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Optimum age of weaning piglets
Livestock Production Science, 5(1978) 1--2 © Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
1
Guest Editorial
OPTIMUM AGE O F WEANING PIGLETS
A. AUMA[TRE
LN.R.A., 78350 Jouy-en-Josas (France)
In reflecting over the past t w e n t y years, one will realise the considerable changes in management systems and in economic trends associated with raising pigs in Europe. Improvement in sow productivity was a goal dictated by the e c o n o m y of pig breeding. Early weaning, which was proposed during the nineteen-fifties b y the well-known Iowa Research Team headed by D.V. Catron in order to prevent the loss of newborn piglets, might be one solution for pulling through a high percentage of newborn piglets without suckling their mother. One of the main difficulties of the practical application of weaning at 2 days was the failure of ovulation in sows which were suckling for such a short time. The increase in ovulation failure after very early weaning (less than 7 days of lactation time) limited for years the broad application of early weaning. In addition, pig producers were n o t able to control carefully the feeding of piglets weaned at 2 days with liquid synthetic milk, which had been developed successfully under laboratory conditions. Also, the effect of environmental and housing conditions, in particular the importance of air temperature, was nearly u n k n o w n for very y o u n g piglets of 2--3 kg live weight. However, recent progress in feed formulation has shown that a lot of problems involving nutrition and environment may be solved successfully. In particular, the possibility of using pelleted dry food for piglets weaned at one week of age and reared in a controlled environment was an important step forward. Recent scientific work referred to the reproductive behaviour of sows when litters were weaned at various ages from 3 to 56 days after farrowing. New attempts to wean piglets earlier in practice have been made in Europe, particularly during the last five years. With caution, a decrease of the mean age from 8 weeks to 5 weeks, then from 5 to 3 weeks was generally proposed from experimental and practical evidence. In order to review the results of research and to consider o p t i m u m procedures for practice~the E.A.A.P. Commission on Pig Production organised a working party to study the increase of sow productivity per annum. The valuable work by D. Smidt and co-workers in GSttingen in the mid-sixties has clearly shown the physiological relationships in weaning, and it formed a basis for reviewing the available evi-
dence on the effects of early weaning on reproductive performance of sows. The main aspects are the onset of oestrus, the ovulation rate and the average litter size subsequent to successive early weanings. Since then, considerable data have become available for quantifying these relationships and thus forming a basis for developing optimal procedures. Particularly the danger involved in decreasing the length of lactation below 14 days was clearly shown in relation to saving and optimizing the conditions of reproductive ability of the sow. The influences of several environmental factors on the performances of the weaned piglets have been considered: J. le Dividich and A. Aumaitre paid special attention to the physical parameters e.g. {e.g. air temperature) and hygienic conditions. By analysing data on early weaning from numerous experiments during the last few years, it was possible for J.H.A. te Brake to perform close economical computations for measuring the progress which could be expected in terms of yearly return per sow weaned early or not. Both review papers are published in this issue of "Livestock Production Science". Additional reports concerning the effects of early weaning on the rate of culling of sows were discussed by H. van der Heyde; S. Zivkovic listed the new systems of management attending the application of early weaning in large herds, and Ferradini and Vanderhaegen presented the results of an economic enquiry based on effective performances in selected herds. H.E. Nielsen reviewed the experiments considering the possible effect of early weaning on later performance of the pig during the growing finishing period and on carcass quality. Finally, J. Bourne drew attention to the role of suckling in the transmission of immunity from the sow to the piglets. Some conclusions following the discussions of the reports consisted of practical recommendations for the application of early weaning on a large scale. -- F r o m the experimental evidence thus far one can specify the limits and the possible advantages of early weaning, and the necessary know-how for a reasonable improvement of the productivity of the sow and the performances of the piglets. -- The age of 3--4 weeks could be recommended to breeders for the weaning of their piglets. The more exact age to be chosen depends on the reproductive ability of the sow, the specific economic situation and the professional knowledge of the pig breeder. Finally, for the intensive conditions of housing, management and rearing of breeding sows in European countries, early weaning appears to be an effective way of improving the productivity per annum of the animals. Weaning time could be based on the recent scientific knowledge of its consequences b o t h for the sow and the young animal. However, more research seems to be necessary to ascertain the long-term effect of early weaning on sows and particularly on the ovulation rate, embryonic mortality and productive life, under the different conditions of management found in the different countries.
