Effect of timing of paddock allocation in tropical grass on performance, nitrogen excretion, and enteric methane emissions from dairy cows.

The objective of this study was to investigate the influence of timing of paddock allocation (AM or PM) in tropical grass on nutritive value of the herbage, dry matter intake (DMI), milk yield and composition, ruminal fermentation, nitrogen excretion, and enteric CH4 emissions of dairy cows. Twenty cows were grouped in pairs and randomly distributed within pair to one of two treatments. PM herbage had greater contents of dry matter (DM), soluble carbohydrates, starch, and nonfibrous carbohydrate to protein ratio and lower contents of neutral detergent fiber and acid detergent fiber. There was no treatment effect on DMI, N excretion, milk yield, and CH4 emissions. However, milk protein and casein yields tended to be greater for PM than AM, while milk urea nitrogen concentration was lower for PM than AM. The increase in nutritive value of the afternoon relative to the morning herbage within the framework of this study was not large enough to increase DMI and milk yield or to decrease CH4 emission intensity by the dairy cows as hypothesized. The findings indicate that PM treatment can be a simple and useful grazing strategy that results in an herbage harvest with greater nutritional value and in lower excretion of urea N into milk.

Fibrolytic enzymes improve the nutritive value of high-moisture corn for finishing bulls.

Exogenous fibrolytic enzymes (EFE) improve the energy availability of grains for nonruminant animals by reducing encapsulation of the endosperm nutrients within grain cell walls; however, these benefits are unknown in the treatment of corn-based silage for cattle. The objective of the present study was to evaluate the effects of adding EFE at ensiling on the nutritive value of high-moisture corn (HMC) and snaplage (SNAP) for finishing Nellore bulls. The EFE dose was 100 g/Mg fresh matter in both HMC and SNAP. Diets were 1) a SNAP + HMC control (without enzyme addition); 2) SNAP + HMC EFE (with enzymes); 3) a whole-plant corn silage (WPCS) + HMC control (without enzyme addition); and 4) WPCS + HMC EFE (with enzymes). In addition to the silages, the diets were also composed of soybean hulls, soybean meal, and mineral-vitamin supplement. The statistical design was a randomized complete block with a factorial arrangement of treatments, and the experiment lasted 122 d. For in situ and in vitro analyses, 2 cannulated dry cows were used. There was no interaction between the diets and EFE application (ADG, P = 0.92; DMI, P = 0.77; G:F, P = 0.70), and there was no difference between the SNAP and WPCS diets regarding the DMI (P = 0.53), ADG (P = 0.35), and feed efficiency (ADG:DMI, P = 0.83). Adding EFE to the HMC and SNAP at ensiling did not affect ADG but decreased DMI (P = 0.01), resulting in greater feed efficiency by 5.91% (P = 0.04) than that observed in animals fed diets without the addition of EFE. Addition of EFE to HMC resulted in reduced NDF content and increased in vitro and in situ DM digestibility compared with untreated HMC. No effects were found for the addition of EFE to SNAP. Fecal starch decreased with EFE application (P = 0.05). Therefore, the diet energy content (TDN, NEm, and NEg) calculated from animal performance increased (P = 0.01) with the addition of EFE to HMC. In conclusion, exchanging the NDF from WPCS with that from SNAP did not affect the performance of finishing cattle, whereas the addition of EFE to HMC at ensiling improved animal performance by increasing the energy availability of the grain.

Corn grain-processing method interacts with calcium salts of palm fatty acids supplementation on milk production and energy balance of early-lactation cows grazing tropical pasture.

