Twenty-four 1-year-old boars of proven fertility were assigned randomly to one of two temperature-controlled trailers. A control group in each trial was held at 17 ± 0·5°C while the other group was exposed to a diurnal ambient temperature cycle. Cycles followed a sine-wave pattern with minimum and maximum temperatures occurring at 04.00 and 16.00 h respectively. Cycling temperature ranges were 17 to 33 ± 0·5°C (low-temperature stress), 19·5 to 35·5 ± 0·5°C (medium-temperature stress), and 22 to 38 ± 0·5°C (high-temperature stress). Semen samples were collected every 3 or 4 days over an experimental period of 42 days.

Low-temperature stress and medium-temperature stress boars were not affected significantly in the five parameters of semen quality observed. The difference between controls and high-temperature stress boars was highly significant for motility, abnormal spermatozoa, gel-free volume, and total spermatozoa per ejaculate. Concentration of spermatozoa was not affected by treatment. Significant time effects were observed for motility, abnormal spermatozoa and total spermotozoa per ejaculate. Significant differences began to appear after 2 or 3 weeks and changes still appeared to be occurring at 6 weeks.

The possibility of using quantitative kinematic traits as indirect selection criteria for sport performance could be beneficial to perform an early genetic evaluation of the animals. The genetic parameters for objectively measured kinematic traits under field conditions have been estimated for the first time, in order to potentially use these traits as indicators of gait quality in future selection of the Lusitano breed. The repeatability within three different types of training (dressage, bullfighting and untrained) was also discussed. A total of 176 males (4 to 14 years old) were recorded at trot in hand using a 3D videographic system. The speed and 10 kinematic traits were studied (one temporal, two linear and seven angular variables). The genetic parameters of the kinematic variables were estimated using VCE software. The heritability estimates were moderate to high (0.18 to 0.53). The stride length and the forelimb angular variables presented the highest heritabilities (0.49 to 0.53), whereas the hindlimb angular variables revealed the lowest values (0.18 to 0.40). More than half of the genetic correlations were moderately to highly positive (mostly 0.20 to 0.70; up to 0.88 between hindlimb traits). The dressage and bullfighting groups presented the highest repeatabilities (over 0.6) in the majority of the traits, maybe because of the acquired gait regularity expected in animals subjected to specific training, and suggesting a greater influence of the individuals over the kinematic traits studied in these two subpopulations than in the untrained subpopulation. The longer swing phase duration and the larger range of motion of the elbow, hock and pelvis joints observed in the dressage group may indicate a better gait quality of this group, according to FEI (International Equestrian Federation) standards. The bullfighting and untrained groups were more similar to each other in terms of kinematic traits. Selection of young horses for characteristics such as stride length and the hindlimbs traits can apparently contribute to further genetic improvement of the performance of Lusitano breed.

The effect of the time of mating on ewe fertility and subsequent lamb growth was examined in Clun sheep in Scotland. The flock of 249 females was divided into six mating groups, the first was put to a fertile ram on 12 October 1962, the remainder being added at two weekly intervals.

There was a marked decline in the average number of lambs born per female lambing as the time of mating moved from October to December (b = −0·007 per female per day). Other components of fertility were not affected.

The mean birth weight was slightly greater in the later mating groups; however, by the time the lambs were 9 weeks of age, the trend was reversed, the regression of 9-week weight on day of mating being −0·063 lb per day.

