Mature Live Weight Research Articles

Crossbreeding experiment on Indonesian local rabbits: the heterosis effect on growth performance

Abstract. The study aims to investigate the heterosis effect of crossing two imported rabbits with local rabbits on growth characteristics and performance using a nonlinear regression model. The study utilized three rabbit breeds: Flemish Giant rabbits (F), Rex rabbits (R), and Indonesian local rabbits (L). Selective breeding consisted of three breeds: F (FF), R (RR), and L (LL). Two crosses were formed between the male ancestors of L and the respective female ancestors of F (LF) and R (LR). Each offspring's body weight (BW) was measured every 3 d starting from birth. FF exhibited the highest BW among purebred animals. The LF crossbreed had a greater estimated mature weight compared with purebred animals. The predicted mature live weight of the asymptotic value for LR animals was higher than for LL rabbits but lower than for RR rabbits. The heterosis effect was lower when crossing L and F animals compared with crossing L and R animals. The average heterosis impact values were 4.68 for LF and 15.32 for LR. LF rabbits showed superior heterosis effects when the growth parameter and inflection point were determined using a logistic model. This study emphasizes the use of strategic breeding to optimize rabbit growth and performance by offering detailed insights into growth dynamics and heterosis effects in different crossbreeding situations.

The period of gestation of rabbits and its fertility connection

The work researched the effect of multiple pregnancy on the gestation period of a female rabbit. To research the reproductive characteristics of female rabbits, physiologically mature live weight of at least 3 kg was selected. The reproductive characteristics of female rabbits were researched during three births. In the experiment, we used rabbit breeds such as New Zealand white and white giants, which were mated according to the scheme NZBxNZB and NZBxWG. The first litter of rabbits was analyzed as a control, and the second and third litters were analyzed as experimental groups. In the experiment, the polygamy ratio was 5:1. Female rabbits were mated in the morning and evening. The day of mating and the day of birth were recorded. The results obtained show that the length of the gestation period in rabbits is directly affected by the number of offspring. It has been established that the gestation period lasts longer in rabbits with a small number of offspring compared to rabbits with a large number of offspring.

Comparison of Nonlinear Growth Models to Estimate Growth Curves in Kivircik Sheep under a Semi-Intensive Production System.

The Kivircik is an indigenous sheep breed from Turkey, and it has superior meat quality compared to other indigenous breeds. Therefore, farmers prioritize Kivircik lamb fattening instead of milk production. Here, we aimed to determine the best nonlinear growth model, i.e., Gompertz, Logistic, Von Bertalanffy, and Brody, to describe the growth curve of Kivircik lambs. The body weight data from birth until 150 days of age belonging to 612 lambs were used as the material of this study. The best fitting model was selected by considering the adjusted coefficient of determination (R2adj), residual mean square, and Akaike's (AIC) and Bayesian information criteria (BIC). Even though the Brody model had a better statistical fit, considering its biological interpretation, the Gompertz model was identified as an appropriate model for describing Kivircik lamb growth. Male lambs, twin lambs, and lambs born in winter had higher mature live weights (44.2 kg, 71.2 kg, and 38.5 kg, respectively) and rate of weight gain (2.1, 2.6, and 2.0, respectively). However, our subgroups revealed a similar rate of maturity (0.01). Growth models are important tools for deciding the optimal slaughter age and they provide valuable information on the management practices of both sexes, birth types, and birth seasons. These results can be applied to breeding programs for early selection, enabling intervention strategies when needed.

Animal- and herd-level factors associated with onset of puberty in grazing dairy heifers

