Italian Heavy Draught Horse Research Articles

Proteomic analysis to understand the relationship between the sarcoplasmic protein patterns and meat organoleptic characteristics in different horse muscles during aging

The study investigates the changes in meat organoleptic characteristics and sarcoplasmic proteins of 3 horse muscles during aging. Longissimus lumborum (LL), semimembranosus (SM) and semitendinosus (ST) muscles, were removed from 12 Italian Heavy Draft Horse carcasses and aged for 1, 3, 6, 9 and 14 days. The lowest values of hardness and chewiness were found in LL muscle. During aging, a decrease of hardness was observed in ST muscle reaching the lowest value at 14 days. 2DE revealed a decrease of 15 sarcoplasmic protein spots in all muscles. Muscle-differences were found at 14 days. An increase of tropomyosin spots was found in LL muscle while, ST was characterized by a rise of superoxide dismutase, phosphoglucomutase-1 and two isoforms of myoglobin. Principal component analysis applied to color, texture parameters and spots volume differentiated the muscles into three different clusters. Data revealed that myofibrillar, glycolytic and mitochondrial proteins are potential muscle-biomarkers to monitor post-mortem processes and meat quality characteristics in horse meat.

Genetic Variability in the Italian Heavy Draught Horse from Pedigree Data and Genomic Information.

This study aimed to investigate the genetic diversity in the Italian Heavy Horse Breed from pedigree and genomic data. Pedigree information for 64,917 individuals were used to assess inbreeding level, effective population size (Ne), and effective numbers of founders and ancestors (fa/fe). Genotypic information from SNP markers were available for 267 individuals of both sexes, and it allowed estimating genomic inbreeding in two methods (observed versus expected homozygosity and from ROH) to study the breed genomic structure and possible selection signatures. Pedigree and genomic inbreeding were greatly correlated (0.65 on average). The inbreeding trend increased over time, apart from periods in which the base population enlarged, when Ne increased also. Recent bottlenecks did not occur in the genome, as fa/fe have shown. The observed homozygosity results were on average lower than expected, which was probably due to the use of French Breton stallions to support the breed genetic variability. High homozygous regions suggested that inbreeding increased in different periods. Two subpopulations were distinguished, which was probably due to the different inclusion of French animals by breeders. Few selection signatures were found at the population level, with possible associations to disease resistance. The almost low inbreeding rate suggested that despite the small breed size, conservation actions are not yet required.

Genetic Parameters of Linear Type Traits Scored at 30 Months in Italian Heavy Draught Horse.

Simple SummaryCurrent selection in the Italian Heavy Draught Horse (IHDH) is based on linear type traits scored on foals, but the studbook admission of candidate mares and stallion requires an additional evaluation of linear type traits at adult age, about 30 months. The study intended estimating the genetic parameters of these traits to evaluate the possible shift from type scored on foals to adult. Results showed a moderate heritability of traits, and a positive genetic trend was observed in the traits of selection interest. This suggests the feasibility of using linear type traits scored at adult age for genetic improvement of the IHDH.The Italian Heavy Draught Horse (IHDH) breed is selected based on linear type traits (LTT) evaluated at young age on six-month-old foals. However, animals retained for reproduction are scored also at adults age (about 30 months), and the evaluation is mandatory for the final official admission to the stud book of candidate mares and stallions. This study aimed to estimate genetic parameters of LTT scored at 30 months to consider if they are feasible for selection instead of using foal data and to reduce costs of selection plan. Data included 19 years of evaluation for 14 LTT and an overall score. Analyses were performed on 5835 females and 856 males via animal model. The heritability ranged from 0.03 (upper line length) to 0.40 (frame size). Traits of selection interest (head size and expression; temperament/movement; fleshiness; fore diameter; rear diameter) reported heritability between 0.21 and 0.31. High genetic correlations were obtained among traits related to muscular development, 0.73 on average. Positive genetic trends were found in traits of selection interest, already selected from foal type trait data. Accounting for genetic parameters estimated in adult animals instead in foals is feasible in IHDH selection.

Genetics of Lifetime Reproductive Performance in Italian Heavy Draught Horse Mares.

