Early life nutrient intervention
What is the impact on sow longevity, lifelong effect on progeny performance?
By Tsungcheng Tsai, Jon Bergstrom, Kyle Coble, Sara Hough, Uislei Orlando, Steve Dritz and Charles MaxwellEmerging evidence suggests that body condition, fertility and lameness dictate the longevity of sows. Among these factors, body condition is the only attribute interrelated to other causes for early culling from sow herds.
Overweight gilts at breeding are at risk for poor breeding rate, vulnerable to osteochondritis, low lactation intake and have a higher risk of pregnancy and postpartum complications. Moreover, genetic selection for increased litter size and milk production increases the demand for nutrient supply, exacerbating the challenge for the over-condition primiparous sows to obtain sufficient nutrients during lactation, creating excessive weight loss and bone density reduction which leads to failure to rebreed for subsequent reproductive cycles.
The modern breed of terminal line swine is selected for high lean tissue yields and greater feed efficiency. Without a doubt, these phenotype responses are expected to be present in gilts. That poses a risk for breeding gilts that are fed nutrient-sufficient diets during the development period to surpass their ideal body weight at breeding age.
To overcome the detrimental effects of over-conditioned gilts, several works evaluated the body weight management strategy either by restricting intake or reducing dietary nutrient concentration during the development period to suppress the growth of gilts. Both approaches showed promising outcomes in decreasing growth rate of gilts without impairing reproductive performance. However, most of these works were limited to only one farrowing cycle or the evaluation was only initiated upon the confirmation of conception. Therefore, this effect on sow's longevity remains unclear.
Vitamin D Unlike slow growth, 25 hydroxy vitamin D has been spotlighted in humans and swine lately. Swine production has evolved from outdoor production to indoor confinement environments, aiming to increase safety and biosecurity. This practice, however, limits the pigs from sunlight exposure, an essential step for Vitamin D transformation.
Vitamin D was first identified by Adolf Otto Reinhold Windaus, and its metabolism was later documented by Hector Deluca’s lab. Since then, many physiological functions have been correlated to vitamin D. In swine, 25-hydroxycholecalciferol (25(OH)D3) has received considerable attention since its commercialization for inclusion in swine feeds in recent years. Research has shown potential benefits from supplementing 25(OH)D3 in swine diets, ranging from increased sow and progeny plasma vitamin D status, improved nutrient digestibility and reproductive performance, as well as increased number of fetal muscle fibers, and decreased incidence of osteochondritis in growing pigs.
Little information is available concerning subsequent growth performance in pigs from sows fed higher levels of Vitamin D3 or 25(OH)D3. Flohr et al. (2016) found that progeny derived from 25(OH)D3-fed sows increased average daily gain and average daily feed intake when compared to progeny of sow fed 800 IU/kg vitamin D3, and the magnitude of improvement was comparable to vitamin D3 supplemented at the equivalent level.
This study aimed to investigate the effectiveness of slowing the growth rate of gilts in addition to 25(OH)D3 supplementation on sow longevity and progeny performance. We hypothesized that reduced dietary nutrient concentration during gilt development can hinder growth rate and, together with 25(OH)D3 supplementation, can reduce reproductive stresses, extending longevity in sows and improving the progeny growth performance.
Dietary treatmentsTo gain insight into nutrient level and 25(OH)D3 on sow longevity, a total of three groups of gilts (n = 60 in each group, PIC Camborough) were received at nine weeks of age (average BW: 21.2±0.67 kg) and assigned to one of four dietary treatments. Treatments comprised two levels of dietary nutrients (Adeq: optimal growing diets that exceed NRC 2012 recommendations or Low: a moderately slow-growing diet where SID Lys and ME levels were gradually reduced by 0.03% and 0 kcal/kg, 0.15% and 146 kcal/kg, and 0.15% and 150 kcal/kg, respectively) and two sources of vitamin D [StD: 1653 IU cholecalciferol/kg or HyD: 500 IU cholecalciferol/kg + 50 mcg calcifediol (ROVIMIX HY-D® DSM Nutritional Products North America)] during development phase 1 (22 to 57 kg), 2 (57 to 91 kg), and 3 (91 kg until breeding).
Dietary nutrient level treatment was withdrawn at the end of the gilt development period and during the gestation and lactation stages, while gilts and sows remained on their vitamin D treatments through four reproduction cycles. Caliper scores were measured at breeding, d 35 of gestation, and again at d 60 of gestation to allow adjustment of the intake allowance. Replacement gilts (n = 12 in each cycle) were handled and treated the same as the initial three groups of gilts and introduced to each group at the end of each cycle.
ResultsGilts fed low-nutrient diets grew slower during the development period when compared to gilts fed Adeq diets, resulting in lighter BW at the end of the development period at 26 weeks of age (Figure 1A, 135.4 vs 142.8 kg, P < 0.01). Slowing growth during the development period didn’t appear to impact conception rate (89.2% vs 85.3%, P = 0.16). Interestingly, gilts fed Low diets lost less BW during lactation and had a greater 10th rib backfat thickness at weaning (Figure 1B, P = 0.03 and P < 0.01, respectively).
This suggested that using a low energy and reduced protein diet during gilt development can promote their ability to restore their body condition during lactation, which boosted survivability throughout the four parity cycles (P = 0.09) and thus extended their longevity (Figure 2). With the increase in survivability and increased litters/gilt placed, gilts fed Low diets produced more total number of born, born alive, and weaned progeny over four parity cycles.
As for 25(OH)D3, supplementing 25(OH)D3 didn’t significantly affect sow longevity, which is likely due to the air ventilation design in the sow facility (drop-side curtains). Note that gilts fed HyD diets had higher plasma 25(OH)D3 across all sampling time points (Figure 3), while gilts fed StD diets averaged 40 to 50 ng/ml.
This level is higher than the Danish indoor-housed sows (25 to 30 ng/ml) reported by Lauridsen et al. (2010) and close to a recent survey from Danish outdoor herds with an average of 67 ng/ml (Jakobsen et al., 2022). Despite the lack of a significant effect on reproductive performance, maternal 25(OH)D3 appeared to establish metabolic imprinting in the progeny. HyD sows' progeny gained more weight and had a 4 kg heavier market weight than StD sows' offspring (Figure 4) without changing backfat. Moreover, they also had a heavier carcass weight and a higher yield percentage.
Our results found that reducing dietary nutrient density with a high fiber and low energy diet during gilt development facilitated a lifelong effect on gilt’s survivability, and gilts fed diets containing 25(OH)D3 enhanced their progeny’s growth performance substantially. Our study shed light on how nutrient manipulation before puberty affects longevity of sows and generated questions that warrant further investigation. References:Flohr, J.R., Woodworth, J.C., Bergstrom, J.R., Tokach, M.D., Dritz, S.S., Goodband, R.D., DeRouchey, J.M., 2016. Evaluating the impact of maternal vitamin D supplementation on sow performance: II. Subsequent growth performance and carcass characteristics of growing pigs. Journal of animal science 94, 4643-4653.
Jakobsen, S.S., Jakobsen, J., Nielsen, J.P., 2022. Vitamin D Levels in Sows from Five Danish Outdoor Herds. Animals 12, 299.
Lauridsen, C., Halekoh, U., Larsen, T., Jensen, S.K., 2010. Reproductive performance and bone status markers of gilts and lactating sows supplemented with two different forms of vitamin D. Journal of animal science 88, 202-213.
Tsai and Maxwell are with the Department of Animal Science, University of Arkansas; Orlando and Dritz are with PIC North America; Bergstrom and Hough are with DSM Nutritional Products; and Coble is with JBS Live Pork, LLC.
