Effect of thyme essential oil on rumen parameters, nutrient digestibility, and nitrogen balance in wethers fed high concentrate diets / Efeito do óleo essencial de tomilho sobre os parâmetros ruminais, a digestibilidade dos nutrientes e o balanço de nitrogênio em borregos alimentados com elevado teor de concentrado

This trial aimed to evaluate the effects of thyme essential oils (EO) on rumen parameters, nutrient digestibility and nitrogen balance in wethers fed with high-concentrate diet. Twenty rumen-cannulated wethers were blocked according to body weight (BW= 64.0±2.1kg), and received one of the following treatments: 25mg of monensin/kg of dry matter (DM; MON) or doses of thyme EO (1.25, 2.50 or 3.75g/kg of DM). The diet was composed of 90% concentrate. Thyme EO was composed mainly by thymol (46.6% of DM) and p-cymene (38.9% of DM). The nutrient intake and apparent digestibility were similar among treatments. The inclusion of 3.75g of thyme EO tended (P= 0.07) to increase butyrate compared to MON and 1.25OE and wethers fed with 1.25g of thyme EO tended (P= 0.07) to decrease ruminal pH on the 14th day compared to MON. The treatments did not affect acetate:propionate ratio, total short chain fatty acids (SCFA) and nitrogen retention. Results from this study suggest that adding thyme EO to high-concentrate diets may be used as an alternative to monensin as feed additive in feedlot lambs.(AU)

O objetivo do estudo foi avaliar os efeitos do óleo essencial (OE) de tomilho nos parâmetros ruminais, na digestibilidade e no balanço de nitrogênio em borregos alimentados com elevado teor de concentrado. Vinte borregos providos de cânulas ruminais foram blocados de acordo com o peso corporal (PC=64,0±2,1kg) e receberam um dos tratamentos: 25mg de monensina/kg de matéria seca (MS; MON) ou doses de OE de tomilho (1,25; 2,50 ou 3,75g/kg de MS). A dieta foi composta por 90% de concentrado. A composição do OE de tomilho foi principalmente timol (46,6% da MS) e p-cimeno (38,9% da MS). A ingestão e a digestibilidade dos nutrientes foram semelhantes entre os tratamentos. A inclusão de 3,75g de OE de tomilho tendeu (P=0,07) a aumentar o butirato em relação aos tratamentos MON e 1,25OE. Os borregos alimentados com 1,25g de OE tenderam (P=0,07) a apresentar menor pH ruminal no 14º dia comparado a MON. No entanto, os tratamentos não afetaram a relação acetato:propionato, concentração total de ácidos graxos de cadeia curta e retenção de nitrogênio. Os resultados sugerem que a adição de OE de tomilho em dietas com elevado teor de concentrado pode ser uma alternativa à monensina como aditivo alimentar para cordeiros em confinamento.(AU)

Thyme essential oil for sheep: effect on rumen fermentation, nutrient digestibility, nitrogen metabolism, and growth / Óleo essencial de tomilho para ovinos: efeito na fermentação ruminal, na digestibilidade dos nutrientes, no metabolismo de nitrogênio e no crescimento

Two experiments were conducted to evaluate the effect of thyme (Thymus vulgaris) essential oil (EO) doses on rumen fermentation, nutrient digestibility, and nitrogen metabolism, as well as performance and coccidia oocyst discharge. In experiment I, 20 rumen-cannulated wethers received the experimental diets containing 80% dry matter (DM) of haylage and 20% DM of concentrate. Treatments were 25mg of monensin/kg DM or doses of 1.25, 2.50, or 3.75g of thyme EO/kg DM. In experiment II, 50 ewe lambs received the same diets from experiment I, including a diet without feed additives. Wethers fed with diets containing 1.25g/kg DM of thyme EO had higher molar proportion of propionate (P= 0.03) and butyrate (P< 0.01), and lower (P= 0.04) acetate to propionate ratio than other treatments. Adding thyme EO to diets increased (P= 0.02) nitrogen retention compared to monensin. The performance of ewe lambs was not affected (P≥ 0.05) by treatments. However, lambs fed monensin had a lower (P= 0.04) number of coccidia oocyst discharge than others. Adding 1.25g/kg DM of thyme EO in high-forage diet improved ruminal fermentation. Thyme EO enhanced nitrogen metabolism, however, it did not improve performance.(AU)