The objective of our study was to investigate the associative effects of feeding Ca salts of palm fatty acids (FA) and corn grain-processing method on production, nutrient digestibility, energy balance, and carryover effects of early-lactation dairy cows grazing a tropical pasture. Treatment diets were offered from 3 to 16 wk postpartum (treatment period), in which all cows grazed elephant grass (Pennisetum purpureum L. Cameroon) and treatments were added to a concentrate supplement. Treatments were flint corn grain-processing method either as fine ground (FGC) or steam-flaked (SFC) associated with Ca salts of palm FA supplementation either not supplemented or supplemented (CSPO). From 17 to 40 wk postpartum (carryover period) all cows received a common diet fed as total mixed ration. During the treatment period, a tendency for an interaction between CSPO and corn grain-processing method were observed for milk yield, milk fat yield, and energy-corrected milk (ECM), as CSPO caused them to increased to a greater extent in the FGC diet compared with the SFC diet. Furthermore, a tendency for an interaction between CSPO and corn grain-processing method was observed for body weight change, because CSPO increased body weight loss in the FGC diet but not in the SFC diet. The CSPO increased milk yield, milk fat yield, 3.5% fat-corrected milk, ECM, and cumulative milk yield compared with not supplemented. Also, CSPO increased energy intake, milk energy output, and energy partitioning toward milk, whereas reduced energy was allocated to body reserves. The SFC increased milk yield, ECM, milk protein yield, milk casein yield, and cumulative milk yield, and decreased milk urea N compared with FGC. The SFC compared with FGC also increased body condition score and body weight change, and increased energy partitioning toward body reserves. During the carryover period, an interaction between CSPO and corn grain-processing method was observed for milk yield, which occurred because CSPO maintained higher milk yield in the FGC diet but not in the SFC diet. Therefore, in the carryover period, the additive effect between SFC and CSPO that occurred in the treatment period was not maintained throughout the carryover period. However, CSPO increased yields of milk fat, protein, casein as well as fat-corrected milk and ECM. In conclusion, corn grain-processing method interacts with CSPO supplementation on production responses and carryover effects of grazing cows. When CSPO was fed in the FGC diet, milk production increased to a greater extent than when fed in the SFC diet, but also caused greater mobilization of reserves at early lactation. This suggests an interaction between fat supplementation and corn grain-processing method on energy partitioning of dairy cows. Also, both supplementation with CSPO and SFC were effective strategies to increase energy intake and yields of milk and milk solids. The carryover effect on milk production was greater for CSPO supplementation than corn grain-processing method, whereas feeding SFC diets had lower mobilization of reserves and less body weight and body condition score variation throughout lactation.

Effect of sources of calcium salts of fatty acids on production, nutrient digestibility, energy balance, and carryover effects of early lactation grazing dairy cows.

The objective of our study was to investigate the effects of sources of calcium salts of fatty acids (FA) on production, nutrient digestibility, energy balance, and carryover effects of early lactation grazing dairy cows. Treatment diets were offered from 3 to 16 wk postpartum (the treatment period), in which all cows grazed elephantgrass (Pennisetum purpureum 'Cameroon') and treatments were added to a concentrate supplement. The treatments were (1) control (concentrate without supplemental fat); (2) concentrate with calcium salts of soybean FA (CSSO); and (3) concentrate with calcium salts of palm FA (CSPO). From 17 to 42 wk postpartum (the carryover period), all cows received a common diet fed as a total mixed ration. During the treatment period, CSPO increased milk yield, milk fat yield, 3.5% fat-corrected milk, energy-corrected milk, and cumulative milk yield compared with control and CSSO. Treatment CSSO increased the yield of milk but did not affect 3.5% fat-corrected milk or energy-corrected compared with control. Also, CSSO decreased milk fat yield, dry matter intake, neutral detergent fiber digestibility, and body weight and body condition loss. Compared with control, both CSSO and CSPO increased feed efficiency (3.5% fat-corrected milk:dry matter intake), and CSPO increased feed efficiency compared with CSSO. When considering energy partitioning (as % energy intake), CSPO increased energy partitioning toward milk and increased energy mobilized from body reserves compared with control and CSSO. Furthermore, CSSO tended to reduce the mobilization of energy from body reserves compared with control. In the carryover period, no differences in milk composition were observed among treatments. A treatment by time interaction was observed during the carryover period for milk yield because cows on CSPO maintained higher production compared with control and CSSO cows until 30 wk postpartum; CSSO had a lower carryover effect sustaining higher milk yield compared with control until 25 wk postpartum. In conclusion, supplementation with CSPO was an effective strategy to increase energy intake and yields of milk and milk solids and it had a greater carryover effect. Supplementation with CSSO resulted in lower mobilization of reserves and less variation in body weight and body condition throughout lactation.

