Tropical Animal Health and Production

The nasal exudate from 42 goats of the Mixteca Region in the state of Puebla, Mexico, was evaluated. A strain was isolated after 4 days of incubation. This strain was identified according to its phenotypic characteristics and by means of a species-specific polymerase chain reaction (PCR), as well as by sequencing of the amplified product. The species-specific PCR amplified a 407-bp fragment of 16S RNAr subunit, and the product sequencing revealed 100% homology with Histophilus somni 129PT. The nucleotide sequence was deposited in the GenBank under accession number HM032735. This is the first worldwide isolation of H. somni from nasal exudates of a clinically healthy goat.

This study aimed to evaluate the performance, feed efficiency, feeding behavior, and cortisol concentrations of lambs ranked into different groups of Residual Feed Intake (RFI) and Residual Intake and Gain (RIG). Forty Santa Inês lambs with a mean initial age of 120 ± 30 days and mean initial (IBW) and final body weight (FBW) of 28.9 ± 3.2 and 43.7 ± 3.9 kg, respectively, were used. The animals were fed at an automatic feed and water station (Intergado®) for 60 days and classified at the end of the experiment as low-RFI/RIG, medium-RFI/RIG, and high-RFI/RIG according to RFI and RIG. Performance, feed efficiency measures, ingestive behavior, temperament, and cortisol concentrations were measured, and Pearson’s correlation analysis was performed to evaluate the relationship between the variables studied. The variables that differed most between RFI groups were dry matter intake, feed conversion, and feed efficiency, with better values in efficient animals (RFI−). Regarding the RGI groups, the average daily gain of animals classified as RIG- was 19.37% lower than that of animals classified as RIG± and 39.28% lower than that of animals classified as RIG+. Only the hourly feeding rate per day (p = 0.04) differed significantly between RFI and RIG classes, while no differences were observed for the ingestive behavior variables or cortisol. The number of visits to the feed bunk (total, with or without intake) showed no correlation with any performance or efficiency measure. Identifying animals ranked into different RFI and RIG classes shows that more efficient animals have a lower feed intake for the same weight gain and spend less time at the feed bunk.

The objective of this study was to evaluate the effects of replacing the protein source of soybean meal (SBM) with different levels of bitter vetch seeds (BVS) in the diets of finishing Awassi ram lambs on performance, and carcass characteristics. Diets were designed based on replacing SBM with BVS as a percentage of the diet. Diets were: control (0% BVS), substituting 5% of SBM (5% BVS), 10% of SBM (10% BVS) and the entire SBM in the ration with BVS (15% BVS). Forty eight lambs (18.74 ± 3.95 kg initial body weight and 70 days of age) were randomly assigned to 4 treatment diets (12 lambs/treatment). Lambs were given an adaptation period of 10 days and the experiment lasted for 84 days. At the end of the trial, a digestibility experiment was performed and 6 lambs from each treatment were slaughtered to evaluate carcass characteristics. Average daily gain tended (P = 0.07) to be higher for lambs fed 10% BVS when compared to the other diets. Neutral detergent fiber digestibility was higher (P < 0.01) in control diet compared to the other diets. Fat depth (C) and leg fat depth (L3) tended (0.05 < P < 0.1) to be affected by BVS levels in the diet. Leg total lean % was the highest (P < 0.05) in 5% BVS and 10% BVS diets. These results suggest that substituting SBM with BVS in the diets did not influence performance or carcass characteristics of lambs. However, the cost of ration formulation decreases since SBM is a very expensive component of the ration.

Infection experiments, morphological observations and transmission experiments were conducted with an unidentifiedTheileria sp. isolated from a naturally infected ox. The results showed that the protozoa could multipy extensively in a splenectomized ox and the parasitaemia could reach 52·69%. TheTheileria sp. was polymorphic: being pear-shaped, circular, elliptical, rod-like, comma-shaped, three-leafed- or cross-shaped and having many other irregular-shapes which were seldom detected. In erythrocytes, the anaplasma-like protozoa grew, producing protoplasm which could extend and clump together, and developed into many polymorphic protozoa. Some of the protozoa propagated themselves by budding. The protozoa could not be transmitted byHaemaphysalis longicornis orHyalomma detritum. The pathogenicity, vector ticks and life cycle of this protozoan are unknown.

