Revista Colombiana de Ciencias Pecuarias

Effects of dietary supplementation with Erythrina americana on the seminal characteristics of rams

Tue, 01 Oct 2024 00:00:00 -0500

Background: The use of antioxidants of natural origin is an alternative to improve the cryopreservation of sheep semen. Objective: To evaluate the effect of Erythrina americana diet supplementation in the seminal characteristics of rams. Methods: Ten rams were randomly distributed in two treatments: l) group with addition of E. americana (20% dry matter basis) in the diet (AEA, n=5), and 2) the control group without addition of E. americana (SEA, n=5). Both diets were balanced iso-proteinically and iso-energetically. The feeding period of the rams was eleven weeks. The ejaculates were obtained through an artificial vagina and were evaluated fresh (37 °C) and refrigerated (5 °C). Volume (VOL) was evaluated with a tube graduated in milliliters, sperm concentration (CON x10⁶) with a photometer and mass motility (MM, 1-5), individual motility (IM), normality (N) and live sperm (L) by microscopic observation. Results: The fresh semen showed that the inclusion of E. americana in the diet of rams did not modify (p>0.05) the parameters of VOL, CON, MM, and N, but decreased (p<0.05) the IM and L. In refrigerated semen the variables L and N were not different (p>0.05) among the treatment groups; however, IM was improved by the AEA group (p<0.05) compared to the SEA group. Conclusion: The supplementation with E. americana in the diet of rams reduces the sperm quality in fresh semen but is beneficial in the cooling process for refrigerated semen.

Influence of genetic merit on the price of Nellore bull semen in Brazil

Otávio Detoni — Tue, 01 Oct 2024 00:00:00 -0500

Background: The genetic test for Expected Progeny Differences (EPDs) is one of the newest technologies to reduce uncertainty in calf production. It provides information about the genetic composition of a bull, which relates to its propensity to produce offspring with specific growth and quality characteristics. Objective: To evaluate the influence of EPDs reports on the variation of Nellore bull semen prices for artificial insemination in the Brazilian beef cattle industry. Methods: Ordinary Least Squares (OLS) regressions were estimated. The study utilized genetic data provided by GENEPLUS as well as market prices of semen and physical measurements of the bulls collected from the Alta Genetics Insemination Agency. Results: Genetic results, except for age at first calving, weaning weight, and weight at 120 days EPDs, have little influence on semen prices. For each additional day expected for the first calving of the progeny average price of semen decreases by 0.66%. For each additional kg expected in weaning weight, the semen price was 1.73% higher. Furthermore, for each additional kg expected in the progeny at 120 days, semen price increased by 2.46%. Conclusion: Joint analyses of genetic reports and physical characteristics of bulls may provide a better explanatory power.

Relationship between body weight and dorsal area in female buffaloes

Tue, 01 Oct 2024 00:00:00 -0500

Background: The body weight (BW) of animals at various growth stages is an important piece of information for the decision-making process. In the current "livestock 4.0" or precision livestock farming it becomes necessary to know if body measurements obtained from the dorsal view of an animal are related to its BW. Objective: To evaluate the relationship between BW and dorsal area (DA) of water buffaloes (Bubalus bubalis) reared in southeastern Mexico. Methods: The BW (340 ± 161.68 kg), hip width (HW), thorax width (TW), and body length (BL) were measured in 215 female Murrah buffaloes aged between 3 months and 5 years. The DA (m2) was calculated using the mathematical formulae for the area of a trapezoid, considering HW, TW, and BL in the calculation. The relationship between BW and DA was assessed with correlation and regression models. Results: The correlation coefficient between BW and AD was 0.96 (p<0.001). The linear equation had the highest determination coefficient (R2 = 0.94) along with the lowest mean square error (MSE = 1716.86), root MSE (RMSE = 41.43), Akaike Information Criterion (AIC = 1603.36), and Bayesian Information Criterion (BIC = 1610.10). Conversely, the allometric equation exhibited the highest values of MSE, RMSE, AIC, and BIC. Based on the quality of fit by the k-folds technique, the three proposed equations showed consistent adjustments, with more than 90% accuracy (R2 = 0.92). The quadratic equation exhibited the lowest mean squared prediction error and mean absolute error. Conclusion: The DA can be used as a good predictor of BW in buffaloes, especially when incorporated into first and second-degree linear equations.