ABSTRACT Aims To explore animal- and herd-level risk factors influencing age at puberty in predominantly Holstein-Friesian dairy heifers managed in seasonal, pasture-based systems. Methods Heifers born in spring 2018 (n = 5,010) from 54 commercial dairy herds in New Zealand were visited on three occasions when the mean heifer age, within herd, was 10 (visit 1; V1), 11 (V2) and 12 (V3) months old. Blood samples were collected on each visit and liveweight, stature and anogenital distance (AGD) were measured at V2. Heifers were defined as having reached puberty at the first visit where blood progesterone was elevated (≥ 1 ng/mL). Animal-level response variables included pubertal status by V1, V2 and V3, and age at puberty (or age at V3 plus 31 days for those that had not attained puberty by V3). To explore herd-level management factors, farmers answered a questionnaire relating to animal location, land type, health, feeding, and management between weaning and mating. A partial least squares regression was undertaken to identify herd-level factors associated with the greatest influence on puberty rate within herd. Results The mean age at puberty was 352 (SD 34.9) days. Heavier animals at a greater proportion of expected mature liveweight based on their breeding value for liveweight, or animals with a higher breed proportion of Jersey and lower breed proportion of Holstein, were associated with earlier puberty. Herd puberty rates varied widely among enrolled herds, and averaged 20%, 39% and 56% by V1, V2 and V3, respectively. Liveweight, followed by breed and land type, had the greatest influence on the herd puberty rate. Heifer herds with a greater mean liveweight (absolute and proportion of expected mature weight) or greater Jersey proportion had more animals that reached puberty at any visit, whereas herds located on steep land or with greater Holstein breed proportions had lower puberty rates. Management-related factors such as vaccinations, provision of feed supplements, and weighing frequency were also herd-level risk factors of puberty but had less influence. Conclusions and clinical relevance This study highlights the importance of having well-grown heifers for increasing the chances of earlier puberty onset and the effect of breed and youngstock management to achieve growth targets. These outcomes have important implications for the optimal management of heifers to achieve puberty before their maiden breeding and for the timing of measurements to potentially incorporate a puberty trait in genetic evaluations.

Gomperzt non-linear model for predicting growth performance of commercial broiler chickens

An experiment was conducted to estimate growth parameters for commercial broiler chickens in Indonesia. The data was collected from July 2021 to June 2022. A total of 1,570 samples consisting of four strains of broiler chickens were collected from 74 houses. The samples were daily weighed from 0 to 7 days of age, and they were weekly weighed from 1 to 5 weeks of age. A nonlinear Gompertz growth model was fitted to the observed body weights (BW). The results for five growth parameters were as follows: the asymptotic value (A) of the mature live weight ranged from 3.733 to 5.044 kg; the turning point of growth (B) ranged from 4.499 to 4.561; the value growth rate constant (K) ranged from 0.049 to 0.059 kg/week; Inflection points in ranged from 25.292 – 30.970 days, and 1.373 – 1.855 kg for inflection age (IA) and inflection weight (IW), respectively. The model was an excellent fit for the growth data in the commercial broiler with a low Akaike information criterion (AIC), and high coeffi-cient determination (R2).

Economic values for sustainable dairy cattle breeding in the tropics: A focus on climate change responsive traits

The goal of this study was to estimate economic values for feed efficiency (FE), resilience (RE), adaptability (AD), and disease resistance (DR). The indicator traits that were used to measure; FE, RE, AD and DR were residual feed intake (RFI), variance deviations in milk yield, heat stress using milk reduction due to an increase in temperature humidity index (THI) by 1 and brucellosis disease resistance, respectively. A bio-economic model was developed in python using both simple profit functions and risk-rated profit models and was used to compute economic values for FE, RE, AD, and revise economic values for traits in the existing breeding goal, which included milk yield (MY), fat yield (FY), protein yield (PY), age at first calving (AFC), calving interval (CI), pre-weaning daily gain (DG), post-weaning daily gain (PDG), mature live weight (LW), pre-weaning survival rate (PSR), post-weaning survival rate (PWR), and productive lifetime (PLT). The economic value for brucellosis disease resistance was derived using selection index methodology. The risk-rated economic values for the climate change responsive traits were; KES -15.54, KES 47.37, KES 175.48, and KES -58.71 for FE, RE, AD, and DR respectively. The revised risk-rated economic values for the other traits were; KES 47.6, KES 132.8, KES 136.1, KES -334.9, KES -171.9, 8.3 g/day, 3.4 g/day, KES -30.8, 7.49%, 7.66%, and KES 63.9 for MY, PY, FY, AFC, CI, DG, PDG, LW, SR, PSR, and PLT respectively. The profits realised per year were; KES 705.71, and 77,473.70 for the current breeding goal (CBG) and climate change responsive breeding goal (CCRBG) respectively. These economic values indicate that inclusion of climate change responsive traits in breeding goal would increase response to selection of dairy cattle in the tropics.

