NUTRITION ▶▶▶
Maintaining calcium levels in sow blood
Preparturient sows, the farrowing process and the piglets themselves interrelate in many ways. Zooming in on all these factors, it appears that calcium levels in a sow’s blood are likely to play a role in the farrowing process. That inspired the development of a new drinking water additive.
BY PIETER LANGENDIJK, RESEARCHER, TROUW NUTRITION W
FR2 BEL TN2 TN1 ES1
GER PLN NL2 CAN NL4 FR1
ES2 Control –1.50
0.1 –0.75 0.00
* Gestawean OxiLiv, Trouw Nutrition 26
hile hyperprolific sows and genetic selection continue to yield larger litters, swine produc- ers remain challenged by an enduring prob- lem: stillbirths. Stillbirth levels continue to
hover around 10%; however, the problem is highly variable with farms reporting stillbirth ranges of 6–15% in individual herds. Higher stillbirth rates have been linked with neonatal
Figure 1 - Meta-analysis of a drinking water additive* and a and North America.
0.7 0.6 0.5 0.5
0.4 0.4 0.4
0.3 0.3 0.3
0.2 Drinking water additive* 0.75 1.50
mortality, presenting both an economic and animal welfare incentive to reduce the number of stillborn piglets.
Farrowing time, oxygenation, stillbirth risk To understand how physiological factors within the sow, oxy- gen restriction during farrowing and the length of the farrow- ing process itself all contribute to stillbirths, it is helpful to un- derstand the dynamics at work during farrowing. Within the sow, uterine contractions drive foetuses through the uterine horns towards the cervix. These contractions occur regularly (every one to ten minutes) and may last one to three minutes. Contractions travelling along the uterine horns compress the piglets and more importantly their placentas, causing tempo- rary reductions in oxygen-rich blood to the foetuses. If the farrowing process is extended (as is the case when more foe- tuses are present), the cumulative effect of insufficient oxy- gen will compromise the fitness of the piglets and in some cases cause stillbirth. Among piglets born later in the litter, the consequences of ex- tended farrowing times can be seen in fewer live piglets born and reduced performance. Studies at the Trouw Nutrition Swine Research Centre found that piglets born late in the litter had more symptoms of poor oxygenation and performed less well in lactation and after weaning. Looking at performance, reduced oxygenation levels during farrowing negatively im- pact uptake of colostrum by the neonate, neonatal survival and gain during lactation and post-weaning phases.
Considering the calcium connection Findings from studies comparing sows that experienced is- sues during the farrowing process to sows that farrowed an entire litter without a stillborn piglet show that a sow’s ability to maintain calcium levels in the blood is a distinguishing fac- tor when it comes to distress. In the last few hours before the onset of farrowing, a sow’s calcium levels may begin to drop. This decline is a consequence of the sow’s calcium require- ment for colostrum secretion and for control of uterine con- tractions during farrowing. In studies at the Swine Research Centre, scientists observed that sows farrowing litters without any stillborn piglets were able to maintain their blood calcium levels as farrowing ap- proached. In contrast, scientists noted that sows with litters in- cluding stillborn piglets showed a clear drop in calcium levels.
▶PIG PROGRESS | Volume 36, No. 7, 2020
study
PHOTO: TROUW NUTRITION
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