1 Feed crushing size and uniformity

1.1 Crushing particle size Cabrera et al. (1994) reported that the corn pulverization particle size has no effect on the performance of laying hens. When the sorghum pulverization particle size is reduced from 1000 μm to 400 μm, the egg production rate, egg weight and feed conversion rate are improved; The smashing particle size of sorghum does not improve the performance of broilers aged 4 to 14 days and 7 to 28 days old. Healy et al. (1994) reported that for corn, hard endosperm sorghum and soft endosperm sorghum, the highest weight gain and feed conversion rate of the 7-day-old chicks were 700, 500 and 300 μm, respectively. Etc. (1994) believes that if the sorghum is properly processed, its nutritional value to broilers is similar to that of corn. Kansas State University personnel found that when the feed size was reduced from 1000 μm to 500 μm, the rate of weight gain of broilers fed complex diets was increased, while that of broilers fed a simple diet was less affected.

Healy et al. (1994) reported that when the grain size of weaned piglets was reduced from 900 μm to 500 μm, the processing cost of the diet increased, which was less than the compensation caused by the increase in feed conversion ratio. When the granulated size of corn in the growing pig diet was changed from 509 to 1026 μm, it had no significant effect on the daily weight gain of the pig; however, with the decrease of the particle size, the feed conversion rate was improved and the optimal particle size range was 509~. 645 μm (Zanotto et al., 1996). When the corn granule size in the finishing pig diet is between 400 and 1200 μm, the feed conversion rate is increased by 1.3% for every 100 μm reduction in grain size (Wondra et al., 1995a). When the pulverization size of corn was reduced from 1200μm to 400μm, the feed intake and digestible energy intake of the lactating sow, the dry matter of the diet, the digestibility of energy and nitrogen, and the litter weight gain of the piglets increased. The dry matter and nitrogen in the feces The content was reduced by 21% and 31%, respectively (Wondra et al., 1995c, d). Kim (1995) also found that the daily weight gain of piglets was significantly increased when the size of corn in the simple diet was reduced from 1000 μm to 500 μm, while the daily weight gain of pigs composing complex diets was less affected by the size of corn crushed. The suitable size of the feed for pulverization of the piglets from 0 to 14 days and 14 to 35 days after weaning is 300 μm and 500 μm (healty et al., 1994); the growth and finishing pigs and sows are 500 to 600 μm and 400 to 600 μm, respectively (Wondra et al., 1995c, d).

Ying et al (1998a, b) reported that when the corn in the lactating cows was finely pulverized, the digestibility of starch in the rumen and the whole digestive tract and the digestibility of organic matter in the rumen were significantly increased, and the milk yield was significantly increased. Reis et al. (1998) also found that when dairy cows fed finely comminuted diets, the milk fat percentage decreased significantly. Yu et al. (1995) showed that finely pulverizing corn in dairy cows can significantly increase feed conversion ratio.

1.2 Crushing uniformity The roller mill has a higher uniformity of crushing than the hammer mill (McEllhiney, 1983). The conversion rate (Luce et al. 1996) and growth growth rate (Peet et al., 1997) of wheat when pulverized by a roller mill were higher than those of a hammer mill. When the pulverization uniformity of corn is increased, the performance of finishing pigs is not affected, the digestibility of dry matter, nitrogen and total energy of the diet tends to increase, and the dry matter discharge of the manure is reduced; the corn is crushed by a roller mill, which is smaller than the hammer. The mill can increase the nutrient digestibility in the diet and reduce the dry matter in the manure by 19% and the nitrogen output by 12% (Wondra et al., 1995).