Carcass traits of two indigenous African (Sanga) breeds (Afrikaner and Nguni), one indigenous African composite breed (Bonsmara), one foreign composite breed (Santa Gertrudis) and two continental European breeds (Brown Swiss and Pinzgauer) were compared. Treatment means were adjusted to the mean overall subcutaneous fat proportion (47 g/kg). Despite differences in maturity type, only the Afrikaner dressed out significantly (P < 0·05) lower than the foreign breeds. Both Sanga breeds and the Bonsmara had significantly higher muscle yields than the Santa Gertrudis and Pinzgauer, mainly due to the high intermuscular fat of the latter two breeds. When muscle yield was expressed per unit of bone, the Afrikaner and Bonsmara compared favourably with the larger breeds, due to their low bone and intermuscular fat yield, while the Nguni had a relatively high bone yield. The Santa Gertrudis had the lowest muscle yield due to its high bone and intermuscular fat yields, especially when compared with the smaller Bonsmara composite. Both Sanga breeds had significantly higher (P < 0·05) proportions of total weight, meat and bone (Afrikaner P > 0·05) in the high-priced cuts compared with the other breeds at the same subcutaneous fat level. Despite the statistical significance, differences were small in magnitude and probably of little commercial value. At the same time mean subcutaneous fat proportion, tissue yield and distribution patterns expected of late maturing breeds were observed for smaller indigenous breeds, suggesting that it was specific breed effects rather than maturity type effects, which were evident.

Individual energy balances (EB) and total net energy intake (NEI) were modelled to quantify the energy content of the explanatory variables body-weight change corrected for gut fill (BWC) and body condition-score change (BCSC). A total of 6147 records from 213 lactating dairy cows, 71 Holstein-Friesians, 71 Jerseys and 71 HolsteinJersey F1-crosses was analysed (1st, 2nd and >2nd lactation). Data were collected during 210 days of lactation, from calving to week 30. Individual EB were calculated as total energy for lactation (MJ NEL) minus estimated energy necessary for maintenance and production. Body-weight changes were calculated as differences between weekly means of body weight corrected for gut fill (BWCw) as well as from polynomial regression (BWCp). BCSC were differences between assessed body condition scores. The study included analyses of 1- and of 4-week periods for BWCw and BWCp, of differences between measuring periods for BCSC as well as separate analyses of data from cows in either negative or positive energy balance.

Analysis of repeated measurements were performed applying mixed model theory. Models for EB contained type of dairy cow, lactation and type of roughage as fixed effects, week of lactation and either BWCw, BWCp or BCSC. Models for NEI contained type of dairy cow, lactation and quality of roughage as fixed effects, week of lactation as well as energy corrected milk, metabolic body weight and either BWCw, BWCp or BCSC as covariates.

Most plausible energy contents per unit body tissue change were estimated for BWCp from weekly data with either EB (with energy partitioned into milk production and maintenance fixed) or NEI (no restrictions concerning partitioning) as the response variable. The estimated energy contents for BWCp were 15·40 and 10·47 MJ NEL, respectively.

The heavy reliance on imported soybean meal (SBM) as a protein source makes it necessary for the European pig industry to search for alternatives and to develop pigs that perform efficiently when fed such ingredients. Digestion and metabolism are major physiological processes contributing to variation in feed efficiency. Therefore, an experiment was conducted to assess the effects of replacing SBM with increasing levels of rapeseed meal (RSM) in diets for young pigs on apparent total tract digestibility (ATTD) of energy and nutrients, nitrogen (N) balance, energy metabolism and carbohydrate, protein and fat oxidation. Four diets were fed to 32 pigs (22.7±4.1 kg initial BW) for three weeks. The diets consisted of a control cereal grain-SBM basal diet and three test diets where SBM and wheat were partially replaced with 10%, 20%, and 30% of expeller RSM. Increasing level of RSM in the diets linearly reduced ATTD of organic matter, CP, total carbohydrates, dietary fiber and energy. Utilization of digested nitrogen (DN) for N retention and total N excretion were not affected by RSM inclusion, however, RSM inclusion induced a shift in N excretion from urine to feces. Despite a linear increase in liver to metabolic BW ratio, heat production and utilization of metabolizable energy (ME) for retention were not affected by increasing RSM inclusion. In conclusion, replacing SBM with up to 30% of expeller RSM in nutritionally balanced diets for young pigs reduced the ATTD of most nutrients and energy, but did not affect N and energy retention in the body or efficiency of utilization of DN or ME for retention.

