Instituto de Ciencia Animal: fifty years of scientific research at the service of beef production in Cuba

El Instituto de Ciencia Animal, cincuenta años de investigaciones científicas al servicio de la producción de carne bovina en Cuba

Duniesky Rodríguez,^I

^IInstituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba.

This study presents the main scientific results of beef production, obtained in the Instituto de Ciencia Animal, mainly related to the use of grasses, forages and agro-industrial residues, as sources of animal food. The essential elements for a good development of feeding systems are reported. This research also states the knowledge related to stocking rate, grazing methods, supplementation level, and other indicators that allow to optimize each fattening system, with possibilities of obtaining gains near to the kilogram liveweight per day in systems in which the use of oleaginous seeds and cereals only contribute to complement nutritional deficiencies.

Key words: feeding, management, fattening, bovine.

RESUMEN

Se recopilan los principales resultados científicos obtenidos por el Instituto de Ciencia Animal en la producción de carne vacuna, relacionados fundamentalmente con la utilización de pastos y forrajes y residuos agroindustriales, como fuentes de alimentación animal. Se informan los elementoses enciales para el buen desempeño de los sistemas de alimentación. Se refieren además conocimientos relacionados con la carga animal, métodos de pastoreo, nivel de suplementación,y otros indicadores que permiten optimizar cada sistema de ceba, con posibilidades de obtener ganancias cercanas al kilogramo de peso vivo diario en sistemas en los que el uso de cereales y semillas oleaginosas solo contribuye a complementar las deficiencias nutricionales.

Palabras clave: alimentación, manejo, ceba, bovinos.

INTRODUCTION

The use of grasses and forages for bovine feeding is essential for meat production in Cuba because the characteristics of the digestive system of these animals allow them to use feeds with high fiber levels. Under these conditions, the use of supplementation is aimed to complement grass deficiencies, with the objective of optimizing each feeding system and achieve higher meat productions per surface unit.

Out of the results of these researches, the Instituto de Ciencia Animal developed different technologies of national and international renown, specifically in the Latin American area. Knowledge and developed techniques in this field were implemented in different productive areas, not only in Cuba but also in tropical areas. Due to the importance of studies about this subject, a gathering of the main results was carried out, with the objective of spreading the work of the Instituto de Ciencia Animal, aiming to the improvement of beef production.

MOLASSES IN BEEF PRODUCTION

Studies for the exploitation of agro-industrial residues in bovine feeding started with the creation of the Instituto de Ciencia Animal. By-products of sugar industry were, during this stage, an endless source for the development of researches on animal nutrition.

Sugar cane molasses, like the raw matter that originates it, has a great availability of sugars and low protein content so researchers started to work on supplementation with non-protein sources of nitrogen. Urea, specifically, reached percentages of 9 % of molasses inclusion, which helped to achieve weight gains near a kilogram of liveweight per day (Preston et al. 1967). 

The first studies in this scientific field demonstrated that animals fed with concentrated or fresh forage, when urea molasses was provided, decreased the intake of this supplement. Therefore, in order to increase the intake, it was necessary to limit the access to other food sources so the energy from the molasses could represent between 70 and 80 % of the animal requirements and constitute the main feeding source. However, once the sugar molasses became the main food source of the diets, it was necessary to research on the alternatives for offering a fiber source to counteract the negative effects of the use of this by-product, as the only food source, can cause to animal health.

Several researches were developed in order to determine the optimal level of forage of these feeding systems. Ad libitum supply of forage, up to 1.5, 2.5, 3.5 and 4.5 % of animal liveweight, was tested. It was determined, as the most proper value, the inclusion of 1.5 %, avoiding the substitution effect of the food (Elías et al. 1967and Martin et al. 1968).

A variant for feeding systems based on molasses-urea was the use of restricted grazing, in which the animals have access to grass for 1.5 h, twice a day (Morciego et al. 1970). This can be a way of diminishing costs of feeding systems due to the decrease of the use laborwork and agricultural machinery.

Using a diet based on molasses and restricted forage, these diet components, although they provide almost 90 % of the total metabolizable energy, do not provide more than 30 % of total N, so it was necessary to add a true protein source for fulfilling this deficiency.

It is important to point out that before the development of these studies, sugar cane molasses was only used as animal supplement. Regarding the studies developed by the institute, researches started to use it as the main food source in cattle systems from Cuba, so it represented a new fattening method using liquid diets. With this technology, more than 10,000 bulls were fattened under commercial conditions.

Preston and Muñoz (1971) began to study torula yeast supply and determined that the optimal supply of this protein source was around 700 g/d, which allows to obtain a proper productive performance.

Molina and Preston (1975) evaluated the use of fish meal and encapsulated methionine, as well as their combination as protein supplement for animals consuming molasses urea. These authors found an increase in daily gain, which increased the offering of fish meal. This was much related to its high biological value and to the need of supplying by-passing true protein to degradation of ruminal microorganisms.