Simple SummaryFertility is a very important fitness trait in animal production because of its significant economic importance, particularly in species with low reproductive efficiency. For this reason, it should be included as a breeding objective, particularly in horses, where the trait has received less interest than in other species. In this study, we attempted to identify a variable able to detect the lifetime reproductive performance of Italian Heavy Draught Horse (IHDH) mares and to analyze its possible implementation for breeding purposes, with the final aim to increase mares’ fertility efficiency. A phenotypic variable to be used early in life (at least after 3 breeding seasons) has been identified and validated in the study and its genetic component estimated. Results obtained indicated the proposed phenotypic measure of fertility as a good predictor of the lifetime reproductive success in IHDH mares and the variable showed high heritability (that is, the transmittable genetic component) for a fitness trait. Therefore, the use of the lifetime fertility rate proposed in this study for breeding purposes seems feasible, although some limitations could occur in the accuracy of individual breeding value estimates of mares and stallions.Our aims were to find a phenotypic variable to express mares’ lifetime reproductive performance after 6 breeding seasons (BS) in Italian Heavy Draught Horse breed (IHDH), and to estimate its heritability. At first, 1487 mares in a training dataset were used to implement and validate a set of predictive coefficients (LFR-C) or equations (LFR-E) to estimate a lifetime foaling rate (LFR) after 6 BS, i.e., the number of foals generated divided by the opportunities to do so. Then, 3033 mares in a dataset with at least 3 registered BS, was used to estimate LFR for mares with 3, 4, or 5 registered RS. This dataset contained actual (n = 1950) and estimated (n = 1443) LFR, obtained by LFR-C, and LFR-E; Arcsine transformation of LFR-C and LFR-E were also analyzed in single trait animal models to estimate heritability. Overall, the LFR showed a moderate but significant genetic variation, and the heritability of the trait was high (0.24) considering it is a fitness trait. The arcsine transformation of LFR did not show any improvement of heritability. The present study indicates the possible use of a linear LFR variable for breeding purposes in IHDH breed considering both complete and incomplete reproductive careers.

Mitochondrial DNA variation in the Italian Heavy Draught Horse.

BackgroundIn the last decades, Italy as well as other developed countries have registered a decrease in the population size of many local horse breeds. The continuous crossbreeding has determined the dilution of genetic heritage of several native breeds. The Italian Heavy Draught Horse (IHD) is the only autochthonous Italian coldblooded horse among these breeds; therefore, it represents a resource to be preserved. In 1927, the first generation of this breed was officially created by crossing different Heavy Draught horses with local mares and recorded in a Studbook.MethodologyTo provide the first comprehensive overview of the genetic diversity of Italian Heavy Draught horses from Central Italy, we produced and phylogenetically analysed 52 mitochondrial DNA (mtDNA) control-region sequences. Furthermore, we evaluated data available from GenBank (N = 568) to have a more complete scenario and to understand the relationships with other European Heavy Draught horse breeds.ResultsAmong the IHD samples that were analysed, we identified ten of the 17 haplogroups described in modern horses. Most of these sequences fell into L, G, and M lineages, thus showing the overall mtDNA legacy of the ancestral mares that were probably used at the initial stages of breeding selections a long time ago. The high mitochondrial haplotype diversity (Hd = 0.969) found in our samples reflected the multiple maternal origins of the horses. Our results highlighted a considerable percentage of haplotypes shared especially with Bardigiano and Hungarian Heavy Draught breeds. Furthermore, both the presence of four unique haplotypes detected in our samples and their absence among all equine mitochondrial published data demonstrate a mitochondrial peculiarity that needs to be further investigated and preserved with careful breeding practices.

Biochemical reference intervals for the Italian Heavy Draft horse

Established breed-specific reference intervals are important for monitoring the health status of horses. Serum biochemical breed-specific reference intervals have been evaluated in horses and other animal breeds, but there are no studies for the Italian Heavy Draft horse. The aim of this study was to determine biochemical reference intervals for the Italian Heavy Draft horse living in central Italy. Moreover, the comparison between different physiological status (pregnancy and no pregnancy) and age (foals and adults) has been executed. Inclusion criteria were established before blood collection. Blood samples were collected from 309 apparently healthy horses (mares, stallions and foals). Serum parameters were evaluated in the Clinical Pathology Laboratory at the Teaching Veterinary Hospital of the University of Perugia. Reference intervals were determined by using well-described, modern analytical and statistical methods (Anderson-Darling test, Mann-Withney U test). Serum biochemical RIs for the IHDH are reported. Differences between the IHDH and both sport and other working horses are evident. Significant differences are indicated between pregnant and non-pregnant mares and between foals and adults. This is the first study reporting the serum biochemical RIs in the IHDH. The results suggest that breed-specific RIs should be used for the IHDH. Moreover, significant variations of biochemical analytes have been found between subjects with different physiological status and age.