In order to investigate the rationale of manipulating post-ovulation progesterone (P4) concentrations, luteal activity was measured in 10 Holstein-Friesian cows treated with a progesterone-releasing device (CIDR, 1·9 g P4) inserted on the morning of day 2 post-oestrus for a period of 7 days and compared with 10 untreated control animals. Milk samples were collected daily during afternoon milking from 7 days pre- to 24 days post-oestrus and P4 concentrations were measured using enzyme-linked immuno-sorbent assay (ELISA). The milk P4 profiles were used to assess the effects of early post-oestrus P4 elevation on five intervals of the luteal phase. In the treated (T) and control (C) animals, the mean interval from oestrus to P4 rise (≥3 μg/l), was 2·38 (s.e. 0·18) and 4·90 (s.e. 0·28) days, respectively, (P < 0·01). The mean interval from oestrus to the attainment of peak P4 concentrations was not significantly different (P > 0·05) between the T (14·75 (s.e. 1-62) days) and С (14·30 (s.e. 0·70) days) animals, with cows in the T group showing a more variable (F7 9 = 4-30, P < 0·05) interval to the occurrence of the peak. The interval from peak P4 to corpus luteum (CL) regression (when P4 fell below ≥3 μg/l) was not significantly different between the T (4·13 (s.e. 1·30 days) and С (5·60 (s.e. 0·88) days) groups. Furthermore, CIDR insertion did not alter luteal phase length, number of days with P4 concentrations ≥3 μg/l (T = 16·50 (s.e. 0·80) v.C = 15·00 (s.e. 0·47) days) or the interval from oestrus to CL regression (T = 18·88 (s.e. 0·79) v.C = 19·90 (s.e. 0·41) days). We conclude that treatment with CIDR 2 days after oestrus successfully increased the availability of P4 to cows without significantly affecting luteal phase characteristics.

The objective of this study was to evaluate effects of natural zeolite (clinoptilolite) on nutrient digestibility, carcass attributes and performance of Holstein steers given a diet containing urea. Forty-five Holstein steers (309 (s.d. 11·2) kg) were given diets as follows: control diet based on maize and soya-bean meal (SBM); treatment 2 (T2), control diet (without SBM) containing 20 g/kg urea; treatment 3 (T3), control diet (without SBM) containing 20 g/kg urea and 30 g/kg zeolite. Just before feeding, ruminal ammonia levels were low in all treatments. At 2·5 h post feeding, steers given T2 and T3 diets had higher ( P<0·05) ruminal ammonia concentration than the control. At 5·5 h post feeding, steers on T3 diet had the highest ruminal ammonia concentration, which was higher ( P<0·05) than the value for steers given T2 diet. Plasma urea nitrogen level increased post feeding for all treatments. At 3 h post feeding, the level for steers given T2 diet was higher ( P<0·05) than those on control and T3 diets but at 6 h post feeding, the level was higher for steers on T3 diet. No differences ( P>0·05) were observed in dry-matter intake among treatments. Live-weight gain and gain: food ratio were highest ( P<0·05) for steers on the control diet, with no differences ( P>0·05) between steers given T2 and T3 diets. Including zeolite in a diet containing urea had no effect ( P>0·05) on total tract digestibility coefficients of dry matter, organic matter and crude protein but increased ( P<0·05) digestibility of neutral-detergent fibre and acid-detergent fibre. Hot carcass weight and kidney, pelvic and heart fat weight of steers were highest in control, intermediate in T3 and least in T2 ( P<0·05). No differences ( P>0·05) were found in longissimus muscle area and fat thickness over longissimus muscle among treatments. Including 30 g/kg of zeolite in a diet containing 20 g/kg of urea decreased ruminal ammonia nitrogen concentration, plasma urea nitrogen level and increased fibre digestibility but its effect on feedlot performance was negligible.

