Dept. of Anim. Husbbandry.

Fac.Vet. Med., Alex. University.

Effect of Mothering ability on the development of behavior and performance of lambs

(With 5 Tables)

By

U.S. MAHROUS; I.S. MENEEH

and MADEHA DARWISH*

*Dept. Anim. Hygiene Fac. Vet. Med., Assuit. Univ.

(Received at 26/3/2005)

تأثير قدرة الأم على تطوير السلوک والأداء في الحملان

أسامة محروس , إبراهيم منيع , مديحة درويش

أجريت هذه الدراسة على عدد (4) أربعة نعاج أمهات معهم (8) توائم وأيضا عدد (8) نعاج أمهات معهم (8) ثماني حملان مفردة, لقد تم وضع کل أم وأبناءها من الحملان لمدة أسبوعين في جزء منفصل عن الآخرين , وبعد ذلک تم تجميعهم في حظيرتين کل حظيرة تشتمل على أربعة توائم وأربعة حملان مفردة مع أمهاتهم. هذا وقد تم تمييز هذه الحملان بوضع علامات بالدهان على ظهورهم ثم ترکت هذه الحملان للرضاعة من أمهاتهم التي تم توفير العليقة المرکزة لهم يومياً صباحاً ومساءاً. بالاضافه إلى ذلک قد تم توفير الدريس وکذلک ماء الشرب بصفة دائمة. هذا وقد تم دراسة السلوکيات بواسطة کاميرا فيديو تم تثبيتها بسقف الحظيرة من عمر (3) ثلاثة أسابيع وحتى فترة الفطام عند عمر (8) ثمانية أسابيع بعد الولادة. هذا وقد أثبتت النتائج المتحصل عليها من هذا البحث أن الحملان التؤام تتميز بتردد أو تکراراً عالي للرضاعة, الرقاد, الوقوف, وقضاء وقتاً أطول لفترات الرضاعة, بينما تميزت الحملان المولودة وحيدة بتردد عالي للتغذية, الشراب, المشي, الجري, الهرش, الحک , التمطيع , سلوک الاستکشاف ونشاطات اللعب والتي تشتمل على النطح والقفز بالإضافة إلى قضاء وقت أطول في التغذية والشرب والرقاد. وقد لوحظ أيضا أن الحملان المولودة وحيدة قد اکتسبت زيادة في وزن الجسم عن الحملان التؤام في الفترة من أسبوعين حتى أربعة أسابيع بعد الولادة, وبعد ذلک الحين فصاعداً لوحظ أن الحملان التؤام قد أظهرت زيادة في وزن الجسم حتى فترة الفطام, هذا وفى العموم فإن اجمالى الزيادة في وزن الجسم کانت عالية في الحملان المولودة وحيدة عن الحملان التؤام.

SUMMARY

Four ewes had 8 twin lambs and eight mothers had 8 single lambs were placed with their own lambs in a separate partitions for 2 weeks then grouped together in two pens each pen lodged 4 twin and 4 single lambs with their dam. Lambs were identified by painting marks on their backs, then  left to suckle their dams which provided with daily supply of  concentrate ration at morning and evening. Moreover, after concentrate ration, dams were regular supplied with hay, ad-libitum. The water was supplied through water troughs permanently. Behavioral observations were carried out by video camera hanged on the ceiling of the chamber from the third week till weaning period at 8th week. The obtained results indicated that twin lambs had higher frequencies of suckling, laying, standing, and spent longer time of suckling and standing while, the single born lambs had higher frequencies of feeding, drinking, walking, running, scratching, rubbing, stretching, exploratory behaviors and playing activities including butting and jumping as well as spent longer time feeding, drinking and laying. The singleton lambs gained more weight than twins during the period from the 2nd till 4th week of age, thereafter the twins gained better weight until 8^th week (weaning), although the overall body weight gain was higher in the singletons than twin lambs.

Key Words: Lambs, Behavior, Mother ability, Weaning.

Introduction

Multiple births are common in sheep although twin fetuses experienced  much higher rates of prenatal mortality / morbidity than age- and weight-matched singletons (Gardner et al, 2004). Moreover, as the ewe has only two teats, there is a risk of high mortality in these highly fertile breeds unless the lambs are artificially reared. Good lamb survival depends upon the maternal care and teat finding. The survival of the neonate relies on the integrated expression of appropriate behaviors from both the mother and young. In precocious species, like sheep, the speed with which the lamb stands and seeks the udder is related to lamb survival (Dwyer, 2003).

