Características de fermentação da silagem de seis variedades de milho indicadas para a região semiárida Brasileira

Avaliaram-se as características fermentativas e a qualidade das silagens de seis variedades de milho, de ciclos precoce e superprecoce - BRS Caatingueiro, BRS Assum Preto, BR 5033 Asa Branca, BR 5028 São Francisco, Gurutuba e BRS 4103 - indicadas para a região semiárida brasileira. Foram utilizados silos experimentais, em delineamento inteiramente ao acaso, com seis tratamentos (variedades) e quatro repetições. Avaliaram-se: matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), extrato etéreo (EE), carboidratos totais (CHO), carboidratos não fibrosos (CNF), pH, nitrogênio amoniacal como parte do nitrogênio total (N-NH3/NT), ácidos orgânicos e digestibilidade in vitro da matéria seca (DIVMS) das silagens. Os valores médios encontrados para a silagem foram: MS= 28,7%; MO= 94,9%; PB= 8,3%; FDN= 49,9%; FDA= 27,5%; EE= 3,8%; CHO= 82,7%; CNF= 32,8%; pH= 3,8; N-NH3/NT= 2,9%/NT; ácido láctico = 7,6%; ácido acético = 0,6%; ácido butírico = 0,3% e DIVMS= 57,9%. As variedades BR 5028 - São Francisco e Gurutuba destacaram-se das demais em relação ao teor de matéria seca. A variedade BRS Caatingueiro apresentou maior teor de carboidratos não fibrosos em relação às demais. As silagens de todas as variedades foram classificadas como de excelente qualidade, por apresentarem potencial para ensilagem no semiárido brasileiro

Evaluation of elephant grass silage with the addition of cassava scrapings

The objective of this experiment was to evaluate the effects of adding cassava scrapings on gas and effluent losses, dry matter recovery, pH, contents of N-NH3, organic acids and volatile fatty acids and the bromatological composition of elephant grass silages. It was used a randomized complete design, with four levels of cassava scrapings (0, 7, 15 or 30% natural matter) each one with four replications per level. The grass was cut at 50 days of regrowth and ensiled in 15-L silos, equipped with a Bunsen valve to allow gas outflow. The gas losses decreased quadratically with the addition of cassava scrapings, whereas effluent losses decreased linearly. Dry matter recovery increased quadratically with the addition of cassava scrapings. Dry matter (DM) concentration increased but crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose (HEM) decreased linearly with the addition of cassava scrapings. The pH value and lactic acid concentration increased quadratically with the addition of cassava scrapings. Contents of N-NH3 and butyric acid decreased quadratically with the addition of cassava scrapings, whereas acetic acid content decreased linearly. Addition of cassava scrapings reduced gas and effluent losses and improved the fermentation profile of elephant grass silages and the level of 7% already ensures this improvement.

Acurácia, precisão e robustez das estimativas da digestibilidade aparente da matéria seca determinada com o uso de indicadores em ovinos