Dois experimentos foram conduzidos para avaliar o efeito de doses de óleo essencial (OE) de tomilho (Thymus vulgaris) sobre a fermentação ruminal, a digestibilidade de nutrientes e o metabolismo de nitrogênio, bem como sobre o desempenho e a descarga de oocistos de coccídeos. No experimento I, 20 ovinos canulados receberam dietas experimentais contendo 80% de matéria seca (MS) de pré-secado e 20% de MS de concentrado. Os tratamentos foram 25mg de monensina/kg de MS ou doses de 1,25, 2,50 ou 3,75g de OE de tomilho/kg de MS. No experimento II, 50 borregas receberam as mesmas dietas do experimento I, incluindo uma dieta sem aditivos. Os animais alimentados com dietas contendo 1,25g de OE de tomilho apresentaram maior proporção molar de propionato (P=0,03) e de butirato (P<0,01) e menor (P=0,04) relação acetato/propionato do que outros tratamentos. A adição de OE de tomilho nas dietas aumentou (P=0,02) a retenção de nitrogênio em comparação com a monensina. O desempenho de cordeiros não foi afetado (P≥0,05) pelos tratamentos. No entanto, cordeiros alimentados com monensina apresentaram menor (P=0,04) número de oocistos de coccídeos. A adição de 1,25g/kg de MS de OE de tomilho na dieta forrageira melhorou o perfil da fermentação ruminal. O OE de tomilho aumentou a retenção de nitrogênio, no entanto não melhorou o desempenho.(AU)

Crude glycerin decreases nonesterified fatty acid concentration in ewes during late gestation and early lactation.

Crude glycerin is a gluconeogenic substrate in ruminants and may help to decrease the occurrence of pregnancy toxemia. The objective in this trial was to determine the effects of feeding a diet containing crude glycerin on DMI, milk yield, milk composition, and blood metabolites in periparturient ewes and lamb performance. One hundred eighteen 90 (±1.1)-d pregnant Santa Inês ewes were used. After lambing, 32 ewes (62.8 ± 1.3 kg BW) were allotted in a randomized complete block design defined by prelambing diet, BW, BCS, lambing date, type of birth (single or twin), and sex of offspring. Diets were isonitrogenous (13.0 ± 0.3% CP, DM basis), composed of concentrate and raw sugarcane bagasse (70:30 ratio, DM basis), and fed ad libitum daily. Crude glycerin (83.6% glycerol) levels were 0 or 10% (DM basis), corresponding to the experimental diets G0 and G10, respectively. From 8 until 56 d of lactation, DMI was determined. In the same period, once a week at 1000 h, the ewes were separated from the lambs and mechanically milked after intravenous administration of 10 IU of synthetic oxytocin. Three hours after the first milking, ewes were milked again and milk yield and composition were determined. Glucose, NEFA, and ß-hydroxybutyrate (BHBA) were determined at -14, -7, 0, 7, 14, 28, and 56 d relative to lambing and insulin was determined at -14, -7, 0, and 7 d. Crude glycerin did not affect DMI (2.2 kg/d for G0 vs. 2.2 kg/d for G10; = 0.93) or milk production (171 g/3 h for G0 vs. 164 g/3 h for G10; = 0.66). However, there was a decrease ( = 0.01) in milk fat percentage (8.1% for G0 vs. 7.0% for G10) for ewes fed glycerin. Ewes fed the G10 diet had decreased ( < 0.01) NEFA concentration (0.27 mmol/L for G0 vs. 0.18 mmol/L for G10). There was an interaction between diet × time for glucose ( = 0.04), insulin ( = 0.05), and BHBA ( = 0.01); feeding glycerin increased glucose (5.61 mmol/L for G0 vs. 7.42 mmol/L for G10; < 0.01) and insulin concentrations (10.5 µIU for G0 vs. 24.5 µIU for G10; < 0.01) at parturition compared with G0. The BHBA was less ( = 0.02) on the day of lambing (0.40 mmol/L for G0 vs. 0.29 mmol/L for G10) and it was greater ( < 0.01) on d 56 for ewes fed the G10 diet (0.46 mmol/L for G0 vs. 0.61 mmol/L for G10). There was no effect of diets fed to ewes on lamb growth from birth to weaning. Crude glycerin improved energy balance of periparturient ewes, suggesting a reduced risk of developing clinical metabolic-related disorders. Crude glycerin can be added at 10% of ewes' diets without affecting DMI and milk yield.

Investigation of mechanisms involved in regulation of progesterone catabolism using an overfed versus underfed ewe-lamb model.

