs: Serum
la ctofe rrin conc entra tions as a pr edict or of IgG
concentration and its relation to health status from birth to
12 weeks of life. Small Ruminant Research 116: 219-228.
Gowane, G.R., Swarnkar, C.P., Prince, L.L.L. and Kumar
Arun. 2018. Genetic parameters for neonatal mortality in
lambs at semi-arid region of Rajasthan India Livestock.
Science 210: 85-92.
Khan, A., Sultan, M.A., Jalvi, M.A. and Hussain, I. 2006. Risk
factors of lamb mortality in Pakistan. Animal Research 55:
301-311.
Malik, R.C., Singh, R.N., Acharya, R.M. and Dutta, O.P.
1980. Factors affecting lamb survival in crossbred sheep.
Tropical Animal Health and Production 12: 217-223.
Mandal, A., Prasad, H., Kumar, A., Roy, R. and Sharma, N.
2007. Factors associated with lamb mortalities in
Muzaffarnagari sheep. Small Ruminant Research 71:
273-279.
Morris, C.A., Hickey, S.M. and Clarke, J.N. 2000. Genetic
and environmental factors affecting lamb survival at birth
and through to weaning. New Zealand Journal of
Agricultural Research 43: 515-524.
Mousa-Balabel, T.M. 2010. The relationship between sheep
management and lamb mortality. World Academy of
Science, Engineering and Technology 41: 1201-1206.
Mukasa-Mugerwa, E., Lahlou-Kassi, A., Anindo, D., Rege,
J.E.O. Tembely, S., Tobbo, M. and Baker, R.L. 2000.
Between and within breed variation in lamb survival and
the risk factors associated with major causes of mortality
in indigenous Horro and Menze sheep in Ethiopia. Small
Ruminant Research 37: 1-12.
Pachlag, S.V., Patnayak, B., More, T. and Sahni, K.L. 1974.
Incidence of lamb mortality under semi-arid condition of
Rajasthan. Indian Journal of Animal Sciences 44: 384-
388.
Piwczynski, D., Sitkowska, B. and Wisniewska, E. 2012.
Application of classification trees and logistic regression
to determine factors responsible for lamb mortality. Small
Ruminant Research 103: 225-231.
Radostits, O.M., Leslie, K.E. and Fetrow, J. 1994. Herd
Health: Food Animal Production Medicine. 2 edn., WB
nd
Sanders Co., Philadelphia, pp 527-606.
Refshauge, G., Brien, F.D., Hinch, G.N. and van de Ven, R.
2016. Neonatal lamb mortality: factors associated with the
death of Australian lambs. Animal Production Science 56:
726-735.
Sawalha, R.M., Conington, J., Brotherstone, S. and
Villanueva, B. 2007. Analyses of lamb survival of Scottish
Blackface sheep. Animal 1: 151-157.
Schreurs, N.M., Kenyon, P.R., Mulvaney, F.J., Morel,
P.C.H., West, D.M. and Morris, T. 2010. Response of
additional ewe lamb live weight during gestation on birth
and weaning weight of offspring and live weight of the ewe
lamb at weaning. Animal Production Science 50: 528-532.
Sharif, L., Obeidat, J. and Al-Ani, F. 2005. Risk factors for
lamb and kid mortality in sheep and goat farms in Jordan.
Bulgarian Journal of Veterinary Medicine 8: 99-108.
Shrivastava, C.P., Prasad, S.P., Singh, L.B. and Patnayak,
B.C. 1983. Mortality in Marwari lambs grazing exclusively
in range land of hot arid region. Indian Journal of Animal
Sciences 53: 681-683.
Southey, B.R., Rodriguez-Zas, S.L. and Leymaster, K.A.
2001. Survival analysis of lamb mortality in a terminal sire
composite population. Journal of Animal Science 79:
2298-2306.
Szumilas, M. 2010. Explaining odds ratios. Journal of the
Canadian Academy of Child and Adolescent Psychiatry
19: 227-229.
Swarnkar, C.P. and Singh, D. 2010. Questionnaire survey
on sheep husbandry and worm management practices
adopted by farmers in Rajasthan. Indian Journal of Small
Ruminants 16: 199-209.
Turkson, P.K. and Sualisu, M. 2005. Risk factors for lamb
mortality in Sahelian sheep on a breeding station in
Ghana. Tropical Animal Health and Production 37: 49-64.
Vatankhah, M. and Talebi, M.A. 2009. Genetic and non-
genetic factors affecting mortality in Lori-Bakhtiari lambs.
Asian-Australasian Journal of Animal Sciences 22: 459-
464.
Neonatal lamb mortality
Indian Journal of Small Ruminants 2019, 25(1): 59-69 69