Índice temático Volumen 37, 2024

Tue, 01 Oct 2024 00:00:00 -0500

Effects of feeding-phase duration and anticoccidial inclusion on growth and carcass traits of broilers

Tue, 01 Oct 2024 00:00:00 -0500

Background: A typical broiler production program includes three feeding phases: Pre-starter (from day 1 to 10), Starter (11-21 days), and Grower (from day 22 to slaughter). The program should allow the bird to express its genetic potential and respond to the nutritional challenges. Objective: To determine the effect of duration of the starter and grower phases on growth performance parameters (feed intake and feed conversion), mortality, skin pigmentation, and carcass yield in broiler chickens. Methods: A total of 1,500 Ross 308 AP male broilers were randomly assigned to five feeding programs with different duration, feed presentation (pellet vs. crumble), and anticoccidial (narasin + nicarbazin vs. salynomicin). The variables evaluated were growth performance (body weight, feed intake, and feed conversion), carcass (weight and yield), breast weight and yield, and skin pigmentation. Statistical evaluations were conducted on d 28 and 40 of age. Results: On d 28 of age, differences (p<0.05) were observed for body weight and feed conversion, but not for feed intake. T4 and T5 resulted in the best weight and feed conversion. Differences (p<0.05) were recorded on d 40 for body weight, with higher values in T4 and T5 compared to T1. Carcass weight differed between T1 and T4 (p<0.05), without difference for carcass or breast performance. The statistical analyses of carcass pigmentation showed an effect on redness (“a”) and yellowness (“b”) at d 28. Conclusions: Body weight and feed conversion of broilers from d 22 to 28 improve by extending the starter phase one week, using pelleted feed added with an ionophore anticoccidial. Skin pigmentation of broilers at slaughter is not affected by restricting pigment intake for one week.

Gastrointestinal parasites in common opossums (Didelphis marsupialis) of urban protected areas in Antioquia, Colombia

Tue, 01 Oct 2024 00:00:00 -0500

Background: The common opossum (Didelphis marsupialis) is a generalist species that hosts several parasites. Nevertheless, no information is available on the specific parasites that this species may host when it inhabits urban areas. Objective: To evaluate the presence and frequency of gastrointestinal parasites of urban opossums in the Aburrá Valley, Antioquia, Colombia. Methods: A total of 70 opossums were captured in six protected urban areas using Tomahawk traps during six months. From these animals we obtained 65 fecal samples which were fixed wit SAF solution and analyzed with direct smear and sedimentation techniques. Results: Sixty-one samples were positive for, at least, one parasite (93.9%) and 60 were positive for two or more parasites, averaging five parasites per animal. We observed nematodes in 58 samples (89.2%), protozoa in 46 samples (70.7%), acanthocephalans in 29 samples (44.6%), and cestodes in eight samples (12.3%). The most frequent parasite was Aspidodera spp. in 80% of the samples. In addition, this is the first study reporting the presence of eggs of Toxocara spp., Hymenolepis spp., an Oxyuridae parasite, and coccidians Eimeria didelphidis, E. caluromydis, and E. marmosopos in D. marsupialis. The latter is also reported in Colombia for the first time. Toxacara spp. is common to dogs and cats, while Hymenolepis and Oxiuridae are common to rodents. We found no association between parasites and sex or life stage of opossums, nor to the urban area of origin. Conclusions: Urban opossums in the Aburrá Valley host a high frequency and diversity of gastrointestinal parasites compared to other areas in Latin America. Some parasites are reported here for the first time.

Author index for Volume 37, 2024

Tue, 01 Oct 2024 00:00:00 -0500

Subject index for Volume 37, 2024

Tue, 01 Oct 2024 00:00:00 -0500

Peer-Reviewer index for Volume 37, 2024

Tue, 01 Oct 2024 00:00:00 -0500