Alterations in progesterone (P4) catabolism due to high feed intake underlie some effects of nutrition on reproduction. Based on previous research, we hypothesized that high feed intake could potentially increase P4 catabolism, likely due to increased liver blood flow. However, there could also be an opposing action due to increased circulating insulin, which has been shown to inhibit hepatic expression of key enzymes involved in P4 catabolism. To test which effect would have the greatest impact on circulating P4 during a 1- and 2 -mo time frame, we used a noncyclic ewe model. The plane of nutrition was controlled, and effects on circulating insulin, P4 catabolism in response to exogenous P4, and steady state mRNA for key hepatic enzymes were evaluated. Twenty-four F Dorper × Santa Inês ewe lambs (5 mo old and approximately 25 kg BW) were used. After 14 d of adaptation, ewes were randomized into 2 groups: ad libitum fed (Ad), with intake of 3.8% DM/kg BW, or restricted feed intake (R), with 2% DM/kg BW, for 8 wk. At wk 4 and 8, ewes received an intravaginal P4 implant to evaluate P4 catabolism. As designed, Ad ewes had greater daily feed intake than R ewes (means of 1.8 [SE 0.03] and 0.6 kg/ewe [SE 0.01]; < 0.001) and greater weekly gain in BW (means of 1.7 [SE 0.12] vs. -0.1 kg/ewe [SE 0.03]; < 0.001). Mean circulating insulin of samples collected from -0.5 to 7 h after the start of feeding was over 5-fold greater in Ad ewes than in R ewes (least squares means of 8.2 [SE 0.93] vs. 1.5 µIU/mL [SE 0.16], respectively, at wk 4 and 12.0 [SE 1.02] vs. 2.2 µIU/mL [SE 0.18], respectively, at wk 8; < 0.001). Although both groups received the same P4 treatment, mean circulating P4 of samples collected from -0.5 to 7 h after feeding was much lower in Ad ewes than in R ewes (least squares means of 3.2 [SE 0.32] vs. 5.5 ng/mL [SE 0.32], respectively, at wk 4 and 2.8 [SE 0.28] vs. 5.2 ng/mL [SE 0.28], respectively, at wk 8; < 0.001) indicating much greater P4 catabolism in ewes with high feed intake. Unexpectedly, there was no effect of diet on hepatic mRNA concentrations for , , , or at wk 4 or 8 in spite of dramatically elevated insulin. Therefore, high energy/feed intake primarily increased P4 catabolism with no evidence for offsetting effects due to insulin-induced changes in hepatic P4 metabolizing enzymes.

Associação entre o óleo de soja e o óleo de peixe na dieta de cabras em lactação como estratégia para melhorar o perfil de ácidos graxos do leite / Association between soybean oil and fish oil in the diet of lactating goats as a strategy to improve milk fatty acids profile

Os objetivos neste experimento foram avaliar os efeitos da associação entre o óleo de soja e o óleo de peixe na dieta de cabras em lactação sobre o consumo de matéria seca e de nutrientes, a variação do peso corporal, a produção e composição do leite, assim como o perfil de ácidos graxos. As cabras foram alocadas em baias individuais, onde receberam dieta composta por 50% de feno de "coastcross" e 50% de concentrado. Foram utilizadas nove cabras mestiças Boer x Saanen multíparas, distribuídas em três quadrados latinos 3 X 3. O experimento teve duração de 51 dias, divididos em três períodos de 17 dias, sendo os 13 primeiros dias para adaptação dos animais às dietas e os 4 dias subsequentes para colheita de amostras e de dados. Os tratamentos experimentais foram: a) dieta controle (CT), sem adição de óleo; b) dieta contendo 3% de óleo de soja (OS); e c) dieta contendo 2,5% de óleo de soja + 0,5% de óleo de peixe (OS+P). A inclusão dos óleos reduziu (P<0,05) o consumo de matéria seca, no entanto aumentou (P<0,05) a eficiência alimentar dos animais, sem afetar (P>0,05) a produção de leite. Houve efeito (P<0,05) da dieta no perfil de ácidos graxos do leite, sendo que ambos os tratamentos com adição de óleo elevaram as concentrações de ácidos graxos de cadeia média e longa, reduzindo os de cadeia curta. O tratamento com a combinação do óleo de soja com o óleo de peixe foi o que promoveu os maiores aumentos na concentração de ácido vacênico (398%), rumênico (352%) e de CLA total (341%) no leite. Os resultados permitem concluir que a suplementação lipídica elevou a eficiência alimentar dos animais e que o fornecimento de óleo de soja em combinação ao óleo de peixe aumentou a concentração no leite dos ácidos graxos benéficos à saúde humana.

The aims in this experiment were to determine the effects of the association between soybean and fish oils on dry matter intake (DMI) and nutrient intake, body weight change, milk production and composition and milk fatty acid profile of dairy goats. The animals were housed in tie stalls and fed a 50% of coastcross hay and 50% concentrate diet. Nine multiparous crossbred Boer x Saanen goats were assigned in tree 3 X 3 Latin Squares. The experimental period lasted 51 days; divided into three periods of 17 days, being the first nine days used to adapt goats to diets and the 4 other days for data collection. Experimental diets were: a) control diet (CT) without oil; b) control diet supplemented with 3% of soybean oil (SO); and c) control diet supplemented with 2.5% of soybean oil plus 0.5% of fish oil (SO+F). DMI was negatively influenced by oil addition. However, feed efficiency was higher in diets with oils, maintaining similar milk production (P>0.05 for all comparisons). The supply of oils changed milk fatty acids profile (P<0.05), increasing the concentrations of medium and long-chain fatty acids and reducing short-chain. Milk from goats fed the SO+F diet had higher concentration of vaccenic (398%), rumenic acid (352%) and total CLA (341%). The results indicate that the oil supply increased the feed efficiency of goats, and that the combination of soybean and fish oils caused a higher elevation of fatty acids considered to have health benefits.

