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We investigated the effectiveness of mate allocation strategies accounting for non-additive genetic effects to improve crossbred performance in a two-way crossbreeding scheme. We did this by computer simulation of 10 generations of evaluation and selection. QTL effects were simulated as correlated across purebreds and crossbreds, and (positive) heterosis was simulated as directional dominance. The purebred-crossbred correlation was 0.30 or 0.68 depending on the genetic variance component used. Dominance and additive marker effects were estimated simultaneously for purebreds and crossbreds by multiple trait genomic BLUP. Four scenarios that differ in the sources of information (only purebred data, or purebred and crossbred data) and mate allocation strategies (mating at random, minimizing expected future inbreeding, or maximizing the expected total genetic value of crossbred animals) were evaluated under different cases of genetic variance components. Selecting purebred animals for purebred performance yielded a response of 0.2 genetic standard deviations of the trait “crossbred performance” per generation, whereas selecting purebred animals for crossbred performance doubled the genetic response. Mate allocation strategy to maximize the expected total genetic value of crossbred descendants resulted in a slight increase (0.8%, 4% and 0.5% depending on the genetic variance components) of the crossbred performance. Purebred populations increased homozygosity, but the heterozygosity of the crossbreds remained constant. When purebred-crossbred genetic correlation is low, selecting purebred animals for crossbred performance using crossbred information is a more efficient strategy to exploit heterosis and increase performance at the crossbred commercial level, whereas mate allocation did not improve crossbred performance.

Abstract When considering methodologies for collecting behavioral data, continuous sampling provides the most complete and accurate data set whereas instantaneous sampling can provide similar results and also increase the efficiency of data collection. However, instantaneous time intervals require validation to ensure accurate estimation of the data. Therefore, the objective of this study was to validate scan sampling intervals for lambs housed in a feedlot environment. Feeding, lying, standing, drinking, locomotion, and oral manipulation were measured on 18 crossbred lambs housed in an indoor feedlot facility for 14 h (0600–2000 h). Data from continuous sampling were compared with data from instantaneous scan sampling intervals of 5, 10, 15, and 20 min using a linear regression analysis. Three criteria determined if a time interval accurately estimated behaviors: 1) R2 ≥ 0.90, 2) slope not statistically different from 1 (P > 0.05), and 3) intercept not statistically different from 0 (P > 0.05). Estimations for lying behavior were accurate up to 20-min intervals, whereas feeding and standing behaviors were accurate only at 5-min intervals (i.e., met all 3 regression criteria). Drinking, locomotion, and oral manipulation demonstrated poor associations (R2) for all tested intervals. The results from this study suggest that a 5-min instantaneous sampling interval will accurately estimate lying, feeding, and standing behaviors for lambs housed in a feedlot, whereas continuous sampling is recommended for the remaining behaviors. This methodology will contribute toward the efficiency, accuracy, and transparency of future behavioral data collection in lamb behavior research.

The paper presents the results of a study on the relationship between acidification (pH) and standard quality characteristics of the meat of Polish Large White × Polish Landrace pig crossbreds. The meat for the study was obtained from 184 F1 Polish Large White × Polish Landrace fatteners from a herd free of the stress-sensitivity gene. The obtained results were analysed in groups formed according to the meat’s measured pH45 values (≤ 6.3; 6.3–6.7; > 6.7) and pHu values (≤ 5.3; 5.3–5.6; > 5.6). Increasing measured pH45 values were paralleled by greater water-holding capacity and plasticity, lower drip loss, darker colour L* as assessed visually and with equipment, and greater content of muscle pigments (P < 0.01) of the evaluated meat. Higher pHu values had a more pronounced impact on WHC, free drip loss, tenderness, water content, and colour parameters: a*, b*, chroma C* (P < 0.01), and hue angle ho (P < 0.05). The obtained simple correlations between pH45 and pHu acidity and meat-quality characteristics indicate that the measured pH45 value was correlated more closely than ultimate acidification (P < 0.01) with visually assessed colour intensity, tactilely assessed meat hardness, colour lightness L* (P < 0.01), hue angle ho (P < 0.05), and muscle pigment content. On the other hand, pHu was more strongly correlated with water-holding capacity, drip loss, meat tenderness as well as water and protein content (P < 0.01).

