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1.
J Dairy Sci ; 106(9): 6041-6059, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37474365

ABSTRACT

This study evaluated the physical effectiveness of whole-plant corn silage (CS) particles stratified with the Penn State Particle Separator, composed of 19- and 8-mm-diameter sieves and a pan, for lactating dairy cows. Eight Holstein cows (27.6 ± 2.8 kg/d of milk, 611 ± 74 kg body weight; 152 ± 83 d in milk) were assigned to two 4 × 4 Latin squares (22-d periods, 16-d adaptation), where one square was formed with rumen-cannulated cows. Three CS particle fractions were manually isolated using the 8- and 19-mm diameter sieves and re-ensiled in 200-L drums. The 4 experimental diets were (% dry matter): (1) CON (control): 17% forage neutral detergent fiber (NDF) from CS (basal roughage), 31.5% starch, and 31.9% NDF; (2) PSPan: 17% forage NDF from CS + 9% NDF from CS particles <8 mm, 25.9% starch, and 37.9% NDF; (3) PS8: 17% forage NDF from CS + 9% NDF from CS particles 8 to 19 mm, 25.5% starch, and 38.3% NDF; and (4) PS19: 17% forage NDF from CS + 9% NDF from CS particles >19 mm, 24.9% starch, and 38.8% NDF. Cows fed PS8 had greater dry matter intake and energy-corrected milk yield (22.4 and 26.9 kg/d, respectively) than cows fed CON (20.8 and 24.7 kg/d) and PS19 (21.2 and 24.8 kg/d), but no difference was detected between PSPan (21.6 and 25.8 kg/d) and other treatments. Milk fat concentration was greater for PS8 than CON, with intermediate values for PSPan and PS19. Milk fat yield was greater for cows fed PS8 than CON and PS19, and cows fed PSPan secreted more fat than CON cows but were not different from cows fed the other 2 diets. Cows fed CON had a lower meal frequency than cows fed PSPan, shorter meal and rumination times than PS8, and greater meal size and lower rates of rumination and chewing than the other 3 diets. Total chewing per unit of NDF was higher for PS8 than PSPan, although neither treatment differed from CON or PS19. Cows fed PS19 had higher refusal of feed particles >19 mm than cows fed CON and PSPan. The refusal of dietary NDF and undigested NDF in favor of starch were all greater for PS19 than on the other treatments. Cows fed PS19 had a greater proportion of the swallowed bolus and rumen digesta with particles >19 mm than the other 3 diets. Cows fed CON had the lowest ruminal pH and greatest lactate concentration relative to the other 3 diets. Plasma lipopolysaccharide was higher for cows fed CON and PSPan than for cows fed PS8 and PS19, and serum d-lactate tended to be lower on PSPan than for CON and PS8. In summary, the inclusion of CS fractions in a low-forage fiber diet (CON) reduced signs of ruminal acidosis. Compared with CS NDF <8 and >19 mm, CS NDF with 8- to 19-mm length promoted better rumen health and performance of dairy cows. These results highlight the importance of adjusting CS harvest and formulating dairy diets based on the proportion of particles retained between the 8- and 19-mm sieves.


Subject(s)
Silage , Zea mays , Female , Cattle , Animals , Silage/analysis , Lactation , Digestion , Rumen/metabolism , Fermentation , Milk , Dietary Fiber/metabolism , Diet/veterinary , Starch/metabolism , Lactic Acid/metabolism
2.
J Dairy Sci ; 104(6): 6792-6802, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33741155