Energy efficiency of growing ram lambs fed concentrate-based diets with different roughage sources.

Poor-quality roughages are widely used as fiber sources in concentrate-based diets for ruminants. Because roughage quality is associated with the efficiency of energy use in forage-based diets, the objective of this study was to determine whether differing the roughage source in concentrate-based diets could change the energy requirements of growing lambs. Eighty-four 1/2 Dorper × 1/2 Santa Inês ram lambs (18.0 ± 3.3 kg BW) were individually penned and divided into 2 groups according to primary source of dietary roughage: low-quality roughage (LQR; sugarcane bagasse) or medium-quality roughage (MQR; coastcross hay). Diets were formulated to be isonitrogenous (2.6% N) and to meet 20% of physically effective NDF. After a 10-d ad libitum adaptation period, 7 lambs from each group were randomly selected and slaughtered (baseline). Twenty-one lambs in each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg BW. The remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction: 70% or 50% of the ad libitum intake. Retentions of body fat, N, and energy were determined. Additionally, 6 ram lambs (44.3 ± 5.6 kg BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to establish the ME content of the 2 diets at the 3 levels of DM intake. There was no effect of intake level on diet ME content, but it was greater in the diet with LQR than in the diet with MQR (3.18 vs. 2.94 Mcal/kg, respectively; P < 0.01). Lambs fed the diet with LQR had greater body fat (g/kg of empty BW) and energy concentrations (kcal/kg of empty BW) because of a larger visceral fat deposition (P < 0.05). Using a low-quality roughage as a primary source of forage in a concentrate-based diet for growing lambs did not change NEm and the efficiency of ME use for maintenance, which averaged 71.6 kcal/kg(0.75) of shrunk BW and 0.63, respectively. On the other hand, the greater nonfibrous carbohydrate content of the diet with LQR resulted in a 17% better efficiency of ME use for gain (P < 0.01), which was associated with a greater partial efficiency of energy retention as fat (P < 0.01). This increased nutritional efficiency, however, should be viewed with caution because it is related to visceral fat deposition, a nonedible tissue.

Apparent digestibility, nitrogen balance, and ruminal constituents in ram lambs fed high-concentrate diets containing soybean hulls.

Corn often constitutes the main portion of high-concentrate diets fed to feedlot lambs. However, soybean hulls (SH) may be used to replace corn, and may reduce feed costs and the risk of acidosis. The objective of this experiment was to determine the effect of SH inclusion rate in high-concentrate diets on DMI, apparent digestibility of nutrients, N balance, and some rumen constituents. Sixteen ruminally fistulated Santa Inês ram lambs (44.3 ± 5 kg of BW and 6 mo old) were housed in suspended metabolism crates. A randomized complete block design experiment with 4 diets and 4 blocks was used. Blocks were defined by BW, and diets were allotted randomly within block. The control diet contained 70% corn and 0% SH. In the remaining diets, SH replaced corn at the rate of 15, 30, or 45% of the original corn concentration, which resulted in 0, 10.5, 21.0, and 31.4% of SH in the dietary DM. The DMI (kg/d) increased linearly (P < 0.01) with increasing dietary SH inclusion. A trend was observed for linear decreases (P = 0.10) in apparent DM, OM, and nonfiber carbohydrate digestibility, and a trend was observed for an increase (P = 0.08) in NDF digestibility with increasing dietary SH addition. Apparent digestibilities of CP and ether extract and ADF digestibility were not affected by SH inclusion rate. Total ruminal concentration of short-chain fatty acids was affected quadratically (P = 0.03) by diet; acetate concentration increased linearly (P < 0.01), whereas quadratic effects were observed on propionate concentration (P = 0.03) and acetate-to-propionate ratio (P < 0.01) with increasing dietary SH. Ruminal pH increased linearly (P < 0.01) as corn was replaced by SH. Nitrogen retention was not affected by the addition of SH, in spite of a linear increase in urinary N (P < 0.01). The replacement of corn grain with up to 45% SH (31.4% of SH in the dietary DM) resulted in a trend to decrease apparent digestibility of DM and to increase NDF digestibility, presenting a fermentation pattern that would reduce the risk of acidosis.

Growth, feed intake, carcass characteristics, and eating behavior of feedlot lambs fed high-concentrate diets containing soybean hulls.

