Livestock Science最新文献

This study evaluates nutritional and management strategies aimed at exploiting compensatory growth (CG) in weanling-to-beef systems in Uruguay. The evaluation encompassed productivity, economic viability, and environmental impact. The Grange Beef System Model, augmented with Uruguayan national technical coefficients, was used. Four weanling-to-beef systems were modeled: 1) forage only with no CG (FNC), 2) forage only with management improvements to exploit CG (forage with CG; FWC), 3) forage with concentrate supplementation during two winter feeding periods (forage with supplementation; FWS), and 4) forage with supplementation during the first winter followed by feedlot finishing (forage with feedlot; FWF). The systems purchased spring-born Angus calves at 8 months of age and 180 kg live weight (LW) and finished with a slaughter weight of 550 kg. FWS system was used as reference with the performance parameters obtained during 5 years of systems experimentation. FNC used the performance parameters of FWS but during winter periods, LW gain was lower due to the absence of concentrate supplementation. FWC used the previous FNC performance parameters, but increased LW gain after the first and second winter restriction period due to improved grazing management practices thereby exploiting CG. FWF is based on the FWS system but instead of moderate supplementation during the second winter (concentrate: 3.0 kg/d/head), steers are feedlot finished (concentrate: 9.5 kg/d/head) exploiting CG due to previous summer-autumn restriction period. FNC and FWC increased age at slaughter, reducing net beef production by 21 and 11 % relative to FWS, respectively. In contrast, FWF reduced age at slaughter, increasing beef production by 93 % compared to FWS. FWS and FNC had similar profitability expressed in net margin; however, FWC and FWF increased net margin by 33 and 107 % compared to the FWS, respectively. FNC and FWC increased greenhouse gas (GHG) emissions intensity per beef produced by 17 and 3 % relative to FWS, respectively; meanwhile, FWF reduced GHG intensity by 10 % relative to FWS. Due to the inclusion of concentrates in the diet for FWS and FWF systems, the only net producers of human edible energy and protein were the forage-only systems (FNC and FWC). In summary, strategically harnessing CG in both pasture and feedlot finishing stages within a weanling-to-beef system in Uruguay successfully increased profitability. Feedlot finishing reduced GHG emissions per beef produced. However, the forage-only farm systems emerged as the only net producers of human-edible energy and protein.

Pigs’ N and P excretions are partially lost as NH₃ or phosphate, resulting in potential environmental pollution and health risk for humans and animals. A study was conducted to investigate if supplementation of microbial phytase and free amino acids (AA) allows to decrease monocalcium phosphate (MCP) and solvent extracted soybean meal (SBM) in N- and P-reduced diets, and if these feeding strategies decrease environmental impacts while maintaining growth performance and meat quality traits. The impacts on greenhouse gas emissions (global warming, GW) and on acidifying emissions were modelled. Therefore, a total of 192 mixed-sexed pigs (body weight, BW: 32.6 ± 0.3 kg) were randomly allocated to 4 dietary treatments (4 pens per treatment and 12 pigs per pen, 48 pigs per treatment). Three-phase feed, supplemented with individual AA to maintain appropriate digestible AA to Lys ratios, were fed. The control treatment (CON) was formulated to contain 185 to 150 g kg^-1 CP (as-fed). In the ‘low reduction’ treatment (LRT) and the ‘high reduction’ treatment (HRT), SBM and thus CP contents were reduced (LRT: 185 to 123 g kg^-1; HRT: 161 to 123 g kg^-1; as-fed). In the ‘alternative protein’ treatment (APT), SBM was completely replaced with rapeseed meal and faba beans to achieve CP contents of 169 to 123 g kg^-1_, close to HRT. Monocalcium phosphate was not supplemented in all treatments after the starter period (60 kg BW). Average daily gain (ADG) and gain to feed-ratio (G:F) did not differ between CON and other treatments during the overall grower-finisher period. Pigs of HRT and APT showed less lean compared to pigs of CON, being correspondent with the reduced loin muscle of those animals (P < 0.05). The meat quality traits did not differ between treatments although SBM per pig was markedly reduced or totally replaced (16, 13, 6.5, and 0 kg SBM per pig in CON, LRT, HRT, and APT, respectively). Nitrogen excretion was reduced (P < 0.05) by 13, 20, and 12% in LRT, HRT, and APT, respectively, compared to pigs fed the CON diet. Phosphorus excretion was reduced by 23, 25, and 5% in LRT, HRT, and APT, respectively, compared to CON. Consequently, the lower N intake reduced acidification and GW impacts by up to 14% and 7%, respectively. Results indicate that CP- and P-reduced diets for grower-finisher pigs are effective in lowering N and P releases into the environment, while growth performance and meat quality traits are maintained.