Supplementation with Ca salts of soybean oil interacts with concentrate level in grazing dairy cows: intake, ingestive behavior, and ruminal parameters.

In this study, we investigated the associative effects of concentrate levels and Ca salts of soybean oil (CSSO) supplementation on performance and ruminal parameters of mid-lactation dairy cows grazing on tropical pasture. Twenty-four Jersey × Holstein cows were used in a randomized block design and assigned to four treatments arranged in a 2 × 2 factorial design. Factors evaluated were concentrate levels (low, 3 kg/day vs. high, 7 kg/day of concentrate) and CSSO supplementation (without CSSO vs. with 250 g CSSO cow/day). All cows grazed on elephant grass (Pennisetum purpureum cv. Cameroon) and received the supplemental treatments for a 90-day period. The high concentrate level decreased forage intake and grazing time. In addition, the high concentrate level increased rumen propionate concentration and microbial synthesis and tended to decrease ammonia-N compared with low concentrate level. The addition of CSSO tended to decrease valerate, isobutyrate, isovalerate, and microbial synthesis. In conclusion, feeding CSSO for mid lactating cows grazing on tropical pasture had negative effects on rumen function. In contrast, CSSO supplementation tended to interact with concentrate level and increased energy intake when fed at low concentrate level. Feeding the high level of concentrate was an effective strategy to increase energy intake and microbial synthesis and improve N utilization.

Supplementation with Ca salts of soybean oil interacts with concentrate level in grazing dairy cows: milk production and milk composition.

In this study, we investigated the associative effects of concentrate levels and Ca salts of soybean oil (CSSO) supplementation on milk production, milk composition, and milk fatty acids of mid-lactation dairy cows grazing on tropical pasture. Twenty-four Jersey × Holstein cows were used in a randomized block design and assigned to four treatments arranged in a 2 × 2 factorial design. Factors evaluated were concentrate levels (low, 3 kg/day vs. high, 7 kg/day of concentrate) and CSSO supplementation (without CSSO vs. with 250 g CSSO cow/day). All cows grazed on elephant grass (Pennisetum purpureum cv. Cameroon) and received the supplemental treatments for a 90-day period. Interactions between concentrate level and CSSO were detected for milk yield, milk yield components, energy-corrected milk (ECM) and 3.5 % fat-corrected milk (FCM). Milk yield increased when CSSO was fed in a low concentrate level, while it decreased milk production in a high concentrate level. Yields of fat, protein, lactose, 3.5 % FCM, and ECM were not affected with CSSO in the low concentrate, but reduced in the high concentrate level. CSSO increased proportions of monounsaturated milk FA, C18:2 trans-10 cis-12, and polyunsaturated FA, and reduced proportions of saturated milk FA in milk. In conclusion, feeding the high level of concentrate was an effective strategy to improve milk yield and solid production. CSSO supplementation increased milk production when fed at low concentrate level but did not affect yield of solids.

Replacing soybean meal for cottonseed meal on performance of lactating dairy cows.

Cottonseed meal (CSM) is an alternative source of protein, and previous studies have been shown that it can replace soybean meal (SBM) without decrease animal performance. However, Brazilian CSM has a different chemical composition compared with the usual CSM reported in the literature. The objective of this experiment was to evaluate the effects of replacing SBM for Brazilian CSM on performance and energy balance of mid-lactating dairy cows. Forty-two Holstein cows were used in a replicate 3 × 3 Latin square design. Increasing contents of CSM (0, 15, and 30% of dry matter (DM)) were fed in diets to replace SBM. Milk yield and feed efficiency were linearly reduced with the replacement of CSM for SBM (P = 0.001). Milk fat content tended to increase quadratically (P = 0.07) with CSM addition. Replacing SBM for CSM affected milk protein content quadratically (P = 0.05). Milk urea nitrogen and plasma urea nitrogen (PUN) tended to respond quadratically (P = 0.06 and 0.10) when CSM replaced SBM to the diets. Variation in body weight (BW) also responded quadratically as CSM replaced SBM (P = 0.05). Altogether, the findings suggest better performance when cows receive SBM diet compared with the Brazilian CSM diet.