The objectives of this experiment were to determine the effects of replacing ground corn with soybean hulls (SH) in high-concentrate diets on the growth (56-d period), carcass characteristics, and eating behavior of feedlot lambs. Sixty-four Santa Inês ram lambs (18.3 ± 2.8 kg of BW and 69 ± 5 d of age) were assigned to a randomized complete block design experiment with 8 blocks and 4 diets. The control diet contained 10% coastcross (Cynodon sp.) hay, 70% corn, and no SH (SH0) in the dietary DM. In the remaining diets, SH replaced corn at the rate of 15 (SH15), 30 (SH30), or 45% (SH45) of the original corn concentration, resulting in 0, 10.5, 21.0, or 31.4% SH in the dietary DM. Dry matter intake increased linearly (P < 0.01) when SH replaced ground corn (1.0, 1.0, 1.1, and 1.1 kg/d for SH0, SH15, SH30, and SH45, respectively). There was no effect on ADG of lambs, with values of 276, 278, 282, and 287 g for SH0, SH15, SH30, and SH45, respectively. Feed efficiency decreased linearly (P < 0.01) with SH inclusion. Carcass measures were not affected by SH as a replacement for ground corn. Eating time, expressed as minutes per day and minutes per gram of NDF, showed a quadratic effect (P < 0.05), whereas no effect was observed when expressed as minutes per gram of DM. Rumination, in minutes per day, was not influenced by dietary SH inclusion, but a linear decrease (P < 0.01) was observed when this variable was expressed as minutes per gram of NDF. Soybean hulls can replace up to 45% of the ground corn (31.4% of SH in the dietary DM) in high-concentrate diets fed to feedlot lambs without negative effects on ADG and carcass measures. The linear decrease in feed efficiency (11.6% reduction from SH0 to SH45) suggests that optimal dietary SH inclusion rates should be dictated by the relative costs of SH and corn.

Winter-feeding systems for gestating sheep II. Effects on feedlot performance, glucose tolerance, and carcass composition of lamb progeny.

Mature pregnant crossbred ewes (n = 90) were used in a randomized complete block design experiment and were assigned to 1 of 3 winter-feeding systems differing in primary feed source: haylage (HL), limit-fed corn (CN), or limit-fed dried distillers grains (DDGS). Effects of these winter-feeding strategies on postweaning progeny performance were determined. Lamb progeny (n = 96) were weaned at 61 ± 4 d of age and fed a common high-concentrate diet. Lambs were assigned to feedlot pen (n = 18) based on dam mid-gestation pen. Growth rate, DMI, and ADG were determined for the first 40 d of the finishing period. At 96 ± 4 d of age, 1 wether lamb was randomly selected from each pen (n = 18) for a glucose tolerance test. The experiment was terminated, and lambs were slaughtered individually when they were determined to have achieved 0.6-cm 12th-rib fat thickness. After a 24-h chill, carcass data were collected and a 2.54-cm chop was removed from each lamb from the LM posterior to the 12th rib for ether extract analysis. Additional carcass measurements of bone, muscle, and fat from the shoulder, rack, loin, and leg were collected on 35 carcasses. At weaning, lamb BW was not different among treatments, whereas final BW tended to be greater (P = 0.09) for lambs from ewes fed DDGS and CN during gestation than from those fed HL. Overall lamb growth rate from birth to slaughter was not different among treatments. Lambs from ewes fed DDGS vs. CN or HL tended to have a greater initial insulin response (P = 0.09). Dressing percent was less (P = 0.04) in lambs from ewes fed DDGS, but no difference (P = 0.16) was detected in HCW among treatments. As expected, 12th rib fat thickness was similar among treatments, whereas LM area was largest to smallest (P = 0.05) in lambs from ewes fed CN, HL, and DDGS, respectively. Proportion of internal fat tended to be greatest to smallest (P = 0.06) in lambs from ewes fed DDGS, CN, and HL, respectively. Calculated boneless trimmed retail cuts percentage was less (P = 0.04) in lambs from ewes fed DDGS than CN or HL. Loin muscle weight as a percentage of wholesale cut tended (P = 0.10) to be greater in lambs from ewes fed CN and HL than DDGS, whereas other muscle, bone, and fat weights and proportions were similar (P > 0.24) among treatments. Prepartum diet during mid to late gestation of ewes altered postnatal fat and muscle deposition and may be associated with alterations in insulin sensitivity of progeny.

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections.

This trial was carried out in Piracicaba, São Paulo State, Brazil, to comparatively evaluate the degree of resistance to naturally acquired gastrointestinal nematode infections in sheep of the following genetic groups: purebred Santa Ines (SI), SI crossbred with Dorper (DO x SI), Ile de France (IF x SI), Suffolk (SU x SI), and Texel (TE x SI). Fifteen ewes from each group were raised indoors until 12 months of age. At this age, they were moved to pasture that was naturally contaminated by nematode infective larvae and were evaluated from December to May, 2007. Rainfall ranged from 267 mm in January to 37 mm in April. Maximum and minimum mean temperatures ranged from 32.5 degrees C to 19.0 degrees C in March and from 25.9 degrees C to 12.8 degrees C in May. There was an increase in the mean number of eggs per gram of feces (EPG) after animals were placed on pasture with significant difference between the SI (80 EPG) and IF x SI (347 EPG) groups in January; and the DO x SI (386 EPG) and TE x SI (258 EPG) groups in May. The highest mean fecal egg count (FEC), 2073 EPG, was recorded for the TE x SI group in February. All groups showed a progressive reduction in body weight throughout the experiment of 12.0% (TE x SI) to 15.9% (SU x SI). In general, the animals with the highest FEC presented the lowest packed cell volumes (PCV); the highest correlation coefficient between FEC x PCV occurred in the SU x SI sheep in January (r=-0.70; P<0.01). Similarly, there was an inverse relationship between FEC and blood eosinophil values, with the highest correlation coefficient in the TE x SI sheep in February (r=-0.64; P<0.05). Immunoglobulin G (IgG) levels against Haemonchus contortus antigens increased in all groups as a result of the exposure to parasites and remained relatively constant until the end of the study, with the exceptions of SU x SI and TE x SI, which showed a rise in IgG levels during the last sampling that coincided with a reduction in mean FEC. In conclusion, crossbreeding Santa Ines sheep with any of the breeds evaluated can result in a production increase and the maintenance of a satisfactory degree of infection resistance, especially against H. contortus and Trichostrongylus colubriformis, the major nematodes detected in this flock.