Nonlinear Models for the Prediction of Yearly Live Weight of Cattle

Background: Growth of animals is important for milk and meat production. In developing countries record keeping is difficult and usually complete recording cannot be obtained from the cattle farming. Mathematical models are used to predict values from incomplete or partially recorded data and reduces the confusion for calculating the yield. Therefore, a study was conducted to know the growth of cattle by comparing three non-linear models and predicts the mature live weight. Mehods: The live weight of cattle at 15 day intervals from 15 to 365 days was recorded and calculated the yearly live weight and weight gains of three genotypes (Red Chittagong cattle, Non-descriptive deshi and their cross) of cattle. Three nonlinear model (Brody, Gompertz and von Bertalanffy model) was fitted to weight-age data of 120 female cattle from 15 to 365 days in three locations. Result: The average live weight and weight gain of three genotype cattle ranging from 198.5 to 207.89 kg and 306 to 361 g/day, respectively. The brody model provides better goodness of fit than other models in all genotypes and Gompertz and the von Bertalanffy model showed better matched between the observed and estimated weights

Indigenous chicken production in Fiji Islands: knowledge, constraints and opportunities.

ObjectiveThe objective of the study was to understand and document socio-economic characteristics, production parameters, challenges and management practices used by Fijian households which keep indigenous chickens.MethodsA survey involving 200 households was carried out in coastal and inland communities of Fiji’s wet and semi-dry ecoregions. Data on the influence of ecoregion and location of households relative to the sea on management practices, challenges and productivity of indigenous chickens were analyzed using logistic regression and general linear model of SAS software.ResultsIrrespective of location relative to the sea and ecoregion, households indicated that they kept indigenous chickens for food and income generation. The Welsummer was the most (p>0.05) preferred breed. Households in the semi-dry inland communities had the largest (p<0.05) flocks compared to those in semi-dry coastal communities and the wet region. Chickens in the semi-dry region performed better (p<0.05) than those in the wet region in terms of number of clutches per year and mature live weight. Predators and feed shortages were the biggest challenges faced by households in all areas. The mongoose was ranked as the most (p>0.05) common predator followed by domestic dogs. Most households in the wet ecoregion’s coastal communities housed their chickens at night, whereas communities in semi-dry ecoregion housed their chickens most of the time (p<0.05). In all regions, no households sold their chickens to commercial markets (p>0.05). Households in semi-dry ecoregion were more likely (p>0.05) to sell their chickens at the local market place.ConclusionThe productivity of local chickens in Fiji is low because of feed shortage, predators such as the mongoose and lack of market linkages.

An Important Genotype for Sustainable Extensive Goat Production Systems of Turkey: The Gökçeada Goat

In this study, it was aimed to report some traits of Gökçeada goats, which raised under the natural conditions of Gökçeada, with respect to their protection within the scope of genetic resources. In this respect the information obtained from the goats supplied from the Island and reared in a semi-intensive system at Çanakkale Onsekiz Mart University and also the information obtained from the literature were collected and the biological and zootechnical identifications of the Gökçeada goat were performed. Gökçeada goats, which are predominantly black, have yellow or red blazes on both sides of their heads including their eyes. It was seen that Gökçeada goats had similar body measurements and lower live weights as compared to those of the same species on the mainland. The birth weight and the mature live weight of Gökçeada goats were found as 2.55 kg and 38 kg, respectively, whereas their mean kid yield per goat at birth was determined as 1.6 to 1.8 kids. Individuals with a milk yield of 591 kg were striking in the Gökçeada genotype, in which the mean lactation length and the mean lactation milk yield were determined as 251 to 259 days and 227 to 245 kg, respectively. Its milk fat (4.92-5.75%) and milk protein (3.29%) resembled those of our other native breeds. It is necessary to reveal, with more elaborate studies, the potential for Gökçeada goat cheese that is greatly demanded on the Island. It was determined that the Gökçeada kids, which were considered as dairy kids, had some small but nonfat carcass and that their meat was soft and of a light color and had a slight smell. One should be careful about the adaptation of the Gökçeada genotype, which successfully maintains itself under the island conditions and which is the source of income for producers, to intensive and extensive goat production systems.