With the modernisation of pig breeding facilities, pigs may be exposed to both on-farm and off-farm sources of stray voltages. Data from ruminant species suggest that exposition to stray voltages may be a source of stress and impair animal welfare, but data are scarce for pigs. The aim of this study was to evaluate the impact of stray currents of voltages under 0.5 Volts in pig housing on piglet behaviours and some biomarkers after weaning. Two replicates of 820 piglets were reared in a farm naturally exposed to stray voltage for seven weeks. The difference in electrical potential between the floor and each drinker and feeder was measured every two weeks. Piglets exposed to high-voltage drinkers (HVD > 125 mV) spent more time orally manipulating pen mates (P = 0.0031). They also spent more time lying inactive with open eyes (P = 0.0027) and less time nosing pen mates (P = 0.043), but these effects were influenced by the voltage in feeders (P = 0.0021 and P = 0.024, respectively). Piglets exposed to high-voltage feeders (HVF > 50 mV) spent less time lying with their eyes closed (P = 0.024) and more time aggressing pen mates (P = 0.0081). Fifty days after entering the farm, blood hydroperoxide concentration was higher in piglets exposed to HVD (P = 0.039). The increase in socio-negative behaviours and oxidative stress in pigs exposed to stray voltages in pig housing suggested that stray voltages might have moderate detrimental consequences for piglets in post-weaning facilities.

This study evaluated the effect of different levels of fresh microalgae (Chlorella vulgaris) in a feedlot diet on the performance, carcass traits, and meat quality of lambs. Forty-five, four-month-old wether lambs were randomly assigned to one of three dietary treatments: 1) CONTROL, without algae; 2) MEDIUM, with 0.5 % dry matter (DM) algae; or 3) HIGH, with 1 % DM algae added to a basal diet consisting of barley hay and commercial feedlot pellets in a 41:59 ratio. The lambs were fed for 98 days and then slaughtered. Microalgae supplementation did not affect (P ≥ 0.09) growth performance, wool quality, rumen fermentation parameters, carcass weight, dressing percentage, or subcutaneous fat thickness of the lambs. However, microalgae supplementation at 0.5 % DM increased (P ≤ 0.05) the concentration of alpha-linolenic acid (ALA; C18:3n-3), arachidic acid (C20:0), and total omega-3 long-chain (n-3 LC) fatty acids in the longissimus lumborum et thoracis (LTL) muscle of lambs, compared to the CONTROL. Intramuscular fat (%) was similar between the CONTROL and the MEDIUM group (av. 3.65 %), but was lower (P = 0.044) in the HIGH group (3.1 %). Therefore, our results indicate that adding 0.5 % DM microalgae to lamb diets can increase the levels of alpha-linolenic acid and total n-3 LC PUFA in fresh lamb meat without affecting lamb performance or carcass characteristics.

This study aimed to evaluate the effects of black pepper (BP) extract on growth performance, nutrient digestibility, serum total protein, blood urea nitrogen (BUN), creatinine, counts of Lactobacillus and Escherichia coli (E. Coli), back fat thickness, lean meat percentage (LMP), and fecal gas emission in grower pigs. A total of 160 crossbred grower pigs [(Landrace × Yorkshire) × Duroc] with an average initial body weight (BW) of 25.31 ± 1.29 kg were used in a 42-day feeding trial. Pigs were randomly assigned to four experimental treatments. The basal diet was composed of soybeans and corn to meet or exceed the NRC (2012) recommendations. The dietary treatments included: basic diet, basic diet + 0.025 %, 0.05 %, and 0.1 % BP extract. There were eight replicates per treatment, each comprising five pigs (three gilts and two barrows). All data were subjected to statistical analysis using general linear model procedures (SAS 2001, SAS Institute Inc., Cary, NC, USA), with the pen serving as the experimental unit. The results indicated a linear improvement in BW and average daily gain of pigs during days 1–28, 28–42, and the overall period with increasing levels of BP extract in the diet. The apparent total tract digestibility (ATTD) of crude protein (CP) and lean meat percentage (LMP) increased linearly with BP treatment at the end of the experiment (p < 0.05). In addition, total protein, BUN, and creatinine levels were not affected by the BP extract (p > 0.05). Some fecal microbes, such as Lactobacillus and E. coli, did not change considerably when pigs were fed BP extract (p > 0.05). No apparent response to faecal gas emission of NH₃, total mercaptans, or H₂S was observed in relation to the BP extract in the pig diet (p < 0.05). Dietary supplementation with 0.1 % BP extract improved growth performance by increasing the ATTD of CP and improving LMP without adverse effects in grower pigs.

