Sheeva Bhattarai

Vitamin D has been shown to influence growth in both fetuses and piglets. Pigs housed indoors rely solely on their feed as a source of vitamin D since they are never exposed to natural sunlight. UVB light is effective in improving the vitamin D status in sows and piglets housed indoors. This study aimed to investigate an innovative method for UVB lighting to enhance the vitamin D status of gestating sows to a level that could positively impact the growth of both fetuses and suckling piglets. A total of 386 sows were included at the time of insemination. Of these, 197 were exposed to a daily dose of UVB light, and 189 sows served as a control group. Both sows and piglets in the UVB group had significantly higher vitamin D levels in serum samples at the time of farrowing than sows and piglets from the control group. No statistically significant differences in litter weight or the number of liveborn or stillborn piglets were observed between groups. UVB light installed in an electronic sow feeder was successful, but, unfortunately, the lamp used in the study was unable to induce the production of vitamin D to the desired level in the sows. Further studies are needed to investigate the effect of higher doses of UVB light.

Anemia is a common condition in sow herds. We aimed to study the effects of severe iron deficiency during gestation on sow and piglet health outcomes with an experimental model for blood-removal-induced iron deficiency anemia. In total, 18 multiparous sows (8 in trial I and 10 in trial II) were allocated to either a blood removal group or a control group. Hematologic parameters were monitored at regular intervals and the tissue iron concentrations were measured for the sows and newborn piglets after farrowing. In trial I, the mean liver iron content was reduced to 46.7 µg/g in the blood removal sows compared to 252.6 µg/g in the controls (p < 0.001). In trial II, sows in the blood removal group had lower iron content in the liver (147.8 µg/g), kidney (46.3 µg/g) and spleen (326.5 µg/g) compared to the control sows (323.2 µg/g, 81.3 µg/g and 728.9 µg/g, respectively; p = 0.009, 0.016, 0.01, respectively). In trial I, piglets from sows in the blood removal group had significantly decreased hematocrit (Hct), red blood cells (RBC) and a tendency for reduced hemoglobin (Hb) compared to the control piglets. We established a blood removal model that resulted in mild- to severe degrees of sow anemia and reduced tissue iron stores at farrowing.

Previous studies have indicated that high piglet blood hemoglobin concentration (HbC) at birth lead to better performance later in life. The primary objective of this study was to investigate the association between sow and piglet blood HbC at farrowing. A secondary objective was to investigate the relationship between sow HbC and probability of stillbirths. Farrowings were observed in 22 sows in a Danish commercial herd. Maternal blood HbC was measured 1–3 days before farrowing using a HemoCue 201 + Hb device. Similarly, HbC was measured from 144 offspring piglets before colostrum intake. Total number of born piglets per litter and parity of the sow were recorded and stillborn piglets were identified using a lung flotation technique. The association between HbC in sows and piglets was determined using a linear mixed model. The relationship between sow HbC and probability of stillbirths was determined using a generalized linear model. The mean HbC of the sows and piglets were 106.9 ± 12.2 and 124.4 ± 19.9 g/L, respectively. A tendency towards a positive association between HbC of the piglets and HbC of the sow around farrowing was found (P = 0.058). Additionally, the probability of stillbirths was negatively associated with the sow HbC (P = 0.021). These results indicate that HbC in newborn piglets may be increased by increasing the sow HbC. Furthermore, stillbirth rates might be reduced by increasing the HbC of the sow.