Global warming caused by climate change is a challenge for dairy farming, especially in sub-Saharan countries. Under high temperatures and relative humidity, lactating dairy cows suffer from heat stress. The objective of this study was to investigate the effects and relationship of heat stress (HS) measured by the temperature–humidity index (THI) regarding the physiological parameters and milk yield and composition of lactating Holstein Friesian crossbred dairy cows reared in the humid coastal region of Tanzania. A total of 29 lactating Holstein Friesian x Zebu crossbred dairy cows with 50% (HF50) and 75% (HF75) Holstein Friesian gene levels in the second and third months of lactation were used. The breed composition of Holstein Friesians was determined based on the animal recording system used at the Tanzania Livestock Research Institute (TALIRI), Tanga. The data collected included the daily temperature, relative humidity, daily milk yield, and physiological parameters (core body temperature, rectal temperature, respiratory rate, and panting score). THI was calculated using the equation of the National Research Council. The THI values were categorized into three classes, i.e., low THI (76–78), moderate THI (79–81), and high THI (82–84). The effects of THI on the physiological parameters and milk yield and composition were assessed. The effects of the genotype, the parity, the lactation month, and the interaction of these parameters with THI on the milk yield, milk composition, and physiological parameters were also investigated. The results show that THI and its interaction with genotypes, parity, and the lactation month had a highly significant effect on all parameters. THI influenced (p ˂ 0.05) the average daily milk yield and milk fat %, protein %, lactose %, and solids–not–fat %. As the THI increased from moderate to high levels, the average daily milk yield declined from 3.49 ± 0.04 to 3.43 ± 0.05 L/day, while the fat % increased from 2.66 ± 0.05% to 3.04 ± 0.06% and the protein decreased from 3.15 ± 0.02% to 3.13 ± 0.03%. No decline in lactose % was observed, while the solid–not–fat % declined from 8.56 ± 0.08% to 8.55 ± 0.10% as the THI values increased from moderate to high. Also, the THI influenced physiological parameters (p ˂ 0.05). The core body temperature (CBT), rectal temperature (RT), respiratory rate (RR) and panting score (PS) increased from 35.60 ± 0.01 to 36.00 ± 0.01 °C, 38.03 ± 0.02 to 38.30 ± 0.02 °C, 62.53 ± 0.29 to 72.35 ± 0.28 breaths/min, and 1.35 ± 0.01 to 1.47 ± 0.09, respectively, as the THI increased from low to high. The THI showed a weak positive correlation with the average daily milk yield and fat percentage, whereas the protein, lactose, and solids–not–fat percentages showed negative relationships with THI (p ≤ 0.05). CBT, RT, RR, and PS showed positive relationships (p ≤ 0.05) with THI. These negative relationships indicate that there is an antagonistic correlation between sensitivity to HS and the level of production. It is concluded that the THI, the genotype, the parity, and the lactation month, along with their interactions with THI, significantly influenced the milk yield, milk composition, and physiological parameters of lactating Holstein Friesian dairy crosses at THI thresholds ranging from 77 to 84.