Efeitos de fontes e formas de processamento do amido na utilização de nutrientes e parâmetros ruminais de vacas em lactação / Effects of starch sources and processing on nutrient digestibility and ruminal parameters of lactating cows

Cinco vacas holandesas pluríparas, com cânulas no rúmen e no duodeno, foram distribuídas em delineamento de quadrado latino 5 x 5. As vacas foram submetidas a cinco rações experimentais contendo 40 por cento de cana-de-açúcar, 60 por cento de concentrado e cerca de 30 por cento de amido. As rações diferiram quanto ao processamento ou à fonte principal do amido utilizado: milho grosseiramente moído, milho finamente moído, milho floculado a 310g/l, milho floculado a 360g/l ou raspa de mandioca. Não houve diferença (P>0,05) no consumo de matéria seca entre os tratamentos. A digestibilidade ruminal do amido foi maior na ração que continha raspa de mandioca. As digestibilidades ruminal da fibra em detergente neutro e da fibra em detergente ácido não diferiram entre os tratamentos. Os dados médios de pH ruminal se mantiveram acima de 6,0, exceto às 2 e às 4h após a alimentação com a dieta que continha raspa de mandioca. Não houve efeito significativo dos tratamentos sobre a concentração de ácidos graxos voláteis totais. O processo de floculação promoveu aumento da digestibilidade do amido do milho, em relação à moagem de forma grosseira. A digestibilidade ruminal do amido presente na raspa de mandioca foi maior do que a do milho, independentemente da forma de processamento utilizada.

Five multiparous lactating Holsteins cows, cannulated in the rumen and proximal duodenum, were used in a 5 x 5 latin square. Cows were fed a 40:60 forage: concentrate diet (40 percent fresh sugar cane and 60 percent concentrate). Diets were formulated to have 30 percent of starch and treatments were starch sources and ration processing forms: cracked corn, finely ground corn, flaked corn at 310g/l, flaked corn at 360g/l, or cassava scrapings. No difference (P>0.05) was observed among treatments for dry matter intake. Starch ruminal digestibility was higher for cassava scrapings treatment. NDF and ADF digestibility were similar among treatments. Average values of ruminal pH were above 6, except at 2 and 4h after feeding the cassava diet. There was no effect of treatment on concentrations of total volatile fatty acids. The flocculation process increased corn starch digestibility. Ruminal degradability of the cassava scrapings starch was higher than corn, without effect of processing form.

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay.

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

Avaliação do efeito do bagaço de cana-de-açúcar in natura obtido por dois métodos sobre o desempenho e o comportamento ingestivo de bovinos de corte / Effect of raw sugar cane bagasse on performance and ingestive behavior of beef cattle

Avaliou-se o efeito da utilização do bagaço de cana-de-açúcar in natura (BIN), obtido por dois métodos de extração do açúcar, moagem convencional ou difusão, como fonte de fibra em dietas que continham bagaço tratado sob pressão e vapor (BTPV), como principal fonte de volumoso sobre o desempenho e o comportamento ingestivo de bovinos confinados. Para avaliação do desempenho, foram utilizados 84 machos não castrados das raças Nelore, Canchim e Holandesa, com média de peso inicial de 270kg, distribuídos em delineamento de blocos ao acaso. Para a avaliação do comportamento ingestivo, foram utilizados quatro garrotes da raça Nelore, em delineamento de quadrado latino 4 x 4. Os tratamentos consistiram na substituição do BTPV pelo BIN na matéria seca, constituindo as dietas experimentais: 5 por cento BIN moagem convencional; 5 por cento BIN difusão, 10 por cento BIN difusão e 15 por cento BIN difusão. O consumo de MS foi menor no tratamento com 15 por cento de BIN obtido por difusão (BINdif), em relação ao teor de inclusão de 10 por cento. Não houve diferença (P>0,05) entre os tratamentos para ganho diário de peso, conversão alimentar e peso vivo final entre os tratamentos. Os tempos despendidos com as atividades de ruminação (minutos/kg de MS) e mastigação (minutos/kg de MS ou de FDN) foram maiores (P<0,05) no tratamento com 15 por cento de BINdif na dieta. O BINdif pode ser utilizado como fonte de fibra íntegra em até 15 por cento da MS da dieta sem prejudicar o desempenho dos animais.

