17/01/2024
Supplementation of alfalfa hay and grass cobs in piglet rearing
Source: landwirt.com
Roughage has a positive effect on digestion and keeps piglets occupied. Scientists at the Bavarian State Laboratories for Livestock and Agriculture (LfL Bayern) investigated whether supplementing with alfalfa hay and grass cobs reduces the intake of rearing feed and thus reduces performance.
As part of the Animal Welfare project, piglets at the Schwarzenau Teaching, Research, and Technical Center (LVFZ) were offered high-fiber feed in addition to their piglet rearing feed. In an initial trial, alfalfa hay, corn silage, and grass cobs were tested. The addition of these high-fiber feeds did not impair piglet rearing feed intake or rearing performance compared to the control group. Two further trials were conducted to determine whether these results would also be evident under practical conditions (group feeding, liquid feeding, spot mix). Alfalfa hay was used in the first trial, and grass cobs in the second.
Experimental setup
For each of the two trials, 192 piglets were selected and equally divided into a test group and a control group based on weight, sex, and pedigree. The test groups were each given chopped alfalfa hay or grass cobs as a supplement to their rearing feed. The control groups received no roughage. The piglets were kept in 16 pens of 12 piglets each on plastic slats without bedding. Fiber feed was provided in additional troughs and weighed daily as needed. Unrequisite feed was assessed and reweighed daily.
The two trials were divided into two feeding phases. Phase 1 ranged from 9.5–18.0 kg live weight, Phase 2 from 18.0–30.0 kg (or more). Piglet rearing feed consumption was determined daily per pen. Piglet live weights were recorded weekly. Once a week, feces were scored (grade 1–4 from hard to watery). The feed analyses were conducted in the laboratory of the Bavarian State Research Center for Agriculture (LfL).
All animals received the same piglet rearing feed throughout both trials. The experimental rations were simple, consisting of wheat, barley, soybean meal (48% crude protein), mineral feed, soybean oil, and fumaric acid. The rations corresponded to the farm's proven piglet rearing feed.
The alfalfa hay used had a crude fiber content of approximately 30%, indicating a harvest at the beginning of flowering. The crude fiber content of the grass cobs, however, corresponded to the table value for a harvest at the leaf stage. For comparability, the intakes of piglet rearing feed, alfalfa hay, and grass cobs were based on 88% dry matter.
Since there were no dropouts in either trial, the data from all animals could be included in the analysis. The weight development of the piglets was almost identical in both trials.
Alfalfa hay supplement
The table (see image below) shows the daily weight gain, feed intake and the resulting feed efficiency figures for both groups.
Daily weight gain in the alfalfa group was 523 g, only slightly lower than in the control group (530 g). The fiber-rich alfalfa hay offered was not consumed in the expected amount compared to the first trial. While alfalfa consumption in the individual-feeding trial rose to 40 g per animal per day toward the end of rearing, alfalfa consumption under practical conditions was about half that at 21 g. In both the previous and the present trial, a significant increase in alfalfa intake was observed in the last week of the trial (Fig.). The consumption of piglet rearing feed was satisfactory at 912 g per day in the test group and 888 g in the control group. Since the animals in the alfalfa group had a higher feed intake (912 versus 888 g) at the same performance (523 versus 530 g daily gain), this resulted in less favorable feed efficiency values (1.75 versus 1.69 kg feed per kg gain). Consequently, concentrate costs per 1 kg gain were 2 cents higher in the test group than in the control group. Both the test and experimental group animals had feces of normal consistency (Table).
Gracobs allowance
Daily weight gain in the grass cobs group was 541 g, almost identical to that in the control group (540 g). In the sixth week of the trial, the piglets in group feeding consumed 40 g of grass cobs per day. In the previous trial with individual feeding, the animals had consumed up to 65 g per day. The consumption of cobs, especially at the beginning of rearing, was significantly higher than that of alfalfa (see figure). While the piglets in the control group achieved a total feed intake of 906 g per day, the animals in the grass cobs group consumed as much as 927 g per day. The addition of grass cobs showed no effect on feed efficiency values, with values of 1.69 and 1.72 kg feed per kg gain.
Roughage makes sense
As in the trial with individual feeding at on-demand stations, the following was observed during feeding at the short trough with Spotmix: the supplementary groups with alfalfa hay and grass cobs also consumed more piglet rearing feed. Therefore, a displacement of concentrates by high-fiber feeds was not the case. During group feeding at the short trough, the concentrates were always available to all animals, and thus their interest in the fiber sources was less pronounced. This could explain the lower consumption of fiber sources in group feeding at the trough compared to the trial with individual feeding at on-demand stations. No differences were observed in the assessment of fecal consistency. In both trials, fecal consistency was normal. The feeding trough with the separately offered roughage was frequently visited. It was well accepted both as food and as an enrichment material.
Conclusion
The supplementation of alfalfa hay and grass cobs in piglet rearing primarily serves as an enrichment material. In the present study, this did not lead to a displacement of piglet rearing feed and had no negative effects on performance. The slightly higher feed intake of the test group with alfalfa supplementation led to a lower feed conversion ratio.