Cereal supply as starch sources were also studied because sucrose is the main source of carbohydrates in molasses. Elías and Delgado (1976) evaluated a semi-integral diet with molasses-urea, using four combinations of maize and wheat in supplementation, and obtained weight gains between 840 and 1000 g/d, without differences among treatments. These authors demonstrated that true protein from these food sources may represent 6 % of it, and maintain a proper productive performance.

These studies and some others carried out in Cuba and in different countries, allowed to establish and encourage the use of molasses as food source for ruminants. This is a current aspect because allows the feeding systems with molasses-urea to obtain liveweight gains between 800 and 900 g/animal/d.

SUGAR CANE STRAW AND BAGASSE PITH IN MEAT PRODUCTION

Another by-product from sugar industry, evaluated for its use in cattle nutrition, is sugar cane bagasse pith. It shows low protein level and high fiber content of low digestibility, which limits its intake. However, with a proper supplementation, it can be used as diet complement and contribute to the productive development of animal husbandry.

Martin and Elías (1978) evaluated three protein sources (fish meal, torula yeast and soybean meal) and two NPN: TP (80:20 and 60:40). There was no effect on productive performance due to the protein source used, but there was a response to the relation of protein used, in favor of the lowest use of NNP. This supports the need of using nitrogen in this fiber sources for the functioning of ruminal micro-flora as well as other nutrients by-passing degradation of ruminal bacteria.

Hanke and Martin (1983) worked with sugar cane straw, predigested or not with sodium hydroxide at 4 %, in integral diets. This represented 53 % of the diet, apart from the fact that animals fed with treated straw achieved gains superior to 1 kg of liveweight. There were also favorable results, of more than 900 g, with untreated straw, which demonstrates the beneficial effect of physical grinding in materials with high amount of fiber. Besides, chemical treatment can be avoided because it is expensive and can contaminate the environment.

Among the alternatives to increase digestibility of residues from gathering centers, Stuart (1988) and Stuart and Fundora (1994) used ammonium because a part of it becomes ammonia salts of organic acids that can be used as a nitrogen source by the ruminal micro-flora (Ortiz and Stuart 1983), and, consequently, help to synthesize proteins.

These studies allowed to develop an exploitation technology in gathering centers of the country, which consisted on moving cattle during food scarcity seasons, which coincides with residue generation.

MEAT PRODUCTION IN GRAMINEOUS GRAZING

Due to the characteristics of the digestive system of ruminants, pastures and, mainly, grasses, play an important role as essential food source. Due to the competence for the use of grains for feeding, specifically regarding ruminants, it has been necessary to research and optimize meat production systems based on grasses, in order to produce with higher efficiency. In addition, new varieties are introduced, which were necessary to study for its use in cattle rearing.

The stocking rate was another important aspect because it directly related to productivity generated in a cattle rearing area (Delgado and Alfonso 1974). In a system of pangola grass, without irrigation and with fertilization, stocking rates of 3.5 and 5 animals/ha were used, with systems of rotational grazing of four and ten paddocks. These results showed a decrease of the daily gain per animal, possibly due to the decrease of the capacity to select more nutritive grasses due to the increase of the stocking rate. Likewise, they also allowed to increase meat production per hectare, while the stocking rate increased, frOm 3.5 to 5.0 bulls/ha. Therefore, it should be interpreted that, under these conditions, grass yield was enough to support the stocking rate. Valdés et al. (1981), after fertilizing star grass with 100 kg of N per hectare, demonstrated a decrease of individual gain and gain per surface unit.

The studies carried out also demonstrated a marked seasonal growth, related to rains and DM availability during rainy season. Later, the effect of a protein source during dry season was evaluated, because nutritional quality of grass decreases during this period.

Delgado et al. (1975) supplemented four sources of true protein with molasses-urea (fish meal, soy bean, sunflower and cotton), under pangola grazing during dry season and a stocking rate of 4 animals/ha. Supplement contained 32 % of CP and 72 % of NNP. This demonstrated again the importance of using foods by-passing ruminal degradation and their advantages for productive performance.

Cited authors also demonstrated that, during dry season, the use of NPN has an important function for supplementing the requirements of ruminal microorganisms with protein deficiencies of grass. They obtained good productive results with the use molasses-urea at 10 %. Nevertheless, during rainy season, this supplement decreased productive performance regarding molasses-urea at 6 %, because the increase of grass protein value provokes an excessive intake of urea, which affects efficiency use of energy, used for excreting the excess of ammonium through urea (Delgado et al. 2002).

Molasses-urea was also evaluated as a supplement in the meat production systems in grazing. However, as it is not the main food source, urea percentage in molasses increased at 12 %, as a way of limiting the intake, related to the addition of 150 g of fish meal. This technique produces the same beneficial effects on productive performance as a supplement composed by 45 % of maize, and gains higher than 600 g/d are obtained (Delgado et al. 1980a).