The neonatal behavior developed after parturition and later on the time spent in various activities was shown to be varied as the neonates grown up and depending on their health condition (Lickliter, 1987). Infants spent nearly 70% of the observation time lying down during the first week of age and continued to be more frequently lying down during the next 3 weeks (accounting for 60-70% of the observation time), then declined rapidly following the 4th week and progressively until the 15th week of age. The conditions in which the neonates grown up could affect their behavior, such as the sternal recumbency which was found to be increased with age from 47% to 57.6% between the 5th and 17th week of age for calves housed in stalls and from 45.5% to 55% for those housed in pens (Albright, et al., 1991). The aim of this study was to investigate the effect of maternal environment either in the uterus or after birth on the development of the lambs' behavior till weaning.

Materials and Methods

This experiment was carried out on 12 mother ewes (age average 3 years), four of them had 8 twin lambs and eight mothers had 8 single lambs. After parturition ewes were placed with their own lambs in a single partition for 2 weeks to prevent the risk of confusion between lambs and their dams. Thereafter   they grouped together in two rooms each one lodged 4 twin and 4 single lambs with their dams.

Lambs were identified by colored paint on their backs and left to suckle their dams with daily supply of the mothers with concentrate ration at morning and evening and daily supplying with hay after concentrate ration ad-libitum. The water supplied ad libitum through water troughs.

For behavioral observations a video camera was hanged on the ceiling of the chamber with a video recording from 7:00 a.m. till 5:00 p.m. A focal sampling method was utilized in this study according to Martin and Frs (1986). The behavioral observations were carried out from the 3rd week of age till weaning at 8th week of age. The behavioral data were analyzed by using MSTAT (1984) system with the following model:

Yijk = µ + Ai + (AB)ij + eijk

Where: Yijk =An individual observation. µ= Overall mean Ai= Effect due to the ith type of birth i.e. i=1 for Single birth and 2 for twin birth. (AB)ij=Effect due to interaction between type of birth and the age till weaning and eijk=Random effect.

The productive performance of lambs was evaluated through biweekly weighing of the lambs from 2 weeks of age till 10th week of age and the weight gain were then calculated and analyzed by MSTAT (1984).                                       

Results

Ingestive behavior: (Table 1)

The data presented in table (1) showed that frequency of suckling was significantly higher (P<0.01) in twins lambs (2.82+0.25) than single lambs (1.89+0.10), moreover, the suckling bouts were significantly longer (P<0.01) in Twins born lambs (1.53+0.29 min/h) than single lambs (0.77+0.07). Moreover, the suckling frequency and bouts were increased from 3rd till the 4th week after parturition where the frequency of nursing  was high in both twins and single lambs ((5.70+1.01 and 3.12+0.27, respectively) with longer bouts (3.91+1.48 and 0.93+0.13 min/h) then showed gradual decline till the weaning. On the other hand, the feeding frequency and feeding time were higher in single lambs (9.19+0.27 and 19.20+0.65) than twin lambs (8.57+0.35 and 18.51+0.87) respectively. However, a reverse trend was observed for feeding frequency which reached its peak during the 8th week after parturition (10.94+0.65) in both single (10.90+0.86) and in twin born lambs. Moreover, the feeding bouts were longer in the twin than single born lambs (31.49+2.06 vs. 29.43+1.85 min/h) respectively.

The drinking time and frequency were higher in single than twin lambs (0.12+0.02 and 0.07+0.02 vs. 0.10+0.02 and 0.06+0.02, respectively). However, the drinking was more frequent with longer bouts during the third weeks after parturition especially in single born lambs (0.30+0.08 and 0.17+0.05, respectively), whereas, in twin lambs it was frequent (0.25+0.10) with longer bouts (0.22+0.08) during the 5th week then showed gradual decline in both drinking frequency and bout with progress in age.

Resting and Movement activities: (Table 2)

Lambs born in twins spent longer time of lying (Table 2) especially during 3^rd, 4^th and 6^th weeks after parturition, moreover the frequency of lying showed the same trend. Although, the mean values of frequency and time of lying were not significantly differ between the single and twin born lambs, these values were declined with age till weaning. The standing time and frequency as well as walking frequency reached the peak values during the 4^th week after parturition in both twins and single born lambs. While, the running frequency reached its peak during the 4^th week after parturition in the single born lambs (9.60+0.90) and during the 5^th week in twin born lambs (8.78+1.17), these values were declined gradually till weaning with no significant difference could be observed between single and twin born animals. Generally, the difference between the single and twin born lambs in movement activities was not clear and could not be judged.

Body care activities: (Table 3)

The developmental changes in the body care activities of lambs showed that scratching activities were gradually increased till the 4^th week after parturition in both single and twin born lambs with higher frequency for twin born lambs (9.08+1.02 vs. 8.84+0.74), then declined gradually to the lowest level during the 8^th week after parturition (3.65+0.55 and 2.99+0.35, respectively). Moreover, the mean values of scratching activities were higher in single born lambs than twin born lambs (5.39+0.25 vs. 5.13+0.30). The rubbing activities were shown to reach its peak during the 7^th week after parturition in single born lambs (0.90+0.18) and during the 4^th week in twin born lambs (0.63+0.20). On the other hand, the stretching activity showed its peak value during the 4^th week after parturition for both single and twin born lambs (1.38+0.14 and 1.45+0.23).