This study was conducted to evaluate effects of replacing steam pressure treated sugar cane bagasse by two types of raw sugar cane bagasse extracted through grinding or diffusion, on performance and ingestive behavior of beef cattle. Eighty four young bulls (Nelore, Canchim and Holstein) with 270kg of body weight at the beginning of the experiment were used in a randomized block design. Ingestive behavior was evaluated using four Nelore young bulls in a 4 x 4 Latin square design. Treatments were the direct substitution of steam pressure treated sugarcane bagasse by raw bagasse (RB), corresponding to the experimental treatments: 5 percent RB from grinding; 5 percent RB from diffusion; 10 percent RB from diffusion and 15 percent RB from diffusion. Dry matter intake was lower in treatment with 15 percent of bagasse obtained by diffusion (BINdif) in comparison to 10 percent BINdif. There were no differences (P>0.05) among treatments for average daily gain, feed conversion and final live weight. Ruminating time (minutes/kg of DM) and chewing time (minutes/kg of DM or NDF) was greater (P>0.05) when BINdif was added at 15 percent level to diets. BINdif can be added up to 15 percent of the dietary DM with no detrimental effect on beef cattle performance.

Desempenho, parâmetros da carcaça e comportamento ingestivo de cordeiros alimentados com cana-de-açúcar ensilada ou in natura / Performance, carcass characteristics and ingestive behavior of feedlot lambs fed fresh or ensiled sugar cane

Trinta cordeiros da raça Santa Inês, 26,2±0,6kg e 151±1,7 dias de idade, foram confinados para avaliar os efeitos da utilização de silagens de cana-de-açúcar sobre o desempenho, as características da carcaça e o comportamento ingestivo. As rações experimentais foram compostas de 50 por cento de volumoso e 50 por cento de concentrado, diferindo quanto ao tipo do volumoso utilizado: cana-de-açúcar in natura, silagem de cana-de-açúcar sem aditivo e silagem de cana-de-açúcar aditivada com Lactobacillus buchneri (5x10(4) UFC/g de MV). Não houve diferença (P>0,05) para o consumo de MS, ganho de peso vivo, conversão alimentar e parâmetros de carcaça entre os tratamentos. O tempo de ingestão (min/g FDN) e a eficiência de ruminação (g MS/h) foram menores (P<0,05) para os tratamentos contendo silagem de cana-de-açúcar. Silagens de cana-de-açúcar não alteraram o desempenho e as características da carcaça dos cordeiros em relação à cana de açúcar in natura. A utilização do aditivo microbiano contendo o L. buchneri na ensilagem da cana-de-açúcar não alterou as variáveis avaliadas.

Thirty Santa Ines ram lambs, 26.2±0.6kg and 151±1.7 day-old, were penned to evaluate the effects of feeding sugar cane silages on performance, carcass characteristics and ingestive behavior. Lambs were fed a 50:50 (concentrate:roughage ratio) TMR. Experimental treatments were: fresh sugar cane, sugar cane silage without additive and sugar cane silage treated with Lactobacillus buchneri (5x10(4) cfu/g wet basis). No differences (P>0.05) on dry matter intake, average daily gain, feed conversion and carcass characteristics were observed among treatments. Eating time (min/g NDF) and rumination efficiency (g DM/h) were lower (P<0.05) for silage diets. Sugar cane silage had no detrimental effect on lamb performance and carcass characteristics compared to fresh sugar cane. Adding L. buchneri to sugar cane silage did not change the evaluated characteristics.

Fontes nitrogenadas em rações contendo bagaço de cana-de-açúcar hidrolizado no desempenho de bovinos confinados em terminação / Nitrogen source on performance of feedlot young bulls fed hydrolyzed sugarcane bagasse diets

Oitenta e um machos não castrados das raças Nelore (27), Canchim (27) e Holandesa (27), com peso médio inicial de 360kg e idade média de 18 meses, foram utilizados para avaliar os efeitos da substituição de fonte de proteína verdadeira (farelo de soja), por nitrogênio não protéico (NNP), uréia ou amiréia (fonte de nitrogênio não protéico de suposta liberação gradativa) sobre o desempenho de bovinos confinados. O delineamento experimental foi o de blocos inteiramente ao acaso com três animais por baia e nove baias por tratamento. Os blocos foram delineados de acordo com o peso inicial e na raça. As rações experimentais continham BTPV (45 por cento MS da dieta) e BIN (5 por cento MS da dieta) como fontes de volumosos e 50 por cento de concentrado. Os tratamentos consistiam de: 1) concentrado contendo farelo de soja (FS); 2) concentrado contendo uréia e 3) concentrado contendo amiréia (A-150S). O consumo de matéria seca (CMS) foi de 8,99; 7,43 e 7,69kg/dia, o ganho de peso diário (GPD) foi de 0,983; 0,368 e 0,404kg/dia e a conversão alimentar (CA) 9,56; 20,14 e 19,54kg MS/kg de ganho para os tratamentos FS, uréia e A-150S, respectivamente. As rações com FS apresentaram proporcionalmente maior (P<0,01) CMS e maior GPD e melhor CA em relação aos tratamentos uréia e A-150S. As rações com uréia e A-150S não diferiram (P>0,05) entre si. A substituição do FS por fontes de NNP reduziu o desempenho de bovino de corte em terminação.

