Articles / Dissemination, Feeding, Swine

MInerals in pig diets: Calcium

MV. Júlia Pié Orpí - 18/10/2016

INTRODUCTION

Diets should supply six kinds of nutrients: water, carbohydrates, fat, protein (aminoacids), minerals and vitamins. One of these groups, minerals, are a little percentage in pig diets, but they are of a great importance to ensure a proper health and productive performance. They can be classified into two groups: macrominerals and microminerals. Calcium is among the first group.

Minerals’ functions are miscellaneous: from structural to a broad variety of regulatory functions. Pigs having no access to forage or pasturage has created the need to supplement the diet with minerals to reach the animals’ requirements.

CALCIUM

Calcium is an important element for bones’ development and so is its presence in soft tissues, since it takes part of coagulation, muscular concentration and energetic metabolism processes.

REQUIREMENTS

There are different factors affecting calcium requirements, such as its bioavailability in the diet, calcium/phosphorus ratio and the presence of D vitamin. They also depend on the animal’s physiologic state, because requirements vary depending on the moment (growing phase, gestation, lactation…).

Regarding these factors, FEDNA’s recommendations consider if sows are in gestation or lactation and the productive level; and they show there is an increase of calcium needs in lactating sows (increase of the minimum requirements).

Recommendations for feed for reproductive sows and boars under standard situations. General norms. FEDNA (2013).
		Standard gestation	Standard lactation (1)	Adult boars
Calcium (2), min-max	%	0.81 – 1.05	0.95 – 1.05	0.85 – 1.00
Recommendations for feed for reproductive sows and boars of high production performances and boars in growing stage. General norms.
		Gilts in gestation or last month of gestation (3)	Hyperprolific in lactation (4)	Boars in growing stage >130 kg PV
Calcium (2), min-max	%	0.85-1.05	0.93 – 1.05	0.85-1.05

(1) Sows with 10 live piglets/farrowing.

(2) Amount expressed in total calcium.

(3) Farms increasing their size with high percentages of gilts or second-gestation sows or sows during the last month of gestation.

(4) Recommended levels under temperate/warm temperatures and more than 12 live piglets/farrowing.

Source: FEDNA

On the other hand, NRC (2011)’s recommendations also consider the number of gestation, the expected size of the litter, the days in gestation, piglets’ weight gain, among other factors.

Recommendations for sows in gestation or lactation. NRC (2012)
	Gestation				Lactation
Gestation number	1		3		1	2+
Weight when farrowing (kg)	140		185		—	—
Weight gain before farrowing (kg)	65.0		52.2		—	—
Expected litter size	12.5		13.5		—	—
Days in gestation	0-90	90-115	0-90	90-115	—	—

Weight after farrowing (kg)	—	—	—	—	11	11.5
Piglets’ daily weight gain (g)	—	—	—	—	230	230
Calcium requirements
% of calcium	0.61	0.83	0.49	0.72	0.71	0.68

Source: NRC (2012)

CONCLUSION

To ensure a proper calcium supply through the diet, apart from supplementing it with the recommended levels, it’s important to consider the different factors affecting its bioavailability, but also that an excess of calcium can negatively affect the organism.

There are natural substances capable of increasing mineral absorption in the digestive tract. Such components could help to supply enough minerals to the animals while reducing the levels of calcium and phosphorus in the diets, so that the environmental impact of animal farming could be reduced.