Effect of beef sire expected progeny difference for carcass conformation on live animal muscularity scores and ultrasonic muscle and fat depths, and on carcass classification and composition of their progeny

peer-reviewedThe objective was to examine the effect of sire expected progeny difference (EPD) for carcass conformation score on the live animal and carcass traits of their progeny. In each of 4 years a Charolais sire of high and one of average EPD for carcass conformation score were mated to spring-calving suckler cows and the bull and heifer progeny were taken to slaughter at 455 (s.d. 25.2) and 607 (s.d. 29.5) days of age in 4 and 3 years, respectively. The difference in EPD between the sire EPD groups for carcass conformation and fat scores (scale 1 to 15), and carcass weight were, 0.45 units, −0.53 units and 9.7 kg, respectively. Muscularity scores were recorded at weaning (7 to 9 months of age) and pre-slaughter, and ultrasound measurements were recorded pre-slaughter. Carcass weight, and conformation and fat scores were recorded at slaughter and an 8-rib pistola from the right side of each carcass was dissected into lean, fat and bone. There was no significant effect of sire EPD group on live weight or carcass weight, but kill-out proportion, ultrasound muscle depth and the Irish Cattle Breeding Federation muscularity scores were greater (P < 0.001) for progeny of the high than the average EPD group. Bull progeny of high EPD sires had better (P < 0.001) Signet muscularity scores and carcass conformation scores than bull progeny from average EPD sires, whereas there was no effect of sire EPD group on heifer progeny. Compared to progeny of the average EPD sire group, those from the high EPD group had a lower weight of kidney and channel fat (P 0.06) and carcass fat score (P < 0.05), lower proportions of fat (P < 0.001) and bone (P < 0.01) in the pistola, and higher weight of pistola, both absolutely (P < 0.01) and relative to carcass weight (P < 0.05), higher proportions of lean and high-value cuts in the pistola and higher carcass value (P < 0.001). Linear regression analysis showed that a 1 unit increase in sire EPD for carcass conformation score increased (P < 0.01) carcass lean proportion by 19.4 g/kg. In conclusion, although sire EPD for carcass conformation score was reflected in the conformation score of intensively-reared bull progeny and not in extensively-reared heifer progeny, carcass lean proportion and carcass value were higher for both genders

A Comparison of the Productivity of Suckler Cows of Different Breed Composition

End of project reportThe findings obtained in a comparison of 5 suckler dam breed types {Limousin x Friesian (LF), Limousin x (Limousin x Friesian) (LLF), Limousin (L), Charolais (C) and Simmental x (Limousin x Friesian) (SLF)} and their progeny through to slaughte

Effect of age and nutrient restriction pre partum on beef suckler cow serum immunoglobulin concentrations, colostrum yield, composition and immunoglobulin concentration and immune status of their progeny

peer-reviewedThe effect of cow age (multiparous (MP) v. primiparous (PP)) and nutritional restriction pre partum (grass silage ad libitum v. straw only ad libitum for the last 15 (s.d. 3.3) days of gestation) on cow serum immunoglobulin (Ig) concentration, on colostrum yield, composition and Ig concentration and on calf serum Ig concentrations (at ~8 and 48 h post partum) using spring-calving Limousin Holstein-Friesian cows and their progeny was studied over 3 years. The method of colostrum administration (stomach tube vs. assisted suckling within 1 h post partum) on calf immune status was also investigated. When feeding colostrum the target was to give each calf 50 mL per kg birthweight via stomach tube. Colostrum yield and Ig concentration were measured following administration of oxytocin and hand-milking of half (Experiments 1 and 2) or the complete udder (Experiment 3). Following an 8-h period after birth during which suckling was prevented a further colostrum sample was obtained. There was no significant difference in first milking colostrum Ig subclass concentrations between the within-quarter fractions or between the front and rear quarters of the udder in either MP or PP cows. Colostrum Ig subclass concentrations at second milking were 0.46 to 0.65 of that at first milking. Compared to MP cows offered silage, colostrum yield and the mass of colostrum IgG1, IgG2, IgM, IgA and total Ig produced was lower (P < 0.001) for PP cows and the mass of IgG1, IgM and total Ig produced was lower (P < 0.05) for MP cows offered straw. Calves from PP cows and MP cows offered straw had significantly lower serum IgG1 and total Ig concentrations at 48 h post partum than calves from MP cows offered silage but there was no difference (P > 0.05) between colostrum feeding methods. In conclusion, calves from PP cows and MP cows offered straw had a lower humoral immune status than those from MP cows offered grass silage

