BREEDING & GENETICS ▶▶▶
Colostrum: Do sows achieve full potential?
Sows are exceptionally well equipped for their task: to provide colostrum and milk to their offspring. However, genetic progress in terms of sow prolificacy is changing the requirements of that valuable talent.
BY MARCELLO G. MARCHESI, INDEPENDENT INTERNATIONAL CONSULTANT A
t farrowing, sows produce colostrum for about 24 hours. This helps piglets on their way, as they are born without any antibodies to protect them. Colostrum is an extremely rich source of anti- bodies (immunoglobulins), essential for the piglet’s defence against infections. At birth, the piglet leaves the uterus at a temperature of ap- proximately 38.5°C and enters into a farrowing room where the temperature is often in the range of 20–24°C (even though the creep area may be 30°C). The newborn piglet will quickly suffer from cold chills and will go into a negative en- ergy balance. Apart from antibodies, the colostrum provides warmth and energy. After about six hours, changes start in the piglet’s gut mecha- nism. It becomes impervious to the passage of immuno- globulins and, after 24 hours, the piglet can no longer absorb them. It is common to see farrowing room caretakers “back-fostering” small three-day-old piglets onto newly far- rowed sows “to give them more colostrum”. That provides no benefit at all. Colostrum production is higher in multiparous sows when compared to gilts. Studies from Padova University, Italy, on nearly 14,000 piglets showed a significant difference in the hazard ratio of survivability of third-parity sows compared to first-parity sows.
Higher prolificacy and increased variation The Rutherford Report show that over a 13-year period there has been an increase of 3.0 pigs born alive, which has pro- voked an increase of 5.4% in pre-weaning mortality. A French study from ITP on 12,000 piglets showed that as the average numbers born rose from below 11 to more than 16, the aver- age birth weight declined from 1.59 kilogrammes to 1.26kg. More importantly, the percentage of piglets weighing less than 1.0kg increased from 7% to 23%.
26 ▶PIG PROGRESS | Volume 36, No. 9, 2020
The phenomenon intrauterine growth retardation (IUGR) is more frequent with hyperprolific sows. An interesting paper from 2019 clearly demonstrated the higher variability in birth weights in large litters. The low prolific group (10.25 born alive) had an average birth weight of 1.5kg with a standard deviation of 40 grammes, while the highly prolific group (14.69 born alive) had an average birth weight of 1.37kg but an enormous standard deviation of 220g. A recent article in this magazine also mentioned that ques- tions have been raised in both the Danish and Dutch parlia- ments about the welfare of piglets in highly prolific sows.
The limiting factor to sow productivity It is generally recognised that the bare minimum piglet re- quirement is to receive 200g of colostrum over the first 24 hours. An intake of 250g has been shown to provide a very good chance of survival. Various research has shown high variability in colostrum yield, from a minimum of 900g up to 5,900g. A similar varia- tion exists in the concentrations of immunoglobulin (IgG). Unfortunately, at least 30% of hyperprolific sows do not pro- duce enough colostrum. They also have longer farrowings, which reduces colostrum yield. A litter of 16 will need 4,000g of colostrum over the first 24 hours. The quantity of colos- trum intake affects not only pre-weaning mortality, but also mortality up to 42 days of age.
Hierarchy and the mammary gland Any farrowing room caretaker will say that the strongest pigs will also take the front teats, the weakest the back teats. The growth rates follow a similar pattern. During a 21-day lactation, mammary tissue weight can in- crease by 50%. Similarly, mammary DNA can increase by 100%. Mammary growth is affected by litter size, dietary in- take and gland location. To maximise mammary growth, all functional teats must be “milked”. The gilt’s first lactation will determine her milking capacity in her future parities. The gilt should be allowed to suckle the same number of piglets as she has functional teats. In case of any pre-weaning mortality, other piglets should be fostered onto her to maintain the development of her mammary glands. Various research has shown some very interesting
PHOTO: MARCELLO MARCHESI
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