Eighty-one young bulls (27 Nellore, 27 Canchim, and 27 Holstein), averaging 18-month-old and weighting 360kg of initial body weight (BW), were used to evaluate the effects of nitrogen sources on feedlot performance. Treatments were assigned in a completely randomized block design using three steers per stall and nine per treatment. Blocks were defined by initial BW and breed. Experimental treatments were: 1) soybean meal, 2) urea, and 3) starea. Diets were isonitrogenous and isoenergetic composed by 50 percent concentrate and 50 percent forage (45 percent hydrolyzed sugarcane bagasse + 5 percent in natura sugarcane bagasse). Dry matter intakes (DMI) were 8.99, 7.43, and 7.69kg/day, average daily gains (ADG) were 0.983, 0.368, and 0.404kg/day and feed efficiencies were 9.56, 20.14, and 19.54kg DM/kg of gain for soybean meal, urea and starea treatments, respectively for steers fed. Diets with soybean meal showed proportionally higher (P<0.01) DMI, higher average daily gain and better feed efficiency compared to urea and starea diets. No differences (P>0.05) between urea and starea treatments were observed. Replacement of soybean meal by nonprotein nitrogen sources decreased the finishing beef steers performance.

Effects of feeding a high-grain diet at a restricted intake on lactation performance and rebreeding of ewes.

Fifty-six mature Polypay ewes were used in two experiments to examine the effects of feeding a high-grain diet at a restricted intake on milk production and composition, lamb performance and out-of-season breeding. Ewes were fed either a high-grain diet (85% concentrate and 15% forage) or a high-forage diet. The high-forage diets were 68% forage and 32% concentrate in Experiment 1 and 80% forage and 20% concentrate in Experiment 2. Forage forage and 20% concentrate in Experiment 2. Forage source was orchardgrass hay (Experiment 1) or alfalfa cubes (Experiment 2). Feed intake of the high-grain diet was restricted by 20% (compared with ewes fed high forage) so that intake of energy was similar for both dietary groups. Daily milk production was 19% higher (P < .05) in Exp. 1 and 8% higher (P < .10) in Exp. 2 for ewes fed high grain than for those fed high forage (2.71 vs 2.28 kg/d and 3.18 vs 2.95 kg/d in Exp. 1 and 2, respectively). Milk protein percentage and daily amount of milk protein were higher (P < .05) and the percentage of milk fat was lower (P < .03) for ewes fed the high-grain diet than for those fed the high-forage diet. Diet did not affect milk fat production (grams/day) or lamb growth rate. In both experiments blood insulin concentration was higher for ewes fed the high-grain diet than for those fed the high-forage diet; however, no improvements in reproductive performance were observed. Limit feeding high-grain diets is an effective alternative to forage for lactating ewes.

Effects of limit feeding a high-grain diet on puberty and reproductive performance of ewes.

In Exp. 1, 39 ewe lambs (initial BW 29 +/- .1 kg) were used in a 2 x 2 factorial arrangement with two breeds (Polypay and Targhee) and two diets (high-forage and high-grain) to examine the effects of restricting intake of a high-grain diet on onset of puberty and lamb performance. The experimental diets were fed from 13 to 40 wk of age. The high-forage diet was composed of 80% alfalfa cubes and 20% supplement. The high-grain diet was 90% concentrate and 10% alfalfa cubes. Feed intake of the diets was controlled so that lambs fed the high-grain diet had the same growth rate as those fed the high-forage diet. Plasma insulin concentration was higher (P < .001) for lambs fed the high-grain diet than for those fed the high-forage diet. However, no diet effect on age at puberty was observed. In Exp. 2, 88 mature Targhee ewes were used to determine the effects of limiting intake of a high-grain diet on pregnancy and number of lambs born per ewe. Intake of the high-grain diet was restricted to achieve similar ME intake between diets. There were no diet effects on number of lambs born per ewe or subsequent lamb performance. Ewes fed the high-forage diet had a lower (P < .001) weight gain than those fed the high-grain diet. It was concluded that restricting intake of high-grain diets is an effective alternative to feeding high-forage diets for meeting the nutrient requirements of ewe lambs and gestating ewes; however, no improvements on reproductive performance were observed.