The use of different grazing systems in animal production also contributed to the increase of their productivity. Valdés et al. (1981) used two grazing systems (continuous and rotational) with four paddocks and a stocking rate of three, four and five animals per hectare, in a Coast cross Bermuda grass. A stocking rate higher than three animals provoked a decrease of gain per area, and decreased the animal response during both seasons of the year. The beneficial effect of continuous grazing, regarding the rotational, laid on the possibility of accessing to the tender regrowths of grass. However, while the stocking rate increased in the continuous grazing, the level of weeds increased, compared to the rotational one, which can represent higher overgrazing of the area while the stocking rate increased.

Delgado et al. (1980b) evaluated the grazing system of leaders and followers, and demonstrated its beneficial effect regarding the traditional grazing method, specifically in the aspects of animal performance and parasites of the animals.

Using natural pastures without irrigation or fertilization, Feria et al. (2002) evaluated three grazing methods: rational intensive rotational, traditional rotational and continuous grazing. These authors demonstrated that the rational intensive rotational grazing maintained a stocking rate superior to 2.73 animals/ha, regarding the 1.95 achieved by the other grazing systems, due to the proper use of the “jumping art” and the changes of paddock occupation days according to the season. Besides, a gain of more than 500 g/d/animal was maintained.

Martin and Ruiz (1986) evaluated the effect of grazing time on productive performance in a pangola grassland with a stocking rate of 1.8 animals/ha. Animals had 6 and 8h of daily grazing, 18 h of evening-night grazing and all-day grazing. In all these treatments, forage availability was enough, so it is recommended evening-night grazing system because it reached the best productive results, which could be related to the highest energy value of grass and to differences between day and night temperatures under Cuban climatic conditions. Night temperatures should be closer to the best comfort range of animals.

The previously mentioned researches were generated during growth stages. Nevertheless, Valdés and Castillo (1993) designed a grazing system based on grasses, in order to implement the entire beef production cycle with animals that began with 130 kg of liveweight and ended with 405 kg, during a fattening-growth period of 18 months. This technological proposal consisted on restricting 25 % of the grazing area during rainy season, and fertilize it for producing silage that could be offered to animals during dry season, together with a supplement of molasses-urea at 10 %. This system favored the development of fattening-growing stages within the same grazing area with the use of a stocking rate according to the grassland yield, which allowed grazing segregation during rainy season in order to fulfill the food deficit during dry season.

The high fiber level and the low protein level that influence on the cellulolytic bacterial population are aspects that contribute to the low yield of grazing systems during dry season. One of the alternatives for solving this nitrogen deficit has been the preparation of diets that include some sources of true protein, as well as high levels of non-protein nitrogen (NPN) in order to meet the protein requirements. However, in cattle feeding, a self-regulation of the voluntary intake of traditional supplements has economical and practical interest.

An important step for the study of supplementation was the evaluation of different components as intake regulators. Valdés et al. (1984) evaluated different levels of sodium chloride and its combination with ammonium sulfate. These studies can be considered as pioneers in the creation of ruminal activator supplements and the studies of Jordán et al. (2005) were very important. These authors obtained gains between 900 and 1100 g/d, in grazing and with stocking rates of 3 and 5 animals per hectare.

MEAT PRODUCTION IN SILVOPASTORAL SYSTEMS

Due to the scarcity of fertilizers and their high prices, the association of legumes with grasses was researched, in order to search initially for nitrogen fertilization of the area, thanks to the ability of legumes to fix nitrogen on the soil. Likewise, it was also needed an increase of the grass nutritional value and a food of higher protein value, like legume leaves. Their protein level can be higher than 20 %, which is very necessary in feeding systems with tropical grasses that, many times, have no more than 7 % of crude protein.

Castillo et al. (1989) took the first steps for the inclusion of leucaena in 30 % of a grazing area with guinea grass cv. Likoni. This way, the beneficial effect of including leucaena on grazing areas was verified. After analyzing the health of animals, the weight of thyroid was not affected, and it was lower than that reported in literature. Gradually, steps were taken for increasing the amount of leucaena in grazing, and confirm its effect on animal production. Castillo et al. (1992) increased the inclusion level of leucaena in 50% of the area and used a stocking rate of two and three animals per hectare.

During the dry period, there were no differences in the productive performance with the stocking rate of two animals/ha, whether leucaena was in 30 or 50% of the area. However, after the stocking rate was increased up to 3 animals, there was a decrease in the productive performance, related to the deficit of food for meeting the animal requirements.

Nevertheless, this system obtained the highest liveweight gain/ha/year because gains during the rainy period were over 600 g in all the treatments, using a stocking rate of three animals in 50 % of the area. This evidences the possibilities of this system, considering the need of complementing voluminous food for minimizing the deficit of the grazing area during dry season.