Ganzi horse is distributed in the Ganzi Tibetan Autonomous Prefecture. As we all know, this region on the southeast of the Tibetan Plateau is characterized by low oxygen levels, low atmospheric pressure, and intense ultraviolet light. The extreme environment causes the genomic variation of plateau animals for environmental adaptation. At present, the genetic diversity and the genetic basis of high-altitude adaptation of Ganzi horses remain unclear. Here, an extensive genetic analysis was conducted utilizing whole-genome sequencing data from 145 individual horses. The analysis of autosomal genetic diversity confirmed that Ganzi horses had experienced low intensity artificial selection and had high genetic diversity. Examination of mitochondrial DNA information from whole-genome sequencing data revealed multiple maternal origins for Ganzi horses. Further, four different selective scanning methods were used to identify positive selected genomic regions and genes associated with high-altitude adaptation. We identified genes associated with altitude adaptation at selection windows in Ganzi horses, such as EPAS1, ABTB2, RHOQ, and TMEM247. Notably, EPAS1 and OR52A1J gene exhibited high select signal values, different nucleotide diversities, and haplotype patterns, and missense mutations in EPAS1 (A > T) and OR52A1J (C > T) were found to be more frequent in high-altitude horses. Moreover, our research illuminated significant gene flow between Ganzi and Chaidamu horses, which may be related to the formation of Ganzi horses. In general, these findings not only enhance our understanding of this unique native breed but also further our understanding of Ganzi horse's high-altitude adaptation.

The objective of this study was to compare the inbreeding coefficients estimated from pedigree data (F_PED), traditionally used for internal monitoring by herds and breeding programs, with genomic estimates through the genomic relationship matrix (F_GRM) and runs of homozygosity (F_ROH). Besides, we used the genotype data to obtain the linkage disequilibrium (LD), population effective size (Ne), runs of homozygosity (ROH) islands and functional analysis of the genes presented in ROH islands. Male calves and sires from a closed Nellore herd (Lemgruber line) were genotyped with the Z-chip v2 (Neogen, Lincoln, Nebraska, USA) that contains approximately 30 thousand SNP markers. After quality control, 1088 animals and 21,351 SNPs remained for analysis. Runs of homozygosity (ROH) segments were identified in all analyzed animals, with an average number of 57.93 and average length of 2.95 Mb. We observed a higher occurrence of ROH up to 9 Mb, suggesting a proper mating scheme, which corroborate with LD and Ne analysis results. Estimates of F_PED, F_GRM and F_ROH ranged from 0 to 0.2856, from 0.0705 to 0.3686 and from 0.0229 to 0.2762, respectively. Low to moderate correlations were observed between F_PED and F_GRM (0.17, P < 0.001); F_PED and F_ROH (0.20, P < 0.001) and F_GRM and F_ROH (0.92, P < 0.001). Nevertheless, considering our results we were successful in use runs of homozygosity for estimating autozygosity in a closed Nellore herd. Besides, from ROH islands, we were able to identify a candidate gene (HTR1A) for docility in this Nellore herd.