1
Guest Editorial
OPTIMUM AGE O F WEANING PIGLETS
A. AUMA[TRE
LN.R.A., 78350 Jouy-en-Josas (France)
In reflecting over the past t w e n t y years, one will realise the considerable changes in management systems and in economic trends associated with raising pigs in Europe. Improvement in sow productivity was a goal dictated by the e c o n o m y of pig breeding. Early weaning, which was proposed during the nineteen-fifties b y the well-known Iowa Research Team headed by D.V. Catron in order to prevent the loss of newborn piglets, might be one solution for pulling through a high percentage of newborn piglets without suckling their mother. One of the main difficulties of the practical application of weaning at 2 days was the failure of ovulation in sows which were suckling for such a short time. The increase in ovulation failure after very early weaning (less than 7 days of lactation time) limited for years the broad application of early weaning. In addition, pig producers were n o t able to control carefully the feeding of piglets weaned at 2 days with liquid synthetic milk, which had been developed successfully under laboratory conditions. Also, the effect of environmental and housing conditions, in particular the importance of air temperature, was nearly u n k n o w n for very y o u n g piglets of 2--3 kg live weight. However, recent progress in feed formulation has shown that a lot of problems involving nutrition and environment may be solved successfully. In particular, the possibility of using pelleted dry food for piglets weaned at one week of age and reared in a controlled environment was an important step forward. Recent scientific work referred to the reproductive behaviour of sows when litters were weaned at various ages from 3 to 56 days after farrowing. New attempts to wean piglets earlier in practice have been made in Europe, particularly during the last five years. With caution, a decrease of the mean age from 8 weeks to 5 weeks, then from 5 to 3 weeks was generally proposed from experimental and practical evidence. In order to review the results of research and to consider o p t i m u m procedures for practice~the E.A.A.P. Commission on Pig Production organised a working party to study the increase of sow productivity per annum. The valuable work by D. Smidt and co-workers in GSttingen in the mid-sixties has clearly shown the physiological relationships in weaning, and it formed a basis for reviewing the available evi-
dence on the effects of early weaning on reproductive performance of sows. The main aspects are the onset of oestrus, the ovulation rate and the average litter size subsequent to successive early weanings. Since then, considerable data have become available for quantifying these relationships and thus forming a basis for developing optimal procedures. Particularly the danger involved in decreasing the length of lactation below 14 days was clearly shown in relation to saving and optimizing the conditions of reproductive ability of the sow. The influences of several environmental factors on the performances of the weaned piglets have been considered: J. le Dividich and A. Aumaitre paid special attention to the physical parameters e.g. {e.g. air temperature) and hygienic conditions. By analysing data on early weaning from numerous experiments during the last few years, it was possible for J.H.A. te Brake to perform close economical computations for measuring the progress which could be expected in terms of yearly return per sow weaned early or not. Both review papers are published in this issue of "Livestock Production Science". Additional reports concerning the effects of early weaning on the rate of culling of sows were discussed by H. van der Heyde; S. Zivkovic listed the new systems of management attending the application of early weaning in large herds, and Ferradini and Vanderhaegen presented the results of an economic enquiry based on effective performances in selected herds. H.E. Nielsen reviewed the experiments considering the possible effect of early weaning on later performance of the pig during the growing finishing period and on carcass quality. Finally, J. Bourne drew attention to the role of suckling in the transmission of immunity from the sow to the piglets. Some conclusions following the discussions of the reports consisted of practical recommendations for the application of early weaning on a large scale. -- F r o m the experimental evidence thus far one can specify the limits and the possible advantages of early weaning, and the necessary know-how for a reasonable improvement of the productivity of the sow and the performances of the piglets. -- The age of 3--4 weeks could be recommended to breeders for the weaning of their piglets. The more exact age to be chosen depends on the reproductive ability of the sow, the specific economic situation and the professional knowledge of the pig breeder. Finally, for the intensive conditions of housing, management and rearing of breeding sows in European countries, early weaning appears to be an effective way of improving the productivity per annum of the animals. Weaning time could be based on the recent scientific knowledge of its consequences b o t h for the sow and the young animal. However, more research seems to be necessary to ascertain the long-term effect of early weaning on sows and particularly on the ovulation rate, embryonic mortality and productive life, under the different conditions of management found in the different countries.