Effect of replacing forage sorghum silage with biomass sorghum silage in diets for F1 Holstein × Zebu lactating cows

The objective of this study was to evaluate the replacement of forage sorghum silage (FS silage) with BRS 716 biomass sorghum silage (BRS 716 silage) in diet of F1 ½ Holstein × ½ Zebu cows on their nutrient intake and digestibility, ingestive behavior, nitrogen balance, and milk yield and composition. The experimental design was in two 5 × 5 Latin squares, simultaneous, composed, each, by five animals, five treatments, and five experimental periods. The study included 10 cows with an initial body weight (BW) of 544 ± 12.84 and 88 ± 14 days of lactation at the beginning of the experiment. The treatments were defined by replacement FS silage at levels 0, 25, 50, 75, and 100% with BRS 716 silage. The roughage:concentrate ratio in the total dry matter (DM) of the diets was 75:25. The replacement of FS silage with BRS 716 silage reduced (p < 0.01) the dry matter intake and digestibility of dry matter, but it had not changed average milk yield (12.68 kg/day; p = 0.94), feed efficiency, body weight, the score of body condition, and the average daily gain of the cows. The milk composition was not changed except casein/total protein in milk that decreased and that increased linearly milk urea nitrogen. The inclusion of BRS 716 silage increased the activities of rumination and chewing and decreased the periods of feeding and idleness. The replacement of up to 100% of FS silage with BRS 716 silage in the diet of F1 Holstein × Zebu cows does not alter average milk yield, despite changing diet intake and digestibility.

Productive and reproductive performance of females F1 Holstein x Gir daughters of proven bulls

Records of 234 lactations from F1 Holstein x Gyr daughters of proven bulls were used in this study for the evaluation of productive and reproductive characteristics of cows. Data were collected from a private farm located in the municipality of Santo Antônio do Monte, MG, Brazil. The objective of this study was to evaluate the effects of Holstein bull's PTA milk (predicted transmitting ability) calving year, season, and parity on the productive and reproductive characteristics of F! cows. The productive characteristics analyzed were total milk production (TMP), average daily production (ADP), days in milk (DIM), and milk yield per day of calving interval (MYDCI). The studied reproductive characteristics were service interval (SI), calving interval (CI), and gestation length (GL). The results were subjected to statistical analysis and means for significant effects were compared using Duncan's test at a significance level of 5%. F1 animals efficiently expressed their genetic potential for milk production with an average total milk production of 7842.61 kg and average daily production of 24.53 kg. Means for days in milk, milk yield per day of calving interval, service interval, calving interval, and gestation length were 322.52 days, 20.73 kg, 106.0 days, 383.23 days, and 276.18 days, respectively. Properly managed F1 Holstein x Gyr daughters of proven bulls fed a balanced diet efficiently expressed their genetic potential for milk production without adverse effects on reproduction. Moreover, Holstein x Gyr cows should be selected based on parents' PTA for milk traits and other factors such as environmental conditions and management.

Effect of different roughage sources associated banana pseudostem hay on the nutritional and behavioral parameters and performance of F1 Holstein/Zebu lactation cows

The objective of this study was to evaluate the association of pseudostem hay of banana trees of different roughages in the diet of F1 Holstein/Zebu cows on their nutrient intake and digestibility, nitrogen balance, microbial synthesis, ingestive behavior, and milk production. The experiment was distributed in two simultaneous 4 × 4 Latin squares. The treatments were as follows: diet 1-sorghum silage as exclusive dietary roughage; diet 2-sorghum silage (70%) associated with 30% pseudostem hay of banana trees (dry matter basis); diet 3-70% elephant grass with 30% pseudostem hay of banana trees (dry matter basis); and diet 4-70% sugarcane with 30% banana pseudostem hay (dry matter basis). The roughage/concentrate ratio was 75:25. The animals fed with sorghum silage presented 14.45% higher intake (p = 0.01) to that of animals fed hay and elephant grass. The diets containing silage and silage with hay showed digestibility of neutral detergent fiber corrected for ash and protein that was 57.75% higher (p < 0.01) than that of other diets. Cows fed elephant grass spent more time intake (p = 0.01). Diets did not influence milk yield (p = 0.47), and the milk yield corrected for 3.5 fat (p = 0.22), final weight (p = 0.06), and intake efficiency (p = 0.57), presenting a mean of 14.16 kg/day, 15.94 kg/day, 590 kg, and 0.9 kg of milk/kg of ingested dry matter, respectively. The utilization of pseudostem hay associated with other roughage can be an alternative to milk yield in F1 Holstein/Zebu cows.