The head shaking activity showed gradual increased with the progress in lamb age to reach its peak value during the 8^th week after parturition in both single and twin born lambs (10.84+0.64 and 10.80+0.74, respectively). Generally, it was slightly higher in single than twin born lambs except during the 6^th week where the reverse condition was observed (7.82+0.57 vs. 7.19+0.45).

Exploratory behaviors: (Table 4)

The exploratory behavior showed gradual decline with age of lambs specially after the 4^th weeks of age where the highest frequencies of litter, wall and other explorations were observed during the 4^th week after parturition in single born (8.16+0.69, 8.50+0.74 and 18.34+1.35, respectively) and twin born lambs (7.80+0.92, 6.35+0.88 and 15.28+1.87, respectively). Thereafter, these activities showed gradual decline to reach the lowest frequencies during the 8^th week after parturition in single  (3.38+0.33, 3.04+0.33 and 5.62+0.46, respectively) and twin born lambs (3.82+0.43, 2.63+0.36 and 5.90+0.70, respectively), Whereas, the trough exploration showed progressive decrease with age from the 3^rd till the 8^th week after parturition in both single born (3.75+0.64 to 0.93+0.22) and twin born lambs (3.23+079 to 0.88+0.17).

Social activities: (Table 4)    

The development in the social activities or playing activities showed increase in the butting and jumping frequencies from 3^th to the 4^th week after parturition in single born  (1.47+0.30 and 0.78+0.21, respectively) and twin born lambs (1.20+0.44 and 0.53+0.19, respectively). These activities were declined gradually with age till the 7th week of age then it began to increase again. Moreover, the single born lamb showed higher butting frequency than twin born lambs (0.67+0.08 vs. 0.60+0.11, respectively). Moreover, jumping frequency showed the same trend (0.32+0.05 and 0.18+0.04, respectively).

Productive performance: (Table 5)

The body weights of the single born lambs were heavier than twin born lambs during the 2nd week  (10.00+0.69 vs. 9.31+1.07 kg); 4th week (13.44+0.85 vs. 12.10+1.23 kg); 6th week (14.78+0.88 vs. 13.46+1.32 kg); 8th week (17.22+1.07 vs. 15.87+1.45 kg) and 10th week after parturition (21.72+1.41 vs. 19.73+1.87 kg). Moreover, the single born lambs gained more weight than twin born lambs during the age period of 2-4 weeks (3.44+0.22 vs. 2.79+0.32 kg), then the twin born lambs gained better during the age period of 4-6 weeks (1.36+0.15 vs. 1.34+0.12) and during the age period of 6-8 weeks (2.41+0.25 vs. 2.34+0.23 kg). However the overall body weight gain was higher in the single born lambs than twin born lambs (11.72+0.83 vs. 10.43+1.07 kg).

Discussion

Ingestive behavior:

Production of twins or triples is not indicator to the ability of mother to spare a good maternal environment for them. Moreover, the competition for nursing between lambs could affect both time of nursing and amount of milk suckled by each lamb during the pre-weaning period. This could affect development of the digestive system of the litter and so the ingestive behavior, performance, and survival percentage.

The mothering ability of the ewe to care her lambs depends upon variation in the physiological efficiency of the ewe, especially those related to milk production which is affected by birth type, parity and the ability of the ewe to nurse the newly born lambs. In this study a highly significant effect to the birth type on suckling frequency, suckling time, feeding frequency, feeding time, drinking frequency and drinking time by the lambs is mostly attributed to the ability of dam to mothering her lambs. Moreover, the chance of suckling was greater for the single than twin lambs and the development of their digestive tract during pre-weaning period. The lighter lambs stood earlier and attempted to suck for less time (17.7 and 2.4 min v. 32.4 and 10.5 min, P<0.05) than heavier ones (Kuchel and Lindsay 1999).

The suckling was more frequent with longer bouts in twin lambs, which may be attributed to the competition between lambs to take their chare of milk. However, the reverse trend was observed for feeding and drinking since the development of the digestive tracts in single lambs occurs more rapidly. Litter size had a retarding influence on the behavior of multiple-born lambs that could not be accounted for birth weight (Dwyer, 2003)

Resting and movement activities:

The time spent lying down decreased and the time of standing, frequency of standing, walking and running increased gradually as the age of lambs increased either in single or twin born lambs. This could be attributed to the development of muscular tone and increasing the demand of the animal for searching for feed and exploration of their environment. On contrary, Lickliter (1987) found that mean time spent walking, running and standing sustained stable throughout the first 15 weeks following birth. Whereas, Coe, et al., (1992) observed that the amount of time spent lying decreased from 90 to 75% (between 1st and 25th week). However, the behavioral profiles of welfare parameters in commercial veal calf facilities revealed that calves spent approximately 25 and 75% of the time in standing and lying respectively and the calves performed 17 and 19 lying and standing transitions per day (Stull, 1992). On the other hand, Hinch, et al., (1982) stated that running incidence found to be declined with age with highest and lowest frequencies at 10 and 18 months of age, respectively.