Hematologic reference intervals for the Italian Heavy Draft horse

Established breed-specific reference intervals (RIs) are important for monitoring the health status of horses. Breed-specific RIs have been evaluated in horses and other animal breeds, but there are no studies on breed-specific RIs for Italian Heavy Draft horse (IHDH). The aim of this study was to determine hematologic RIs for the IHDH living in central Italy. The comparison between different physiological status (pregnancy) and age (foals and adults) have been executed. Inclusion criteria were established for selection of subjects and for blood collection and handling. Blood samples were collected from 309 apparently healthy horses (mares, stallions and foals). Complete blood count (CBC) was performed on Sysmex-XT1800iV hematology at the Teaching Veterinary Hospital of the University of Perugia. RIs for IHDH were determined by using well-described, modern analytical and statistical methods as recommended by the CLSI and QALS guidelines. Hematologic RIs for the IHDH are reported. Differences between hot-blooded, cold-blooded, and warm-blooded horses are evident. Significant differences have been found for five analytes (WBC, MCHC, PLT, monocytes, basophils) between pregnant and non-pregnant mares and 12 analytes (RBC, Hgb, MCV, MCH, MCHC, RDW, PLT, WBC, lymphocytes, monocytes, eosinophils, basophils) between foals and adults. This is the first study reporting the hematologic RIs in the IHDH. The results suggest that breed-specific RIs should be used for IHDH due to the difference with published data regarding cold-blooded, hot-blooded, and warm-blooded breeds. Moreover, significant variations of hematological analytes have been found between subjects with different physiological status and age.

Genetics of linear type traits scored on young foals belonging to the Italian Heavy Draught Horse breed

In small horse breeds, the small size of stud-farms can bias genetic parameters’ estimations, excluding many breeders from the selection. The study aimed to find a method to include small stud-farms in genetic analysis and to estimate genetic parameters for linear type traits in Italian Heavy Draught Horse (IHDH). Stud-farms were grouped according to an increasing number of criteria: (i) geographical location and housing system; (ii) target productions and vaccination of foal; (iii) stud's body condition. These groups allowed 6 contemporary groups (CG) of environmental units (CG1-CG6) in a dataset of 11,357 scores of young foals and 17,441 subjects in pedigree. Model fitting increased with the number of CG levels. Considering the CG6, heritability varied from 0.149 (upper line direction) to 0.375 (head size/expression). The greatest genetic correlations (from 0.810 to 0.887) involved fleshiness, fore, and rear diameters. The use of CG allowed retaining many records. Genetic estimates indicated a possible genetic improvement for heavy draught and meat production.

Evaluation of behaviour in stabled draught horse foals fed diets with two protein levels

The present work is aimed at evaluating the behaviour of Italian Heavy Draught Horse (IHDH) foals reared in semi-covered stables and fed two isoenergetic total mixed rations with different dietary protein levels (13.2% and 10.6% of CP on dry matter). The study was prompted by the restrictions for nitrate emissions in farms of the European Nitrate Directive. One suggested solution is to reduce dietary protein while maintaining normal performance and welfare, but there is a lack of literature in studies of horses. The behaviours of 20 foals of 437±60 kg of BW, aged 379±37 days and stabled in four pens by sex (S) and diet (D) were video recorded and analysed to build a suitable ethogram including 18 behaviours in six categories: ingestion, resting, maintenance, movement, social activities, other. The percentage of the daily time spent in each behavioural category and single behaviours was analysed via a single traits GLM including S, D and their interaction. Daily activity was consistent with existing literature: foals spent about 33% of the day in ingestion activities and 41% in resting, whereas social interactions constituted 8% of the time and individual maintenance <2%. Concerning diet, foals fed high protein spent more time in movement (19.62±0.73% of day v. 10.45±0.73% in low-protein (LP) foals; P⩽0.001), whereas the LP group increased resting (43.42±1.12% v. 38.02±1.12%; P⩽0.001). No stereotypies were found, and daily activity followed the typical values for draught breeds for foals in both dietary groups, a result that suggests the maintenance of well-being after dietary protein reduction. This result, together with the findings of a companion study showing no changes in growth performances of foals, showed that a reduction of CP in foal diet is reconcilable with the maintenance of performance and welfare.