Describing the energy partition during the production phase of broiler breeders helps to define the energy requirements of breeders. This study aimed to determine the energy intake partition for maintenance, tissue growth, and egg production in broiler breeders during the laying phase. An energy and nitrogen balance study was carried out in a respirometry chambers with fifty Cobb 500 broiler breeders from 27 to 63 weeks old. Every four weeks, 5 birds were individually housed in a respirometry chamber and fed according to the guidelines. Feed intake (FI), excreta, and egg output were recorded daily. O₂ consumption (VO₂) and CO₂ production (VCO₂) were measured under feeding and fasting conditions to calculate total and fasting heat production (THP and FHP, respectively). The collected data were used to calculate the retained energy (RE) in the egg and body as protein or fat by using energy balance calculations. Linear regressions were used to fit the collected data as a function of age. The measured apparent metabolizable energy corrected for zero-nitrogen retention (AMEn, kJ/kg feed) was higher than formulated. The FI and apparent metabolizable energy intake (AMEi) showed the highest values at 31 and 35 weeks (P > 0.05). Linear regression was not significant (P > 0.05) for FHP, THP, heat increment (HI), egg mass, and RE in the egg as fat and as protein, suggesting that these parameters remained constant as the bird aged. The RE in the body as protein increased (P < 0.005), while the RE in the body as fat decreased (P < 0.0001) as the birds aged. Variation in the AMEi influenced RE in the body (P < 0.05) but not in the egg (P = 0.109). It can be concluded that net energy for maintenance does not change during the laying phase and represents an expenditure of 267.1 kJ/kg^0.75 per day in broiler breeders under a feed-controlled program. As expected, energy is primarily used for maintenance and egg production in the net energy system, with excess energy stored preferentially as fat rather than protein.

The objective of the present study was to investigate the optimal inclusion rate of 2 independent extracts with different properties derived from the olive industry [triterpenic acid extract (TAE) and a polyphenol extract (PE)] on productive performances in broiler chickens from 0 to 45 d under challenging conditions. In addition, antiparasitic protection of the TAE was evaluated at d 21 and d 28 through intestinal scoring and oocyst counts, as well as the blood antioxidant activity of the PE at d 45. Wood shavings as bedding material came from a commercial farm with a coccidia load sufficient to create a subclinical coccidiosis situation with minor macroscopic lesions, and a nutritional challenge was imposed using poor raw materials to cause intestinal dysbiosis. There were 9 dietary treatments (8 replicates/treatment and 15 broiler chickens/pen), a positive control (PC) supplemented with commercial coccidiostat (Na monensin), 4 increasing concentrations of TAE (30, 60, 90, and 120 ppm), and 4 increasing concentrations of PE (10, 20, 30, and 40 ppm). For the overall experiment the PC had greater average daily gain (ADG) and average daily feed intake (ADFI) (P < 0.001) than the mean of TAE treatments. Besides, the ADG, body weight, and ADFI increased linearly throughout the whole experiment as the TAE level of the feed increased. With respect to the anticoccidial activity, the 120 ppm TAE treatment showed greater concentration of E. acervuline DNA copies at 21 d than the 30 ppm TAE treatment (P < 0.05), the rest of the treatments being intermediate. Concerning the PE treatments, for the overall experiment, ADG was the greatest in the PC treatment (P < 0.001), and the ADFI was similar in the PC treatment to the mean of PE treatments. There was no effect of the PE on antioxidant activity. In conclusion, under the conditions of this study, the inclusion of TAE does not reach the productive performance indicators achieved by a commercial coccidiostat in our intestinal challenge situations. Also, the inclusion of PE has a positive effect on productive performance on the overall period.

The experiment was conducted to evaluate the inclusion of different sources of fat on the intake and digestibility of nutrients, serum metabolites, and growth performance of feedlot lambs. Forty male Dorper × Santa Inês lambs (averaging 22.27 ± 2.79 kg of body weight; mean ± standard deviation) with approximately 4 months were distributed in a completely randomized design. Five experimental diets were tested: no added fat (NAF), whole soybeans (WSB), calcium salts of fatty acids (CSFA), soybean oil (SO), and full fat corn germ (CG). Nutrient intake was affected by the inclusion of different fat sources in diets (P < 0.05) except for the neutral detergent fiber (aNDFomp). The CSFA diet showed the highest nutrient apparent digestibility (P < 0.05), except for the digestibility of aNDFomp and non-fibrous carbohydrates. Nitrogen retention was higher (P = 0.003) in animals fed the CSFA diet. Albumin (P = 0.038), albumin:globulin ratio (P = 0.042), glucose (P < 0.001), and cholesterol (P = 0.032) were affected by the inclusion of different fat sources in feedlot lamb diets. Lambs fed NAF and CSFA diet showed the highest average daily gain (P = 0.001) and final body weight (P = 0.036). The use of 3.5 % calcium salts of fatty acids (protected fats); improves the diet digestibility and promoted the highest growth performance parameters in feedlot lambs.