H. Hamudikuwanda

Effect of different dietary energy level intakes on efficiency of estrus synchronization and fertility in Mashona goat does

The objective of the study was to determine the effects of three dietary energy levels: 0.27 (low level: LL); 0.53 (medium level: ML), and 1.06 (high level: HL) MJMEkg(-1)W(0.75) on estrus synchronization and fertility in Mashona goat does. Forty-five multiparous Mashona goat does of average bodyweight 19.9+/-2.5kg were randomly allocated in equal numbers to the three dietary energy levels. The diets were made from a complete feed ration providing 9.83MJMEkg(-1)DM and 15.5% CPkg(-1)DM. Does were fed initially during a 60-day pre-synchronization period, and blood samples were collected twice a week for the determination of plasma progesterone concentrations to ascertain ovarian activity. Intramuscular injections of cloprostenol (100µg each) were administered 11 days apart. Immediately after the second injection of cloprostenol, three fertile bucks were introduced to the does and were left with the does for 21 days. The does were maintained on their dietary treatments throughout gestation except for those does in the LL treatment. Pregnancy was diagnosed 90 days post-mating using an ultrasound scanner. After pregnancy diagnosis, does on the LL treatment were randomly allocated to ML (n=7) and HL (n=8) treatments. During the pre-synchronization period, does on the LL treatment lost 12.3% whereas those on ML and HL treatments gained 2.1 and 28.8% of their initial bodymasses, respectively. The proportion of does exhibiting overt estrus within 96h after the last cloprostenol injection was significantly lower (P<0.05) for does on the LL treatment (60%) than for those on ML (93%) or HL (100%) treatments, respectively. However, based on plasma progesterone concentrations, the percentage of does on the LL treatment that exhibited ovarian cycles was numerically lower than that of does that were bred (40 versus 73%). Conception, fecundity and twinning rates were significantly lower (P<0.05) on the LL treatment than on the ML and HL treatments. These results indicate that feeding Mashona goat does 0.27MJMEkg(-1)W(0.75) compared to 0.53 and 1.06MJMEkg(-1)W(0.75) reduces the expression of estrus, conception, fecundity and twinning rates, and that feeding 0.53MJMEkg(-1)W(0.75) suffices for optimum reproduction. In addition, the results suggest that cloprostenol administration may induce ovarian cycles in reproductively quiescent does on dietary energy restriction.

Dry matter intake, apparent digestibility and excretion of purine derivatives in sheep fed tropical legume hay

Four ruminally cannulated wethers (31+/-1.3kg) were used in an experiment with a 4x4 Latin square design to estimate the DM intake, apparent digestibility, nitrogen balance, rumen ammonia and microbial protein production. The sheep had ad libitum access to either Cassia rotundifolia (Cassia), Lablab purpureus (Lablab), Macroptilium atropurpureum (Siratro) or Stylosanthes guianensis (Stylo). Dry matter intake of cassia was lower (P<0.001) than that of lablab, siratro and stylo hays. Organic matter intake was greater (P<0.001) for lablab, siratro and stylo hays than that of cassia. Dry matter digestibility was higher (P<0.05) for lablab hay, than that of cassia, siratro and stylo hays. The organic matter digestibility ranged from 0.579 for cassia hay to 0.617 for stylo hay and there were no differences (P0.05) among the legume hays. Nitrogen intake was highest (P<0.05) in sheep given stylo hay and least in sheep fed cassia hay. Animals given lablab, siratro and stylo hays had higher (P<0.05) faecal and urinary N compared to those on cassia hay. Rumen ammonia N concentration was highest (P<0.05) in sheep given lablab while sheep offered siratro and stylo had intermediate values, and least in animals fed cassia hay. The ammonia levels were above the recommended optimal level of 50mg N/l. The total purine derivative excretion in the urine and microbial N supply was not different (P0.05) among treatments. From the presented findings it is concluded that the intake and digestibility in sheep of the four legume hays are variable and provide adequate rumen ammonia N for maximum rumen microbial growth making then ideal protein supplements to ruminants fed low quality roughages.