Is meat quality from Longissimus lumborum samples correlated with other cuts in horse meat?

The present work aims to investigate if the variation of each parameter in Longissimus lumborum muscle could correspond to the same or to a similar variation of the parameter in the other muscles. The work presents results of Pearson's correlations between Longissimus lumborum samples and other muscle samples, such as Biceps femoris, Rectus femoris, Semimembranosus, Supraspinatus and Semitendinosus in horse meat. A total of 27 male IHDH (Italian Heavy Draught Horse) breed foals were employed. They were slaughtered at 11 months of age and the above-mentioned muscles were sampled. The Longissimus lumborum muscle showed to be representative of other muscles and of the whole carcass for some chemical parameters (moisture, protein and ash) and for some fatty acids profile patterns such as C12:0, C14:0, total monounsaturated fatty acid and polyunsaturated fatty acid, but poor correlations were recorded for intramuscular fat concentration, rheological and colorimetric parameters. Although almost all the qualitative parameters in meat are affected by the anatomical site and by the muscle, the Longissimus lumborum is often not representative in horse meat with regard to modifications of this parameters.

Comparative characteristics of DNA polymorphisms of κ-casein gene (CSN3) in the horse and donkey.

The aims of this study were to assess the genetic variability in the exon 1 of the κ-casein gene in four Italian horse populations (Italian Saddle horse, Italian Trotter, Italian Heavy Draught horse, and Murgese horse) and in a sample of Martina Franca donkey by estimating genotype, allele and haplotype frequencies, as well as several population genetic indices. Genotyping of the selected polymorphisms was performed using the PCR-RFLP technique with two restriction enzymes: PstI and BseYI aimed to discover the presence of c.-66A>G and c.-36C>A polymorphism, respectively. Both these loci were found to be polymorphic in horses with some differences depending on the breed. No genetic variability was observed in Martina Franca donkey breed. In the equine species no selective pressure for milk purpose was performed, therefore the polymorphisms at milk protein loci were mainly considered as result of natural selection or as indirect consequence of selection oriented to increase body size or to improve conformation. From this point of view these two single nucleotide polymorphisms and particularly the c.-36C>A one could be useful instruments for population studies.

In vivo performance of Italian Heavy Draft Horse weanlings fed two protein levels and slaughtered at two ages.

This study aimed at evaluating in vivo performance, growth parameters, intakes, dressing percentage, and blood parameters in Italian Heavy Draft Horse (IHDH) weanlings fed 2 CP levels up to the 2 typical ages of slaughter. Forty-one weanlings were grouped in 8 pens according to sex, age, and BW. After a transition period, animals were randomly assigned to 2 isoenergetic diets containing different CP levels: 10.6 and 11.2% CP in DM for low protein (LP) and 13.2 and 14.7% CP in DM for high protein (HP) diets in the first and second phase, respectively. About half of the animals (n = 22) were slaughtered when aged 13 mo (end of first phase); the remaining animals (n = 19) were slaughtered at 18 mo (end of second phase). Animals were weighed, measured for withers height, and scored in vivo for fleshiness and BCS at 3 wk intervals. Feed intake in each pen was measured weekly, and feed samples were collected every 2 mo. Blood samples from venous jugular were collected in both phases to analyze plasma protein, urea, glucose, bilirubin, hepatic enzymes, and mineral content. Growth parameters were estimated within phase by modeling BW as a function of age using fourth-degree Legendre polynomials. During the first phase, a different linear coefficient (P = 0.051) for the growth curve was observed between females fed a HP or a LP diet, while males showed differences only on quadratic and cubic Legendre coefficients. However, no significant differences were detected in ADG between the CP levels and sexes. In the second phase, Legendre coefficients were not different between treatments for the remaining weanlings, and once again no differences were found on ADG. The DM intake was influenced by diets in both periods, greater in the HP diet as compared with the LP diet (P < 0.001). No differences due to diet were observed for fleshiness or BCS scores at the end of each phase or in the dressing percentage at slaughter. As expected, plasma urea was greater (P < 0.001) in animals fed the HP diet but was within a normal range for healthy horses. In conclusion, a small dietary protein restriction (i.e., on average 3% of DM) did not change the in vivo performance of IHDH weanlings up to 13 or up to 18 mo of age.