Forty days after mating, 16 pregnant sows were randomly allocated to two diets containing either sugar-beet pulp (SBP) or wheat straw (WS) each offered at two levels (1·0 or 1·5 × maintenance energy requirement (M), where M = 460 kJ digestible energy (DE) per kg0·75 per day). Diets were iso-nitrogenous, and contained similar levels of DE together with 260 g non-starch polysaccharides (NSP) per kg dry matter (DM) largely derived from either the SBP or the WS. A 7-day NSP and DM balance was made between day 60 and 100 of gestation. During lactation sows had ad libitum access to a conventional sow diet which contained neither SBP or WS.

Outputs of both fresh and dry faeces from sows given diet WS were significantly greater than the outputs from sows given the corresponding SBP diets (P <0·05), and outputs were significantly greater at the higher feeding level for both diets (P < 0·05). There was a tendency for higher urinary outputs from sows given diet WS, but these were variable and not significantly different from those from sows given diet SBP. The apparent digestibility and retention of DM was significantly greater for the SBP diet than for diet WS but were not significantly affected by feeding level. The apparent digestibilities of the total NSP and each of the individual constituent monomers were significantly higher for diet SBP than for diet WS (P < 0·001), but were independent of feeding level (P> 0·05). Xylose was the most poorly digested NSP constituent from both diets. Apparent digestibility coefficients for the remaining NSP constituents in diet SBP were > 0·8 and were > 0·52 in diet WS, with the uronic acids and mannose being the most highly digested NSP fractions from diets SBP and WS respectively.

Two milk replacers identical in composition except for the protein source, which was either fish-protein hydrolysate (FPH) or dried skim milk, were offered either twice or four times daily to castrated British Friesian male calves in four ratios: 100 FPH 0 Milk; 67 FPH 33 Milk; 33 FPH 67 Milk and 0 FPH 100 Milk. Concentrates and hay were offered ad libitum, and the calves were weaned at 42 days of age. Feed intake and calf live weight were recorded to 100 days of age.

There were no differences in growth rate up to weaning due to frequency of feeding. Up to 67% FPH there were no differences in growth rate but calves on the 100% FPH diet showed a 40% depression in growth compared with the other three levels. Up to 100 days there was no apparent effect of treatment on live-weight gain, but only differences of 12 to 13% would be significant.

The results indicate that at least two-thirds of the milk protein could be replaced by FPH. The need for further work using dried material and FPH from other species is discussed.

The intakes of concentrates and hay by individuals in three groups of ewes were estimated at three-weekly intervals in late pregnancy from faecal output; chromic oxide was incorporated as a marker in the concentrates. The groups were: (1) 16 mature ewes, (2) 16 2-year-old ewes, (3) eight mature and eight 2-year-old ewes. A constant daily hay allowance of 734 g dry matter (DM)/sheep was given but the concentrate was increased from an equivalent of 96 g DM/sheep at the beginning of the experiment to 435 g at the end. Individual concentrate intakes were most variable when the group allowance was small (CV over 50% in the mixed group) but variation decreased when amounts of concentrates were increased to contribute up to 47% of the total digestible DM intake. The CV for the total digestible DM intake ranged from 13 to 24%.

The younger sheep were at no disadvantage when penned with mature ewes. Intakes by individual ewes were compared with their calculated requirements and several twin-bearing ewes were shown to have a substantial energy deficit which was confirmed by their higher plasma ketone concentrations.

A major practical difficulty in group-feeding pregnant ewes is to ensure that the ewes with the highest foetal burden are adequately fed.

All possible inter-age genetic correlations were calculated for each of twelve linear body measurements taken at 3-monthly intervals up to 2 years of age on 120 pairs of uniformly reared, liberally fed one-egg and two-egg twin dairy heifers. Genetic correlations between first and second-year mean size are also given. The influences of age, age interval, degree of maturity and body part on genetic correlation are examined.