Having a successful heifer raising operation is not only relevant financially, but also influential for the future of the dairy herds. Milk feeding has a significant role on the health and growth of calves before weaning, in addition to the direct progressive effects on future performance post-weaning. Therefore, the aim of this study was to compare the effects of constants amount of milk (CMS) versus step-up/step-down (SUSD) on calf performance in two different suckling schedules of suckling milk gradually till 9th weeks of calf age, then decreasing it till weaning. For this study, forty Holstein heifers calves utilized between birth and 8 months of age were randomly divided into four groups of 10 calves each. Grouping was performed according to suckling protocol (constant versus variable) and suckling schedule (2 versus 3 times/day). Each calf suckled 600 kg of milk in a suckling period of 120 days. Body weight (BW), in addition to five body measurements: chest girth (CG), height at wither (HW), height at rump (HR), body length (BL), and diagonal length (DL), were recorded weekly. The heaviest BW was observed on SUSD calves suckling twice/day which had also the highest HW at weaning. Similarly, were BW, HW, and CG at 6 months of age. Also, the same group achieved the largest daily BW (0.902 kg/day), BL (0.246 cm), and CG (0.338 cm/day) gains during the pre-weaning phase. However, CMS suckled 3 times/day calves had the largest daily BW gain between birth and 6 or 8 months of age. CMS twice/day calves had the largest daily gain in CG from weaning to 6 months and from weaning to 8 months of age followed by SUSD suckling 3 times/day calves. Also, CMS twice/day calves had the largest daily gain in rump height from birth to 8 months of age compared to other groups. It can be concluded that when equal amounts of milk were fed during the suckling period, suckling protocol affected growth rate before weaning but that effect diminished as calf age increased after weaning.

Studies reporting the effects of oxytocin on the health of lactating animals are lacking and still no such data is available on Nili Ravi buffalo, the most prominent Asian buffalo breed. The present study was conducted to investigate the effect of oxytocin on physiological and metabolic parameters of lactating Nili Ravi buffaloes. Healthy lactating buffaloes (n = 40) of recent calving were selected from a commercial dairy farm situated in the peri-urban area of district Faisalabad, Pakistan. These buffaloes were randomly allocated to two equal groups viz experimental and control, comprising 20 animals each. Twice-a-day (morning and evening) milking practice was followed. The experimental and control buffaloes were administered subcutaneously with 3 mL of oxytocin (10 IU/mL) and normal saline respectively, prior to each milking. Serum biochemical profile including glucose, total cholesterol (tChol), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), total proteins (TP), C-reactive protein (CRP), liver enzymes aspartate transaminase (AST), alanine transaminase (ALT), and metabolic hormones triiodothyronine (T3) and thyroxine (T4) were studied. Results revealed significantly higher (P ≤ 0.01) levels of glucose, total cholesterol, LDL-C, triglycerides, total proteins, and C-reactive protein in experimental (oxytocin-injected) lactating buffaloes compared to control group. Liver enzymes AST and ALT as well as serum T4 concentration was significantly higher (P ≤ 0.01) in oxytocin-injected lactating buffaloes as compared to control animals. It was concluded that oxytocin had the key role in increasing the metabolic parameters and hormones, resulting in the optimization of production. But, at the same time, it may pose a threat to the animal health.

There are inconsistent results for the association of Mycobacterium avium subspecies paratuberculosis (MAP) infection with production and reproduction in dairy cows. Determination of these associations in each region is essential to encourage participation of dairy cattle producers in disease control programs. This study was conducted in Shiraz, southern Iran, to quantify the association of subclinical MAP infection with 305-day milk production and calving interval in Iranian Holsteins. A total of 21 dairy herds were selected for the study and in each herd, quarter milk samples were collected from ten to 12 dairy cows for PCR analysis. Data about parity, calving interval, length of lactation period, total milk production and 305-day milk production were also provided for each animal. Overall, 252 individual milk samples were collected. Herd- and individual-level prevalence of MAP infection were 23.8% (95% CI, 6.2–41.4%) and 3.2% (95% CI, 1.3–5.1%), respectively based on IS900 nested PCR. The results for 305-day milk production revealed a 248 kg reduction in positive cows compared with negative ones (P = 0.009). When cows from positive herds were compared with cows from negative herds, a 335-kg reduction in 305-day milk production (P = 0.005) and a 30-day increase in calving interval (P = 0.057) were observed in the former group. These findings support the previous results that paratuberculosis infection is negatively associated with the performance of the animals.