O objetivo foi avaliar a acurácia, precisão e robustez das estimativas da digestibilidade aparente da matéria seca obtidas utilizando-se como indicadores fibra em detergente ácido indigestível (FDAi), fibra em detergente neutro (FDNi) indigestível, lignina em detergente ácido (LDA), LDA indigestível (LDAi) e óxido crômico em comparação ao método de coleta total de fezes. Dezoito ovinos (56,5 ± 4,6 kg PV) foram designados aleatoriamente a dietas compostas de 25, 50 ou 75% de concentrado e feno de Coast cross por 25 dias. As fezes foram coletadas por cinco dias para determinação da digestibilidade aparente da MS. As amostras de alimentos e fezes foram incubadas no rúmen de três bovinos por 144 horas, para obtenção das frações indigestíveis. Óxido crômico foi administrado a 4,0 g/animal/dia. A acurácia foi avaliada pela comparação do viés médio (DAMS predito - DAMS observado) entre os indicadores; a precisão, por meio da raiz quadrada do erro de predição e do erro residual; e a robustez, pelo estudo da regressão entre o viés e o consumo de matéria seca, o nível de concentrado e o peso vivo. A recuperação fecal e a acurácia das estimativas da digestibilidade aparente da MS foram maiores para FDAi, seguida pela FDNi, LDAi, pelo óxido crômico e depois pela lignina em detergente ácido. O viés linear foi significativo apenas para FDAi, FDNi e LDAi. O uso de óxido crômico permitiu estimativas mais precisas da digestibilidade aparente da MS. Todos os indicadores foram robustos quanto à variação no consumo de matéria seca e apenas LDAi e óxido crômico foram robustos quanto aos níveis de concentrado na dieta. O óxido crômico não foi robusto quando houve variação no peso vivo animal. Assim, a FDAi é o indicador mais recomendado na estimativa da digestibilidade aparente da MS em ovinos quando o objetivo é comparar aos dados da literatura, enquanto o óxido crômico é mais recomendado quando o objetivo é comparar tratamentos dentro de um mesmo experimento.

Suplementação nitrogenada com ureia comum ou encapsulada sobre parâmetros ruminais de novilhos alimentados com feno de baixa qualidade

Foi realizado um experimento de suplementação com novilhos fistulados no rúmen com o objetivo de verificar a utilização de ureia encapsulada como fonte de nitrogênio de liberação mais lenta e uniforme ao longo do tempo, bem como seu efeito sobre a degradabilidade da parede celular do feno. Os tratamentos foram: Feno + sal mineralizado (SM); Feno + suplemento proteico com ureia comum (SU); Feno + suplemento proteico com ureia encapsulada fórmula 1 (UE1); e Feno + suplemento proteico com ureia encapsulada fórmula 2 (UE2). O volumoso utilizado foi feno de Tifton (Cynodon dactylon L.) de baixa qualidade (PB: 4,62% e FDN: 83,46%). Foram realizadas medidas de pH e N-NH3 ruminais e parâmetros de degradação ruminal da FDN do volumoso. Verificou-se efeito (P<0,05) da suplementação nitrogenada sobre a concentração de nitrogênio amoniacal no rúmen; no entanto, a ureia encapsulada não foi diferente (P>0,05) da ureia comum. Os valores de pH e degradabilidade in situ não foram afetados pelos tratamentos (P>0,05), ao serem comparados os suplementados ou não suplementados com proteína degradável no rúmen e ao serem comparadas fontes de nitrogênio não proteico. A ureia encapsulada não demonstrou superioridade sobre a ureia comum, provavelmente pela baixa eficiência da sua proteção. A utilização de ureia encapsulada e a suplementação de proteína degradável não foram eficientes em aumentar a degradabilidade da parede celular do volumoso utilizado.

Nutritive value and physical characteristics of Xaraes palisadegrass as affected by grazing strategy

The aim of this study was to ascertain whether the defoliation frequency based on a fixed rest period would generate variable sward structural and physiological conditions at each subsequent grazing event. The relative importance of the physiological age was established in comparison with the chronological age in the determination of the forage nutritive value of Xaraes palisadegrass [Brachiaria brizantha (Hochst ex A. RICH.) STAPF. cv. Xaraes]. Two grazing frequencies were defined by light interception (LI) at initiation of grazing (95% LI - ""target grazing"" [TG] or 100% LI - ""delayed grazing"" [DG]) and one based on chronological time, grazing every 28 days (28-d). Forage produced under the TG schedule was mostly leaves (93%) with a higher concentration of crude protein (CP; 138 g/kg in the whole forage), a lower concentrations of neutral detergent fibre (NDF) in the stems (740 g/kg), and higher in vitro dry matter digestibility (IVDMD) of the leaves (690 g/kg), compared to the other treatments. Lower grazing frequency strategies (DG and 28-d) resulted in forage with higher proportions of stems (10 and 9%, respectively). Strategies based on light interception did not produce pre-graze forage with a uniform nutritive value, as the indicators varied across grazing cycles. The treatment based on fixed days of rest did not result in uniformity.