Genetic correlation was in general very high. No significant difference was found between body parts in mean genetic correlation over the period studied. For a fixed age interval, genetic correlation increased with age; from a fixed age, it decreased with lengthening age-interval.

The main systematic trends found in the data were accounted for in terms of the amount of development taking place. Genetic correlation appeared to decrease exponentially with difference in degree of maturity, and a formula is given for calculating an approximate value for the expected genetic correlation between size at any two ages. Its range of applicability and its place in a general study of the genetic properties of a population of growth curves are discussed.

Three trials were conducted to investigate the effect of length of journey by road to the abattoir, resting and feeding before slaughter on carcass characteristics of pigs of about 200 lb live weight.

Trial 1 investigated feeding or no feeding on the morning of slaughter, followed by a ½-hr or 8-hr journey by lorry to the abattoir with all pigs ending their journey and being killed at the same time. Ninety-six pigs were divided equally among the four treatments and the trial was repeated with a further 108 pigs. Measurements recorded on the live pigs and their carcasses included the live weight before the imposition of treatments, weight of liver, carcass and matured sides and the composition of a sample joint. Trial 2 studied lairaging overnight with food and water after a ½-hr or 8-hr journey to the abattoir compared with these journey lengths on the morning of slaughter. Eighty pigs were divided equally among the four treatments. Similar measurements to those in trial 1 were recorded. Trial 3 involved 49 pigs applied to each of three treatments, or 7-hr journey on the day of slaughter, with all pigs finishing their journey and being slaughtered at the same time.

In trial 1, pigs which travelled for 8 hr before slaughter had carcasses averaging 0·9% less than those which travelled for ½ hr, regardless of whether or not they were fed. It could not be established where this loss occurred. Liver weights were greater for those pigs which were fed and was greatest for those pigs which were fed and had the ½-hr journey. Streak thickness was found to be decreased by feeding, but was not affected by the length of the journey. No effects of the treatments were found on pH or eye-muscle colour, but the ultimate pH of the pigs fed before the 8-hr journey was lower than for the other treatments. Trial 2 pigs showed no effect of the treatments on carcass weights. Liver weights were similar on all treatments except for the treatment involving 8-hr journey followed by lairage where the liver was about 220 g (16%) heavier. The ultimate pH value was lowest among pigs which travelled 8 hr on the morning of slaughter but was similar for pigs on the other treatments. In trial 3, loss of live weight tended to increase with increasing journey length. Pigs on the 7-hr journey treatment had about 90 g (6%) more liver than those on the shorter journeys. pH1 values increased with length of journey and the longer the journey the thinner tended to be the maximum shoulder fat thickness.

From the differences in the results from the three trials, notably with carcass weight, it may be inferred that the behaviour and handling of pigs during the journey and during loading and unloading, may play an important part in determining the result of the length of the journey, resting and feeding. Further work is considered necessary to study such factors.

The effect of proportion of dietary rumen non-degradable protein during food restriction on the weight of components of the digestive tract, carcass and subsequent growth was investigated in 37 Scottish Blackface wether lambs (initial live weight, 25 kg). Lambs were given individually ad libitum for 4 weeks a complete pelleted diet containing 150 g/kg white fish-meal (HP, 10·4 MJ metabolizable energy (ME) per kg dry matter (DM), 195 g crude protein (CP) per kg DM). Seven lambs were then slaughtered and 15 were switched to a diet containing no white fish-meal (LP, 10·4 MJ ME per kg DM, 122 g CP per kg DM) offered at 18 g DM per kg M per day, i.e. sufficient to maintain constant live weight. A further 15 continued to receive the HP diet at the same rate as the lambs given LP. After 6 and 12 weeks, five lambs on each diet were slaughtered. At 12 weeks the remainder received the HP diet ad libitum for a further 7 weeks before slaughter. During food restriction on both diets, the proportion of live weight formed by the carcass, the dissected components and the chemical composition remained the same as in the initial slaughter group. The relative weight of the non-carcass components fell during food restriction on both diets. There was a significant (P < 0·05) interaction between slaughter date and dietary treatment for reticulo-rumen weight as a proportion of empty body weight (EBM); it was smaller in lambs on the HP diet after 12 weeks of restriction (HP: 0·022, LP: 0·026). A similar pattern was observed for the small intestine and the total digestive tract. During the 7 weeks of realimentation, lambs previously on HP and LP diets had similar intakes (1343 and 1208 g DM per day) and digestive tract components, body components and chemical composition of carcass and non-carcass components were all unaffected by previous treatment. The apparent digestibility of CP of the HP diet was greater than that of the LP diet although it was overall less degradable in the rumen. When both groups of lambs were realimented on the HP diet, there were no differences in the apparent digestibility of any of the dietary components. A high dietary protein: energy ratio during restriction reduced the weight of some of the components of the digestive tract but did not significantly affect carcass composition. The effect did not persist following realimentation and did not significantly influence subsequent performance.

