Kleber da Cunha Peixoto Júnior

Concentrações de nitrogênio na dieta, no sangue e no leite de vacas lactantes no período pós-parto

Twenty-four lactating dairy cows were assigned to a completely randomized block design to compare the effects of isoenergetic diets but different crude protein (CP) levels: P100- 100%, P133- 133% or P166- 166% of the NRC (1989) requirements on the concentrations of urea nitrogen in plasma (PUN) and milk (MUN). Increasing levels of CP were obtained by adding urea to the diet. Feeds, milk, and blood were all collected weekly from 30 days before to 60 days after parturition. Milk yield and body weigh were also registered weekly in this trial. Milk yield averaged 12.4, 13.3, and 13.4 kg/d, respectively, on P100, P133, and P166 treatments and increased linearly with the incremental levels of urea in the diet. Concentrations of PUN and MUN also increased linearly when rumen-degradable protein (RDP) was increased in the diet resulting, respectively, in the following equations: Y= 16.83 + 0.202 X and Y= 13.73 + 0.219 X. A highly significant correlation coefficient (r= 0.603) between PUN and MUN was observed in this study. It can be concluded that PUN and MUN are useful indicators of dietary RDP levels and that higher contents of dietary nitrogen improved milk yield.

Effects of Microbial Inoculants on Chemical Composition and Fermentation Characteristics of Sunflower Silage Produced in Experimental Silos

Sunflower (20.0% DM and 10.0% CP) was ensiled in 16 plastic experimental silos, forming four treatments: control, Sil-All (S. faecium, P. acidilactici, L. plantarum, amylase, hemicellulase, and cellulase), Silobac (L. plantarum, S. faecium, and Lactobacillus sp.), and Pioneer 1174 (S. faecium and L. plantarum). Silos were opened 125 days after ensiling and sampled to proceed chemical analyses. Pioneer increased soluble carbohydrates, ethylic alcohol concentration, and buffering capacity. This inoculant decreased pH, ammonia, and acetic acid concentration compared to control. Pioneer also increased starch content compared to control, but Sil-All decreased. The DM, CP, ADIN, NDF, ADF, and lignin contents, In vitro digestibility of the DM, DM losses, aerobic stability, propionic, butyric and lactic acids did not suffer influence of treatments.Sunflower (20.0% DM and 10.0% CP) was ensiled in 16 plastic experimental silos, forming four treatments: control, Sil-All (S. faecium, P. acidilactici, L. plantarum, amylase, hemicellulase, and cellulase), Silobac (L. plantarum, S. faecium, and Lactobacillus sp.), and Pioneer 1174 (S. faecium and L. plantarum). Silos were opened 125 days after ensiling and sampled to proceed chemical analyses. Pioneer increased soluble carbohydrates, ethylic alcohol concentration, and buffering capacity. This inoculant decreased pH, ammonia, and acetic acid concentration compared to control. Pioneer also increased starch content compared to control, but Sil-All decreased. The DM, CP, ADIN, NDF, ADF, and lignin contents, In vitro digestibility of the DM, DM losses, aerobic stability, propionic, butyric and lactic acids did not suffer influence of treatments.

Avaliação da monensina administrada pela forma convencional ou por dispositivo de liberação lenta (bólus) em bovinos alimentados com forragens de baixo valor nutritivo e suplementados ou não com uréia

The objectives of this study were to evaluate the effects of sodium monensin supplied as a conventional form or as a controlled release capsule (bolus) on ruminal fermentation profile of bovine fed low nutritive value forage, supplemented or not with non-protein nitrogen. Twelve rumen-fistulated cows (736 kg of BW) were allocated in blocks, in function of body weight, using two successive 28-day periods (24 experimental units). The treatments were arranged as a factorial 3 x 2, where two forms of monensin administration (conventional or controlled release capsule), at doses of 300 mg/anim.day, were compared to the control, in combination with the supplementation or not with urea (20g/100kg BW). The low nutritive value hay (Tifton 85) was the only feed offered. Ruminal fluid was sampled on the 28th day at 0, 2, 4, 6 and 8 hours after first meal and the hay was incubated for 0, 6, 12, 24, 48, 72, and 96 hours, between the 24th and 27th day, for evaluation of in situ degradability. The only effect caused by urea administration was the increase in ruminal ammonia nitrogen concentration. Regardless on the urea supplementation, the conventional and bolus forms of monensin decreased respectively the dry matter intake in 25.4% and 27.8%, the effective degradability of hay NDF from 17.4 to 34.4% and from 11.9 to 12.7%, depending on the ruminal passage rate used, and increased the molar proportion of propionic acid in 60.2 and 42.7%, when compared to the control. However, they did not alter pH, total VFA or ammonia concentrations. Based on ruminal acetate/propionate ratio, bolus treatment showed an efficiency of 77%, when compared to conventional treatment, corresponding to liberation of 232 mg of sodium monensin/anim.day.

