|Abstract:||Low blood glucose levels in sows at the start of farrowing have been associated with increased farrowing duration and higher stillbirth rates and low blood glucose levels in piglets at birth have been linked to increased pre-weaning mortality. This study used 32 sows and gilts and 443 piglets in a cross-sectional survey to evaluate the effects of various sow and litter parameters on sow blood glucose levels on the day of farrowing, and identify factors associated with piglet blood glucose levels at birth. A blood sample was collected from an ear vein of each sow or gilt every 2 hours from feeding (at 0600 h) to 12 h after feeding (1800 h). Samples were analyzed for blood glucose concentration using 2 hand-held diabetic glucometers. Sow body condition (on a scale of 1 – extremely thin to 5 – very fat), parity, litter size, litter weight, farrowing duration, and farrowing interval were also recorded or calculated. Blood samples were collected at birth from the vena subcutanea abdominis from every other piglet born in each litter, and glucose levels were measured using the same 2 glucometers as used for sows. At birth, all piglets were weighed, gender was recorded, and the vitality of piglets was assessed using a score from 1 to 4 (1= ideal, normal appearance, high mobility; 2 = normal appearance but limited breathing or mobility; 3 = stillborn; 4 = mummified).
Data were analyzed using SAS v 9.4. Sow/litter was the experimental unit, piglet was a sub-sample of the litter. For data that met normality and homogeneity of variance assumptions, PROC MIXED was utilized, data not meeting these assumptions were analyzed using PROC GLIMMIX. A repeated measures analysis was conducted on sow blood glucose values at times over the 12 h measurement period using PROC MIXED with sow as the SUBJECT and time as the REPEATED measure. The PDIFF option was utilized to compare least-squares means, and differences were considered significant at P ≤ 0.05. A regression analysis was performed using PROC REG of SAS to determine the relationship between sow blood glucose and sow and litter parameters and piglet blood glucose levels and piglet parameters.
Sow blood glucose levels, averaged over the 12 h measurement period, increased linearly (P < 0.05) with body condition score, and decreased linearly (P < 0.05) with litter size and total litter weight, and farrowing duration. There was no effect (P > 0.05) of either piglet birth weight or gender on piglet blood glucose levels at birth. However, blood glucose levels increased (P < 0.05) with birth order and piglet viability score.
In conclusion, the results of this study generally found relatively small effects of a range of sow parameters on blood glucose levels immediately prior to and during the farrowing process. The effects of a number of piglet parameters on piglet blood glucose levels at birth were also generally small. The exception to this was for piglet viability at birth, with low viability and stillborn piglets having substantially elevated blood glucose levels.