Background: Anemia characterized by low hemoglobin concentration (HbC) is common in indoor housed pregnant sows. Iron is essential for hemoglobin synthesis and a number of metabolic processes including DNA synthesis and regulation of enzyme systems. In sows, anemia has been linked to lower HbC in piglets and increased occurrence of stillbirths. Therefore, the main objective of this study was to evaluate the effect of iron injection on hematology of pregnant sows and their offspring. Other objectives were to evaluate the effect of this injection on the probability of stillbirths and to study the tolerability of injected iron.Results: A sow herd with bi-weekly batch farrowing was selected for the study and 100 sows at mid-gestation were randomly assigned to either a treatment (FeT) or a control (FeC) group. At the time of recruitment to the study (baseline), 46% of the sows in the herd were anemic with a HbC less than 103 g/L. However, none of the anemic sows had iron deficiency anemia on erythrocyte characterization. HbC decreased numerically during gestation in both the FeT (− 2.48 g/L) and FeC (− 2.99 g/L) groups but the decrease was insignificant between the groups (P = 0.79). Likewise, the change from baseline to farrowing and from baseline to post-farrowing in other hematologic variables was similar for both groups. The percentage of transferrin saturation was not statistically different between groups (P = 0.14). There was a batch effect (week of breeding) in most of the hematologic variables. The probability of stillbirth in the two groups did not differ (P = 0.94). None of the hematologic variables in piglets was significantly different between the two groups. The sows tolerated the iron injection well.Conclusions: Intramuscular injection of two doses of 2500 mg iron 2 weeks apart at mid-gestation did neither change hematologic variables in sows nor in the piglets at farrowing. Similarly, iron treatment did not reduce the probability of stillbirths among the offspring. The sows recruited in this study tolerated the iron injections well. Further characterization of erythrocytes did not support that sows had iron deficiency anemia at baseline. Therefore, further studies on animals with well-defined anemia and with focus on the iron regulating hormone hepcidin are recommended.

Hematologic reference intervals are useful tools for interpretation of laboratory results in swine practice and research. Until now, there were no hematologic reference intervals established for gestating Danish sows and those established in other countries are either out-dated, produced using very few sows or incomplete with few variables. In the past few decades there have been significant increases in litter size due to breeding, as well as the development of new analytical procedures for hematology and statistical procedures for calculating reference intervals. Therefore, hematologic reference intervals representing current pig production and technology are greatly needed. The main objective of this study was to provide updated and complete hematologic reference intervals for Danish sows at mid-gestation. Blood samples were collected at mid-gestation from 248 sows belonging to five commercial herds in Denmark and the samples were analysed for several hematologic variables using the Advia 2120i Hematology System. The reference intervals were calculated according to the guidelines of American Society for Veterinary Clinical Pathology. The reference interval for hemoglobin concentration was 103.1–145.0 g/L. For red blood cells, hematocrit and mean corpuscular volume, the 95% reference intervals were 4.98–7.50 × 1012/L, 0.32–0.47 L/L, 57.0–69.3 fL, respectively. The reference intervals established in this study are different from those previously reported in the literature. These reference intervals add to the current knowledge and will be useful in the prevention, diagnosis and treatment of several disease conditions in gestating sow populations.

Objective: To determine associations between stillbirths and sow hematological parameters at farrowing. Materials and methods: A total of 160 sows from a high-performing Danish farrow-to-finish herd were chosen for the study. Standard hematological parameters were measured in sows within nine days before farrowing. At farrowing, dead piglets were collected and stillborns were identified using a lung floatation technique. The number of live-born piglets and parity of the sow was recorded after termination of farrowing. A generalized linear model was fitted to analyze the associations between each hematological parameter and the probability of stillbirth. Results: The mean (standard deviation) sow hemoglobin concentration before farrowing was 108.5 (8.6) g/L. In total, 29 sows (18.1%) were anemic ie, hemoglobin concentration below 100 g/L. The mean number of total born and stillborn piglets per litter was 16.3 (4.1) and 1.2 (2.2), respectively. The average parity of sows was 2.8 (1.8). Piglet stillbirth was associated with several hematological parameters of the sow, namely hemoglobin concentration, mean cell hemoglobin concentration, mean corpuscular hemoglobin, red blood cell distribution width, hemoglobin distribution width, platelet distribution width, number of reticulocytes, reticulocyte hemoglobin content, and reticulocyte cellular volume. Parity of the sow and total number of piglets born per litter were also associated with stillbirths. Implications: The probability of piglet stillbirth in this study is affected by several hematological parameters of the sow. There is also an association between probability of stillbirth and parity of the sow.