2 Dietary mixing uniformity

Mccoy et al. (1994) reported that when feeding broilers with full-price diets, the uniformity of diets had little effect on their growth performance, and the feed conversion ratio increased linearly with the increase of mixing uniformity; When the chickens were fed 80% of NRC standard non-full-price diets, their growth performance improved with increasing feed mixing uniformity (variation coefficient from 40.5% to 12.1%). Traylor et al. (1994) reported that when the variation coefficient of feed uniformity of piglets decreased from 106.5% to 12.3%, the daily gain and feed conversion ratio increased by 32.5% and 19.2%, respectively, while the uniformity variation of diet in finishing pigs When the coefficient decreased from 53.8% to 14.8%, there was no significant improvement in production performance. Therefore, the uniformity of diet mixing has a greater impact on young animals and when feeding non-full-price diets. Therefore, the suitable coefficient of variation for the uniformity of diet for broilers and piglets is 12%; the coefficient of variation for feed mixing uniformity of finishing pigs is at least 15%.

3 hot processing

3.1 Granulation Because pellets have many advantages over powders, they are widely used in the production of broiler chickens, turkeys and weaned piglets. The daily gain and feed conversion ratio of broiler feed pellets are better than powder. The recent impact on the quality of granulation and the ratio of pellets to fines in the diet has been a concern for the performance of broilers. Wilson et al. (1998c) reported that when three to six weeks old broilers fed whole pellets, the production performance was higher than that of feed pellets + fine flour diet. The turkey is more sensitive to the quality of the pellets and the fines in the pellets than the broilers. Proudfoot and Hulan (1982) found that when the fines content of turkey grains increased from 0 to 60%, their production performance decreased.

Wang Xiangyang (1995) granulated raw soybean powder and reduced the content of trypsin inhibitor from 27.36 to 14.30 mg/g. John-ston et al. (1998a,b) fed corn or sorghum powder to finishing pigs and sows respectively. The feed conversion ratio, total energy apparent digestibility and nitrogen digestibility of pellets were significantly higher than that of powders. There is no significant difference in weight. Traylor et al. (1996) reported that the average daily gain and feed conversion rate of pigs fed pellets before 5 days of age increased by 25% and 36%, respectively, and the particle diameter (2 to 12 mm) did not affect pig growth. Performance; pigs with a diameter of 4 mm during the 0 to 29 days of age had the highest daily gain and feed conversion rate; the growth rate of pigs at the age of 29 days to finishing was not affected by the form of feed, but the feed of pellets The conversion rate is better than the powder. Stark et al. (1994) also reported that when feeding sifted pellets to piglets, the feed conversion rate was 4.5% higher than that of pellets containing 15% or 30% fine powder; in finishing feeds for finishing pigs, with pellets The proportion of fine powder increased from 0 to 60%, the feed conversion rate decreased, and there was no significant difference between daily gain and nitrogen digestibility and backfat thickness.

Shi Qinghe (1997) increased the daily weight gain, feed intake and feed conversion rate by 161.92%, 88.74% and 28.01%, respectively, on the granulated processing of the mixed mixed diet of the young sheep; the rumen disappearance rate and total digestion of nutrients There was no significant difference in apparent digestibility.

Although granulation has advantages, retinol, vitamin K, ascorbic acid, carotene, vitamin E, and thiamine are more sensitive to granulation (Gadient, 1994). Van der Poel (1997) reported that the granulation temperature at 75 ° C and 95 ° C can reduce the activity of β-glucanase by 40% and 70%, respectively, and the β-glucanase and cellulase above 110 °C. All activity is lost. Israelson et al. (1995) reported that when the granulation temperature was 79 ° C, the phytase activity decreased by 45.8%, and at 80 ° C, it decreased by 87.5%, and the activity loss was large.

3.2 Expansion and maturation Compared with extrusion and granulation, expansion and maturation and extrusion have the characteristics of short time, high temperature and high pressure. Jin Zhengyu (1998) believes that the bulking material has better palatability and higher utilization than the pellet material. Chae and Han (1998) pointed out that puffing is more effective than granulation in controlling Salmonella.

