The low digestibility of poor quality fibers such as crop residues is due to the high lignin content of the cell wall. Sodium hydroxide, ammonia and urea are most often used in the treatment of poor quality fibres.
FORAGE SUPPLEMENTS
Herbaceous legumes
HBLs have higher levels of CP than energy, suggesting that they need to be supplemented with a fermentable energy source to utilize CP efficiently (Van Eys et al., 1986; Nsahlai et al., 1998). HBLs have great potential for use as supplements in resource-poor communities because they are inexpensive, convenient, and require no other external inputs (Nsahlai et al. 1998). Farm-grown feed supplements such as alfalfa and cow hay f. , provide essential nutrients needed for improved use of poor quality forage by rural livestock producers during dry periods.
Browse supplements
Although both HBLs and browse plants are rich in crude protein and other nutrients, and have a high potential to be used as protein supplements, some of them contain anti-nutritional factors that directly or indirectly have detrimental effects on animal performance. In a review, Kumar and Vaithiyanathan (1990) have shown that increasing the levels of tannins reduces the eradication of vitroDM.
Leucaena leucocephala (Leucaena), a multipurpose plant
- Nutritive value of Leucaena
- Detoxification of Leucaena
- Limitations of cottonseed meals
When Leucaena is supplemented, it promotes high rumen ammonia levels and rumen pH ranges between 7.14 and 7.24 (Bonsi et al., 1995). They are described by Coppocket al. 1987) as multi-nutrient supplements rich in energy, fiber, protein and phosphorus.
NUTRITION-REPRODUCTION INTERACTIONS IN THE MALE RUMINANT
Rams fed oat hay and supplemented with lupine seeds, which are known to be rich in metabolisable energy (14.1MJ kg) and protein (35.5g/kg) (Dugmore, 1995), had increased spermatozoa production per testis and had heavier testes than fed rams. on the control diet (table 1.12). There is therefore a direct correlation between the plane of nutrition and spermatozoa production (Rekwot et al., 1988, citing Asdell, 1955).
SUMMARY
Previous studies on the effect of gossypol on reproductive performance in ruminants have focused on bulls. Although detailed histological studies have been performed on the effect of gossypol on testicular tissues of bulls, no such studies have been performed on sheep. Similarly, changes in serum levels of some minerals were studied in cattle fed cottonseed oil meal; this is not the case with sheep. The effect of Leucaena leucocephala (Leucaena) supplementation on ram fertility was investigated in Merino rams (52.7 kg ± 3.6), which were fed Eragrostis hay as a basic diet for 60 days.
There was no significant (P<0.05) treatment effect on serum levels of Zn, Cu and Fe. It was concluded that short-term supplementation of Eragrostis hay with 340 g of Leucaena had no harmful effects on the fertility of the rams.
INTRODUCTION
The positive aspect of Leucaena tends to be masked by some anti-quality factors such as mimosine (Jones and Hegarty, 1984; Hamrnond, 1995) and tannins (Reed et al., 1990). However, little information is available on the effect of Leucaena on the reproductive performance of animals. 1988) reported that Murrah bucks had poor sperm quality when fed Leucaena at 500 g/kg DM basal diet for 97 days. 1971), however, found that Leucaena did not cause deleterious effects on the length of estrus, conception rate, and length of pregnancy in heifers fed a single Leucaena diet, but their calves had lower birth weights. 1981) contrasted the deleterious effect of Leucaena through embryonic death and resorption among heifers grazed virtually exclusively on Leucaena.
Based on scrotal circumference, Kaitho et al. 1997) did not observe any adverse effect of Leucaena supplementation in Ethiopian highlands. This study therefore aimed to investigate the effect of the two roughage supplements on the blood mineral profile and semen characteristics in sheep.
MATERIALS AND METHODS
Semen color was assigned a score of 2 to 1, while consistency was assigned a score of 5 to 0. The description and interpretation of the color and consistency scores were performed according to Boundy (1993) and Bertschinger (1992, unpublished). score of 2 represented yellow, ivory, or white sperm, which was the normal sperm color range, and a score of 1 represented abnormal sperm color. The hemocytometer was placed on a microscope and the sperm cells were counted under high power magnification (x400). All sperm cells that were within the 10 large squares of both chambers were counted and cells whose heads were outside the boundaries of any of the 10 large squares were not counted. Repeated counts were made on two hemocytometers per sample and the concentration per ml was calculated from the average total per 10 large squares. The following formula (Salisbury and Van Demark, 1978) was used to calculate the number of spermatozoa in one gram of testicular tissue.
W= the weight of both testicles in grams. C= number of squares of the hemocytometer in which sperm cells were counted in both chambers. Sperm cells obtained from the tail of the epididymis were fixed in 3% glutaraldehyde and washed in 0.05 M sodium cacodylate buffer.