Combinations of cactus pear with different roughage sources on the production, chemical composition, and milk fatty acid profile of F1 Holstein/Zebu cows

The qualities of food, mainly of animal origin, have always been of concern to consumers. It is known that the composition of animals' diets can influence the composition of the foods produced, such as milk. Thus, the objective of this study was to evaluate diets with cactus pear in combination with different forages for F1 Holstein/Zebu cows on the chemical composition and fatty acid profile of milk. Two simultaneous 4 × 4 Latin squares were used in the experimental design. Four experimental diets were used: Diet 1, sorghum silage as the only roughage; Diet 2, sorghum silage combined with cactus pear in a proportion of 50% of the roughage (dry matter basis); Diet 3, elephant grass (Pennisetum purpureum cv. Roxo) as the only roughage; and Diet 4, elephant grass combined with cactus pear in a proportion of 50% of the roughage. The roughage:concentrate ratio was 75:25. The milk urea nitrogen was higher (16.08 mg/dL) in the milk of cows fed the diet with only elephant grass than that of milk from the other diet groups. The other analyzed variables of the chemical composition of milk were not influenced by the diets. However, there was a change in the sum of the saturated and monounsaturated fatty acids. The content of C16:0 fatty acid was higher and that of C18:0 was lower in the milk of cows fed the cactus pear diets than in that of cows fed the other diets. Higher levels of oleic acid were observed in the milk of cows fed with diets containing elephant grass than those in the milk of the cows in the sorghum forage groups. Conjugated linoleic acid (CLA) was higher in the milk of cows fed cactus pear than in that of the other cows. The combination of cactus pear with elephant grass or sorghum silage in the diet did not alter the chemical composition of milk. However, it influenced the fatty acid profile.

<b>Hay Tifton 85 grass under nitrogen doses in different days of regrowth

The objective of this study was to evaluate the yield, nutritional value and potential ruminal degradation of Tifton 85 hay (Cynodon spp.) harvested at four regrowth ages (28, 35, 42 and 49 days) and fertilized with two nitrogen doses (N; 100 and 300 kg N ha-1). The experimental design was a randomized block design, arranged in a 4 x 2 factorial scheme, with six replications each. Nitrogen fertilization increased (p < 0.05) dry matter yield and digestible dry matter production of hay and also lignin and crude protein contents. Nitrogen fertilization increased (p < 0.01) the dry matter yield and the digestible dry matter production of hay, as well as lignin (p = 0.01) and crude protein (p = 0.01). The neutral detergent fiber corrected for ash and protein (p = 0.01), acid detergent fiber (p = 0.01) and cellulose (p = 0.02) adjusted to the quadratic function regression model of the regrowth ages. For potential rumen degradability hay, it was observed quadratic effect (p = 0.01) with maximum value of 73.1% at 37 days of regrowth. Tifton 85 hay fertilized with 300 kg ha -1 of N and harvested up to 37 days of regrowth results in higher hay dry matter yield, higher crude protein content, and better dry matter rumen degradability. 

<b>Nutritional characteristics of sorghum hybrids hay (<i>sorghum sudanense</i> x <i>sorghum bicolor</i>)

This study evaluated the nutritional characteristics of hay of nineteen hybrids between sorghum and Sudan grass. The experimental design was a randomized block with nineteen treatments and three replications. The chemical characteristics of the respective hays were analyzed 52 days after sowing and 45 and 49 regrowth days. Data were analyzed by analysis of variance, and when the F test was significant, the treatment means were compared by the Scott and Knott test at 5%. Genotypes 1013026 and 1014020 showed similar dry matter content. As for ether extract content, the highest values ranged from 2.20 to 2.66%. Higher values of minerals were observed in hybrids 1013026 and 1011005. In relation to crude protein, higher content values were reported for hybrids 1013021 and 1013020 (14.59 and 15.47% CP). When evaluating the neutral detergent fiber content, lower values varied between 56.05 and 57.07% for hybrids 1013016 and 1011009. Considering the content of acid detergent fiber, values ranged from 32.70 to 35.78%. Values of dry matter digestibility were higher than 50%. All hybrids provide quality hay, however the hybrid 1014019 showed the best nutritional value. 

<b>Nutritional value of sorghum silages

 This study aimed to evaluate the nutritional characteristics and quality of silages of five sorghum genotypes, namely: Volumax, AG2005E, Qualimax, BRS610 and AG2501. The study was conducted at the Experimental Farm Unimontes, in the municipality of Janaúba, state of Minas Gerais. The treatments were distributed in a randomized block design with four replicates. Data were tested by analysis of variance andmeans were compared by Scott-Knott test at a significance level of 5%. The pH values ranged from 3.93 and 4.10. Genotypes differed in all studied nutritional characteristics (p < 0.05). For the acid detergent fiber, differences were detected between the genotypes, AG2501 (35.66%), Volumax (34.89%), AG2005E (34.53%), Qualimax (32.39%) and BRS610 (33.60%). The high participation of lignin was verifiedin all genotypes except for Volumax (4.14%). All silages were within the recommended range 50-65% for in vitro dry matter digestibility and classified as having good quality, however only the AG2005E genotype met nitrogen requirements for microbial fermentation, with 7.06% crude protein. 

