Factors affecting the survival of newborn lambs

European Commission Directorate-General For The Information Society And Media Directorate-General For Agriculture And Rural Development

Description

Agricultural and fisheries research
Veterinary sector and animal health

Sujets

• Animal nutrition
• Sheep

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 13
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Commission of the European Communities
AGRICULTURE
Factors affecting the survival
of newborn lambs
Report
EUR 9744 EN Commission of the European Communities
AGRICULTURE
Factors affecting the survival
of newborn lambs
A seminar in the CEC programme
of coordination of agricultural research
held in Brussels, 22 and 23 January 1985
Edited by
G. Alexander, J. D. Barker, J. Slee
Organized by
J. Slee
AFRC Animal Breeding Research Organization,
Kings Buildings, West Mains Road
Edinburgh EH9 3JQ, Scotland
Sponsored by the
Commission of the Eurpean Communities
Directorate-General for Agriculture
Coordination of Agricultural Research
1985 EUR 9744 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Information Market and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on
behalf of then is responsible for the use which might be made of the
following information
Cataloguing data can be found at the end of this publication
Luxembourg, Office for Official Publications of the European Communities, 1986
ISBN 92-825-5938-6 ^
Catalogue number: (ffij^jj Jpj|BM£f(h
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1986
Printed in Luxembourg PREFACE
This seminar "Factors affecting the survival of newborn
lambs" took place on January 22nd-23rd 1985 at the Commission
of the European Communities, 200 Rue de la Loi, Brussels.
The problem of lamb mortality is important both from the
viewpoint of animal welfare and economic loss. In Britain up
to 4 million newborn lambs die each year. Most lambs in
Britain and Ireland are born outdoors and a major cause of
death is cold exposure combined with starvation. Under these
conditions the thermoregulation of the lamb (including
insulation and heat production) is of vital importance. Many
of the physical and physiological factors affecting thermo­
regulation are subject to genetic control. Environmental fac­
tors such as nutrition and shelter are also of great import­
ance. Research on genetic improvement and on the effective­
ness of environmental changes is highly relevant.
On the continent of Europe, where many lambs are born
indoors, the situation is different. Disease resistance and
ease of lambing will probably be more important in determin­
ing lamb survival. With regard to indoor and outdoor environ­
ments different aspects of lamb and maternal behaviour may
apply and there are likely to be effects of prenatal nutrit­
ion and of litter size. Many of these factors will interact
in producing effects on lamb viability.
This seminar covered two major areas relevant to lamb
survival :
(i) Genetic and physiological factors - including
thermoregulation ;
(ii) Environmental factors - including nutrition
and disease resistance.
The seminar gave an opportunity to compare the relative
importance of lamb mortality and its causes in the different
agricultural systems operating in EEC countries. Where
systems are changing, perhaps with respect to sheep housing
or different nutritional regimes, scientists have lessons to
learn from research in other countries. CONTENT? Page
PREFACE
DAY 1 : PHYSIOLOGICAL AND GENETIC EFFECTS
DETERMINANTS OF HEAT PRODUCTION CAPACITY IN NEWBORN ι
LAMBS AND THEIR EFFECTS ON SURVIVAL
F.A. Eales and J. Small
THERMOREGULATION IN THE NEWBORN LAMB : THE FIRST 36 n
HOURS
J.F. Andrews and J.B. Mercer
GENETIC EFFECTS ON RESISTANCE TO COLD AND SURVIVAL IN 21
NEWBORN LAMBS
J. Slee
MAJOR FACTORS AFFECTING THERMOGENESIS AND COLD 35
RESISTANCE OF NEWBORN LAMBS
M. Vermorel and J. Vernet
BROWN ADIPOSE TISSUE AND FAILING THERMOREGULATION 49
P. Wen sv oor t
PATTERNS OF IMMUNOGLOBULIN CONCENTRATIONS IN LAMB 55
SERUM FROM BIRTH THROUGH THE POST-WEANING PERIOD
F. Klobasa, E. Werhahn and E. Kallweit
ENDOCRINE AND ENZYME ACTIVITY AND MATERNAL EFFECTS IN 63
RELATION TO LAMB SURVIVAL
C. Wollny, R. Wassmuth, S. Meinecke-Tillmann, V. Dzapo
MATERNAL EFFECTS ON LAMB SURVIVAL 79
J.P. Hanrahan
FORECASTING 'CHILL FACTORS' FOR YOUNG LOWLAND LAMBS 8
J.R. Starr
PHYSIOLOGICAL AND BEHAVIOURAL FACTORS AFFECTING LAMB 9
SURVIVAL UNDER PASTORAL CONDITIONS
G. Alexander