ABSTRACT

Our objective was to compare the performance of dairy heifers fed diets based on whole-plant corn silage stored in bunker silos sealed with either standard polyethylene film (white-on-black, actual thickness 121 ± 3.1 µm) covering the top surface, held in place with rows of tires every 3 m (PE) or an oxygen barrier system comprised of an ethylene-vinyl alcohol film (actual thickness 46.7 ± 2.5 µm) lining side walls and covering the silage, protected with a woven anti-UV cover and gravel bags placed around the edges and every 3 m across the silo (OB). Whole-plant corn was mechanically harvested at 39% dry matter (DM), packed in bunker silos, and sealed with PE or OB covering methods. After 6 mo of storage, silos were opened and fed to 26 Holstein heifers (260 ± 89.1 kg of shrunk body weight) for 60 d. Heifers were blocked by initial weight (13 blocks with 2 heifers each block) and housed in individual pens. Diets contained (on a DM basis) 80% corn silage (PE or OB), 17.5% soybean meal, and 2.5% mineral mix. Dry matter intake was measured daily, whereas shrunk body weight, hip height, heart girth, and body condition score were measured at the beginning and end of the experiment. Feeding behavior was recorded on d 24 and 46, and total-tract digestibility was measured from d 26 to 30 and 48 to 52. Data of intake, feeding behavior, and digestibility were averaged by animal for the whole feeding period before the statistical analysis. Data of animal performance were analyzed as a randomized complete block design. Initial shrunk body weight was used as a covariate for analyses of intake and body measures. During feed-out, silage quality was also assessed at the top (15 cm depth from upper surface) and bottom layer (135 cm depth from upper surface) and analyzed as a split-plot design. Silage stored under the OB sealing system had less yeast, mold, and NH3-N, and more lactic acid and ethanol-soluble carbohydrates. An interaction between sealing strategy and silo layer showed that OB silage had lower values of temperature, pH, anaerobic spores, acetic acid, and DM loss, and greater in vitro DM digestibility and aerobic stability, especially in the top layer. The proportion of inedible silage was lower in OB than in PE treatment (0.82 vs. 4.00% DM). Total-tract digestibility was similar between treatments, but animals that received the OB diet had higher DM intake by approximately 9% (9.39 vs. 10.20 kg/d) due to a faster eating rate and a greater number of meals per day. Therefore, OB treatment increased the digestible energy intake by 8% (26.3 vs. 28.3 Mcal/d) and average daily gain by 12% (1.08 vs. 1.21 kg/d). Body condition score change was similar between treatments, but heifers fed OB had greater heart girth and tended to have higher hip height. In conclusion, replacing a standard PE film with an OB sealing system improved silage conservation and performance of growing dairy heifers.


Subject(s)
Silage , Zea mays , Animal Feed/analysis , Animals , Body Weight , Cattle , Diet/veterinary , Dietary Fiber , Digestion , Energy Intake , Female , Silage/analysis
3.
Arq. bras. med. vet. zootec ; 65(3): 847-856, June 2013. tab
Article in Portuguese | LILACS | ID: lil-679122

ABSTRACT

O objetivo deste trabalho foi avaliar as características bromatológicas e agronômicas dos genótipos de milho para a produção de silagem dos cultivares do Ensaio Centro Superprecoce da Rede Nacional de Genótipos de Milho, bem como avaliar se a base genética (híbridos simples, duplos, tripos, intervarietais e variedades cultivadas) ou a dureza dos grãos (duro, semiduro e dentado mole) alteram a indicação de cultivares de milho para silagem. O experimento foi realizado na área experimental da Universidade Tecnológica Federal do Paraná (campus Dois Vizinhos). Os trinta e dois genótipos avaliados foram colhidos quando os grãos encontravam-se no estádio pastoso a farináceo, ensilados em microssilos de PVC e desensilados após 53 dias. Avaliou-se a relação entre as bases genéticas, a dureza do grão e as características individuais dos genótipos quanto à aptidão para a produção de silagem. Não se verificaram diferenças significativas entre os contrastes formados entre as bases genéticas, bem como a dureza dos grãos, para os caracteres estudados. Porém, foi possível identificar genótipos superiores para a produção de silagem pela produção de matéria seca pelos genótipos AS 1555 YG, AS 1572 YG, 30A37, 30A77, 20A78, Dx 908, Dx 603, 2A550, 2B433, AL2007A, Embrapa 1F640, PRE 22T10, PREXT0109, PRE 22D11, DKB330 YG (Test).


The aim of this study was to evaluate the nutritive value and agronomic characteristics of maize genotypes for the silage production cultivars test center network of Super Early National Corn Genotypes; and to assess whether the genetic background (hybrids simple, doubles, triples, intervarieties and cultivated varieties) or the hardness of the grains (hard, soft flint and dent) may change the indication of maize cultivars for silage. The experiment was conducted at the experimental Federal Technological University of Paraná (Campus Dois Vizinhos). Thirty-two genotypes were harvested when the grains were in the dough soft dough stage, micro-ensiled in PVC silos, silage cutters and after 53 days after silage cutters. We evaluated the characteristics and chemical plant parameters of each genotype. We evaluated the relationship between genetic bases, hardness of the grain and individual characteristics of genotypes related to the production of corn silage. There was no significant difference between the contrast formed between the genetic and hardness of the grains for the characteristics studied. However, it was possible to identify superior genotypes for the production of silage whit bases in dry matter production by genotype YG AS 1555, AS 1572 YG, 30A37, 30A77, 20A78, DX 908, DX 603, 2A550, 2B433, AL2007A, EMBRAPA 1F640, PRE 22T10, PREXT0109, PRE 22D11, DKB330 YG (Test).


Subject(s)
Animals , Agriculture , Genotype , Silage/analysis , Zea mays , Food Analysis/methods
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