Effect of suckler cow genotype on cow serum immunoglobulin (Ig) levels, colostrum yield, composition and Ig concentration and subsequent immune status of their progeny

peer-reviewedSurvival of the neonatal calf is largely dependent on humoral immunity. The objective of three experiments reported here was to compare cow serum immunoglobulin (Ig) concentration, colostrum yield, composition and Ig concentration and calf serum Ig concentrations at ~8- and 48-h post partum of spring-calving Charolais (C) and Beef × Holstein-Friesian (BF) cows and their progeny. Cows were individually offered a restricted allowance of grass silage pre partum in Experiments 1 and 2 and silage ad libitum in Experiment 3. In Experiment 1 calves were assisted to suckle after parturition. In Experiments 2 and 3, colostrum yield and Ig concentration were measured following administration of oxytocin and hand milking of half or the complete udder, respectively. It was intended to feed each calf 50 ml (Experiment 2) or 40 ml (Experiment 3) of colostrum per 1 kg birth weight via stomach tube. Following an 8-h period, during which suckling was prevented, a further colostrum sample was obtained. The decrease in cow serum IgG1 concentration pre partum was greater (P < 0.05) in BF cows than C cows. In comparison to BF cows, C cows had a lower colostrum yield (P < 0.001) and the colostrum had lower concentrations of dry matter (P < 0.01), crude protein (P < 0.05), fat (P < 0.05), IgG1 (P = 0.06), IgG2 (P < 0.01), IgM (P < 0.01) and Ig total (P < 0.05). The mass of IgG1, IgG2, IgM, IgA and Ig total in the colostrum produced was significantly lower for C cows than BF cows. Calves from C cows had significantly lower serum Ig subclass concentration at 48-h post partum than calves from BF cows. In conclusion, due to a lower Ig mass produced by their dams, calves from C cows had a lower humoral immune status than those from BF cowsTeagasc Walsh Fellowship Programm

Effect of concentrate feeding level in winter and turnout date to pasture in spring on biological and economical performance of weanling cattle in suckler beef production systems

peer-reviewedThree experiments were carried out to determine the effects of supplementary concentrate feeding level (Low, LC; High, HC) to grass silage and/or turnout date to pasture in spring (Early, ET; Late, LT) for a second grazing season on performance to slaughter of spring-born, weaned beef calves (n = 188). Experiment 1 comprised of two concentrate levels (0.5 and 1.5 kg/day). Experiment 2 comprised of two turnout dates (19 March, 9 April). Experiment 3 comprised of two concentrate levels (0.5 kg and 2.0 kg/day) and two turnout dates (22 March, 12 April). In Experiment 1, live-weight gain during the indoor winter period was 25 kg higher (P 0.05) total live-weight gain for both treatments. In Experiment 2, live weight at turnout to pasture was 11 kg lower (P 0.05), subsequently. In Experiments 1 and 2, live-weight gain during the finishing period and carcass weight, conformation and fat scores did not differ (P > 0.05) between the treatments. In Experiment 3, at turnout to pasture, HC were 35 kg heavier (P < 0.001) than LC, and ET were 12 kg lighter (P < 0.05) than LT, whereas 8 days after late turnout, ET were 13 kg heavier (P < 0.05) than LT. There was a concentrate level × turnout date interaction (P < 0.05) for live weight at the end of the grazing season, whereby the LC, LT treatment were lighter than the other treatments, which did not differ. Live weight at slaughter and carcass weight did not differ (P > 0.05) between the concentrate levels, whereas they were higher (P < 0.05) for ET than LT. Economic and stochastic analysis of Experiment 3 indicated that, in the context of whole-farm systems, (i) feeding HC was dependent on date of sale such that only where progeny were sold at the start of the second grazing season, net farm margin (NFM) was increased, (ii) ET only increased NFM where progeny were retained through to finish and, (iii) taking progeny through to finish was more profitable than selling earlier in the animals’ lifetime. In conclusion, subsequent compensatory growth at pasture diminishes the growth and economic advantage from concentrate supplementation or early turnout to pasture, of young late-maturing cattle

