Cactus Cladodes Opuntia or Nopalea and By-Product of Low Nutritional Value as Solutions to Forage Shortages in Semiarid Areas.

We aimed to evaluate the effect of the cactus cladodes Nopalea cochenillifera (L). Salm-Dyck. (NUB) and cactus cladodes Opuntia stricta (Haw.) Haw. (OUB), both combined with sugarcane bagasse (SB) plus urea, Tifton hay (TH), corn silage (CS), and sorghum silage (SS) plus urea on nutrient intake and digestibility, ruminal dynamics, and parameters. Five male sheep, fistulated in the rumen, were assigned in a 5 × 5 Latin square design. The NUB provided a higher intake of dry matter (DM) and any nutrients than SS. TH provided larger pools of DM and iNDF. The OUB and CS provided a higher DM degradation. CS provided a higher NDF degradation rate. OUB provided a lower ruminal pH. Depending on the collection time, the lowest pH value was estimated at 3.79 h after the morning feeding. There was an interaction between treatments and collection time on VFA concentrations. Due to the high degradation rate, greater energy intake, less change in rumen pH, greater volatile fatty acid production, and feasibility, we recommend using cactus associated with sugarcane bagasse plus urea in sheep diets.

Polyclonal antibody preparations from avian origin as a feed additive to beef cattle: ruminal fermentation during the step-up transition diets.

This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40%, 35%, and 25% of the preparation, respectively) on ruminal fermentation [pH, ammonia-N (NH3-N), lactate, and volatile fatty acids (VFA)] of beef steers during a 21-d step-up diet adaptation. Eight ruminally cannulated Angus crossbred beef steers (658 ± 79 kg of body weight) were assigned in a crossover design to be transitioned from a diet containing ad libitum bermudagrass hay [Cynodon dactylon (L.) Pers.] plus 0.45 kg/d (as fed) of molasses with 0 (CON) or 3 g of PAP (PAP) to a high-grain diet. Transition consisted of three 7-d steps of increased inclusion of cracked corn (35%, 60%, and 82% of the diet DM for STEP1, STEP2, and STEP3, respectively). On each transition day and 7 d after STEP3 (STEP3-7d), ruminal fluid samples were obtained every 3 h for 24 h. Feeding 3 g of PAP daily increased (P < 0.01) average ruminal pH during STEP3 compared with CON steers (5.6 vs. 5.4 ± 0.05, respectively). During STEP1, NH3-N concentration was greater (P < 0.01; 9.4 vs. 6.8 ± 0.74 mM, respectively), and time (min/d) and area (time × pH) of ruminal pH below or equal to 5.2 was lesser (P ≤ 0.03) for steers consuming PAP compared with steers assigned to CON treatment (33.4 vs. 73.3 ± 21.7 min/d and 187.4 vs. 406.3 ± 119.7 min × pH/d, respectively). Steers consuming PAP had greater acetate:propionate ratio at 0, 3, and 6 h relative to diet change compared with CON (2.42, 2.35, 2.29 vs. 1.66, 1.79, and 1.72 ± 0.17, respectively), whereas butyrate molar proportions increased (P = 0.02; 17.1 vs. 11 ± 1.58 mol/100 mol for CON and PAP, respectively) when PAP was not fed at STEP2. Total ruminal lactate concentrations were not affected by PAP feeding (P > 0.11). In conclusion, feeding 3 g/d of polyclonal antibody preparation against S. bovis, F. necrophorum, and lipopolysaccharides was effective in increasing ruminal pH, A:P ratio, and NH3-N concentrations, possibly attenuating the risks of ruminal acidosis in steers during the step-up transition from forage to high-grain diets.

Spineless Cactus plus Urea and Tifton-85 Hay: Maximizing the Digestible Organic Matter Intake, Ruminal Fermentation and Nitrogen Utilization of Wethers in Semi-Arid Regions.

The aim of this study was to evaluate the effect of replacing Tifton-85 hay (Cynodon spp. cv. Tifton 85) with 0, 150, 300, 450 and 600 g/kg dry matter (DM) of spineless cactus (SC, Nopalea cochenilifera Salm-Dyck) plus urea and ammonium sulfate (UAS; 9:1) on DM, digestible organic matter (DOM) and indigestible neutral detergent fiber (iNDF) intakes, as well as ruminal fermentation, N-balance, and microbial protein supply (MPS). Five rumen-fistulated and cannulated crossbred wethers, weighing 43.8 ± 5.80 kg, were randomized in a 5 × 5 Latin square design. Isonitrogenous diets (14% crude protein) were supplied with a roughage/concentrate ratio of 70:30. The DOM intake, N-retained, and MPS showed quadratic responses (p < 0.05), with maximum values estimated at the levels of SC+UAS of 414, 438 and 418 g/kg DM, respectively. Rumen pH and ammonia nitrogen, iNDF intake, N-urinary excretion, and serum urea and plasma ammonia reduced linearly (p < 0.05) with increasing SC+UAS inclusion. Ruminal acetate and propionate concentrations increased linearly with increasing SC+UAS inclusion. In wethers fed diets with a roughage/concentrate ratio of 70:30, roughage constituted of a SC+UAS/hay (Tifton-85) ratio of 41:29 is recommended in order to maximize the DOM intake, N-retention, and MPS.

Miúda (Nopalea cochenillifera (L.) Salm-Dyck)-The Best Forage Cactus Genotype for Feeding Lactating Dairy Cows in Semiarid Regions.

This study aimed to investigate the effects on nutrient intake and digestibility, milk yield (MY) and composition, milk fatty acids profile, and microbial protein synthesis caused by feeding lactating dairy cows four different forage cactus genotypes. Eight Girolando cows (5/8 Holstein × 3/8 Gyr), weighing 490 ± 69.0 kg (means ± standard deviation), and producing 15.5 ± 1.0 kg/d of milk during pretrial were distributed to two contemporaneous 4 × 4 Latin squares. The cows were fed a total mixed ration composed of sorghum silage (385 g/kg of dry matter (DM)), concentrated mix (175 g/kg DM), and forage cactus (440 g/kg DM). The experimental treatments consisted of different cactus genotypes, such as Gigante cactus (GC), Miúda cactus (MC), IPA Sertânia cactus (SC), and Orelha de Elefante Mexicana cactus (OEMC). The feeding of MC provided a higher intake of DM, organic matter (OM), and total digestible nutrients, as well as higher MY, energy-corrected milk, and microbial protein synthesis in comparison with those resulting from the other genotypes tested. The GC promoted lower DM and OM, and the apparent digestibility of neutral detergent fiber. The cows fed with OEMC showed lower MY and milk protein yield and content, and higher unsaturated over saturated fatty acid ratio in milk. Miúda forage cactus increased nutrient intake, digestibility of DM and OM, and microbial synthesis without impairing the milk fatty acid profile.