First lactation records from 971 daughters of 93 Red Danish Milk-breed bulls exported as pregnant heifers from Denmark to 4 Bulgarian and 21 Czechoslovakian herds were analysed and compared to results from corresponding half-sib groups under Danish field progeny tests. Average butterfat production in East European tests was 75% of that in Danish tests.

The results indicate that the true genetic variance and the heritabilities for milk yield, fat content and butterfat yield are higher under the Danish conditions than under the corresponding East European conditions. The genetic correlations between the two environments are estimated to be 0·91, 0·97 and 0·79 for milk yield, fat content and butterfat yield, respectively. Because of insufficient correction for environmental effects, these estimates are considered to be lower than the true parameters.

It is concluded that selection of proven sires in the Danish main population for use in the small East European subpopulations will result in a higher genetic improvement rate than will sire testing and selection within the subpopulations.

Compared with the application of mathematical models to study human diseases, models that describe animal responses to pathogen challenges are relatively rare. The aim of this review is to explain and show the role of mathematical host–pathogen interaction models in providing underpinning knowledge for improving animal health and sustaining livestock production. Existing host–pathogen interaction models can be assigned to one of three categories: (i) models of the infection and immune system dynamics, (ii) models that describe the impact of pathogen challenge on health, survival and production and (iii) models that consider the co-evolution of host and pathogen. State-of-the-art approaches are presented and discussed for models belonging to the first two categories only, as they concentrate on the host–pathogen dynamics within individuals. Models of the third category fall more into the class of epidemiological models, which deserve a review by themselves. An extensive review of published models reveals a rich spectrum of methodologies and approaches adopted in different modelling studies, and a strong discrepancy between models concerning diseases in animals and models aimed at tackling diseases in humans (most of which belong to the first category), with the latter being generally more sophisticated. The importance of accounting for the impact of infection not only on health but also on production poses a considerable challenge to the study of host–pathogen interactions in livestock. This has led to relatively simplistic representations of host–pathogen interaction in existing models for livestock diseases. Although these have proven appropriate for investigating hypotheses concerning the relationships between health and production traits, they do not provide predictions of an animal's response to pathogen challenge of sufficient accuracy that would be required for the design of appropriate disease control strategies. A synthesis between the modelling methodologies adopted in categories 1 and 2 would therefore be desirable. The progress achieved in mathematical modelling to study immunological processes relevant to human diseases, together with the current advances in the generation and analysis of biological data related to animal diseases, offers a great opportunity to develop a new generation of host–pathogen interaction models that take on a fundamental role in the study and control of disease in livestock.

1. Seven experiments involving 191 calves and 40 cows were under- taken over a 2-year period into the effect of copper treatment of hypocupraemic calves on their subsequent performance.

2. Significant increases in mean live-weight gain of copper-treated calves ranging from 19·9 to 34·3 kg/head relative to untreated control groups were obtained in three cases.