Phenotypic characterization and production potentials of exotic goat breeds and their crosses in Rajshahi metropolitan area of Bangladesh

This study was conducted to investigate the morphology, morphometry and production performances of exotic goat breeds and their crossbreds available at Boalia, Shahmokhdum, Rajpara and Matihar thana under Rajshahi metropolitan city. A total of 73 animals’ information was collected from 39 exotic goat flock owners using a semi-structured questionnaire through interviewing of farmers, visual observation and on-spot measurement of the animals. Exotic goat breeds and their crosses were found predominantly higher (&gt;93%) in Rajshahi Metropolitan areas where less than 7% Black Bengal goats were identified. In most cases, deviation of breed specific coat color due to crossing between different types of crossbreds among the populations was noted. The genotype frequencies of Beetal, Kalahari, Sirohi, Jamunapari, Anglo Nubian and their crossbreds and Black Bengal goats were found to be 50.68, 15.07, 13.70, 8.22, 8.22 and 4.11%, respectively. The average mature live weight (12 to 18 months) of those corresponding exotic genotypes in male and female respectively were found 46.88±5.66, 56.07±8.03, 32.67±8.09, 59.54±7.96 and 64.06±4.67 kg, and 21.70±2.24, 22.41±3.64, 17.37±4.05, 24.5±0.5 and 27.47±6.85 kg. Irrespective of genotypes, the mean age at puberty, lactation length, litter size, kidding interval and days open were found 167.50±3.49 days, 76.61±4.90 days, 1.71±0.10, 224.44±5.56 days and 52.64 ± 2.30 days, respectively. However, none of the aforementioned traits differed significantly (P&gt;0.05) among the five different exotic genotypes. In conclusion, this study provides some basic information on the performances of exotic goat breeds or their crossbreds at Metropolitan areas under intensive management conditions which could be utilized for designing proper breeding plan in their conservation and simultaneous improvement.&#x0D; Bang. J. Anim. Sci. 2020. 49 (2): 100-107

Investigating various performance traits of Karakul sheep

Karakul sheep in Turkey is an endangered breed according to the total number of ewes. Two herds of Karakul sheep in Tokat Province, reared similar environmental conditions, kept in situ in vivo conservation as a gene resource. This study aimed to determine various performance traits of Karakul sheep reared in breeder conditions as a gene resource. Least squares means for lambing rate (LR), litter size (LS) and lamb production (LP) were found 95.8±0.60%, 1.04±0.01 and 100.0±0.80%, respectively. It was determined that farm and age had significant effect on LR and LP, while farm and year had significant impact on LS. Survival rate in lambs were found 95.2 and 94.1%, respectively on 90th and 180th days. Means of least squares for live weights of lambs at birth and on 90th and 180th days were identified as 3.35±0.02, 21.52±0.27 and 30.34±0.32 kg, respectively. Live weight after shearing and greasy fleece weight values were 40.73±0.12 and 2.04±0.01 kg for females and 62.65±0.53 and 3.48±0.06 kg for males. Lactation milk yield (LMY) was 104.85±3.73 kg in ewes and lactation duration was 159.01±1.70 days. LMY was affected by the lactation number and farm while lactation duration was affected by lactation number. Results revealed that various performance traits of Karakul sheep conserved in breeder conditions were similar to or better than those previously reported for this breed. Also, the breed is similar to medium size native sheep breeds in terms of growth and mature live weight.

Effects of dietary fat source, breed and vitamin E level on lipid oxidation of muscles from sheep

The effects of diet and levels of dietary vitamin E on lipid oxidation were assessed in lambs in this study. Groups of Suffolk x Lleyn and Scottish Blackface male lambs were fed dietary lipid supplements containing either Megalac (C16:0), or one of two sources of n-3 PUFA: linseed which has a high content of C18:3 n-3, which had been treated with formaldehyde to aid rumen bypass and a mixture of formaldehyde treated linseed plus fish oil to provide EPA and DHA. The diets were based on dried grass had similar levels of fat (60g/kg DM). Vitamin E was included as α-tocopherol acetate at 100 and 500 mg/kg, for the low and high vitamin E diets, respectively. The six dietary treatments were: Megalac with low vitamin E, (ML); Megalac with high vitamin E, (MH); Protected linseed with low vitamin E, (LL); Protected linseed with high vitamin E, (LH); Protected linseed plus fish oil (linfish) with low vitamin E, (LFL); Protected linseed plus fish oil mixture (linfish) with high vitamin E, (LFH). At approximately half of the mature live weight for each breed, animals were slaughtered. This was on average 46 kg for the Suffolk and 36 kg for the Scottish Blackface. The meat from supplemented animals increased susceptibility to lipid oxidation in high PUFA in meat resulted from poor deposition of dietary vitamin E supplements.