Effect of eucalyptus (Eucalyptus citriodora) fresh or residue leaves on methane emission in vitro

Rumen fermentation and methane emission for eucalyptus (Eucalyptus citriodora) fresh leaves (FL) or residue leaves (RL), after essential oil extraction from eucalyptus leaves in comparison with alfalfa (Medicago sativa) hay, were investigated in vitro. Eucalyptus FL and RL were obtained from the Distillery Trees Barras Company, Torrinha City, Sao Paulo, Brazil. The semi-automatic system of gas production was used to measure gas production, methane emission and rumen fermentation after 24 h incubation in vitro. The results showed that the crude protein (CP) contents were 76.4, 78.1 and 181.9 g kg(-1) DM for eucalyptus FL, RL and alfalfa hay, respectively. The neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) were significantly lower in eucalyptus FL and RL than alfalfa hay. The Eucalyptus fresh and residue leaves were rich in total phenols (TP) and total tannins (TT) but had negligible content of condensed tannins (CT). There was significant reduction in cumulative gas production about 54 and 51% with eucalyptus FL and RL, respectively, compared with alfalfa hay. The methane emission (mL/g DM) was reduced (P<0.05) by 53 and 57% with eucalyptus FL and RL, respectively, but the reduction was 21 and 16% when expressed on truly digested organic matter basis. There were a decline (P<0.05) in true dry and organic matter degradation in vitro in eucalyptus FL and RL compared with alfalfa hay substrate. The partitioning factor values were higher (P<0.05) in eucalyptus FL and RL than alfalfa hay. There was no significant difference observed between eucalyptus FL, RL and alfalfa hay in protozoa count. It is concluded that the eucalyptus leaves have potential effect to mitigate CH4 production in vitro, which may be attributed to a decrease in fermentable substrate rather than to a direct effect on methanogenesis.

Influence of palm fatty acid distillate on rumen degradability and protozoa population in buffaloes

Oil and fat as energy sources at low cost are relevant in ruminant nutrition. The aim of this study was to evaluate the effects of palm fatty acid distillate (PFAD) on the degradability and ciliate protozoa population in buffalo. Four rumen fistulated buffaloes were fed a basal diet in a Latin square (4x4) design trial. Treatments were designed with four of different levels of PFAD added directly into the rumen: 0; 200; 420 and 500 g/animal/d. High levels of PFAD (420 and 500 g/d) promoted higher degradation of the soluble fraction and lower in potentially degradable fraction of dry matter (DM) and neutral detergent fibre (NDF) with lower values of potential and effective degradability in two evaluated grasses, bermudagrass and brachiariagrass. Significant decreases in the total number of protozoa/mL of rumen content, Entodinium and ciliates belonging to subfamily Diplodiniinae were observed at higher level of PFDA addition in the rumen. Also, Epidinium and Holotrich ciliates disappeared from the rumen. Significant correlations were observed of the ciliate concentration and composition as a function of dietary lipids content. Entodinium composition increased from 68.0% to 99.6% and Diplodiniinae reduced from 30.4% to 0.4% with increasing PFAD level indicating higher fat toxicity effect on the Diplodiniinae ciliates than Entodinium species and direct action of the larger ciliates on the fibre degradation.

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 Ines 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.