Post-weaning performance and carcass characteristics of steer progency from different suckler cow breed types

peer-reviewedIn two experiments a total of 44 steer progeny of spring-calving Charolais (C) and Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately 2 years of age. Following weaning they were offered silage and 1 kg of concentrate per head daily during a 5 month winter after which they spent 7 months at pasture. In Experiment 1, animals were given a silage/concentrate diet during a finishing period of either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage (fresh weight) during the final 140-day finishing period. Following slaughter, an 8-rib pistola from each animal was dissected. For the two experiments combined C and HF progeny had carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and 454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively. All fat traits were lower for the C than HF progeny but there was no difference in carcass conformation score. Increasing slaughter weight increased carcass weight (P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion (P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass growth but the C progeny had higher meat yield than the HF. Increasing slaughter weight increased fatness and reduced meat yield

The effect of abrupt weaning of suckler calves on the plasma concentrations of cortisol, catecholamines, leukocyte, acute-phase proteins and in vitro interferon-gamma production

End of project reportThe objective of this study was to examine the effect of abrupt weaning (inclusive of social group disruption and maternal separation) on the physiological mediators of stress and measures of immune function. Thirty-eight male and 38 female continental calves were habituated to handling for two weeks prior to bleeding. Calves were blocked on sex, weight and breed of dam and randomly assigned, within block, to either a control (cows remain with calves) or abruptly weaned group (calves removed from cows). Animals were separated into the respective treatment groups at weaning (0 h). Calves were bled at – 168 h, 6 h (males only), 24 h, 48 h and 168 h post weaning. At each sampling time an observer scored the behavioural reaction of calves to sampling. Blood samples were analysed for cortisol, catecholamine concentrations (not sampled at –168 h) and in vitro interferon-gamma production, neutrophil :lymphocyte ratio and acute phase protein concentrations. All continuous data were analysed using a split-plot ANOVA, except that collected at 6 h, which was analysed using a single factor ANOVA model. The effects of weaning, calf sex and time and respective interactions were described. Disruption of the established social groups at 0 h, increased (p<0.001) the plasma cortisol concentration and neutrophil: lymphocyte ratio and reduced the leukocyte concentration (p<0.001) and the in vitro interferon-gamma response to the mitogen concanavalin-A (p<0.001) and keyhole limpet haemocyanin (p<0.001) for weaned and control animals, when compared with –168h. Plasma adrenaline and noradrenaline concentrations were not affected by group disruption. There was no effect of weaning or sex on calf behavioural reaction to handling during blood sampling. Plasma cortisol and adrenaline concentrations were not affected by weaning or sex. Plasma noradrenaline concentration was influenced by weaning x sex (p<0.05) and time x sex (p<0.05). The response increased for male calves with weaning and increased with each sampling time post weaning. For heifers the response was not affected by weaning and plasma concentrations decreased at 168 h post weaning. There was no effect of weaning or sex on leukocyte concentration. The neutrophils : lymphocyte ration increased post weaning (p<0.01) and was affected by sex (p<0.05). Weaning decreased (p<0.05) the in vitro interferon-gamma response to the antigen KLH. There was a time x weaning x sex (p<0.05) interaction for fibrinogen concentration but no effect of treatment on haptoglobin concentration. Abrupt weaning increased plasma cortisol and nor-adrenaline concentrations, which was accompanied by attenuation of in vitro interferon gamma production to novel mitogen and antigen complexes up to 7 days post weaning.European Union Structural Funds (EAGGF