Effect of nutritive level on carcass traits and meat quality of IHDH foals.

The present work describes the effect of nutritive level on horse carcass traits and on meat quality. Eighteen male Italian Heavy Draught Horse (IHDH) breed foals were employed in the study. Soon after foaling they were randomly subdivided into three groups according to three nutritive level classes: 150%, 180% and 200% of maintenance requirements. Live weight, hot carcass weight and dressing percentage of each animal were recorded. After slaughtering, meat samples were collected from Longissimus dorsi muscle. The right half carcass of each animal was then divided into cuts. Each one was subdivided into lean, fat and bones. Live weight, carcass weight and dressing percentage were not affected by nutritive level (P > 0.05). Horses fed with the lower nutritive level showed a higher incidence of lean and a lower incidence of fat (P < 0.01). Moreover, fatty acid profile was not affected by nutritive level (P > 0.05). Probably the tendency of IHDH foals to concentrate adipogenesis in the subcutaneous district could explain the lack of influence of nutritive level on meat quality parameters and its influence on carcass and cut composition, which tend to be richer in fat.

Association of myostatin (MSTN) gene polymorphisms with morphological traits in the Italian Heavy Draft Horse breed

The myostatin (MSTN) gene encodes a protein well known as a negative regulator of muscle mass in mammalian species. In a previous study, we identified single nucleotide polymorphisms (SNPs) in the equine MSTN gene that could be associated with variability of morphological traits in different horse breeds. In this study we carried out a first evaluation of the association of MSTN gene with morphological traits and body measurements obtained at adult age in the Italian Heavy Draft Horse (IHDH), an autochthonous cold-blooded breed currently selected for meat production and for heavy draught. We genotyped 202 horses for four SNPs of the MSTN gene: two located in the promoter (GQ193900:g.26T>C and GQ193900:g.156T>C) and two in the first intron (GQ193900:g.2077T>C and GQ193900:g.2115A>G). Minor allele frequencies of SNPs varied from 0.118 to 0.148. The haplotype [g.26T:g.156T:g.2077T:g.2115A] showed the greater frequency (0.596). Biometric measurements of three body measurements (height at withers, chest girth, and cannon bone circumference) and 14 linear type data related to general aspects (head size and expression, temperament/blood, frame size, fleshiness and bone incidence), trunk (thorax depth, fore diameter, rear diameter, upper line length, and upper line direction) and feet and legs (e.g. side and back view of rear legs, fore and rear feet) were used in the association study. Among the investigated SNPs, the GQ193900:g.26T>C polymorphism was the most interesting as it resulted associated with cannon bone circumference (P nominal=0.001) and side view of rear legs (P nominal=0.006) and suggestively associated with fleshiness (P nominal=0.027). In silico transcription factors binding sites (TFBSs) prediction located putative TFBSs involved in growth and differentiation of multiple cell types, including myoblasts and osteoblasts in the SNP positions, suggesting that the analyzed SNPs could play a functional role. Gene expression studies should be carried out to verify this hypothesis. Further association studies in the present and other heavy horse breeds are needed to confirm the effects of MSTN polymorphisms on morphological traits, and potentially apply these markers in breeding programs to improve selection efficiency for muscularity and strength in horses.

Slaughtering age effect on carcass traits and meat quality of italian heavy draught horse foals.