Diet-induced milk fat depression: Association with changes in milk fatty acid composition and fluidity of milk fat

This experiment was designed to examine changes in milk fatty acids during fish oil-induced milk fat depression (MFD) and to test the theory that these changes are related to milk fat fluidity. The experiment was divided into three periods: 1) Baseline: all cows (n = 12) received a high fiber diet without fish oil (FO) for 12 days; 2) Treatment: 4 cows/group received the following treatments for 21 days: a) Low fiber diet without FO (LF), b) High fiber diet+FO (HF+FO) and c) Low fiber diet+FO (LF+FO); 3) Post-treatment: cows returned to the baseline diet and were monitored for 12 days. FO was included at 1.6% DM and HF and LF diets had 40 and 26% NDF, respectively. Milk fat content and yield were unchanged by the LF diet, but were reduced by FO diets at both dietary fiber levels and recovered in the post-treatment period. FO diets caused a pronounced reduction in stearic and oleic acid concentrations in milk fat and an equally pronounced increase in trans-18:1 fatty acid concentrations. Milk fat mean melting point (MMP) was correlated with MFD (r=0.73) and with milk oleic acid concentration (r=-0.92). The ratio of oleic:stearic in milk fat increased gradually and consistently in response to FO. Trans-C18:1 isomers with double bounds at carbon :<= 10 increased with greater MFD and those with double bonds at carbon ! I I decreased with greater MFD. Trans-9 cis-11 CLA explained more than 80% of MFD and was strongly correlated with trans-10 C18:1. Maintenance of MMP below 39-40 degrees C suggests that the mammary gland was able to secrete only milk fat with adequate fluidity and that MFD could be an adaptation mechanism to prevent secretion of milk with higher MMP. (C) 2007 Elsevier B.V. All rights reserved.

In Vitro Colonic Fermentation and Glycemic Response of Different Kinds of Unripe Banana Flour

This work aimed to study the in vitro colonic fermentation profile of unavailable carbohydrates of two different kinds of unripe banana flour and to evaluate their postprandial glycemic responses. The unripe banana mass (UBM), obtained from the cooked pulp of unripe bananas (Musa acuminata, Nanico variety), and the unripe banana starch (UBS), obtained from isolated starch of unripe banana, plantain type (Musa paradisiaca) in natura, were studied. The fermentability of the flours was evaluated by different parameters, using rat inoculum, as well as the glycemic response produced after the ingestion by healthy volunteers. The flours presented high concentration of unavailable carbohydrates, which varied in the content of resistant starch, dietary fiber and indigestible fraction (IF). The in vitro colonic fermentation of the flours was high, 98% for the UBS and 75% for the UBM when expressed by the total amount of SCFA such as acetate, butyrate and propionate in relation to lactulose. The increase in the area under the glycemic curve after ingestion of the flours was 90% lower for the UBS and 40% lower for the UBM than the increase produced after bread intake. These characteristics highlight the potential of UBM and UBS as functional ingredients. However, in vivo studies are necessary in order to evaluate the possible benefic effects of the fermentation on intestinal health.

Lesions caused by cardiovascular flukes (Digenea : Spirorchidae) in stranded green turtles (Chelonia mydas)

Evidence of infection with spirorchid flukes (Digenea: Spirorchidae) was sought at necropsy of 96 stranded green turtles, Chelonia mydas, that were examined during the course of a survey of marine turtle mortality in southeastern Queensland, Australia. Three species of spirorchid (Hapalotrema mehrai, H. postorchis, and Neospirorchis schistosomatoides) were identified. Severe disease due to spirorchid fluke infection (spirorchidiasis) was implicated as the principal cause of mortality in 10 turtles (10%), and appeared to be one of multiple severe problems in an additional 29 turtles (30%). Although flukes were observed in only 45% of stranded C. mydas in this study, presumed spirorchid fluke infection was diagnosed in an additional 53% of turtles, based principally on characteristic necropsy lesions and to a lesser extent on the histopathological detection of spirorchid eggs. Characteristic necropsy lesions included miliary spirorchid egg granulomas, which were observed most readily on serosal surfaces, particularly of the small intestine. Cardiovascular lesions included mural endocarditis, arteritis, and thrombosis, frequently accompanied by aneurysm formation. Resolution of thrombi was observed to occur via a combination of granuloma formation about indigestible components (spirorchid fluke egg shells) and exteriorization through the vessel wall, which resulted in granulomatous nodules on the adventitial surface. Septic aortic thrombosis complicated by disseminated bacterial infection, observed in five turtles, was recorded for the first time. Egg granulomas were ubiquitous in turtle tissues throughout this study. Although they generally appeared to be mild or incidental lesions, they were occasionally associated with severe multifocal granulomatous pneumonia or meningitis.

