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The objectives of this study were 1) to investigate production and energetic efficiencies among lactating dairy Holstein-Friesian (HF), Jersey (J), and Jersey×Holstein-Friesian (F1) cows over a total lactation at pasture and 2) to measure the associations among efficiency variables and performance traits. Data from 110 cows were available (37 HF, 36J, and 37F1). Breed groups were not balanced for parity; 16 HF, 10J, and 9F1 were in parity 1, whereas the remainder were in parity 2. Milk production, body weight (BW), body condition score (BCS), and estimates of dry matter intake (DMI) corresponding to 51, 108, 149, 198, and 233 d in milk were available. Breed group had a significant effect on all the production parameters investigated: milk yield, solids-corrected milk (SCM), milk fat, protein and lactose concentrations, and milk solids (MLKS; fat+protein yield). Daily MLKS yield was similar for HF and J (1.33 and 1.28kg/d, respectively). There was a tendency for F1 (1.41kg/d) to produce more MLKS compared with HF. The HF breed had higher BW throughout the study compared with F1 and J. Mean BCS was higher for F1 (3.00) and J (2.93) compared with HF (2.76). Mean DMI was similar with HF (16.9kg) and F1 (16.2kg) and was lowest with J (14.7kg). Breed group had a significant effect on all the efficiency parameters investigated: total DMI per 100kg of BW, SCM per 100kg of BW, MLKS per 100kg of BW, and MLKS per total DMI, which tended to be highest for J. Production efficiency based on net energy intake per MLKS was most favorable for F1 and J compared with HF [12.5, 13.0, and 14.1 UFL, respectively, where 1 UFL is defined as the net energy content of 1kg of standard barley for milk production (O’Mara, 2000)]. Significant estimates of hybrid vigor were evidenced for milk yield, milk lactose content, SCM, MLKS, net energy for lactation, BW, BCS, and net energy intake per MLKS. The correlations examined indicated that production efficiency was positively associated with MLKS yield.

The aim of this study was to investigate the effects of animal trait, breed combination, and climate on the expressed levels of heterosis in crossbreeding schemes using tropical cattle. A meta-analysis of 42 studies was carried out with 518 heterosis estimates. In total, 62.5% of estimates were found to be significantly different from zero, the majority of which (89.8%) were beneficial for the studied trait. Trait and breed combination were shown to have a significant effect on the size of heterosis (P < 0.001 and P = 0.044, respectively). However, climate did not have a significant effect. Health, longevity, and milk production traits showed the highest heterosis (31.84 ± 10.73%, 35.13 ± 14.35%, and 35.15 ± 3.29%, respectively), whereas fertility, growth, and maternal traits showed moderate heterosis (12.02 ± 4.10%, 12.25 ± 2.69%, and 15.69 ± 3.26%, respectively). Crosses between breeds from different types showed moderate to high heterosis ranging from 9.95 ± 4.53% to 19.53 ± 3.62%, whereas crosses between breeds from the same type did not express heterosis that was significantly different from zero. These results show that heterosis has significant and favorable impact on productivity of cattle farming in tropical production systems, particularly in terms of fitness but also milk production traits.

Pig and poultry production relies on crossbreeding of purebred populations to produce production animals. In those breeding schemes, selection takes place within the purebred population to improve crossbred performance (CB performance). The genetic correlation between purebred performance (PB performance) and CB performance () is, however, lower than unity for many traits. When is low, the use of CB performance in selection is required to achieve sizable genetic progress. The objectives of this paper were to describe the different components and importance of , and to review existing literature that report estimates in pigs. The has 3 components: 1) genotype by genotype interactions, 2) genotype by environment interactions, and 3) differences in trait measurements. We theoretically showed that direct selection for CB performance reduces the response to selection in purebreds for.