<b>Agronomic traits and nutritional value of forage sorghum genotypes

This study aimed to evaluate the agronomic performance of 24 sorghum genotypes in four Brazilian regions and the chemical characteristics of genotypes grown in Sete Lagoas, state of Minas Gerais. Genotypes BRS655 and 12F37005 had higher average production of green matter (> 44 ton ha-1) and dry matter (> 17 ton ha-1), respectively. Genotypes 12F38019, 12F40019, 12F37005, 12F37043 and Volumax took more days to flower in three of the four municipalities (75-90 days). Genotypes 12F38006, 12F40006 and 12F37016 were taller (> 2 m). Values of dry matter, crude protein and neutral detergent fiber ranged from 37.15 to 50.13; 5.51 to 10.28 and 43.57 to 65.69%, respectively. The genotypes were not different regarding acid detergent fiber content, with mean value of 34.83%. Genotypes 12F38019, 12F37016, 12F39005, 12F39019, 12F37007, 12F37014, 12F39014 and BRS 655 showed the best values of dry matter digestibility (64.31 to 74.20%) and crude protein content (8.33 to 10.28%). Among them, 12F139014 exhibited the lowest lignin content (3.32%), suggesting less effect of this fraction on digestibility. Genotype 12F39014 is the most suitable for cultivation, as it presented the best nutritional value and good dry matter production in the four municipalities.

<b>Chemical composition of sorghum genotypes silages

 The objective was to select sorghum genotypes for silage production using its chemical characteristics. The experiment was carried out in the facilities of Embrapa Maize and Sorghum in Sete Lagoas, state of Minas Gerais, to evaluate the agronomic characteristics, and nutritional quality of silage of twelve sorghum genotypes. We used a randomized block design with three replications. In relation to the production of green matter, the genotypes SF15 Volumax and BR610 stood out (52.07; 48.00 and 41.87 ton ha-1). Regarding pH, genotypes 1015339, 1015347, 1016007, SF15, BRS655, Volumax and BR610 averaged 3.68. All genotypes were similar considering the nutritional value, ammonia nitrogen and water activity. The genotypes SF15, Volumax and BRS610 showed the highest productivity per area, representing the best options for silage production. 

Cinética de fermentação in vitro de fenos da parte aérea de mandioca

Objetivou-se avaliar a cinética de fermentação ruminal dos fenos de diferentes frações da parte aérea de variedades de mandioca, pela técnica semiautomática de produção de gases. O experimento foi conduzido em um delineamento em blocos casualizados, arranjado em um esquema fatorial 4x3, sendo quatro variedades de mandioca (Amarelinha, Sabará, Olho roxo e Periquita) e três frações da parte aérea (terço superior, sobra de plantio e planta inteira). As leituras de pressão dos gases foram realizadas por intermédio de transdutor de pressão e, posteriormente ajustadas para o volume de gases. Foram avaliadas a produção cumulativa de gases, as frações solúvel e insolúvel potencialmente degradável da MS, a taxa de degradação da MS, as degradabilidades potencial e efetiva da MS, a fração indegradável da MS, o potencial máximo de produção de gases, a taxa de produção de gases e o tempo de colonização. A produção de gases aumentou tendendo a se estabilizar por volta de 48 horas e observou-se um maior desaparecimento da matéria seca entre o tempo zero e 24 horas de fermentação. Os valores de produção cumulativa de gases (PCG) dos fenos analisados tiveram uma produção máxima de 50 ml ao final das 96 horas de fermentação. O feno do terço superior da variedade Amarelinha, por apresentar melhores degradabilidade potencial (64,17%) e efetiva (55,65%) da matéria seca e maior potencial máximo de produção de gases (35,69 mL/g de MS), em relação às demais variedades, demonstra superioridade nutricional.

Cinética de fermentação in vitro de silagens da parte aérea de mandioca

Objetivou-se com esta pesquisa avaliar a cinética de fermentação ruminal das silagens de diferentes frações da parte aérea de variedades de mandioca, pela técnica semiautomática de produção de gases. O experimento foi conduzido em um delineamento inteiramente casualizado, com quatro repetições, arranjado em um esquema fatorial 4x3, sendo quatro variedades de mandioca (Amarelinha, Sabará, Olho roxo e Periquita) e três frações da parte aérea (terço superior, sobra de plantio e planta inteira). O material foi ensilado em silos experimentais de PVC, sendo abertos após 56 dias de fermentação. Amostras das silagens foram coletadas e submetidas à pré-secagem, moídas e em seguida procedeu-se ensaio de produção de gases in vitro. As leituras de pressão dos gases produzidos durante as fermentações foram realizadas às 0; 4; 6; 8; 10; 12; 15; 18; 21; 24; 30; 36; 48; 72 e 96 horas após o início das incubações. As leituras de pressão dos gases foram realizadas por intermédio de transdutor de pressão e, posteriormente ajustadas para o volume de gases. O maior desaparecimento ruminal da MS ocorreu nos tempos entre zero e 24 horas. As maiores produções de gases por hora foram obtidas aproximadamente às 48 horas de fermentação para a variedade Olho Roxo na fração planta inteira. As silagens das diferentes variedades e frações da parte aérea de mandioca apresentaram o mesmo potencial de produção de gases. Entretanto, as silagens da variedade Amarelinha nas frações da parte aérea terço superior e sobras de plantio apresentaram melhores degradabilidades efetiva e potencial.