V — DAY 2 : ENVIRONMENTAL, BEHAVIOURAL AND NUTRITIONAL EFFECTS Page
PARTURITION DIFFICULTIES AND PERINATAL MORTALITY IN 115
TEXEL AND MILK SHEEP
L. Elving, P. Grommers and P. van Eldik
RELATIONSHIP BETWEEN BREED, LITTER SIZE, BIRTH WEIGHT 123
AND MORTALITY RATE IN NEWBORN LAMBS
E. Kallweit, D. Smidt and CK. Profittlich
RELATIONSHIP BETWEEN LAMB SURVIVAL AND BEHAVIOUR 135
DURING THE FIRST HOUR AFTER BIRTH
M. Theriez and Yseult Villette
THE EFFECTS OF LITTER SHE ON LAMB SURVIVAL 145
S.A. Kouimtzis
PERINATAL VIABILITY AND BIRTH WEIGHT IN SUFFOLK, 151
MILKSHEEP AND TEXEL SHEEP AND THEIR CROSSES
P. van Osselaer, K. Michels and A. Moreels
RELATIONSHIPS BETWEEN TOE NUTRITION OF THE EWE, LAMB 165
BIRTH WEIGHT AND SURVIVAL IN PROLIFIC CROSSBREDS
H. Everts
EFFECTS OF NUTRITION ON PRENATAL GROWTH AND THE 177
IMPLICATIONS FOR PERINATAL SURVIVAL IN LAMBS
J.J. Robinson and R.P. Aitken
GENERAL DISCUSSION, SUMMARY AND CONCLUSIONS 191
LIST OF PARTICIPANTS 197 DETERMINANTS OF HEAT PRODUCTION CAPACITY IN NEWBORN LAMBS AND THEIR
EFFECTS ON SURVIVAL: SUBSTRATES FOR HEAT PRODUCTION.
F.A. Eales and J. Small
Moredun Research Institute, 408 Gilmerton Road, Edinburgh,
Scotland, EH17 7JH.
ABSTRACT
Respiratory quotient was estimated in 92 Scottish Blackface
lambs aged up to five hours during basal metabolism, summit metabolism
and at the metabolic rate mid-way between basal andt metabolisms
(middle metabolism) in an investigation of the relative contributions
of carbohydrate and lipid as energy substrates. Neither age nor
feeding had any effect on respiratory quotient. The mean respiratory
quotients were, basal metabolism; 0.85, middle metabolism; 0.79 and
summit metabolism; 0.93. The high respiratory quotient during summit
metabolism suggested a marked dependence on carbohydrate at high
metabolic rates. This finding helps to explain the clinical
observation that profound hypoglycaemia is the primary metabolic lesion
in hypothermia due to starvation.
INTRODUCTION
Hypothermia caused by starvation is probably the single most
important cause of death in newborn lambs (Eales, Small and Gilmour,
1983). Such lambs exhibit a marked hypoglycaemia but a comparatively
mild depression of plasma free fatty acid levels, Table 1.
TABLE 1. Plasma composition in healthy and hypothermic lambs aged
24 hours, mean ± SEM
Plasma composition
n Glucose (mM) Free fatty acids (mM)
Hypothermic lambs 19 0.5 ζ 0.16 0.4 ± 0.09
Healthy lambs 32 4.7 ΐ 0.14 1.7 ± 0.19
1 -Reversal of the hypoglycaemia is a highly effective and essential
part of treatment (Alexander 1962; Eales, Small and Gilmour, 1982).
This evidence suggests that the newborn lamb has a greater dependence
on carbohydrate as a substrate for heat production than does the adult
sheep, which can depend almost entirely on lipid (Bennett, 1972). A
restricted ability to utilise relatively abundant body lipid reserves
(2-3% of body weight; Alexander and Bell, 1975) and a dependence on
relatively sparse body carbohydrate reserves (1% of body weight;
Shelley, 1960) would severely limit a newborn lamb's ability to
maintain its body temperature.
There is little published information on substrate utilisation in
newborn lambs. Protein however does not seem to bt: a significant
energy substrate (Alexander, 1962; Eales and Small, 1981).
Respiratory quotient has been studied in Australian lambs of varying
ages at different rates of metabolism (Alexander, 1961; Alexander,
1962; Alexander and Williams, 1968). At basal metabolism, values of
approximately 0.8 were recorded, at summit metabolism,0.8 -0.9 and at a
metabolic rate mid-way between basal and summit metabolisms
approximately 0.7. This evidence suggests that lipid utilisation is
quantitatively more important than carbohydrate utilisation. This
finding is not concordant with the clinical evidence observed in
Scottish lambs. In the light of this discordance we have estimated
respiratory quotient in Scottish Blackface lambs aged up to five hours
at basal metabolism, at summit metabolism and at a metabolic rate mid­
way between basal and summit metabolisms.
MATERIALS AND METHODS
Animals
Pregnant Scottish Blackface ewes were brought into a covered yard
four weeks before the anticipated lambing date. After three weeks the
ewes were removed to individual pens within a sheep house. The ewes
were fed throughout a proprietary complete diet (Ruminant A; Wamman,
Blaxter and Pullar, 1970) ad libitum. The temperature in the sheep
house was 10-15°C.