A team of researchers in Brazil examined the use of spineless cactus as an alternative feed ingredient and to maximize energy intake. The group published its results in the journal of Animal Feed Science and Technology.
“This study aimed to evaluate the effects of spineless cactus inclusion replacing Tifton hay on intake, total and partial (ruminal and intestinal) digestibility of nutrients, fiber dynamics and ruminal parameters in cattle,” said the researchers. “In addition, to identify the ideal ratio of Tifton hay:spineless cactus that would maximize the use of this forage in cattle systems.”
The researchers found that a proportion of hay could be replaced with the cactus to improve energy intake while supporting rumen function, they said.
“It is recommended to include 418 g kg−1 of spineless cactus on a DM [dry matter] basis as a replacement of Tifton hay in the diet of cattle to maximize energy intake without causing adverse effects on ruminal fermentation,” said the researchers. “Thus, a Tifton hay to spineless cactus ratio of 28:42 (70%) in diets with 30% concentrate is recommended for cattle.”
Why cactus?
Altering climate conditions have led to frequent and lengthy droughts and cattle losses from damaged pasture grass or low-quality roughage, said the researchers. Farmers also may turn to imported hay or silage, which is stressing the production system.
However, spineless cactus may offer an alterative feed supplement to use with concentrate during the dry season as it is able to survive long droughts and has a high production potential, they said. It also is less expensive than other roughages.
It has a low crude protein and neutral detergent fiber (NDF) levels, they said. But does have a high non-fibrous carbohydrate contents and a quick NDF degradation rate.
“Due to this composition, spineless cactus presence in the diet associated with protein and fiber sources promotes nutrient degradability increase,” said the researchers.
Adding a non-protein nitrogen compound, like urea, works to increase the protein content of the diets and is lower in cost than a “true” protein source, they said. And, total replacement of a concentrated feed with spineless cactus is possible without generating negative effects in ruminants.
However, less is known about use of the cactus as a silage portion, they said. But, a goal of the study was to explore that use.
“It is suggested that forage replacement (such as hay, silage or straw) does not exceed 50% dry matter, since digestion and animal performance may be impaired,” said the researchers. “Thus, it was hypothesized that providing more digestible feeds (rich in NFC), such as spineless cactus associated with urea, replacing the diet roughage (Tifton hay), could interfere with cattle ruminal metabolism.”
Methods and materials
In the study, five rumen-fistulated steer were placed in a 5 x 5 Latin square design receiving a new trial diet every 16 days with a seven-day adaptation phase, said the researchers. The diets included a control and four with increasing amounts of cactus added.
“The experimental diets consisted of the inclusion of spineless cactus (Nopalea cochenillifera Salm-Dyck) (0; 147; 294; 441 and 588 g kg−1 of DM basis) replacing Tifton hay (Cynodon spp.),” they said. “Urea and ammonium sulfate were added to the diets to adjust the crude protein (CP) content to 150 g kg−1 DM, to meet the requirements of crossbred cattle (½ Holstein-Zebu), with an average daily gain of 1.5 kg.”
Forage, orts and feed concentrate were sampled and fecal dry matter output was assessed for total apparent digestibility of nutrients, they said.
Omasal digesta and ruminal fluid were collected from day 11 to day 13 and indigestible neutral detergent fiber (iNDF) content was checked to estimate partial digestibility, ruminal pool and passage rate, said the researchers. Omasal flow also was established along with rates of indigestion and ruminal pool.
Samples were checked for dry matter, organic matter (OM), ash, CP and ether extract (EE), they said. NDF was analyzed and non-fibrous carbohydrates (NFC) were quantified.
Results
The intake of DM, OM and digestible organic matter (DOM) had a quadratic response to inclusion of cactus in the silage, said the researchers. Intake was highest for the lowest amount of the alternative ingredient.
“The nutrient intake showed a quadratic effect, with a maximum intake of dry matter (8.89 kg d−1) and digestible organic matter (5.75 kg d−1) estimated with 339 and 418 g kg−1 of inclusion, respectively,” they said. “The total and ruminal digestibility of dry matter (DM), organic matter (OM), crude protein (CP), and degradation rate (Kd) of DM increased linearly.”
NFC intake increased as more cactus was added and neutral detergent fiber assayed with a heat sable amylase and corrected for ash and nitrogenous compounds (aNDFom) feeding decreased, they said.
“Except to aNDFom, the DM, OM and CP total and ruminal apparent digestibility linearly increased with spineless cactus inclusion replacing Tifton hay,” they said. “The DM and aNDFom intestinal digestibility linearly decreased; however, there was no effect for OM and CP.”
NDF also had a quadratic effect, with the largest pool of 2.46kg for the diet with 201g kg-1, they said. There was a linear increase for the degradation of NDF of dry matter.
Ruminal pH decreased as more cactus was used in the diet, they said. But, there was no alteration of short chain volatile fatty acid proportion as more as added to the feed.
Source: Animal Feed Science and Technology
Title: Optimizing the use of spineless cactus in the diets of cattle: Total and partial digestibility, fiber dynamics and ruminal parameters
DOI: 10.1016/j.anifeedsci.2016.12.006
Authors: M. Siqueira, M. de Ferreira, J. dos S. Monnerat, J. de L. Silva, C. Costa, M. da Conceição, R. de P.X. de Andrade, L. Barros, T. de B. Melo,