Efeitos de níveis e períodos de adaptação à lasalocida sódica sobre os parâmetros de fermentação ruminal

Effects of adaptation periods to sodium lasalocid and its ionophorum levels were evaluated on ruminal fermentation, using four Holstein-Zebu cross-breed cows. Latin square was the experimental design used, with four periods of six weeks, in which isolated data from the first, second, third and fourth weeks were used to evaluate periods of adaptation, and the last two destined to eliminate residual effects. Treatments were no supplementation and supplementation with 50, 100 and 200 mg of sodium lasalocid/ head/day, and rumen vollaty fatty acid acetic, propionic and butiric, pH, ammonia, liquid turnover and flow rate were measured every week. There were no differences in results for levels or periods of adaptation, and considering these results, it is not recommended the use of sodium lasalocid to modify ruminal fermentation parameters in cattle.

Balanço de nitrogênio e composição do leite de vacas alimentadas com ureia e farelo de soja e dois teores de proteína em dietas com cana-de-açúcar

Braz. J. Vet. Res. Anim. Sci., São Paulo, v. 51, n. 3, p. 242-251, 2014 Abstract It was evaluated the effect of feeding two levels of crude protein (CP) (low: 142 g CP/kg DM; and high: 156 g CP/kg DM) and two nitrogen sources (soybean meal and urea) to dairy cows using sugar cane as forage on microbial protein synthesis, the composition of the milk nitrogen fraction, nitrogen (N) balance and blood parameters. Twelve Holstein cows with an average milk yield of 22.0 ± 2.3 kg/day, and with 235 ± 40 days in milk were included in this study. The animals were grouped into three balanced and contemporary 4x4 Latin squares for an experimental period of 21 days. On the 15th day of each period, milk and urine samples were collected for microbial protein synthesis determination. Total excretion of urine (L/day), milk urea nitrogen (MUN) and blood urea were higher for the diets with high CP, regardless of the nitrogen source. Nitrogen efficiency was higher for cows fed diets with low CP. Cows in the final third of lactation can be fed diets with reduced CP levels, regardless of the nitrogen source, soybean meal or urea, without influencing the synthesis of microbial protein or the composition of the nitrogen fraction of milk.

Desempenho de bezerros da raça Holandesa alimentados com proteína de soja sólida ou líquida

Avaliaram-se os efeitos da substituicao de metade do total de proteina da dieta na forma solida (farelo de soja) por proteina na forma liquida (leite de soja), com relacoes solidos:liquidos de 100,0:0%; 87,5:12,5%; e 75,0:25,0%. Utilizaram-se 24 bezerros machos da raca Holandesa com 60 dias de idade, distribuidos em delineamento em blocos ao acaso, com tres dietas a base de concentrado (80%) e feno de capim coast-cross (Cynodon dactylon) (20%), balanceadas para nitrogenio e energia. Nas dietas com partes liquidas, o intuito foi manter o reflexo de formacao da goteira esofagiana no periodo experimental de 10 meses, no qual os animais foram mantidos em confinamento, sendo abatidos ao atingirem pesos corporais superiores a 400 kg. Em alguns dos animais, dotados de cânulas de rumen, foi possivel detectar neste orgao apenas pequenas quantidades do leite de soja ingerido, confirmando sucesso na formacao da goteira esofagiana. Os ganhos de peso diarios apresentaram reducao linear (1,399; 1,341; e 1,191 kg) a medida que foram fornecidas maiores quantidades de leite de soja. As conversoes de materia seca e proteina bruta em ganhos de peso, durante os ultimos 60 dias experimentais, pioraram conforme aumentaram as quantidades de proteina na forma liquida. O fornecimento de proteina na forma liquida na dieta nao altera os rendimentos de carcaca em bezerros holandeses.