Modelling: effect of feeding plantain pasture to three different breeds of calf/heifer on weight gain and nitrogen leaching in Canterbury

ABSTRACTFour levels of plantain (0%, 25%, 50% and 75% on DM basis) inclusion rate to ryegrass-clover pasture and three target heifer mature live weights, 444 kg (representing Jersey), 529 kg (Friesian), and 492 kg (cross bred Jersey × Friesian) were tested in this modelling exercise for a 30 ha farm and 24-month analysis. The annual average growth rates were 30 kg DM/ha/day and 23 kg DM/ha/day for plantain and perennial ryegrass-white clover, respectively. Feeding plantain increased animal live weight gain, but on a whole farm level, total live weight gain was similar between the three target weight treatments. Stocking rate was identified as a major driver of nitrogen leaching in this study, which resulted in a decreased nitrogen leaching with increased target live weight groups. Increased annual nitrogen leaching value was found from feeding plantain to animals, which contrasts to previous speculation from animal studies.

Characterization of Hilly Chickens in Consideration of Climate Change Factors: Light and Heat

ABSTRACT Hilly chickens were characterized from January 2015 to September 2016 considering climate factors (light and heat). The experimental birds were divided into three groups (heat stress; light and control). The heat was generated in the chicken’s shelter by a black shaded light (Lantern) for two to three hours more after sunset. A lighting device (Lantern) was kept in the chicken’s shelter for the same period for increasing daylight duration. The individual chicken’s egg production, egg weight and mature live weight were studied from onset of egg production. It was observed that reddish brown hilly type chicken produced more (100.80 no/year/chicken) and larger sized (43.21g) eggs than spotted chicken (83.4 no/year/chicken and 40.46g). Among the three treatments, the lighting group produced 7.71 and 5.60 more eggs than the control and heat stress group, and one hour lighting lengths increased egg production 4 to 5.8%. Fifty-five blood samples were collected, and DNA was isolated from whole blood. For genetic characterization, 10 microsatellites markers from FAO recommendation list were used in this study. PCR amplification was performed in an MJ PTC-200 Peltier Thermal Cycler. The gene flow among breeds and genetic differentiation was assessed by computing between-breed genetic parameters: molecular co-ancestry (fij). It was found that genetic diversity of these two types of chickens was moderate. Results indicated that they were originated from the same ancestor. Therefore, priority should be given for implementation of appropriate breeding programme and strategies are necessary to avoid loss of genetic diversity.

Growth of Brahman cross heifers to 2 years of age in the dry tropics

Growth of 1368 Brahman cross heifers from 6 year cohorts was monitored over the 2 years post-weaning in Australia’s northern forest, a low-animal-growth dry tropical environment. Heifers weighing 47–266 kg at weaning were managed in groups weighing &amp;lt;100 kg, 100–149 kg, 150–199 kg, and &amp;gt;199 kg during the post-weaning dry season. Weaner heifers were allocated to receive 300 g/day of a protein meal during the dry season or to basic nutritional management to sustain health. Heifers in three cohorts were allocated to first mating at 1 or 2 years of age, in four cohorts to vaccination against androstenedione, and in a small proportion of two cohorts to ovariectomy post-weaning. Growth was highly variable between seasons and years; average cohort liveweight by the start of 2-year-old mating was 256–319 kg. Heifer groups not receiving protein supplementation gained –16 to 21 kg (2 kg average) during 6-month dry seasons, and 49–131 kg (101 kg average) during wet seasons to reach an average of two-thirds of mature liveweight (445 kg) and 95% of mature hip height (1350 mm) by the start of mating at 2 years. Average body condition score (1–5) fluctuated by 1–2 units between seasons. Hip height gain continued, irrespective of season, commencing at ~0.60 mm/day at 6 months of age, and decelerating by ~0.00075 mm/day through to 2.5 years of age. Standard errors of predicted means across analyses were ~0.015 for average daily weight gains, 0.4 mm for average monthly height gain and 0.06 score units for average seasonal body condition score change. Post-weaning dry-season supplementation increased gains in liveweight, height and body condition score by an average of 0.1 kg/day, 0.1 mm/day and 0.5 units, respectively, during the supplementation period. Periods of poor nutrition or high nutritional demand secondary to reproduction suppressed daily gains in liveweight and hip height, at which times body condition score was also reduced. Subsequent to this, partial to full compensation occurred for all measures. Ovariectomy had negative effects on growth. Androstenedione vaccination had no effect on growth. The main conclusion is that heifer growth in Australia’s dry tropical northern forest region is highly variable between seasons and years, thus limiting significant proportions of some cohorts from reaching target weights for mating at 2 years of age, even after compensatory growth.