The present work describes the effect of slaughtering age on horse carcass traits and on meat quality. Eighteen male Italian heavy draught horse (IHDH) breed foals were employed in the study. Soon after foaling they were randomly subdivided in 3 groups according to 3 age at slaughtering classes: 6 months old, 11 months old and 18 months old. Live weight, hot carcass weight and dressing percentage of each animal were recorded. After slaughtering, meat samples were collected from Longissimus Dorsi muscle between 13th and 18th thoracic vertebra of each animal and then analyzed. The right half carcass of each animal was then divided in cuts. Each one was subdivided into lean, fat and bones. Then, the classification of the lean meat in first and second quality cuts was performed according to the butchers’ customs. Older animals were characterized by a lower incidence of first quality cuts (p<0.01) on carcass. Younger animals showed greater content in protein (p<0.01). Fatty acid profile showed an increasing trend of PUFA connected to the increasing of slaughtering age (p<0.05). The unsaturation index of intramuscular fatty acids was not affected by slaughtering age, confirming that horse meat, if compared to beef, is more suitable from a nutritional point of view. Season influenced reproduction, birth as well as production aspects of this species. The different slaughtering age could represent the way to produce meat of IHDH foals during the entire year without change in the qualitative standard expected by consumers.

Post-thawing colour changes in meat of foals as affected by feeding level and post-thawing time

Abstract. The aim of the present work was to investigate how chromatic properties of foal meat can vary after thawing out in relation to the feeding level of 11 months old horses and to the post-thawing time. Thirty-six Italian Heavy Draught Horse foals were used for the trial. They were subdivided in three groups according feeding level: FL150=150 %, FL180=180 % and FL200=200 % of the energy maintenance requirements. Two different surfaces were investigated for each sample: daily renewed cutting surface and not renewed cutting surface. Lightness fell on both surfaces with the increasing of the feeding level (P&lt;0.01). The redness of both investigated surfaces increased with feeding level (P&lt;0.01), while yellowness decreased (P&lt;0.05). Consumers prefer to purchase meat that is red rather than brown in colour. So, from a chromatic perspective the thawed meat of Italian Heavy Draught Horse foals fed with a lower feeding level proved to be that which best meets the market requirements.

Retrospective and statistical analysis of breeding management on the Italian Heavy Draught Horse breed

This study investigated some aspects of breeding management in the Italian Heavy Draught Horse breed, aiming at improving its efficiency at stud farm level. A first aim was to evaluate the risk of unsuccessful reproduction in mares after an early (3 years) or normal (4 years) age at first foaling, in interaction with different stud rearing systems. A second objective was the examination of the mean time length in which young 2-year-old stallions maintain a genetic superiority on older proven stallions, identifying a ‘genetic lifespan’ in which young stallions can be safely used for reducing the cost of services. Reproductive performance at first and second foaling of 1513 mares were used. Mares had a normal first foal at 3 (n = 745) or 4 years of age (n = 768) in stud farms on the basis of stable (n = 488), feral (n = 345) or semi-feral (n = 680) rearing systems. Logistic regression analysis was performed by modeling the risk of unsuccessful reproduction in the subsequent season (i.e., results at second foaling), as affected by the interaction of age at first foaling × rearing system (six classes). Genetic lifespan of young stallions was estimated by regressing the least square means from a mixed model analysis for repeated measures of individual differences in ‘total merit’ estimated breeding values (EBVs) between young stallions (mean no. of 45/year) and the mean EBV of all proven stallions in a given year of genetic evaluation (mean no. of 483/year). Young stallions born between 1999 and 2005 were used, following each generation (i.e., birth year) from 2 to 7 subsequent yearly genetic evaluations. In comparison with the best reproductive success of second foaling at 4 years in stable systems, the greatest risk of unsuccessful reproduction was at 3 years in feral (+167%) and 3 years in semi-feral conditions (+91%). Young stallions showed a 0.50 s.d. greater EBV at the first evaluation than proven stallions, with a mean annual decrease in EBV of 0.07 s.d./year on proven stallions. Optimal breeding management could be obtained in stud farms by limiting foaling at 3 years, particularly in feral and semi-feral rearing systems, and using young stallions for 3 to 4 years to maintain a perceptible selection differential with older proven stallions and to reduce cost of services. Later, the selection differential with proven stallions become less consistent and genetic improvement could be slowed down.

Colour Changes in Meat of Foals as Affected by Slaughtering Age and Post-thawing Time.

