Mathematical models to predict the lamb weight at birth and at weaning reared in the tropical warm-climate pasture

Our objective was to evaluate the productive parameters of ewes and their lambs in relation to ewe age and to develop models for predicting lamb weight at birth and weaning in a tropical warm-climate pasture. Individual data were collected from 273 ewes and 273 lambs, between 2013 and 2021. During this period all animals were kept on pastures of Brachiaria brizantha cv. Marandu All lambs in the experiments were supplemented in creep-feeding. A descriptive statistical analysis was performed using the PROC SUMMARY procedure in SAS (SAS University Edition, SAS Institute Inc. Cary, CA, USA). Pearson correlation coefficients between variables were estimated using the PROC CORR procedure in SAS (SAS University Edition, SAS Institute Inc. Cary, CA, USA). Model adjustments and variable selection were performed using PROC REG in SAS (SAS University Edition, SAS Institute Inc. Cary, CA, USA). The STEPWISE option and Mallow's C(p) were used to select the variables included in the equations. Outliers were identified by evaluating the studentized residuals based on the predicted values from the equations. Residual analysis was predicted by regression minus observed values and those that fell outside the range of -2.5 to 2.5 were removed. Several statistics were used to assess the predictability of the equations, including the coefficients of determination (r2) and mean standard error (RMSE). The average ewe age at lambing was 3.4 ± 1.7 years, with an average weight of 56.9 ± 8,9 kg and average body condition score (BCS) of 2,4 ± 0.8 points. The average ewe age at weaning was 51.1 ± 7.9, with average BCS of 1.8 ± 0.8 points. The average lamb at birthing was 3.9 ± 0.9 kg. The average lamb at weaning was 21.0 ± 4.9, with daily gain of 0.2 ± 0.1 kg/day and total gain of 17.1 ± 4.7 kg birth to weaning. The lamb produced by ewe at lambing was 5.3 ± 1.7 kg/ewe. The lamb weaned by ewe at weaning was 28.7 ± 10.8 kg/ewe. The ratios of lamb produced per ewe at birth and at weaning were 0.1 ± 0.03 and 0.6 ± 0.2, respectively. The lamb's birth weight showed a positive linear relationship with the age of the ewe, increasing by 115 g per year of age. The regression equations adjusted for ewe age had maximum points ranging from 4.2 to 5.2, occurring at average age of 4,7 years. The other characteristics showed a quadratic tendency. The results suggest the culling of ewes at five years of age to generate lambs with ideal weight at birth and at weaning raised in warm tropical pastures.

Economic impact of poisoning by Brachiaria grass in lambs from birth to finishing receiving to different levels of supplementation

This study aims to evaluate the economic impact of poisoning by Brachiaria grass in lambs from birth to weaning (suckling) and from weaning to slaughter (finishing) different levels of energy protein supplementation (EPS). In addition, we estimated the economic efficiency of removing lambs from the pasture as a control measure to minimize the losses caused by Brachiaria grass poisoning. Seventy lambs were used in the suckling phase, distributed in two nutritional treatments (control and creep feeding). Hospitalization expenses were US$ 1580.80 for the control treatment and US$ 256.16 for the creep feeding treatment. In the finishing phase, 48 lambs were distributed in four nutritional treatments, which consisted of increasing levels of EPS (mineral salt, 0.8, 1.6 and 2.4% of LW). The largest difference in total revenue (US$) was observed between 2.4% of BW EPS and mineral salt (- 2300.28) treatments. Hospitalization expenses were similar between nutritional treatments, being higher in the treatment 1.6% of BW EPS (US$ 578.15). The biggest difference in gross income (US$) observed was between 2.4% of BW EPS and mineral salt (- 1439.43) treatments. The Brachiaria grass poisoning caused economic losses to the sheep farming system, due to the death of lambs, reduced weight gain and lower weights at weaning and in the finishing phase. Brachiaria grass poisoning caused economic damage to the production system. There were direct losses, with the death of the lambs without supplementation, in the suckling and finishing phases. The supplementation increases the performance and reduces the mortality. The supplementation in high levels is efficient in reducing the economic impact of poisoning by Brachiaria grass in both periods of suckling and finishing.

Carcass traits and meat quality of Texel lambs raised in Brachiaria pasture and feedlot systems

Our hypothesis suggests an improvement in carcass and meat quality of pasture-finished animals by introducing concentrate feed into diets. This study aimed to evaluate the effect of different levels of protein-energy supplementation on carcass and meat characteristics of Texel lambs raised on Brachiaria pastures, and compare the results with those obtained from confined animals. Thirty 2-month-old intact lambs were divided into five treatments: pasture with mineral supplementation, pasture containing daily supplies of 0.8, 1.6, and 2.4% BW protein-energy supplementation, and confinement (reference treatment). All animals were slaughtered 104 days after the beginning of the experiment. Lambs submitted to 1.6% and 2.4% BW supplementation presented similar characteristics to animals kept in confinement and were superior to animals treated with 0 or 0.8% of BW supplementation levels (p < .05). Increases of subcutaneous fat thickness were verified for 0.0, 0.8, 1.6, 2.4% BW, and confinement treatments, being respectively of 0.25, 0.74, 1.61, 1.69, and 1.98. Conversely, treatments had no influence on meat physical-chemical characteristics, being all considered moderately soft, juicy (tender), and with mild tastes and odors. Lambs raised on Brachiaria pastures have high-quality meat, but more protein-energy supplementation is needed to be an alternative for the feedlots for young animals.

Performance, Ingestive Behavior and Gastrointestinal Helminths Control of Suckling Lambs Supplemented in Creep-Fed and Not Supplemented in Tropical Pastures

The objective of this study was to evaluate the performance, ingestive behavior and gastrointestinal helminths control of suckling lambs raised on pastures of Brachiaria ssp. supplemented in creep-fed and not supplemented. Thirty-one lambs being 15 lambs in the control treatment (without supplementation) and 16 lambs in the creep feeding treatment (with protein-energetic supplementation) were evaluated. Performance of lambs supplemented was superior to lambs no-supplemented. Lambs without supplemented had weaning age of 81 days and an average gain of 194 grams. Lambs supplemented showed weaning age of 58 days and average daily gain of 268 grams. eggs per gram of stool (EPG) count in the control treatment was 4553, while in the creep feeding treatment the mean was 763. The morbidity rate caused by gastrointestinal helminths in the control treatment was 6.6% and there was no morbidity due to helminths in the treatment creep feeding. The morbidity rate due to hepatogenic intoxication was 46.6% in control and 12.5% in the lambs supplemented. The ingestion of protein-energy supplementation in creep feeding promoted an increase in productive performance of lambs, as well as increased resistance and tolerance to gastrointestinal infections and decreased cases of hepatogenic intoxication by ingestion of Brachiaria spp.