The effects of various treatment options on the nutritional value of wheat straw as well as the growth performance of crossbred calves fed the treated wheat straw were evaluated. Twenty-four female calves (75% Friesian-Borana), weighing 99.3 ± 19.7 kg (aged 6-9 months), were divided into four groups of six animals using a randomized complete block design. The feeding trial lasted approximately 104 days. The dietary treatments were: untreated wheat straw (control T1), wheat straw treated with urea-molasses (T2), urea-lime (T3), and effective microorganisms (T4). Results showed that the treatment options affected the physical silage quality and chemical composition of wheat straw. Calves in the T3 and T4 groups had a higher daily DM intake (3.7 and 3.5 kg/head, respectively) than those in T2 (3.1 kg/head) and T1 (3.02 kg/head) groups. Calves in the T3 (422.7 g/d) and T4 (391 g/d) groups gained greater weight than those in the T2 (281.7 g/d) and T1 (204.4 g/d) groups (P < 0.001). Thus, improving the feed value of wheat straw with urea-lime or effective microorganisms treatment options suggested in this trial could result in cost-effective and significant growth performances when crossbred calves were supplemented with concentrate at a rate of 1.2% of their live weights.

Abstract Growth, meat quality, and carcass traits are of economic importance in swine breeding. Understanding their genetic basis in purebred (PB) and commercial crossbred (CB) pigs is necessary for a successful breeding program because, although the breeding goal is to improve CB performance, phenotype collection and selection are usually carried out in PB populations housed in biosecure nucleus herds. Thus, the selection is indirect, and the accuracy of selection depends on the genetic correlation between PB and CB performance (rpc). The objectives of this study were to 1) estimate genetic parameters for growth, meat quality, and carcass traits in a PB sire line and related commercial CB pigs and 2) estimate the corresponding genetic correlations between purebred and crossbred performance (rpc). Both objectives were investigated by using pedigree information only (PBLUP) and by combining pedigree and genomic information in a single-step genomic BLUP (ssGBLUP) procedure. Growth rate showed moderate estimates of heritability for both PB and CB based on PBLUP, while estimates were higher in CB based on ssGBLUP. Heritability estimates for meat quality traits were diverse and slightly different based on PB and CB data with both methods. Carcass traits had higher heritability estimates based on PB compared with CB data based on PBLUP and slightly higher estimates for CB data based on ssGBLUP. A wide range of estimates of genetic correlations were obtained among traits within the PB and CB data. In the PB population, estimates of heritabilities and genetic correlations were similar based on PBLUP and ssGBLUP for all traits, while based on the CB data, ssGBLUP resulted in different estimates of genetic parameters with lower SEs. With some exceptions, estimates of rpc were moderate to high. The SE on the rpc estimates was generally large when based on PBLUP due to limited sample size, especially for CBs. In contrast, estimates of rpc based on ssGBLUP were not only more precise but also more consistent among pairs of traits, considering their genetic correlations within the PB and CB data. The wide range of estimates of rpc (less than 0.70 for 7 out of 13 traits) indicates that the use of CB phenotypes recorded on commercial farms, along with genomic information, for selection in the PB population has potential to increase the genetic progress of CB performance.

An appropriate housing ventilation system is needed to ensure livestock and poultry health. In this study, 315 90‐d‐old Duroc × Landrace × Yorkshire (DLY) crossbred swine were distributed to three experimental swine houses. Each house had 105 swine, with 15 swine in each pen (including seven males and eight females). The ventilation systems for three houses were naturally ventilated, intermittent negative pressure longitudinal mechanical ventilation, and tunnel ventilation. The experiment was monitored for 28 consecutive days. The average temperature and relative humidity of the tunnel‐ventilated swine house were 19.22 °C and 60.79%, respectively, which were higher than other two swine houses (P < .05). The NH3 and CO2 concentrations in the tunnel‐ventilated swine house were lower than the other systems (P < .05). The average daily growth of swine in the tunnel ventilated was 14.9% higher (P < .05) than that in the natural ventilation. The feed/gain (F/G) ratio was 11.44% higher (P < .05) and abnormal behavior was lower in the tunnel ventilated swine house than those in the naturally ventilated swine house. Our results indicate that the tunnel ventilation is the best ventilation system for swine houses during the winter in northern China. Core Ideas Natural, mechanical, and tunnel ventilation methods ensured the normal production of pigs. The tunnel‐ventilated pig house can provide a better growth environment for pigs. The abnormal behavior of pigs in the tunnel‐ventilated pig house was low. The tunnel ventilation can improve pigs' production performance.