Effects of alkalis, oxidants and urea on the nutritive value of rhodes grass (Chloris gayana cv. Callide)

Two in sacco experiments were conducted to evaluate the impact on the nutritive value of rhodes grass hay (Chloris gayana cv. Callide) of treatment with alkalis or oxidants. In Experiment 1, three alkalis (Ca(OH)(2), NaOH, CaO) and two oxidants (NaOCl and H2O2) were applied at levels of 0, 20, 40, 60 or 80 g/kg of dry matter (DM). NaOH, Ca(OH)(2) and CaO had negative linear effects (P < 0.05) on the neutral detergent fibre (NDF) content and positive linear effects (P < 0.05) on the 48 h in sacco disappearances of DM, organic matter (OM), NDF and acid detergent fibre (ADF). NaOCl reduced (P < 0.05) NDF content but had no effect (P > 0.05) on the in sacco disappearances. H2O2 had no effect (P > 0.05) on the composition or digestibility of rhodes grass hay. In Experiment 2, effects of urea (0, 20, 40, 60 and 80 g urea/kg DM) and water (250, 500 and 750 g/kg DM) treatment of rhodes grass hay were examined in a 5 x 3 factorial experiment. Significant interactions between water and urea (P < 0.05) occurred for concentrations of crude protein (CP) and NDF, and 48 h in sacco disappearances of DM, OM (OMD) and NDE The combinations of water (g/kg DM) and urea (g/kg DM) that resulted in the highest concentrations of CP (281 g/kg DM) and OMD (747 g/kg DM) were 250 + 80 and 500 + 80, respectively. NaOH, Ca(OH)(2), CaO and urea significantly alter the NDF content and digestibility of rhodes grass hay, and urea also increases its CP content. Overall, NaOH was the most efficacious, followed by Ca(OH)(2), CaO, urea, NaOCl and H2O2. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

Effects of adding polyclonal antibody preparations on ruminal fermentation patterns and digestibility of cows fed different energy sources

Nine ruminally cannulated cows fed different energy sources were used to evaluate an avian-derived polyclonal antibody preparation (PAP-MV) against the specific ruminal bacteria Streptococcus bovis, Fusobacterium necrophorum, Clostridium aminophilum, Peptostreptococcus anaerobius, and Clostridium stick-landii and monensin (MON) on ruminal fermentation patterns and in vivo digestibility. The experimental design was three 3 x 3 Latin squares distinguished by the main energy source in the diet [dry-ground corn grain (CG), high-moisture corn silage (HMCS), or citrus pulp (CiPu)]. Inside each Latin square, animals received one of the feed additives per period [none (CON), MON, or PAP-MV]. Dry matter intake and ruminal fermentation variables such as pH, total short-chain fatty acids (tSCFA), which included acetate, propionate, and butyrate, as well as lactic acid and NH(3)-N concentration were analyzed in this trial. Total tract DM apparent digestibility and its fractions were estimated using chromic oxide as an external marker. Each experimental period lasted 21 d. Ruminal fluid sampling was carried out on the last day of the period at 0, 2, 4, 6, 8, 10, and 12 h after the morning meal. Ruminal pH was higher (P = 0.006) 4 h postfeeding in MON and PAP-MV groups when compared with CON. Acetate: propionate ratio was greater in PAP-MV compared with MON across sampling times. Polyclonal antibodies did not alter (P > 0.05) tSCFA, molar proportion of acetate and butyrate, or lactic acid and NH(3)-N concentration. Ruminal pH was higher (P = 0.01), 4 h postfeeding in CiPu diets compared with CG and HMCS. There was no interaction between feed additive and energy source (P > 0.05) for any of the digestibility coefficients analyzed. Starch digestibility was less (P = 0.008) in PAP-MV when compared with CON and MON. In relation to energy sources, NDF digestibility was greater (P = 0.007) in CG and CiPu vs. the HMCS diet. The digestibility of ADF was greater (P = 0.002) in CiPu diets followed by CG and HMCS. Feeding PAP-MV or monensin altered ruminal fermentation patterns and digestive function in cows; however, those changes were independent of the main energy source of the diet.