Identification of best performer hilly chickens of Bangladesh in consideration of climate change factors: light and heat

The best performer hilly chickens in consideration of light and heat were assessed under rural conditions. Based on the survey, the chickens and farm household were selected. The chickens were provided supplementations of concentrate feed (50g/chicken/day). The selected chickens were divided into 3 groups (heat stress, light and control) for the study of their egg production potential. Heat was generated in the chicken's shelter by keeping a black shaded light (Lantern) for 2 to 3 h more after sunset. A lighting device (Lantern) was kept in the chicken's shelter for 2 to 3 h more after sunset for increasing the duration of day light. Temperature and humidity index was calculated from the recorded temperature and humidity. The individual chicken's egg production, egg weight and mature live weight were studied for different types of hilly and non-descriptive desi chickens. It was observed that hilly chickensproduced more eggs than desi. The hen house egg production percentage (19.95%) and yearly egg production (90no/year/chicken) of desi white was significantly higher than spotted hilly (17.29% and 83.4 no egg, respectively) but reddish brown hilly type produced more number (100.80 no/year/chicken) of eggs than all types. The egg weight varied from 41.27 g to 43.85 g. Mature live weight were significantly different between hilly and desi(1438.70 g vs 1309.27 g). Among the 3 treatments, the lighting group hilly chickens produced 7.71 and 5.60 more eggs than control and heat stress group, respectively. One hour lighting length increased egg production by 4 to 5.8%.

Evaluation of the effects of ewe prolificacy potential and stocking rate on herbage production, utilization, quality and sward morphology in a temperate grazing system

AbstractThis study investigated the effect of ewe prolificacy potential (PP; predicted number of lambs born ewe−1 year−1), stocking rate (SR; ewes/ha) and their interaction on herbage dry matter (DM) production, utilization, quality and sward morphology within a temperate grass‐based lamb production system. The study had a 2 × 3 factorial design, consisting of two ewe PP as dictated by sire breed (180 medium prolificacy potential (MP—Suffolk crossbred) and 180 high prolificacy potential ewes (HP—Belclare crossbred)) and three SR: low (LSR; 10 ewes/ha), medium (MSR; 12 ewes/ha) and high (HSR: 14 ewes/ha). Each treatment was managed in a rotational grazing system, with LSR, MSR and HSR treatments grazing to target post‐grazing sward heights (PGSH) of 4.55, 4.15 and 3.75 cm respectively. Herbage DM production (above target PGSH) and utilization were highest at the HSR, intermediate at the MSR and lowest at the LSR (p &lt; .001). Ewe PP had no effect on herbage DM production, utilization, quality or sward morphology (p &gt; .05). The proportion of leaf in the sward (above target PGSH) was 4% greater in MSR and HSR compared with LSR (p &lt; .05). In conclusion, findings demonstrate the potential to support increased ewe PP through the selection of ewe genotypes of a genetically higher PP and lower mature live weight and increased SR within a temperate grass‐based lamb production system.

Analysis of multivariate relations among birth weight, survivability traits, growth performance, and some important factors in Suffolk lambs

Abstract. The aim of this study was to describe the relationships among lambs' birth weight, survivability traits, growth performance, and selected factors in Suffolk lambs kept under a specified extensive management system. Data were collected regarding 1012 Suffolk lambs born during a 3-year period (2012–2014) in one flock. Statistical analyses were conducted using the SAS and CANOCO program software. Birth weight was found to be an important factor influencing survivability and growth performance traits. Lambs with too low a birth weight (&lt; 2.9 kg) had the worst results of practically all the survivability and growth performance traits. A significantly lower percentage of live-born lambs (5.2 to 6.1 %; P &lt; 0.05) was also observed amongst overweight lambs at birth (&gt; 6.0 kg) compared to lambs with a birth weight of 4–5.9 kg. Generally, the highest results of growth performance traits were detected in groups of lambs with a birth weight of 5.0–5.9 and 6.0–9.0 kg. Therefore, the optimal birth weight of Suffolk lambs was in the range of 5.0 to 5.9 kg in the evaluated flock management system. Litter size was found to be the dominant factor influencing birth weight, survivability, and growth performance traits, such that singles tended to have the highest birth weight and growth performance traits, while higher survivability traits were found in twins. The results of multivariate relations also clearly indicated that the selection of lambs should be focused on twins with regard to the monitoring of mature ewes' live weight at mating, which helped to improve the lambs' survivability traits, in particular. The monitoring of ewes' mature live weight at mating should also serve as a tool for flock management to shorten the lambing period in the flock and to improve the birth weight and growth performance traits of lambs. The mature ewe body condition score at mating should be monitored to ensure that lambs are adequately meaty and fatty. This study confirmed the importance of keeping records of birth weight and suggested practical implications of some important factors when improving flock profitability.