Objective: The aim of this study was to estimate genetic parameters, breeding value, and ranking of Holstein Friesian × Local (HF × L) crossbred sires based on multi-trait selection index information. Methods: A total of 51 HF × L crossbred breeding bulls of three different genetic groups (50%HF × 50%L, 62.5%HF × 37.5%L, and 75%HF × 25%L) managed at Central Cattle Breeding and Dairy Farm (CCBDF) were evaluated based on 4,319 half-sib progeny performance data. The descriptive statistical analysis was performed using the R package. Genetic parameters were estimated using BLUPF90 by a single-trait animal model. A selection index was constructed using adjusted breeding values multiplied by variable economic weightage for each trait. Results: Genotype had significant effects on the investigated semen quality attributes (p < 0.05), where 75%HF × 25%L and 62.5%HF × 37.5%L crossbred genotypes both differed significantly from 50%HF × 50%L crossbreds (p < 0.05). In general, better productive and reproductive performances were found with the progression of HF inheritance. Daughters of 75%HF × 25%L crossbred bulls showed the highest average performance in birth weight (27.20 ± 0.09 kg), daily milk yield (8.55 ± 0.06 l), peak milk yield (10.44 ± 0.07 l), and lactation length (233.53 ± 0.85 days). The study investigated variance components of eight productive and reproductive traits such as the birth weight of calf, age at first conception, service per conception, daily milk yield, peak milk yield, lactation length, and calving interval where estimated heritability ranged from 0.09 to 0.32. Genetic correlations among the considered traits were found to be mostly weak. Among the top 20%, breeding bulls belonged to 75%HF × 25%L and 62.5%HF × 37.5%L crossbred groups. Conclusion: This study provides insightful information on the genetic evaluation of different graded bulls that could be the basis for the proven crossbred breeding bulls’ selection process at CCBDF.

Background Tick infestation is the major problem for animal health that causes substantial economic losses, particularly in tropical and subtropical countries. To better understand the spatial distribution of tick species and risk factors associated with tick prevalence in livestock in Pakistan, ticks were counted and collected from 471 animals, including 179 cattle, 194 buffaloes, 80 goats and 18 sheep, on 108 livestock farms in nine districts, covering both semi-arid and arid agro-ecological zones. Results In total, 3,807 ticks representing four species were collected: Hyalomma anatolicum ( n  = 3,021), Rhipicephalus microplus ( n  = 715), Hyalomma dromedarii ( n  = 41) and Rhipicephalus turanicus ( n  = 30). The latter species is reported for the first time from the study area. Rhipicephalus microplus was the predominant species in the semi-arid zone, whereas H. anatolicum was the most abundant species in the arid zone. The overall proportion of tick-infested ruminants was 78.3% (369/471). It was highest in cattle (89.9%), followed by buffaloes (81.4%), goats (60.0%) and sheep (11.1%). The median tick burden significantly differed among animal species and was highest in cattle (median 58), followed by buffaloes (median 38), goats (median 19) and sheep (median 4.5). Female animals had significantly higher tick burdens than males and, in large ruminants, older animals carried more ticks than younger animals. The intensity of infestation was significantly lower in indigenous animals compared to exotic and crossbred cows. Analysis of questionnaire data revealed that the absence of rural poultry, not using any acaricides, traditional rural housing systems and grazing were potential risk factors associated with a higher tick prevalence in livestock farms. Conclusion Absence of rural poultry, not performing acaricide treatments, traditional rural housing systems and grazing were important risk factors associated with higher tick prevalence in livestock farms. Age, gender, breed and animal species significantly affected the intensity of tick infestation. This report also describes the presence of R. turanicus in the Punjab Province of Pakistan for the first time. The outcomes of this study will be useful in the planning of integrated control strategies for ticks and tick-borne diseases in Pakistan.