From 153 lambs studied, 13 of them died before 30 days of age with overall neonatal mortality of about 8.5%. According
to this study, the mortality rates in male and female neonatal lambs were found 10.3 (8/78) and 6.7% (5/70),
respectively. However, there was no significant difference (P>0.05) between immunoglobulins levels of both sexes.
Similarly, Cinpercescu (1977) and Esser et al. (1989) also reported no difference in male or female immunoglobulins
Serum immunoglobulins levels
The present study finding, indicates the average serum immunoglobulins level of surviving lambs (31.71±12.88 ZST
units) were significantly (P<0.05) higher than those that died during the neonatal period (12.77±5.25 ZST units. The mean
serum immunoglobulins level recorded in thisstudy was almost similar to the findings of Reid (1972) and AL salami and
Sinclair (1977), who reported serum immunoglobulin levels of about 27.40±1.70 and 30.90 ZST units, respectively. In the
present study, the majority of lambs had ZST values between 20 and 40 units which are in accordance with findings
recorded by Reid (1972) and Logan and Irwin (1977) in lambs. Based on this study, thirteen lambs out of 153 (8.5%) were
found markedly deficient in serum immunoglobulin level (<13 ZST units), and which died later.
The importance of colostrum in reducing the incidence of neonatal lamb mortality is obvious by the fact that the
nine out of thirteen lambs that died in the present study had an immunoglobulin level below 10 ZST units. Such lambs
would be at high risk of susceptibility to diseases, and subsequent death as the observations reported by Reid (1972),
Findlay (1973) and Logan and Irwin (1977). But according to Villar and Vulich (1980), ZST units in the range of 0-20 are
indications of high risk of subsequent death. According to the present study, most of the mortalities were recorded during
the first week of life. The finding is in agreement with Jordan and Le-Feuvre (1989), Otesile and Oduyo (1991) and Fentie
et al. (2020) who reported maximum morbidity/mortality of lambs during the first week of life.
The lambs that survived the neonatal period had a significantly (P<0.05) higher level of immunoglobulins than those
that died (Table 1). The result is similar with the findings recorded by Sawyer et al. (1977), Villar and Vulich (1980), Otesile
(1994), and Kenyon et al. (2019). However, Bekele et al. (1992) reported no significant differences between mortality
during the neonatal period and immunoglobulins concentration. The newborn leaves the sterile uterus to an environment
containing many pathogens. The neonates are often overcome by infectious diseases, even by agents that are relatively
nonpathogenic to adult animals (Banks, 1982). In the absence of specific immunity at birth due to of placental barriers
(Tizard, 1992), ruminant neonates have to rely on antibodies received via colostrum (Khan and Khan, 1991). These
antibodies play a significant role in the defense mechanism of newborn lambs until their own immune systems are
primed and produce a protective level of antibodies (Tizard, 1992).
In the present study, six lambs out of thirteen (46.15%) showed sign of diarrhea, before death; while four (30.77%)
died after signs of a respiratory disorder and the rest three died with no specific clinical signs. According Fisher (1980),
IgM was the class of immunoglobulin found to be deficient in neonates that died of septicemic and bacteremic causes,
whereas IgG was found to be deficient in neonates that died of diarrhea. IgA seems to be re-excreted and somehow halts
the diarrheic process. According to Smith et al. (1976), a small amount of colostrum IgG, after being absorbed, is secreted
in the nasal and lachrymal secretions of lambs and this plays a valuable role in preventing respiratory infections before
local production of IgA and IgM at the age of 2-3 weeks.
The survival of neonatal lambs was also observed with respect to their birth weight. The mean birth weight was
found 2.41±0.37 kg and the males (2.45±0.31 kg) were found heavier than females flock members (2.37±0.43 kg). The
surviving lambs (2.43±0.35 kg) were also heavier than those that died during the neonatal period (2.21±0.55 kg) . Being
physically weak, the lambs with low birth mass were unable to suckle sufficient amount of colostrum, and as a result, the
immunoglobulins level in their serum was low. The physical weakness and low immunoglobulins led to increased
mortality in lambs with a low birth mass. The finding of the study is similar with the works which were reported by Purser
and Young (1983), Ducrot et al. (1989), Tadich et al. (1990) and Otesile and Oduye (1991). All lambs with higher birth
weight survived the neonatal period. However, according to Poonia et al. (1983), as birth mass increases above 3.0 kg,
the mortality also increases. Contrary to this finding, Dalton et al. (1980) reported that a lamb with a birth mass of from
3.5 to 5.5 kg had the lowest mortality. According to Hindson and Winter (2002), neonatal lambs with low birth weight
often have poor suckling drive or they are unable to compete with stronger lambs for available milk. Hence, they are
disadvantaged both from total milk intake and reduced immunoglobulin intake.
Based on the finding of the present study, it can be concluded that the total serum immunoglobulin levels in neonatal
lambs within the first one to two days of age, had a good indication for the extent of the absorption of colostral antibodies
from the dam. The neonatal lambs with lower average birth weight (2.21 kg) and lower average total serum
immunoglobulin level (12.77 ZST units) had found dead before the first 30 days of their age. Hence, several works have to
be done to further improve the birth weight of newborn lambs as well as the nutritional status of the dam so that lambs
can suckle starting from the first few hours of birth and receive sufficient amount good quality colostrum.
Citation: Demis Ch, Aydefruhim D, Wondifra Y, Ayele F, Alemnew E and Asfaw T (2020). Maternal immunoglobulin in the serum of newborn lambs and its relation with