Effects of aeration on characteristics of sugarcane silage.

Effects of aeration on characteristics of sugarcane silage. This trial aimed at evaluating, the deleterious effects of aeration time on nutritive value and other fermentative characteristics of sugarcane silage. A completely randomized design was used with three treatments and four repetitions per treatment. Fresh chopped sugarcane was exposed to aeration for 0, 4 or 8 hours, and ensiled soon After exposure, the material was ensiled in 12 laboratory silos (plastic buckets). Silos were opened 85 after ensiling, when organic acids contents and chemical composition of silages were determined. Deviation of linearity (p < 0.05) was observed for aeration time on dry matter. A positive linear effect was observed (p < 0.05) on ADF, NDF and soluble carbohydrates content, but negative for ammoniacal nitrogen content and in vitro digestibility of dry matter. For organic acids content, deviation of linearity was observed on acetic acid, with the lowest content (1.5% of DM) observed after 8 hours of aeration, and a negative linear effect was observed for lactic and butyric acids, as well as for pH values. There were no effects on ethanol concentration, which remained very high (22% of DM), regardless of aeration time. Aerobic stability of silage worsened with the increase in aeration time.

Postpartum ovarian activity of Santa Ines lactating ewes fed diets containing soybean hulls as a replacement for coastcross (Cynodon sp.) hay

The Santa Ines, a Brazilian hair sheep, has a non-seasonal breeding activity. Data regarding the duration of the postpartum anestrous period in Santa Ines lactating ewes is lacking and the objective of this trial was to determine the effects of replacing neutral detergent fibre (NDF) provided by coastcross (Cynodon sp.) hay with NDF contained in soybean hulls (SH) on the postpartum ovarian activity-as measured by the serum progesterone (P(4)) concentration. Fifty-six lactating ewes (body weight 56.1 +/- 6.8 kg) were individually penned and used in a randomized complete block design with 14 blocks and four treatments. The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in the control diet (SHO). This resulted in a SH inclusion at rates of 0, 25, 54, and 85% of the dietary dry matter (DM). Blood samples were collected twice weekly from the 14th to 84th day postpartum and the serum P(4) concentrations determined by radioimmunoassay (RIA). It was estimated that the 1st postpartum ovulation occurred 6 days before the date that a serum P(4) >= 1 ng/ml concentration was first recorded. The mean body condition score (BCS; 0-5 scale) was 3.0 +/- 0.19 on day 14 postpartum and the mean BCS at day 56 postpartum increased linearly (P<0.01) with the inclusion levels of SH (3.09, 3.24, 3.34, and 3.36, respectively). Treatments did not differ significantly in the induction of postpartum days to the resumption of ovarian luteal activity (34.1 +/- 15.3 days postpartum). On days 25, 50, and 75 postpartum 36.80, and 100% of the ewes had resumed ovarian activity, respectively. Nonesterified fatty acid concentration decreased quadratically (P<0.05) with the SH inclusion, with values of 0.323, 0.244, 0.204, and 0.216 mequiv./l for the SHO, SH33, SH67, and SH100 treatments being recorded, respectively. Replacement of the NDF provided by coastcross hay with the NDF from the SH did not influence the duration of the postpartum anestrous period in Santa Ines lactating ewes. Considering a 150-day gestation period and the 34 days postpartum anestrous demonstrated in the present study, the current production system of a lambing interval of 8 months (3 lambing events in 2 years) may not be optimizing the production potential and a system in which the lambing interval is shortened by at least 1 month may be feasible. (C) 2008 Elsevier B.V. All rights reserved.