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Zanella et al. (1998) reported that the addition of puffed whole-fat soybeans to broiler diets can increase the weight gain and feed conversion ratio of broilers by using larger soybean meal or baking full-fat soybeans. Garcia et al. (91998) expanded the barley to significantly increase the weight gain of broilers before 14 days of age; and the barley expansion process significantly increased the weight gain of broilers compared to microwave processing. Wilson et al. (1998a) reported that the corn expansion processing conditions for the broiler weight gain and feed conversion rate were as follows: the tempering temperature was 71 ° C, the energy consumption was 12 kWh / t; and the corresponding values ​​of sorghum were 79 ° C and 9 kWh / t. In the production of broiler granules, the general tempering is changed to expander tempering, which can increase the metabolic energy content and the digestibility of fat and starch (Peisker, 1993), and the feed conversion rate is improved (Wilson et al., 1998b). . Rollins (1996) reported that compared with conventional quenching and tempering, steam energy conditioning, enhanced steam conditioning and expander conditioning increased broiler weight gain by 1%, 1% and 5%, respectively, and feed conversion rate improved by 4%. , 3% and 3%.

Van Zuilichem et al. (1996) reported that when whole-fat soybeans were processed by tempering and swelling, they did not affect lysine content and significantly reduced trypsin inhibitor content and protein dispersion index. Cao et al. (1998b) reported that when dry fat processing of whole-fat soybeans increased from 0 to 70 kg/cm2 with cone pressure, the daily weight gain and feed conversion rate of weaned piglets decreased; full-fat soybeans were processed by steam quenching and tempering. At the same time, as the cone pressure increased from 0 to 56 kg/cm2, the daily gain of weaned piglets increased with the feed intake. Richarclson et al. (1998) found that puffed soybeans did not significantly improve their dry matter digestibility, while puffed cottonseed increased their dry matter digestibility. O'Doherty and Callan (1998) produce pigs with similar performance as basal diets. Traylor (1997) in digestive pig diets based on corn, sorghum or wheat meal, nutrient digestibility can be improved by expansion processing, but in wheat-based diets, nutrient digestibility is It is not improved by expansion processing; the wheat coarse powder with higher crude fiber content than corn or the sorghum with lower value than corn has higher nutritional value than corn after expansion processing. Medel et al. (1998) also found that corn in the diet of early weaned piglets had a lower performance improvement than barley. Piao et al. (1997) found that when barley was expanded at 150 °C, the growth rate of growing pigs was better than 100 °C.

Saurer et al. (1996) reported that piglet diets were puffed + granulated or expanded + granulated, which increased pig growth by 8%, feed conversion by 6%, and energy and protein digestibility by 3% and 6 compared with granulation only. %. Pigs in the 8 to 12, 10 to 35 and 35 to 110 kg body weight stage, intake of expanded pellets, feed conversion rate is better than the consumption of ordinary quenched and tempered pellets (Teisker, 1995). Chae and Han (1998) studied the effects of powders, ordinary pellets, expanded materials, expanded pellets and expanded pellets on pig performance and nutrient digestibility. In terms of improving weight gain and feed conversion ratio, piglets were used. The effect of eating common granules with growing pigs is better than that of expanded granules; growth-finishing pigs are better than puffed granules in eating ordinary granules; while piglets are inferior to puffed or expanded granules by feeding ordinary granules. For the expansion or expansion of the diet, the powder has a tendency to increase the energy digestibility, but has no effect on the protein digestibility; when the expansion or expansion is combined with the granulation process, there is no additive effect on the digestibility; The effect of the expansion or expansion of the diet on the performance of the pigs compared to the powder and pellets seems to increase with the age of the pigs. That is, as the age of the pig increases, the grain processing of the diet is sufficient to optimize the production performance. The effect of swelling and puffing on pig performance is also related to the nature of the diet. In the case of expanded and expanded fibrous diets (Sauer et al., 1996), the improvement in pig performance was greater than in the treatment of highly digestible or corn-soybean meal diets (Chae et al., 1997a).