Replacing soybean meal for wet brewer's grains or urea on the performance of lactating dairy cows.

The purpose of this research was to evaluate the partial replacement of soybean meal (SBM) for wet brewer's grains (WBG) or urea on the performance of lactating dairy cows. The second investigated whether WBG ensiled with corn kept animal performance in low- and high-producing dairy cows compared with WBG. In experiment I, 40 Holstein cows were used in 4 × 4 Latin square design. The treatments comprised WBG or urea as partial replacement for SBM, as follows: control (diet based on SBM and 1 % of urea), 10 % of WBG, 20 % of WBG, and 2 % of urea. Dry matter intake (DMI) was not affected by treatments. WBG increased milk yield linearly, but it decreased with urea. Milk fat content responded quadratically to WBG levels. Milk protein content decreased, while plasma urea nitrogen increased with high urea addition. In experiment II, 42 Holstein cows were divided into two groups according to production levels. Eighteen cows composed the group of low producing, while the high-producing group comprised 24 cows. The experimental design was a crossover with two periods of 14 days. The experimental treatments consisted of feeding WBG or WBG ensiled with ground corn. Regardless of the production level, no difference in milk yield and milk composition between treatments was observed.

Starch levels on performance, milk composition and energy balance of lactating dairy cows.

The objective of this experiment was to evaluate the effects of starch levels in diets with the replacement of citrus pulp for corn on milk yield, milk composition, and energy balance of lactating dairy cows. Twenty-eight multiparous Holstein cows were used in seven 4 × 4 Latin squares conducted concurrently, and each experimental period consisted of 20 days (16 days for adaptation and 4 days for sampling). The experimental treatments comprised four starch levels: 15, 20, 25, and 30% in the diet. The dry matter intake increased linearly with increasing starch levels. The milk yield and 3.5% fat-corrected milk yield showed quadratic response to increasing starch levels. The milk protein content and milk total solids content responded linearly to increasing starch levels. The feed efficiency, milk lactose content, milk urea nitrogen, plasma urea nitrogen, and plasma glucose concentration were not affected by starch levels. The estimated net energy for lactation (NEL) intake increased linearly as the starch level was raised. Although the milk NEL output per kilogram of milk was not affected by starch, the milk NEL output daily responded quadratically to starch levels. In addition, the NEL in body weight gain also responded quadratically to increasing starch levels. The efficiency of energy use for milk yield and the NEL efficiency for production also responded quadratically to increasing starch levels. Diets for mid-lactating dairy cows producing around 30 kg/day of milk should be formulated to provide around 25% starch to optimize performance.

Steers performance in dwarf elephant grass pastures alone or mixed with Arachis pintoi.

The inclusion of legumes in pasture reduces the need for mineral nitrogen applications and the pollution of groundwater; however, the agronomic and animal husbandry advantages with tropical legumes are still little known. The objective of this study was to quantify the effect of the use of forage peanut (Arachis pintoi cv. Amarillo) in dwarf elephant grass pastures (Pennisetum purpureum cv. BRS Kurumi) on forage intake and animal performance. The experimental treatments were dwarf elephant grass fertilized with 200 kg N/ha, and dwarf elephant grass mixed with forage peanut without mineral fertilizers. The animals used for the experiment were 12 Charolais steers (body weight (BW) = 288 ± 5.2 kg) divided into four lots (two per treatment). Pastures were managed under intermittent stocking with an herbage allowance of 5.4 kg dry matter of green leaves/100 kg BW. Dry matter intake (mean = 2.44% BW), the average daily gain (mean = 0.76 kg), and the stocking rate (mean = 3.8 AU/ha) were similar between the studied pastures, but decreased drastically in last grazing cycle with the same herbage allowance. The presence of peanut in dwarf elephant grass pastures was enough to sustain the stocking rate, but did not allow increasing forage intake and animal performance.