Body care behavior: 

The developmental changes in the body care activities of lambs revealed that scratching activities showed gradual increase till the 4th week after parturition in both single and twin born lambs with the highest frequency was for twin born lambs. However, it was declined gradually to lowest level during the 8th week after parturition. Moreover, the mean scratching activities were higher in single born than twin born lambs. The rubbing activities reached its peak during 7th week after parturition in single born lambs and during the 4th week after parturition in twin born lambs then declined gradually with age. In contrast the stretching activity showed gradual decline from 3rd week till the 8th week after parturition. Similarly, Hinch, et al. (1982) found that grooming or licking the head, neck or shoulders of an inactive animal significantly increased as the age of bulls and steers increased (from 10 to 14 months). Whereas, rubbing of neck, shoulder, rump on fixed objects showed a reverse trend the highest and lowest frequencies were achieved at 10th and 14th month, respectively. While, Albright, et al. (1991) found that the time spent grooming, investigating and idling activities decreased with age from 13.3 to 3.1% between 5th and 17th week in stall reared calves and from 12.5 to 2.3% for group penned calves. However, Sato, et al. (1991) found that percentages of licking to different body parts were 27, 24, 15, 12, 11, 4, 3, 3 and 1 for neck; head; back; shoulders; rump; belly; hind legs; forelegs and tail, respectively. Social licking with solicitation was mainly oriented to the neck and the areas which the receivers could not themselves reached in self-licking. Furthermore, licking of these areas was accounted for 78% of the total time.

Exploratory behaviors:        

The exploratory behavior showed gradual decline with age of lambs where the highest frequencies of litter, wall and other exploration were during the 4th week while, the lowest frequencies were during the 8th week after parturition in single born and twin lambs. However, the trough exploration showed gradual decline with age from the 3rd till the 8th week after parturition in both single born and twin born lambs. The changes in the exploratory behaviors with age could be attributed to the motivation of the lambs as they build the basic information about their new environment, where they can find the food, the dangerous areas and so on. So that at the beginning the exploratory behavior occurs with highest frequencies then the animals built an information base about their surroundings, consequently these exploratory behaviors take place. Moreover, Deprivation from dam suckling resulted in less time (P<. 001) spent in investigative behavior, shorter duration of movement and a longer latency time, higher number of bleats as well as higher plasma cortisol levels and reduced growth (Napolitano et al, 2003).

Social behavior:

The development in the social activities or playing activities showed gradual increase in butting and jumping frequencies till the 4th week after parturition in single and twin born lambs then these activities were declined gradually with age till the 7th week of age then it began to increase again. The play behavior of lambs (butting and pushing) seemed to be sporting. Moreover, the mounting behavior for their mothers or companions might be developed into subsequent sexual behavior (Tanka et al., 1992). Moreover the single born lamb had the higher butting and jumping frequencies than twin born lambs since the twin lambs were engaged longer time in competition for suckling than single born lambs.

Productive performance:

Growth rates, expressed by average daily gain of lambs over a certain period of life, are characters of great significance in animal breeding. A final weight whether it is a weaning or yearling weight, is dependent firstly on the initial weight and secondly on the daily gain.  Therefore, improving this character yields a marker improvement in the other economic traits. For this reason, many workers were interested to study the effect of various genetic and environmental factors affect growth rate. In our study the body weights of the singletons lambs were heavier than twin born lambs during the 2nd, 4th, 6th, 8th and 10th week after parturition. This could be attributed to the prepartum increase in fetal plasma cortisol in singletons than twins which responsible for maturing a number of systems in preparation for birth and the immediate postnatal period. Thus, it could be argued that relative immaturity in twins may explain their increased susceptibility to stress Gardner et al (2004). Moreover, the single born lambs gained more weight than twin born lambs during the period of 2-4 weeks, then the twin born lambs gained better during the periods 4-6 and 6-8 weeks, although however, the total body weight gain was higher in single than twin born lambs. This could be attributed to the ability of dam to suckle one lamb better than twin or triple lambs, which in turn helps in development of their digestive system and their productive performance. Moreover, Napolitano, et al (2003) suggested that frustration arising from maternal feeding deprivation results in altered endocrine and behavioral responses and reduced growth from emotional disturbances of lambs.

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