The aim of the present work was to investigate how colour changes of foal meat can vary after thawing out in relation to the slaughtering age of the horses and to the post-thawing time. Eighteen Italian Heavy Draught Horse (IHDH) foals were used for the trial. They were subdivided in three groups according to their slaughtering age (6, 11 and 18 months). Two different surfaces were investigated for each sample: a fresh cut surface (daily renewed cutting surface: DRCS), and not-renewed cutting surface (NRCS). The redness of both investigated surfaces increased with slaughtering age (p<0.01). Moreover, this parameter decreased during post-thawing time (p<0.01) only on the NRCS, probably due to the myoglobin oxidation processes. Colour is an important visual cue denoting perceived quality by consumers. So, by a chromatic perspective the thawed meat of IHDH foals slaughtered at 6 and 11 months proved to be that which best meets the market requirements.

Application of Wood’s model to lactation curve of Italian Heavy Draft horse mares

The aim of this work was to study, using Wood’s model, the lactation curve in Italian Heavy Draft horse (IHDH) mares, both for milk yield and composition. Interest in mare’s milk has grown for use in human nutrition, as a substitute for human and cow milk for premature newborns and allergic children. For this study, 7 IHDH mares were used. Milk yield was evaluated fromd 15 to 180 postpartum (every 15d). Wood’s lactation model was used to describe milk yield, fat, protein, and lactose lactation curves in the first 180d in milk (DIM), with a prediction to 210 DIM. Mean values recorded across the considered lactation period for milk yield and constituents were 16.11kg of milk/d, 11.38g of fat/kg, 15.54g of protein/kg, and 69.72g of lactose/kg. The lactation curve showed a peak at 69 DIM, with a persistence index of 6.26. Fat (g/kg) and protein (g/kg) lactation curves decreased during the lactation period; instead, the lactose (g/kg) curve increased from the first to the last DIM. The coefficient of determination values indicated a good model fit by Wood’s model application to IHDH mare lactation. The research showed good aptitude of a heavy horse breed, such as IHDH, for milk production.

Energy and protein allowances and requirements in stallions during the breeding season, comparing different nutritional systems1

This study was conducted to estimate the nutritional value of diets given to stallions of different breeds during the reproductive season, and comparing allowances with requirements. The systems compared were the French INRA, the 1989 NRC, and the 2007 NRC. Data on reproductive activity, daily exercise, BW, BCS, feed intake, and feed composition during 4 mo (from March to June) were recorded on 12 stallions used for commercial AI programs. Stallions belonged to 3 different breeds: Italian Haflinger (IH, n=4), Holstein (HOL, n=4), and Italian Heavy Draft horse (IHDH, n=4). Data recorded were used to estimate the actual energy and protein intakes and theoretical requirements of the stallions using the aforementioned systems. A deviation index [DI = (intake - requirement)/intake × -1] was calculated to allow a comparison among methods as a proportion of under- or overestimates of theoretical requirements. All data were statistically analyzed with a mixed model for repeated measurements. The reproductive activity of the stallions was affected by month (less in March and greater in subsequent months; P<0.05). Daily exercise was generally low during the middle breeding season, and the intensity and kinds of exercise differed according to the breeds. Changes of BW and BCS of the stallions were not statistically significant (P=0.69 and P=0.17, respectively) during the experimental period, and therefore diets could be considered balanced to support all animal needs. However, the energy and protein allowances were not always consistent with the theoretical requirements considering all 3 nutritional systems. Energy and protein INRA recommendations showed, on average, +0.90 and +0.27 greater DI than actual intakes, respectively, for IH and HOL stallions, whereas the theoretical requirements were much closer to allowances for the IHDH stallions (DI close to 0). The 1989 NRC energy and protein recommendations, respectively, were +0.67 and +0.87 greater than intake for IH, +0.28 and +0.43 greater for HOL, and only +0.06 and +0.17 greater for IHDH stallions. The 2007 NRC energy and protein recommendations, respectively, were +0.70 and +0.52 greater for IH, +0.33 and +0.17 greater for HOL, and +0.52 and +0.49 greater for IHDH than actual intakes. Therefore, all systems overestimated the requirements of the stallion, particularly in lighter breeds. Further studies to validate requirements for breeding stallions of different sizes are recommended.