Setting the trajectory for optimal growth
One of the most important transitions in a pig’s life occurs at weaning when piglets are exposed to numerous stressors and challenges. While minimising this stress is the goal of all farmers, undiagnosed iron deficiency anaemia may be contributing to poor performance even if clinical symptoms are not present.
BY CHRIS OLSEN, TECHNICAL SERVICES VETERINARIAN, PHARMACOSMOS O
300 250 200 150
100 50 0
70 80 90 ADG was calculated with 6 kg of weaning wt. 10 100 110 120 Haemoglobin, g/l 130 140 150
n any given farm, as many as 92% of piglets could be considered anaemic due to iron deficiency by having inadequate haemoglobin levels at wean- ing. Studies have shown this can be source of
costly losses in the wean-to-finish period given the close rela- tionship between haemoglobin and growth. Improvements in a herds blood haemoglobin levels at weaning can lead to an economic return of up to € 2,08 per pig marketed.
Prevalence of anaemia in swine farms Iron is a trace element and a vital constituent of haemoglobin. Piglets are predisposed to iron deficiency anaemia as a result of 1. Low body iron at birth, 2. Inadequate supply of iron from milk, 3. No source of environmental iron, 4. Rapid growth rate and
Figure 1 - Association between haemoglobin concentration at weaning and ADG three weeks post-weaning in piglets.
5. Large litter sizes. 200 mg of injectable iron given at day 1 to 3 has long been standard practice for preventing iron deficiency anaemia in piglets. However, recent studies have shown that as many as 92% of piglets remain clinically or sub-clinically anae- mic at the time of weaning as they have outgrown the initial dose of iron given early in life. Several studies evaluated the im- pact of iron deficiency anaemia on post-weaning weight gain. Differences of up to 0.82 kg of growth in the three weeks post-weaning have been reported between piglets with opti- mal haemoglobin levels (> 110g/L) and piglets deficient hae- moglobin (<90g/L) at weaning. One such study, published in 2015, was conducted on five con- ventional sow farms in Denmark with an average size of 1000 sows. All herds were administered a single 200 mg dose of in- jectable iron from different commercial products at 3–4 days of life. One piglet was randomly selected from 20 litters at each farm for blood collection at 1-3 days before weaning. In total 99 piglets were enrolled in the study but three were excluded from analysis after being lost to follow-up. The associations be- tween each measured haematological parameter and the aver- age daily gain (ADG) of piglets in the three-week post-weaning period were evaluated. This study showed a positive associa- tion between haemoglobin and ADG in the three-week post-weaning period, while red blood cells and haematocrit also had positive associations with ADG (Figure 1). An increase in 10 g haemoglobin/l blood at weaning corresponded to a weight gain improvement of 17.2 g daily weight gain in the 3 weeks post-weaning.
Achieving optimal haematological status During the first weeks after weaning, intestinal absorption of iron and other minerals is not fully functional. This explains the importance of optimal haematological status at weaning to achieve peak post-weaning growth. In a peer-reviewed study published in 2010, researchers studied the timing of ex- pression of genes involved in intestinal iron absorption. They concluded that two primary genes necessary for adequate in- testinal absorption of dietary iron did not develop until 25-47 days of age or 1-3 weeks post-weaning. Sufficient stores of iron are critical to growing piglets not only for production of haemoglobin but also for many enzymatic processes in their cells. If iron stores are adequate, this equates to improved oxygen transport, immune function, vitality,
▶ WEANING | JUNE 2020
Estimated ADG, g/day
PHOTO: PHARMACOSMOS
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