Analysis of lactation feed intakes for sows with extended lactation lengths

Abstract

The objectives of this research were to quantify and model daily feed intakes to 28 d of lactation in modern sows. A total of 4,512 daily feed intake (DFI) records were collected for 156 Hypor sows from February 2015 to March 2016. The mean lactation length was 27.9 ± 2.0 d. The data included 9 parity 1, 33 parity 2 and 114 parity 3+ sows. Data were collected using a computerized feeding system (Gestal Solo, JYGA Technologies, Quebec, Canada). The feeding system was used to set an upper limit to DFI for the first 7 d of lactation. Overall, the least-squares means of a model including the random effect of sow indicated that DFI's continued to slowly increase to 28 d of lactation. The DFI data were fitted to Generalized Michaelis-Menten (GMM) and polynomial functions of day of lactation (t). The GMM function [DFIi,t (kg/d) = DFI0 + (DFIA − DFI0)(t/K)C/[1 + (t/K)C]] was fitted with 2 random effects for DFI (dfiAi) and intercept (dfi0i) using the NLMIXED procedure in SAS®. The polynomial function DFIi,t (kg/d) = [B0 + B1 t + B2 t2 + B3 t3 + B4 t4] was fitted with three random effects for B0, B1, and B2 using the MIXED procedure in SAS®. Fixed effects models of the two functions had similar Akaike's Information Criteria (AIC) values and mean predicted DFI's. The polynomial function with 3 random effects provided a better fit to the data based on R2 30 (0.81 versus 0.79), AIC (14,709 versus 15,158) and RSD (1.204 versus 1.321) values than the GMM function with two random effects. The random effect for B2 in the polynomial function allowed for the fitting of the function to lactation records that had decreased DFI after 15 d of lactation. The random effects for the polynomial function were used to sort the lactation records into three groups based on the derivative of the function at 21 d of lactation. Lactation records of the three groups had similar DFI the first two weeks of lactation (P > 0.40). The three groups of sows had substantially different DFI's after 18 d of lactation (P < 0.028). The differences in both actual and predicted DFI's between the three groups increased with each day of lactation to day 28 (P < 0.001). Mixed model polynomial functions can be used to identify sows with different patterns of DFI after 15 d of lactation.

Feed intake patterns of modern genetics lactating sows: characterization and effect of the reproductive parameters

“…As a result, they found two clusters or feeding curves and concluded that both curves were similar after 5 d of lactation. A possible reason for the difference between the previous two studies [ 13 , 19 ] and our results might be that they did not categorize the feeding curves into some patterns by a decrease for individual DFIs of sows. Our results are similar to a previous U.S.A. study which categorized individual DFIs into six patterns using a major drop, a minor drop, a rapid increase, a gradual increase, low DFI only in early lactation and low DFI throughout lactation [ 11 ].…”

“…Concerning the differences reported by Cabezón et al [ 13 ] from day 18 onwards, it is worth noting that in the current study, once the peak of lactation is reached (around day 18), it is observed that the patterns show small variations in the slope (see normalized feed intake graph; Fig. 1 ).…”

“…It is worth mentioning that if previous studies are reviewed, feed intake during lactation has increased in the last 30 years by around 29% (between 21 and 44%) [ 11 , 13 , 19 ], confirming the increase of sow productivity. Moreover, in all studies, it seems that the largest differences in feed intake patterns are found towards the end of lactation, probably due to the large variability in appetite between individual animals in successive days [ 22 ].…”

“…Using mixed-effects linear models with the DFI data in Canada, collected from electronic feeders during lactation, three groups of feeding curves were reported by U.S.A. researchers [ 13 ]. They concluded that there were no differences in DFI during the first two weeks of lactation between the three groups, but the DFI during 18–28 d of lactation differed between them: decrease (14.1% of sows), increase (18.6% of sows) and minor changes (67.3% of sows).…”

“…Hence, following the sow’s consumption in real-time allows one to anticipate future production problems that trigger nutrient deficiency, which clearly has consequences at a productive level. More recently, Cabezón et al [ 13 ] investigated lactation sows’ feed intake patterns using mixed models based on polynomial prediction functions for daily consumption. The analysis allowed sorting the lactation records into three groups that showed similar DFI during the first two weeks of lactation but had substantial differences after 18 days.…”