Impact of including growth, carcass and feed efficiency traits in the breeding goal for combined milk and beef production systems

Improving feed efficiency in dairy cattle could result in more profitable and environmentally sustainable dairy production through lowering feed costs and emissions from dairy farming. In addition, beef production based on dairy herds generates fewer greenhouse gas emissions per unit of meat output than beef production from suckler cow systems. Different scenarios were used to assess the profitability of adding traits, excluded from the current selection index for Finnish Ayrshire, to the breeding goal for combined dairy and beef production systems. The additional breeding goal traits were growth traits (average daily gain of animals in the fattening and rearing periods), carcass traits (fat covering, fleshiness and dressing percentage), mature live weight (LW) of cows and residual feed intake (RFI) traits. A breeding scheme was modeled for Finnish Ayrshire under the current market situation in Finland using the deterministic simulation software ZPLAN+. With the economic values derived for the current production system, the inclusion of growth and carcass traits, while preventing LW increase generated the highest improvement in the discounted profit of the breeding program (3.7%), followed by the scenario where all additional traits were included simultaneously (5.1%). The use of a selection index that included growth and carcass traits excluding LW, increased the profit (0.8%), but reduced the benefits resulted from breeding for beef traits together with LW. A moderate decrease in the profit of the breeding program was obtained when adding only LW to the breeding goal (−3.1%), whereas, adding only RFI traits to the breeding goal resulted in a minor increase in the profit (1.4%). Including beef traits with LW in the breeding goal showed to be the most potential option to improve the profitability of the combined dairy and beef production systems and would also enable a higher rate of self-sufficiency in beef. When considering feed efficiency related traits, the inclusion of LW traits in the breeding goal that includes growth and carcass traits could be more profitable than the inclusion of RFI, because the marginal costs of measuring LW can be expected to be lower than for RFI and it is readily available for selection. In addition, before RFI can be implemented as a breeding objective, the genetic correlations between RFI and other breeding goal traits estimated for the studied population as well as information on the most suitable indicator traits for RFI are needed to assess more carefully the consequences of selecting for RFI.

Screening and characterization of a novel ruminal cellulase gene (Umcel-1) from a metagenomic library of gayal (Bos frontalis)

Gayal is a rare semi-wild bovine species found in the Indo-China. They can graze grasses, including bamboo leaves, as well as reeds and other plant species, and grow to higher mature live weights than Yunnan Yellow cattle maintained in similar harsh environments. The aim of this study was to identify specific cellulase in the gayal rumen. A metagenomic fosmid library was constructed using genomic DNA isolated from the ruminal contents of four adult gayals. This library contained 38 400 clones with an average insert size of 35.5 kb. The Umcel-1 gene was isolated from this library. Investigation of the cellulase activity of 24 random clones led to the identification of the Umcel-1 gene, which exhibited the most potent cellulase activity. Sequencing the Umcel-1 gene revealed that it contained an open reading frame of 942 base pairs that encoded a product of 313 amino acids. The putative gene Umcel-1 product belonged to the glycosyl hydrolase family 5 and showed the highest homology to the cellulase (GenBank accession no. YP_004310852.1) from Clostridium lentocellum DSM 5427, with 44% identity and 62% similarity. The Umcel-1 gene was heterologously expressed in Escherichia coli BL21, and recombinant Umcel-1 was purified. The activity of purified recombinant Umcel-1 was assessed, and the results revealed that it hydrolyzed carboxymethyl cellulose with optimal activity at pH 5.5 and 45°C. To our knowledge, this study provides the first evidence for a cellulase produced by bacteria in gayal rumen.