Sommer et al. (1994) reported that when the rapeseed meal was expanded at 120, 130 and 150 °C, the crude protein dissolution angle was reduced from unprocessed 40% to 17%, 15% and 13%, respectively, and the corresponding rumen degradation rate was from 65%. They decreased to 44%, 35% and 38%, respectively; the digestibility of rumen non-degradable protein residues in the small intestine increased. Swelling increases the rumen protein content of cereals and soybeans by a factor of four, and increases the rumen protein content of soybean meal, rapeseed meal, and corn gluten meal by a small margin (Elstner, 1996). Goelema and Van der Poel (1996) expand processing at 120-150 °C to reduce the degradation rate of protein in most feed ingredients and protein mixes, but the digestibility of proteins in undegraded residues in the small intestine is not affected. And even there is improvement. During the 5th to 20th week of lactation, when the cows ingested the expanded pellets, the standard milk yield increased by 6.4% in the consumption of ordinary pellets (Peisker, 1995).

Coelho (1996) pointed out that expansion and expansion processing have a great impact on the stability of vitamins in feed. Chae et al. (1997c) reported that growth pigs were fed with vitamin diets before puffing, and the growth rate and feed conversion rate were lower than those after puffing.

3.3 Dry-rolling, steam-rolling and steam-pressing Dry-rolling, steam-rolling and steam-pressing are widely used in dairy production. Daun et al. (1998) fed the comminuted or steam-pressed corn to the cows before the birth. As a result, there was no significant difference in the post-natal performance of the cows, and the corn fed to the cows after steaming was more smashed than the feed. Corn has a tendency to increase milk production. Studies at the University of Arizona have shown that steam-squeezed corn or sorghum can increase milk production by 6%, milk protein production by 8%, and raising economic benefit by $0.48/d compared to dry milling and steam rolling. The improvement is greater than corn (Santos et al., 1997). When the cows were fed sorghum or corn for compression, the production performance was similar (Santos et al., 1997). When the cows were fed a compressed corn with a bulk density of 0.30 kg/L, the milk yield was increased by 8% compared to the compressed corn with a bulk density of 0.25 kg/L, steam-rolled corn or coarsely crushed corn (Yu et al., 1995). The optimum bulk density of corn (Yu et al., 1995) and sorghum (Santos et al., 1994a, b) after compression is 0.26-0.32 and 0.30-0.36 kg/L, respectively. Crocker et al. (1998) fed cows with different proportions of compressed corn and dry crushed corn. The results showed that the digestibility of starch increased with the increase of proportion, and the proportion of C18:2 fatty acids in milk fat increased linearly.

3.4 Effects of Microwave Processing on Feed Nutritional Value and Performance of Livestock and Poultry Garcia et al. (1998) reported that microwave processing of barley in diets of broilers from 1 to 42 days of age could increase the number of broilers before the age of 14 days compared with the unprocessed group. weight. Wang et al. (1998) significantly reduced the rumen degradation rate of arginine, isoleucine, leucine, lysine and phenylalanine in microwave processing of whole-fat Canola seeds in dairy cow diets. The digestibility of the above amino acids and proline in the small intestine.

4 Conclusion

In summary, appropriate processing of the feed can improve the nutritional value of the feed and the production performance of the livestock and poultry, and potentially reduce the environmental pollution of livestock and poultry excrement. Although thermal processing has many advantages, it increases the processing cost, reduces the stability of vitamins and the activity of enzymes. When applying, it should weigh the pros and cons and make decisions. In addition to the need to further study the uniformity of diet mix, the quenching and tempering method before granulation (normal steam or expander quenching and tempering) and the quality of pellets on the nutritional value of feed and the performance of livestock and poultry, it is necessary to In addition to sorghum, the suitable pulverization size of other cereals and protein feeds, as well as the accurate and simple method for determining the uniformity of the mixed diet, the factors affecting granulation and its control methods, the basic parameters of different raw materials and diets for expansion and expansion processing, It has made in-depth research in the development of unconventional feed resources (such as feather keratin) and suitable conditions for microwave processing of feed.