Changes in stress-related plasma metabolite concentrations in working Mashona cows on dietary supplementation

Effects of work stress and dietary supplementation on body condition score and plasma metabolite concentrations were determined in 16 multiparous Mashona cows in a smallholder crop–livestock farming area in Sanyati Communal Lands. The cows were divided into four treatment groups of equal numbers. These were: supplemented working (SW), supplemented non-working (SNW), non-supplemented working (NSW) and non-supplemented non-working (NSNW). Cows in the SW and NSW groups pulled carts with 400-l drums of water for a distance of 18 km five times each week for the 12 consecutive weeks of the experiment. During the experimental period, body condition scores were assessed at 2-weekly intervals and plasma metabolite concentrations determined in samples collected once per week. Imposing work reduced (P<0.05) body condition score in the cows. In addition, work induced a decline (P<0.05) in plasma glucose concentrations, and increased (P<0.05) non-esterified fatty acids and serum urea levels circulating in blood. Supplementary feeding improved (P<0.05) body condition score of cows. These results indicate that, using cows for draught results in the mobilisation of body fat and protein reserves, probably to supplement the nutrient demand for draught power. In addition, SW and NSW cows maintained their metabolite levels within the normal physiological ranges, indicating that, for the best welfare of cows that are used in the provision of draught, they should be given supplementary feed.

Effects of Supplementing a Basal Diet of Chloris gayana Hay with One of Three Protein-rich Legume Hays of Cassia rotundifolia, Lablab purpureus and Macroptilium atropurpureum Forage on Some Nutritional Parameters in Goats

Growth and digestibility experiments were conducted on growing East African type goats offered Chloris gayana hay supplemented with one of three high-protein (119–128 g CP/kg DM) legume hays, Cassia rotundifolia (cassia), Lablab purpureus (lablab) or Macroptilium atropurpureum (siratro), and crushed maize to investigate the feed intake, digestibility, growth and urinary excretion of purine derivatives. Goats in the supplemented groups had higher total dry matter and nitrogen intakes and higher N retention and body mass gains than unsupplemented counterparts. The digestibility of dry matter, organic matter and neutral detergent fibre were increased by protein supplementation. Animals on supplemented diets had higher fractional outflow rates of particulate matter from the rumen. The production of protein by ruminal microbes and the efficiency of microbial N production were increased by supplementation. It was concluded that a mixture of low-quality grass hay (61.9 CP/kg DM) and either cassia, lablab or siratro hay, and maize grain can provide a productive balanced diet for growing goats.

Condensed Tannin and Saponin Content of Vigna unguiculata (L.) Walp, Desmodium uncinatum, Stylosanthes guianensis and Stylosanthes scabra Grown in Zimbabwe

Samples of the tropical forage legumes Vigna unguiculata (L.) Walp (cowpea), Desmodium uncinatum (silverleaf desmodium), Stylosanthes guianensis (oxley fine stem stylo) and Stylosanthes scabra (fitzroy) and of natural pasture (veld) hay were analysed and ranked according to their proanthocyanidin (PA) and saponin content. Silverleaf desmodium and fitzroy leaf and stem samples of different ages were also separately analysed for the PA contents. All the samples analysed contained some PA but no saponins. High levels of PA were detected in silverleaf desmodium and very low levels in veld hay and cowpea. In all samples, more of the tannins were bound to protein or neutral detergent fibre (NDF) than were extractable, most being bound to proteins. The proportion of the unextractable PA was greater in younger than in mature materials.

Reproductive Performance and Body Weight Changes in Draught Cows in a Smallholder Semi-arid Farming Area of Zimbabwe

The reproductive performance of 46 cows in a semi-arid, smallholder farming area of Zimbabwe was monitored for a year. Half the cows were used throughout the monitoring period for various draught purposes, including ploughing and procurement of farm produce for marketing using carts. All the cows lost body weight between July and October, after which the cows that were not worked gained weight until June of the following year. In contrast, the cows that were worked continued to lose body weight until January, throughout the time during which they were used to provide draught power, after which they gained weight. Body weights were significantly higher (p<0.05) in non-working than in working cows in January and February. Ovarian activity was higher (p<0.001) in non-working compared to working cows, particularly between November and February, while calving rates were also higher (p<0.05) in non-working cows. It is concluded that using cows for draught purposes caused loss of body weight and reduced ovarian activity and conception rates.