RESULTS
Rams fed the control diet had higher concentrations of PCV, Ca, Mg and Se compared to the other two groups, but P concentration was higher (P Sperm cell lines from Leucaena-fed rams showed a higher incidence of disintegration or degeneration than control and lucem e-fedrams (Figure 2.3). Although there was no significant treatment effect on sperm cell morphology, the incidence of sperm heads with degenerate outlines (DH) was slightly higher among Leucaena fed rams than control and alfalfa fed rams (arrow in A and Bt. The outline of the sperm head of a normal cell is shown in C. Mimosine is anti-mitotic (Holmes et al., 1981) and the tendency towards a low sperm count for Leucaena-fed rams observed in this study may be attributed to the anti-mitotic activity of mimosine. Se deficiency leads to reproductive disorders in ruminants (Cheeke, 1991) and the low levels recorded for control and Leucaena-fed rams may be due to a nutritional deficiency and the chelating property of mimosine. Mimosine forms a ligand with Fe and Fe is an essential component of red blood cells. The trend towards low levels of PCV obtained for Leucaena fed. Leucaena-fed rams had similar intake, blood mineral profile and sperm characteristics to the rams on alfalfa and control diets. PCV of T3 fed rams was higher (P THE LONG-TERM EFFECT OF FEEDING ALFALFA, COTTONSEED CAKE AND A HIGHER LEVEL OF LEUCAENA LEUCOCEPHALA ON RAM FERTILITY. Serum mineral concentrations for all rams fed the three diets were optimal and this was attributed to the high levels of minerals in the legumes and cottonseed cake. It was concluded that long-term supplementation of Eragrostishay with alfalfa, cottonseed cake or Leucaena had no adverse effects on ram fertility. . Cottonseed cake has a high protein content and is used as an inexpensive protein supplement (Coppock et al., 1987). Cottonseed cake was therefore chosen as a comparison in assessing the toxic effects of Leucaena on the histology of ram testicular parenchyma. This study was conducted to assess the long-term effect of the supplementation of Leucaena leucocephala, alfalfa and cottonseed cake on the properties of ram sperm and some blood minerals. The daily amount of food was weighed and given to the animals in one meal each morning and all the food provided was consumed. Rams were weighed biweekly after 12 hours of food and water withholding, and weight was recorded in kg. The tubes containing the collected sperm were kept in a water bath maintained at 37°C until the sperm were assessed for fertility. The parameters used in the evaluation of sperm fertility were pH, wave mobility, viscosity, morphology and number of sperm cells. Primary sperm cell defects were highest, intermediate, and lowest among Leucaena, CSC, and control-fed rams. Secondary sperm defects were highest among control-fed rams and intermediate for Leucaena-fed rams. CSC and Leucaena fed rams had a better germ cell activity shown by the higher number of dividing cells. The difference may have been due to mimosine and DHP being detoxified by rumen bacteria in this study. 1990) showed that gossypol in cottonseed products causes deleterious effects on sperm, Randel et al. 1992) pointed out that gossypol is harmful in the free form. Linseed cake gossypol is in bound form and becomes bound to the amino acids in the CSC protein during the oil extraction process. In immature ruminants, gossypol becomes further bound to protein during digestion in the rumen (Brocas et al., 1997). The differences in treatment were likely due to the high amounts of minerals in the diet in the second study, as evidenced by the high ash levels in the herbaceous legumes. The rest of the rams in the T3-fed group were not affected. The loss of condition and failure to produce sperm were probably due to lack of nutrition. Leucaena contains dihydroxypyridone (DHP), a potent goitrogen (Hegarty et al., 1976) that has been shown to reduce thyroxine levels in calves within a week (Gupta and Atreja, 1998). In the second study, neither 50% of Leucaena nor 23% of cottonseed cake supplemented with Eragrostis hay was harmful to ram spermatozoa. Copper is a component of hemoglobin and these defects have been attributed to abnormalities in the red blood cells (Underwood, 1977). However, their deficiency leads to poor food intake, loss of body condition and reduced reproductive efficiency. the two studies the latter three elements were adequately supplied, probably by the herbal supplements that were rich in minerals. The slight negative effect observed on seed in both studies may be due to handling errors. Effect of dietary Leucaena leucocephala levels on feed intake and feed efficiency of Yankasa rams. Collection and assessment of semen in rams. 1989) Reproductive development and function of Brahman bulls fed diets containing gossypol: growth parameters and semen near puberty. Journal of Animal Science 69: Supplement 1, page 368 (abstracts). The influence of the level of feed intake on the sperm production capacity of the testicular tissue in the ram.
DISCUSSION
INTRODUCTION
MATERIALS AND METHODS
DISCUSSION
GENERAL DISCUSSION AND CONCLUSIONS