Ningxiang pigs are a renowned indigenous pig breed in China, known for their meat quality, disease resistance, and environmental adaptability. In recent decades, consumer demand for meats from indigenous breeds has grown significantly, fueling the selection and crossbreeding of Ningxiang pigs (NXP). The latter has raised concerns about the conservation and sustainable use of Ningxiang pigs as an important genetic resource. To address these concerns, we conducted a comprehensive genomic study using 2242 geographically identified Ningxiang pigs. The estimated genomic breed composition (GBC) suggested 2077 pigs as purebred Ningxiang pigs based on a ≥94% NXP-GBC cut-off. The remaining 165 pigs were claimed to be crosses, including those between Duroc and Ningxiang pigs and between Ningxiang and Shaziling pigs, and non-Ningxiang pigs. Runs of homozygosity (ROH) were identified in the 2077 purebred Ningxiang pigs. The number and length of ROH varied between individuals, with an average of 32.14 ROH per animal and an average total length of 202.4 Mb per animal. Short ROH (1–5 Mb) was the most abundant, representing 66.5% of all ROH and 32.6% of total ROH coverage. The genomic inbreeding estimate was low (0.089) in purebred Ningxiang pigs compared to imported western pig breeds. Nine ROH islands were identified, pinpointing candidate genes and QTLs associated with economic traits of interest, such as reproduction, carcass and growth traits, lipid metabolism, and fat deposition. Further investigation of these ROH islands and candidate genes is anticipated to better understand the genomics of Ningxiang pigs.

With the increasing consumer demand for high-quality lamb, crossbreeding has become a key technology for improving the production performance and meat quality of sheep. To evaluate the meat quality advantages and characteristics of Suffolk (SFK) and Hu sheep (HH) and their F1 crossbreds (SH), thirty-six 3-month-old male lambs of SFK (n = 12), HH (n = 12), and SH (n = 12) were selected and raised in individual pens under the same nutritional and management conditions. After standardized feeding until 6 months of age, the Longissimus dorsi muscle was collected to determine meat quality traits, amino acid and fatty acid profiles, and volatile flavor compounds. The results indicated that the L*, a* and b* values of the SH group were significantly lower than those of the parental breeds (p < 0.05), with tenderness being intermediate between the two parent breeds. Notably, drip loss and cooking loss were significantly lower in the SH group (p < 0.05), indicating superior water-holding capacity. In terms of amino acid profiles, the contents of non-essential amino acids (NEAAs) and sweet-tasting amino acids in the SH group were significantly higher than those of the parent breeds (p < 0.05), with the overall profile meeting the FAO/WHO ideal protein pattern. Analysis of fatty acid profiles revealed that the SH group had significantly lower total saturated fatty acids (SFAs) (p < 0.05) and significantly higher levels of functional fatty acids (such as CLA), resulting in a significantly higher UFAs (unsaturated fatty acids)/SFAs (saturated fatty acids) ratio (p < 0.05) and superior nutritional value of fat. Furthermore, 32 volatile flavor compounds were detected in the SH group; among them, key aroma-active compounds such as isoamyl formate, 3-methyl-1-butanol, and acetoin were significantly higher than in the parental breeds (p < 0.05), contributing to a unique flavor profile. Consequently, this study systematically reveals the advantages of Suffolk × Hu F1 crossbreds in terms of meat quality, nutritional value, and flavor characteristics, providing fundamental data for the optimization of crossbreeding systems, breeding selection, and the quality improvement of sheep meat products.

Crossbreeding is a cornerstone of modern livestock improvement, combining desirable traits to enhance productivity and environmental resilience. This study conducts the first comprehensive genomic analysis of Red Angus × Chinese Red Steppe (RACS) crossbred cattle, evaluating their genetic architecture, diversity, and selection signatures relative to founder breeds (Red Angus and Chinese Red Steppe) and global populations. A total of 119 cattle, comprising 104 RACS crossbreds and 15 Chinese Red Steppes cattle, were genotyped using the GGP Bovine 100k SNP array. Additionally, the public available genotypic data generated using the BovineSNP50 chip from 550 animals across eight beef breeds (Angus, Hereford, Limousin, Charolais, Mongolian, Shorthorn, Red Angus, and Simmental) and one dairy breed (Holstein) were incorporated into the analysis. We aimed to (1) define the population structure of RACS cattle, (2) quantify their genomic diversity and inbreeding levels, and (3) pinpoint regions under selection linked to adaptive and economic traits. We employed runs of homozygosity (ROH) and population differentiation (Fst) analyses to detect selection signals. The results revealed that the crossbred (RACS), Angus, and Red Angus breeds exhibited similar clustering patterns in principal component analysis (PCA), but the crossbred population showed the highest nucleotide diversity and lowest inbreeding coefficients compared to other breeds. Notably, candidate regions associated with immune response, cold adaptation, and carcass traits were identified within the RACS population. These findings enhance our understanding of the genetic makeup of crossbred beef cattle and highlight their potential for genetic improvement, informing future selection and breeding strategies aimed at optimizing beef production in challenging environments.

