Unlocking the performance of your sows

A three-year trial by Novus International has demonstrated the benefits of supplementing gilt and sow diets with chelated trace minerals

Nutrition and feeding have become cornerstones of animal production as a means to improve performance. Research on sow herds strongly relates mineral and trace mineral nutrition with reproductive and locomotive issues, which are the main performance barriers for sows.

Enzymes and proteins that require trace minerals for normal activity regulate important biochemical reactions in pigs. Zinc (Zn) and copper (Cu) are critical for optimal growth and reproduction, as well as proper collagen formation, which is a structural protein that provides strength to bone and other tissues. Manganese (Mn), meanwhile, is a cofactor of the enzyme MnSOD, important in proper cartilage development, and is also vital to energy metabolism within cells. When inadequate levels or unavailable forms of trace minerals are fed, the animal will not meet the demand for growth, reproduction or health and will exhibit suboptimal performance.

In addition, mineral requirements for reproductive animals are questionable and it could be argued that the mineral requirements are increased in today’s highly productive maternal sow lines. In order to minimise under-nutrition of trace minerals, nutritionists usually adopt high inclusion rates of relatively low-cost inorganic trace minerals (ITMs) compared to the usual recommendations.

However, greater ITM inclusion cannot maximise sow performance. Chelated trace minerals (CTMs), on the other hand, provide a more bio-available source of minerals and exhibit less antagonism to other nutrients in the diet. Although several sources of organic trace minerals are available, their use to improve swine production is controversial, with limited data supporting the benefits above adequate sources of ITMs.

Three-year trial
Marketed by Novus International, Mintrex is a CTM where Cu, Zn and Mn are bound to molecules of the methionine analogue HMTBa in a 1:2 ratio. After its effectiveness had been shown in poultry, three years of trials were undertaken to find out if there would be similar benefits in sows.

Starting at gilt development and continuing through the animal’s lifetime, the objectives of the study were to improve sow reproduction performance and leg health by feeding Mintrex Zn, Cu and Mn. The trial, which began in April 2007 and continued until March 2010, involved more than 18,000 replacement gilts and sows (PIC C22 or PIC C29 dam lines) on two sister farms running 6,400 sows each that had a common grandparent farm.

The sows were either fed 100% ITM (ZnSO4, CuSO4 and MnSO4) – the control group – or 50% ITM and 50% Mintrex chelated trace minerals. The total mineral level on both farms was the same, with target supplementation levels of 165ppm Zn, 16ppm Cu and 38ppm Mn in the final diet to reflect accepted industry levels in North America.

Treatments were initiated at weaning (the moment of entry onto the farm) and continued through growing and entry into the breeding herd. Sows remained on treatment until culled from the herd.

Standard farm diets for gestation and lactation were used to reflect industry norms for energy, protein and digestible essential amino acids (the methionine activity in Mintrex was considered during formulation). All feed was mixed at the same feed mill, and feed samples were collected periodically to confirm mineral supplementation levels. Both herds followed standard operating procedures.

Retention rates
The gilt results from the trial indicate the Mintrex group had a significantly lower culling rate than the ITM control group of gilts from first service to first farrowing. At 8.0% versus 8.8%, this was an 11% improvement. For sows reaching four parities, the culling rate in the Mintrex group was 28%, compared to 36% for the ITM group (see Table 1). It’s worth noting that after reaching parity five and above, farm managers consider sows to be old and start culling based upon age, but these results indicate 548 more sows stayed in productivity with the Mintrex diet, and consequently 548 fewer gilts were needed compared to the sows fed ITMs.

Since sows fed Mintrex stayed in the reproduction cycle longer, the second area studied was the reason for culling. This fell into one of two categories: involuntary versus voluntary (involuntary reasons include locomotion, death and disease while voluntary reasons include reproduction and litter performance); and locomotion (leg/walking issues) versus non-locomotion reasons.

Generally, farms want to minimise involuntary and locomotion-related removals, so that managers have more flexibility in culling decisions. In addition, culling due to locomotion, which is about 20% in gilts, dramatically decreases farm profitability. In this trial, the involuntary removal rate and relative removal rate due to locomotion were significantly reduced with Mintrex supplementation.

In gilts from first service to farrowing, relative removal rates due to locomotion were 9.0% versus 13.8% for Mintrex and ITM respectively. The involuntary removal rates were reduced for gilts fed Mintrex (17.3%) compared to gilts fed ITMs (27.1%). Similar results were observed in sows regardless of parity, in that removal rates due to locomotion were reduced by 55% with Mintrex supplementation (10.4% versus 16.1%) compared to sows fed ITMs.

Involuntary culling rates, meanwhile, were reduced by 45% with Mintrex supplementation (19.4% versus 28.1%) compared to sows fed ITMs. Sows fed Mintrex had significantly reduced overall and relative culling rates due to locomotion, reproduction and disease (see Figure 1).

Herd health
Dead sows are a painful and costly issue, but for the group studied up to the fourth parity in this trial, Mintrex reduced mortality by 21%, with 8.6% recorded for sows fed Mintrex and 10.4% for the control sows fed only ITMs. As a result, 116 fewer sows were lost in the Mintrex group. Reduced mortality with Mintrex supplementation was mainly due to improved immune function and overall health status.

This field experiment also provided an opportunity to analyse the aspect of improved sow immunity. This is very important in young pigs as they enter the farm and are introduced to a large number of older sows with an established immune system. The introduction of the vaccination programme used on the trial farms included, among others, a mycoplasma vaccine, systematically administered as each cohort of young gilts arrived.

After vaccination, gilts in the Mintrex group were protected earlier than gilts in the ITM group. This was shown by a quicker and earlier increase of antibodies in the blood, reaching the protective threshold approximately six to eight weeks earlier than the control gilts. This was part of the improved overall health status of the sow herd fed Mintrex chelated trace minerals.

Reproductive performance
Sows fed Mintrex had more total piglets born per litter at parity three and remained in peak performance longer (up to parity five) compared to sows fed ITMs. Sows fed Mintrex until the fourth parity also showed a farrowing rate 2.3% higher (86.8% versus 84.5%) than in the same age group receiving ITMs.

For cumulative reproduction performance up to parity four, sows fed Mintrex had more total born (44.10 versus 40.76), born alive (41.61 versus 38.89) and weaned pigs (36.39 versus 34.64) than sows fed ITMs (see Table 2).

Birthweight is an important economic trait in swine production that’s directly related to sow performance. It’s commonly recognised that low birthweight highly correlates with high mortality, lower postnatal growth rates and a longer period to market. However, litter size has been increasing in the past decades with improvement of genetics, management and nutrition. In this study, piglets born from sows supplemented with Mintrex had higher birthweights than piglets from sows receiving ITMs, while the litter size was similar or larger than the control group (see Table 3). One possible explanation for this increased birthweight was the improvement of body condition of sows through improved health and feed intake, as a result of enhanced mineral nutrition.

Trial conclusions
Mintrex chelated trace minerals supplementation in sow diets is beneficial for maintaining skeletal health and improving survival rates up to parity four, as well as lowering culling rates due to locomotion. These results allow more sows to produce more piglets for longer periods of time.

By improving sow immune function and general health, mortality was decreased dramatically with Mintrex supplementation. Moreover, supplementing sow diets with Mintrex Zn, Cu and Mn chelated trace minerals also increased fertility, piglet birth weight and performance.

These performance benefits of feeding Mintrex chelated trace minerals to sows can directly impact overall production and profitability of breeding units.

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