A Monitoring Study on the Prevalence of Dermatophilosis and Parafilariosis in Cattle in a Smallholder Semi-arid Farming Area in Zimbabwe

The prevalences of dermatophilosis and parafilariosis were monitored for one year in cattle in Sanyati, a semi-arid smallholder farming area in Zimbabwe. The prevalence of dermatophilosis differed (p<0.05) with season and among calves, cows, oxen and bulls. In bulls and cows, dermatophilosis lesions were localized mainly to the inguinal regions and between the front limbs. The prevalence and morbidity of dermatophilosis infection were significantly higher (p<0.05) during the wet season than in the dry season. No mortalities were recorded. The prevalence of parafilariosis was similar to that of dermatophilosis. Infection of cattle by these skin diseases was preceded by high infestation with the tick Amblyomma variegatum. The results suggest that dermatophilosis and parafilariosis have become major diseases that could compromise reproductive performance, draught power availability and overall cattle productivity, particularly during the rainy season in Sanyati smallholder farming area of Zimbabwe.

Rumen degradability and post-ruminal digestion of dry matter, nitrogen and amino acids in three tropical forage legumes estimated by the mobile nylon bag technique

Abstract The ruminal degradability and intestinal digestibility of dry matter (DM), nitrogen (N) and amino acids (AA) in whole plants of tropical forage legumes were estimated in three rumen and duodenal cannulated non-lactating Holstein/Friesian cows using the mobile nylon bag method. The legume samples were incubated in the rumen for 12, 24 and 48 h. After rumen incubation, the mobile bags were pre-incubated in pepsin–HCl solution before inserting into the duodenum and recovering in the faeces. Rumen DM degradabilities of cassia and of siratro were greater than that of lablab and increased with increasing rumen incubation time. The post-ruminal digestibility of undegraded DM was not different between the legumes. Similarly, N degradability was not different among the three legumes after similar incubation periods. However, the intestinal digestibility coefficients of rumen undegradable N in cassia and siratro were greater than that of lablab. The digestibility of total amino acids varied between 0.346 and 0.771. The digestibility coefficients of essential amino acids and non-essential amino acids followed a trend similar to that of total amino acids. Siratro showed the highest digestibilities of individual amino acids, total amino acids and nitrogen with cassia being intermediate and lablab the least. These results indicate that undegraded legume proteins differ as sources of absorbable amino acids in the small intestines.

Acute mammalian toxicity of four pesticidal plants

Many plant species show potential as alternatives to synthetic pesticides but little is known about their acute mammalian toxicity. The single-dose acute oral toxicities of crude aqueous extracts of Strychnos spinosa and Bobgunnia madagascariensis fruits and the foliage of Vernonia amygdalina and Cissus quadrangularis (plant species that are commonly used as pesticides in Southern Africa) were evaluated in BALB/c mice. Plant extracts (up to 75% w/v or v/v) were orally administered to sexually mature mice. Behavioural changes, clinical signs and mortality were monitored for 4 days. Mice that received S. spinosa had generalized tonic muscle spasms and a high mortality of 83%. Those that received B. madagascariensis exhibited signs of buccal and nasal irritation with occasional sneezes during administration and a high mortality of 75% was recorded. C. quadrangularis consumption resulted in much lower mortality of 21% while no clinical signs of toxicity were evident on mice administered V. amygdalina. Chemical analysis showed the presence of secoiridoids in the seedless pulp of S. spinosa. These results indicate that aqueous extracts of S. spinosa and B. madagascariensis fruits and foliage of C. quadrangularis may have deleterious health implications on humans and animals; hence, advice on their safety should accompany promotion of their use.

The Nutritive Value, Intake, Digestibility and Nitrogen Balance of Farm-grown and Prepared Sunflower-based Dairy Calf Meals

The dry matter intake (DMI), digestibility and nitrogen balance of three sunflower-based farm-grown calf meals with different roughage sources (maize stover, MSM; groundnut tops, GTM; and veld hay, VHM) and a commercial calf starter meal (control; CSM) were studied for 47 days (26 days pre- and 21 days post-weaning) in calves. The DMI was lower (but p>0.05) with CSM (0.369 kg/day) than with the farm-grown meals (mean 0.559 kg/day), and the daily weight gain (kg/day) did not differ significantly (p>0.05) between CSM (0.107), GTM (0.053), MSM (0.157) and VHM (0.217). Dry matter, organic matter and protein digestibility were higher (p<0.07) on the CSM than on the GTM treatment. Nitrogen retention was least (p<0.05) in calves fed GTM (3.0 g N/day) compared to those fed MSM (10.4), VHM (5.0) or CSM (3.9). These results indicate that farm-grown and prepared sunflower-based meals are suitable for feeding young calves.