Later, leucaena was increased up to 100% of the grazing area. After comparing it with the area occupied up to 30%, there was an increase of the productive performance of animals, mainly during dry season, when the area with 100% of leucaena surpassed in 150 g/d to that of 30%. So, total liveweight obtained in the year was higher within the same grazing area. The presence of leucaena in the entire area allowed a higher availability of food of better quality, and all the grazing area was benefited with the fixation of nitrogen (Castillo et al. 2000). After analyzing these facts, there was an evaluation of the productive performance of different animal breeds and different supplementation sources.

Castillo et al. (2002) used bulls in the system of leucaena associated to star grass, with a stocking rate of three animals/ha, and reported higher gains in rainy season than in dry season (900 vs. 700 g/animal/d). Díaz et al. (2008a) used a stocking rate of two animals per hectare and Zebu bulls and obtained gains of 700 g/d. However, the supplement used in both studies, belonging to an activator of ruminal fermentation, did not affect the productive performance. This evidenced that, for these feeding systems where protein is not a limiting factor, an energy source in supplementation is needed.

Although leucaena was beneficial for grass yield, rains affected the amount of food. Therefore, biomass banks associated to silvopastoral systems were introduced in the system. Weight gains of 610 g/d were obtained in the silvopastoral system during rainy season. During dry season, 518 g/d of weight gain was obtained with silvopastoral system and CT-115 (Díaz et al. 2009).

The improvement in the animal breeding value influenced positively on the exploitation efficiency of silvopastoral systems because the gains were higher than 900 g/d with Charolais cattle, which was supplemented with 2 kg of an energy supplement that allowed to make a good use of the protein value of grass (Díaz et al. 2008b).

MEAT PRODUCTION IN SYSTEMS OF CREEPING LEGUMES

The grazing systems in which growth stage for fattening animals is developed have inserted creeping legumes in grazing. The objective is to achieve the same beneficial effect as with shrub legumes.

These associations have been mainly carried out in grazing areas of tropical pastures, because they have the lowest nutritional value. Castillo et al. (2003) used a supplement that activates ruminal function during rainy season, and supplemented with final molasses or urea-molasses at 3 % during dry season, in a grazing of natural pastures and associated with creeping legumes, and with a stocking rate of three animals/ha. However, although gains were around 600 g/d, there were no differences with the supplement or without it in both systems. This suggests that the nutritional quality of these grasses do not demand nitrogen supplementation for complementing protein and energy requirements of the rumen. Maybe the energy source to use for supplementation should be more directed to by pass feeds, regarding the molasses that is all degraded in the rumen.

Díaz et al. (2005) increased the gain up to 800 g/d with the use of Zebu animals in the system, but they did not obtain a response to supplementation. Using Charolais males, which have superior breeding value, weight gain increased up to 855 g/d, without the use of supplementation (Díazet al. 2009).

The previously mentioned allowed to develop a production technology that can be applied to growing males and replacement females, oriented to the development of cattle rearing.

SUGAR CANE FORAGE IN BEEF PRODUCTION

The use of integral sugar cane forage as food for cattle had a peak during the 70´s of last century. Nevertheless, in the 90´s, its study was retaken for its implementation in meat production.

Fundora et al. (2007) used sugar cane in integral and semi-integral diets with Zebu animals. It represented 55 % of the consumed dry matter, with weight gains of 900 g/d. These feeding systems were also evaluated with crossbred Holstein animals, with encouraging results in productive performance and gains of 1 kg/animal/d. The voluminous food represented 50 % of the consumed dry matter (Rodríguez et al. 2009a).

The use of different sources of raw matters for producing the supplement has also been studied. The research on this subject demonstrated that maize and soy bean show better performance than wheat bran and norgold, which is an aspect related to raw matter composition. This occurs because the industrial processes that wheat bran and norgold go through provoke the decrease of starch contribution, protein quality and its availability for ruminal microorganisms, in a diet where the main food has low protein percentage (Rodríguez et al. 2013a).

The use of different supplementation frequencies (once or twice a day) was also studied, which allowed to increase daily gain up to 13 %, as well as increase efficiency of food conversion in 15 % (Rodríguez et al. 2013b).This concentrate fractioning allowed a higher stability in the nutrient intake and, consequently, the optimization of the productive process.

CONCLUSIONS

This group of researches, carried out for 50 years, brings the readers a great amount of scientific results that contribute to the efficient use of beef production. Therefore, it is demonstrated that, for the Latin American area, the use of grasses and forages, as well as agricultural residues, have large validity and use  for scientific community and producers.

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Received: December 18, 2014
Accepted: January 28, 2016

Duniesky Rodríguez, Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba. Email: durodriguez@ica.co.cu