3. The frequency of copper injection required to maintain plasma copper levels above 0·60 mg/1 varied from 6 to 12 weeks.

4. The live-weight gain and plasma copper concentration responses are discussed in relation to the pasture herbage concentrations of copper, molybdenum and sulphate.

Inclusion of feed efficiency traits into the dairy cattle breeding programmes will require considering early lactation energy status to avoid deterioration in health and fertility of dairy cows. In this regard, energy status indicator (ESI) traits, for example, blood metabolites or milk fatty acids (FAs), are of interest. These indicators can be predicted from routine milk samples by mid-IR reflectance spectroscopy (MIR). In this study, we estimated genetic variation in ESI traits and their genetic correlation with female fertility in early lactation. The data consisted of 37 424 primiparous Nordic Red Dairy cows with milk test-day records between 8 and 91 days in milk (DIM). Routine test-day milk samples were analysed by MIR using previously developed calibration equations for blood plasma non-esterified FA (NEFA), milk FAs, milk beta-hydroxybutyrate (BHB) and milk acetone concentrations. Six ESI traits were considered and included: plasma NEFA concentration (mmol/l) either predicted by multiple linear regression including DIM, milk fat to protein ratio (FPR) and FAs C10:0, C14:0, C18:1 cis-9, C14:0 * C18:1 cis-9 (NEFAFA) or directly from milk MIR spectra (NEFAMIR), C18:1 cis-9 (g/100 ml milk), FPR, BHB (mmol/l milk) and acetone (mmol/l milk). The interval from calving to first insemination (ICF) was considered as the fertility trait. Data were analysed using linear mixed models. Heritability estimates varied during the first three lactation months from 0.13 to 0.19, 0.10 to 0.17, 0.09 to 0.14, 0.07 to 0.10, 0.13 to 0.17 and 0.13 to 0.18 for NEFAMIR, NEFAFA, C18:1 cis-9, FPR, milk BHB and acetone, respectively. Genetic correlations between all ESI traits and ICF were from 0.18 to 0.40 in the first lactation period (8 to 35 DIM), in general somewhat lower (0.03 to 0.43) in the second period (36 to 63 DIM) and decreased clearly (−0.02 to 0.19) in the third period (64 to 91 DIM). Our results indicate that genetic variation in energy status of cows in early lactation can be determined using MIR-predicted indicators. In addition, the markedly lower genetic correlation between ESI traits and fertility in the third lactation month indicated that energy status should be determined from the first test-day milk samples during the first 2 months of lactation.

Selection signals of Korean cattle might be attributed largely to artificial selection for meat quality. Rapidly increased intragenic markers of newly annotated genes in the bovine genome would help overcome limited findings of genetic markers associated with meat quality at the selection signals in a previous study. The present study examined genetic associations of marbling score (MS) with intragenic nucleotide variants at selection signals of Korean cattle. A total of 39 092 nucleotide variants of 407 Korean cattle were utilized in the association analysis. A total of 129 variants were selected within newly annotated genes in the bovine genome. Their genetic associations were analyzed using the mixed model with random polygenic effects based on identical-by-state genetic relationships among animals in order to control for spurious associations produced by population structure. Genetic associations of MS were found (P<3.88×10−4) with six intragenic nucleotide variants on bovine autosomes 3 (cache domain containing 1, CACHD1), 5 (like-glycosyltransferase, LARGE), 16 (cell division cycle 42 binding protein kinase alpha, CDC42BPA) and 21 (snurportin 1, SNUPN; protein tyrosine phosphatase, non-receptor type 9, PTPN9; chondroitin sulfate proteoglycan 4, CSPG4). In particular, the genetic associations with CDC42BPA and LARGE were confirmed using an independent data set of Korean cattle. The results implied that allele frequencies of functional variants and their proximity variants have been augmented by directional selection for greater MS and remain selection signals in the bovine genome. Further studies of fine mapping would be useful to incorporate favorable alleles in marker-assisted selection for MS of Korean cattle.