Jersey×Holstein crossbreds (J×H; n=76) were compared with pure Holsteins (n=73) for 305-d milk, fat, and protein production; conception rate; days open; proportion of cows pregnant within fixed intervals postpartum; and body and udder measurements during first lactation. Cows were housed at 2 research locations of the University of Minnesota and calved from September 2003 to May 2005. The J×H were mated to Montbeliarde sires, and Holstein cows were mated to Holstein sires. Best Prediction was used to determine actual production (milk, fat, and protein) for 305-d lactations with adjustment for age at calving, and records less than 305 d were projected to 305 d. The J×H (274kg) and pure Holsteins (277kg) were not significantly different for fat production, but J×H had significantly less milk (7,147 vs. 7,705kg) and protein (223 vs. 238kg) production than pure Holsteins. The J×H had significantly fewer days open than pure Holsteins (127 vs. 150 d). Also, a significantly greater proportion of J×H were pregnant at 150 and 180 d postpartum than pure Holsteins (75 vs. 59% and 77 vs. 61%, respectively). The J×H had significantly less body weight (60kg) at calving, but significantly greater body condition (2.80 vs. 2.71). Furthermore, J×H had significantly less udder clearance from the ground to the bottom of the udder than pure Holsteins (47.7 vs. 54.6cm), and greater distance between front teats (15.8 vs. 14.0cm) than pure Holsteins during first lactation.

While studies show that cattle crossbreeding has important role for dairy development, the adoption of crossbred cattle and diffusion of artificial insemination (AI) is found to be at a nascent stage in Assam resulting in the fact that he state has continued to remain as a milk deficit state. Using techniques such as Probit regression, Propensity Score Matching (PSM) and Rank Based Quotient (RBQ) for cross-section data of 245 smallholder dairy farmers distributed in 3 representative districts of Assam, the study examines the constraints of adoption of crossbred cattle along with its contribution to nutritional security in the state. The study finds that factors such as herd-size, knowledge about AI, membership of dairy cooperative society, being beneficiary of government dairy development schemes and milk price significantly influence adoption of crossbred cattle. Furthermore, adoption of crossbred cattle has significant influence on nutritional gain of the people by way of increase in net dairy income/milch animal/day along with enhanced milk and meat consumption. Hence, working on adoption constraints such as higher requirement of feed and fodder by crossbred cattle, higher requirement of care by these animals, difficulty in getting green fodder etc. as perceived by the farmers would incentivize their adoption of the new technology. Overall, the findings of the study advocate for expansion of extension services, strengthening of dairy cooperative society (DCS) network and raising milk price towards diffusion of crossbred cattle.

Pig and poultry production relies on crossbreeding of purebred populations to produce production animals. In those breeding schemes, selection takes place within the purebred population to improve crossbred performance (CB performance). The genetic correlation between purebred performance (PB performance) and CB performance () is, however, lower than unity for many traits. When is low, the use of CB performance in selection is required to achieve sizable genetic progress. The objectives of this paper were to describe the different components and importance of , and to review existing literature that report estimates in pigs. The has 3 components: 1) genotype by genotype interactions, 2) genotype by environment interactions, and 3) differences in trait measurements. We theoretically showed that direct selection for CB performance reduces the response to selection in purebreds for.