Effects of Increasing Oat Groats on Nursery Pig Performance Effects of Increasing Oat Groats on Nursery Pig Performance

In Exp. 1, a total of 225 pigs (241 × 600, DNA, Columbus, NE; initially 13.9 lb BW) were used in a 28-d study to evaluate the effects of increasing ground oat groats on nursery pig growth performance. Pigs were weaned at 21 d of age and randomly allotted to pens and fed a commercial starter diet for 7 d prior to the start of the experiment. Pens of pigs were assigned to 1 of 5 dietary treatments in a randomized complete block design by body weight (BW) with 4 or 5 pigs per pen and 10 pens per treatment. Dietary treatments consisted of 0, 7.5, 15, 22.5, or 30% oat groats added in replacement for corn in the diet. Treatment diets were fed for 14 d with pig weights and feed disappearance collected weekly to determine average daily gain (ADG), average daily feed intake (ADFI), and feed-to-gain ratio (F/G). A common diet was fed from d 14 to 28. Data were analyzed using PROC GLIMMIX with pen as the experimental unit. For the experimental period (d 0 to 14), increasing oat groats resulted in no evidence for differences ( P > 0.05) in ADG, ADFI, F/G, or d 14 BW. There was no evidence ( P > 0.05) for treatment differences during the common phase (d 14 to 28) or the overall period. In Exp. 2, a 7-d preference study was conducted to evaluate the response when pigs were given the choice between the diet with 0% groats compared to either the diet with 7.5 or 30% groats. A total of 48 pigs were used with 4 pigs per pen and 6


Introduction
The post-weaning growth lag is a result of multiple dietary and environmental stressors associated with weaning. Many nutritional strategies seek to target the early nursery phases with highly digestible energy and protein sources to help mediate the lapse in performance. One such nutritional strategy is the use of oat products. Rantanen et al. 3 conducted two experiments comparing various oat products to a corn/soybean control diet. Both studies concluded that refined oat products (steam-flaked oat groats and oat flour) had better feed efficiency than corn in Phases I and II; however, much of this efficiency was lost in Phase III when all pigs were fed a sorghum-based common diet. Furthermore,  investigated 37-lb pig preference of 24 diets varying in cereal grain and cereal grain processing method in a 4-d palatability study. This study included 3 raw sources of oats, thick rolled, cooked, raw naked oats, extruded naked oats, and micronized naked oats at levels ranging from 15% to 100% of the grain portion of the diet. Compared with the control diet, micronized naked oats and thick rolled oats were preferred. While these studies compared the use of many different oat products, there is little research on the sole use of oat groats in nursery pig diets. Groats are the product of the mechanical removal of the hull from whole oats. Thus, the objective of this study was to determine the effects of increasing oat groats on nursery pig growth performance and feed preference.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment. The trial was conducted at the Kansas State University Swine Teaching and Research Center in Manhattan, KS. All diets were manufactured at the Kansas State University O.H. Kruse Feed Technology Innovation Center. Oat groats were sourced from Minnesota, and National Research Council (NRC 5 ) ingredient values were used for diet formulation (Table 1).
For Exp. 1, a total of 225 pigs (241 × 600, DNA, Columbus, NE; initially 13.9 lb BW) were used in a 28-d experiment. Pigs were weaned at 21 d of age and fed a commercial starter diet for 7 d prior to the start of the experiment. Pigs were randomly allotted to pens and were assigned to 1 of 5 dietary treatments in a randomized complete block design by BW with 4 or 5 pigs per pen and 10 pens per treatment. Dietary treatments consisted of 0, 7.5, 15, 22.5, or 30% dietary oat groats replacing corn in the control diet. Treatments were fed for 14 d and a common diet was fed from d 14 to 28. Pigs were weighed and feed disappearance was measured on d 0, 7, 14, 21, and 28. Each pen (4 × 5 ft) contained a 4-hole, dry, self-feeder and a nipple waterer to provide ad libitum access to feed and water.
In Exp. 2, a 7-d preference study was conducted to evaluate the response when given the choice between the 0% groats and either 7.5 or 30% groats. A total of 48 pigs were used with 4 pigs/pen and 6 replications/comparison. Pigs were weighed on d 0 and 7, and feeders were weighed and rotated position within the pen daily to determine ADFI of each diet offered.
Samples of treatment diets were collected upon manufacturing at the feed mill, and proximate analysis (Ward Laboratories, Inc., Kearney, NE) and particle size analysis were conducted on both the composite diet samples and the groats using standard procedures. 6 Data were analyzed as a randomized complete block design using PROC GLIMMIX in SAS (Version 9.4, SAS Institute, Inc., Cary, NC) with BW as a blocking factor and pen as the experimental unit. For the preference study, ADFI and % of feed consumed for total intake were compared between diets fed within each comparison. Results were considered significant at P < 0.05.

Results and Discussion
For the 14 d experimental period, increasing oat groats resulted in no evidence for differences (P > 0.05) in ADG, ADFI, F/G, or d 7 and 14 BW. There was also no evidence (P > 0.05) for treatment differences during the common phase (d 14 to 28) or the overall period, with the exception of a marginally significant linear improvement (P = 0.067) in ADG for pigs previously consuming the highest oat groat diet.
The preference study concluded that when given the choice between the 0 and 7.5% oat groat diets, there was no evidence for difference (P > 0.05) in ADFI or percentage of diet consumed. However, when the nursery pigs were given the choice between the 0 or 30% oat groat containing diets, pigs had increased (P < 0.001) ADFI for the 30% oat groat diet compared to the diet without oat groats.
In conclusion, this experiment demonstrated that increasing oat groats in nursery diets did not impact growth performance; however, when given the choice, pigs preferred the 30% oat groat diet compared to diets without oat groats. Additionally, there was a marginally significant response for improved ADG during the common period for pigs fed the highest concentration of dietary oat groats. Further research should evaluate an oat groat diet immediately post-weaning to determine if there is potential for increased intake during the first week in the nursery.       A total of 225 nursery pigs (initially 13.9 lb BW and 28 d of age) were used in a 2-phase nursery study with 4 or 5 pigs per pen and 10 replications per treatment. ADG = average daily gain. ADFI = average daily feed intake. F/G = feed-to-gain ratio. Feeders were rotated once daily within each pen to eliminate any location bias of feeder.
3 ADFI, % is the percentage of total feed intake for each diet within a comparison.