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Effects of dietary calcium and phosphorus on reproductive performance and bone turnover of sows housed in stalls or group
Weight-bearing exercise, combined with adequate calcium (Ca) and phosphorus (P) intake, is known to improve bone strength. The objective of this experiment was to determine if the recommended levels of dietary Ca and P are adequate for group-housed sows who have a potential for increased mobility. A total of 180 multiparous sows and gilts were used to determine the effects of dietary Ca and P on reproductive performance and bone turnover when housed in stalls or groups. Treatments, arranged as a 3x2 factorial included main effects of dietary Ca:P; 0.70:0.55 (Control); 0.60:0.47 (-15% 1998 NRC); 0.81:0.63 (+ 15% 1998 NRC) and housing; stalls or groups (10-14 per group, modified free-access). Dietary treatments began at 4 wk post-breeding (d0). Sows were fed 2.3 kg∙d⁻¹ from d0 until 2 wk prior to farrowing when the allotment was increased to 3.0 kg∙d⁻¹. Serum samples were collected on d0 and d70 (14 wk gestation), mid-lactation and 1 d prior to weaning (25 d post-farrowing). No differences were seen in total number of piglets born, ADG from birth to weaning, or weaning weight (P>0.05). The number of piglets born live and birth weight were unaffected by diet (P>0.05) but improved in group housing (P<0.03). In late gestation, group-housed sows fed the low Ca diet had reduced serum Ca (diet by housing; P<0.02) while lower serum P levels were seen in group, compared to stall-housed sows, regardless of diet (P<0.03). Osteocalcin (OC), and pyridinoline (PYD) markers of bone formation and resorption respectively, were unaffected by diet or housing (P>0.05). Results from this study suggest that the recommended level of dietary Ca and P as prescribed by NRC 1998, and thus for NRC 2012 is adequate for high-producing sows of modern genetics, whether housed in stalls or groups.
Table 1. The effect of dietary Ca : P and housing on number of piglets born and growth rate
|
|
Stalls (Ca:P%) |
Group (Ca:P%) |
||||
|
|
0.60:0.47 |
0.70:0.55 |
0.81:0.63 |
0.60:0.47 |
0.70:0.55 |
0.81:0.63 |
Live born |
n |
14ᵃ |
14ᵃ |
14ᵃ |
15ᵇ |
15ᵇ |
16ᵇ |
Total born |
n |
15 |
16 |
16 |
16 |
15 |
17 |
Birth weight |
kg |
1.52ᵃ |
1.46ᵃ |
1.48ᵃ |
1.62ᵇ |
1.54ᵇ |
1.59ᵇ |
Weaning weight |
kg |
6.57 |
6.56 |
6.57 |
6.74 |
6.60 |
6.84 |
ADG¹ |
kg∙d⁻¹ |
0.22 |
0.23 |
0.23 |
0.24 |
0.23 |
0.23 |
ᵃᵇ Means in the same row with different superscripts differ (P<0.05)
¹ Average daily gain of piglets from farrowing to weaning
Keywords: calcium, gestation, group-housing