Tropical Animal Health and Production

This work aims to improve the selection program of the Timahdit breed through the use of the parameters of the Von Bertalanffy model as selection criteria and the treatment of uncertain paternity found in pastoral systems. A database containing 12,029 animals and a pedigree file integrating the probabilities of the parents with a total of 48,292 animals were used in the analysis. An individual estimation of the parameters of the model studied by the nonlinear regression procedure Proc NLIN of SAS was carried out, followed by the determination of the fixed effects which influence these parameters by means of a general linear model using the GLM procedure of the SAS software. The treatment of uncertain paternity is solved by an R code translating Average Numerator Relationship Matrix Model (ANRM). Then, the variance and (co)variance components were estimated by a Bayesian approach using the BRMS package. The high heritability values obtained, between 0.52 and 0.55 for the parameters studied, suggest good prospects for genetic responses to selection and the maintenance of sustained genetic progress, especially when environmental conditions are unfavorable. The positive correlations between all the parameters studied show that animals with rapid development tend to have lower weight performance. Finally, with optimal selection based on the genetic values associated with these parameters, we can make the desired changes to the growth curve by choosing breeders that achieve high weight performances as quickly as possible, and that would allow improving the feed efficiency for these animals, as well as increasing the profitability of sheep farms.

The basic diet of ruminants in Mauritius comprises mainly tropical forages, whose productivity is highly dependent on the season. Dry matter concentrations and nutritive value of the three most important grasses (Bothriochloa pertusa, Cynodon plectostachyus and Ischaemum aristatum) on Mauritius were measured on three occasions during the year. They showed an increase in dry matter concentration and a decrease in nutritional value at the end of the dry season, more marked for farms located in the coastal region. To allow animals to meet their nutrient requirements, farmers have to adapt their practices (supplementary feeding, rotational grazing, and fertilization) to the seasonal changes on the island.

During late may 2004, Some dairy cows at Al-Kharj area of central Saudi Arabia, gave birth to severely malformed calves which died, few hours to few days following birth. Samples were collected from the affected calves and their dams of virological and serological investigations. Bovine viral diarrhoea virus was detected by capture enzyme linked immuno-sorbent assay (ELISA) in the brains of affected calves. Serum antibodies were detected in the dams. The present study indicated that in spite of vaccination against BVD in the country, still severe affections of the disease are encountered. Further insight epidemiological studies to elucidate the BVD situation in Saudi Arabia is urgently needed.

The high climatic variability of hot climates of the intertropical zone reduces cattle fertility. In dairy cows in temperates zones, the THI has been used to evaluate the temperature and relative humidity (RH) joint effect in reproduction, but its use is not recommended in all geographic zones; in hot climates, the maximum temperature (Tmax) can provide more convenient information than THI. The objective of this study was to determine the artificial insemination (AI) service seasons and their joint effect with the maximum temperature and relative humidity of the previous seven days, the service day, and posterior seven days to the AI in the tropical milking criollo (LT) heifer’s gestation. Climatic data was used to define three seasons: hot-dry (HD), hot-humid (HH), and fresh-dry (FD), and 313 artificial insemination services from 176 heifers were analyzed over fourteen years. The seasons were determined by cluster analysis. Gestation at first service (GF) was analyzed with a logistic regression model and global gestation (GG) with a mixed linear generalized model. The Tmax of previous seven days insemination $$ \hat{\beta}1= $$  − 0.20 ± 0.09 (p ≤ 0.02) in HD (p ≤ 0.02) and RH of seven days posterior insemination $$ \hat{\beta}2 $$ = − 0.08 ± 0.04 (p ≤ 0.04) in HD (p ≤ 0.01) affected GF. No effect of the Tmax and RH on the service day was observed (p > 0.05). The highest GG probabilities were higher than 0.70 in HH and FD, making those seasons the most suitable for inseminating LT heifers.

The reproductive efficiency of dairy cattle is critical to the economic success and sustainability of the enterprise. Due to its many advantages, artificial insemination has inevitably taken its place in herd management today, and different artificial insemination methods have been developed until today. At the same time, artificial insemination is carried out by commercial artificial insemination operators or do-it-yourself operators in cattle farms. One of the factors affecting the success of artificial insemination is inseminators. The aim of this study was to determine the effect of inseminators on conception rates in reproductive challenges and to reveal the differences between the success rates of inseminators. A total of 227,297 artificial insemination acts carried out by 35 inseminators for 4 years belonging to the Konya Cattle Breeders’ Association in Turkey were assessed for this purpose. In the study, the insemination success rate was determined as 41.36%. In addition, the percentage of inseminators with a total insemination success rate of more than 50% is very low, such as 2.9%, and the percentage of those who achieved 35.9% and below was 9.3%. As a result, it can be stated that the inseminators having a lower success rate than the overall should be retrained to avoid costs or losses in the farms.

The study was carried out to determine the chemical composition of composite pellets of Megathyrsus maximus containing Leucaena leucocephala seed meal at the varying level and growth responses, as well as haematological and serum biochemical of rabbits, fed the pellets for 60 days. The treatment consists of M. maximus and L. leucocephala—100:0, 90:10, 80:20, 70:30 and 60:40, respectively. Results revealed an increase (P < 0.05) in the proximate composition of the grass pellets with an increase in seed inclusion while there was a reduction (P < 0.05) in the NDF contents of the pellets. An increase in the tannin contents was recorded with an increase in seed inclusion to the grass pellets. Rabbits fed with 30 and 40% inclusions of seed in the grass pellets had similar weight gain while the lowest feed conversion ratio was recorded in rabbits fed grass with 30% seed inclusion. Packed cell volume, RBC and lymphocyte in rabbits were altered with feeding grass seed pellet (P < 0.05), although no particular pattern was followed. Total protein, globulin and urea contents were reduced in the rabbits as the contents of the seeds in the grass pellets increased. Albumin contents in pellets with 30% of seeds were higher in the rabbits fed the pellets above other treatments. It can be concluded that increasing the seed meal level up to 30% in grass pellets supported growth response without inflicting any side effects on the health indices of the rabbits.