The effect of cereal type and feeding frequency on intake, rumen fermentation, digestibility, growth and carcass traits of finishing steers offered a grass silage-based diet

peer-reviewedThe effect of concentrate cereal type (rolled barley-based v. rolled wheat-based) and concentrate feeding frequency (one 6 kg feed v. two 3 kg feeds per day) on intake, rumen fermentation, diet digestibility and performance of finishing steers offered grass silage to appetite was evaluated over four experiments using a total of 154 animals. Not all four feeding treatments were used in each of the four experiments. The duration of the growth measurement period was 152, 112, 111 and 113 days for experiments 1 to 4, respectively, after which all animals were slaughtered. Dietary dry matter (DM) intake and in vivo digestibility, final live weight, kill-out proportion, carcass weight, carcass conformation score, carcass fat score and daily liveweight and estimated carcass gain were not affected (P > 0.05) by cereal type or feeding frequency. Cereal type or feeding frequency had no effect (P > 0.05) on feed conversion efficiency (FCE) expressed as either live-weight or carcass gain per unit DM intake. Neither mean rumen fluid pH or concentrations of ammonia or L-lactate were influenced by cereal type or feeding frequency. The mean molar proportion of propionate was higher and that of butyrate lower (P < 0.05) with wheat than with barley. Estimated carcass weight gain and FCE to carcass were similar for wheat based and barley-based concentrate as a supplement to grass silage offered either as one feed or two equal feeds daily

Breed compostition of the Irish cattle herd.

End of Project ReportInformation was collected on cow and sire breeds in both dairy and suckler herds in the National Farm Survey (NFS) in autumn 1998. The number of farms included in the analysis was 1030 with farms containing less than 2 economic size units (equivalent to 3 to 4 dairy cows) excluded from the sample. The main findings of the survey were as follows: • Ninety-eight percent of dairy cows and 96% of dairy herd replacements were Friesian/Holstein • The suckler cow herd contained 46% early-maturing breed crosses (Hereford 31%, Aberdeen Angus 12% and Shorthorn 3%) 2% Friesians, 48% of the three main continental breed crosses (Charolais 17%, Simmental 16%, Limousin 15%) and 4% other (mainly continental crosses). Compared to the adult cows herd replacements had less early-maturing breed crosses and Friesians (total 42%) and more (55%) of the three main continental breed crosses (Charolais 20%, Simmental 15%, Limousin 20%). • Overall, in 1998, it was estimated that the national cow herd consisted of 52% Friesian/Holstein, 23% early maturing breed crosses and 26% late maturing breed crosses. • Forty-seven percent of dairy cows were bred to Friesian/Holstein sires, 26% were bred to early maturing sire breeds and 27% were bred to continental sire breeds. The corresponding figure for dairy herd replacements were 40%, 46% and 13%. • Seventeen percent of suckler cows were bred to early maturing sire breeds, 46% were bred to Charolais, 16% were bred to Simmental, 17% were bred to Limousin and the remaining 6% were bred to mainly other continental breed sires. The sires used on suckler herd replacements were 43% early maturing breeds, 16% Charolais, 10% Simmental, 25% Limousin and 5% other. • Based on the sire breeds used in 1998, the breed composition of the 1999 calf crop was estimated to be 24% Friesian/Holstein, 24% early maturing breeds, 24% Charolais cross, 10% Simmental cross, 12% Limousin cross and 6% other (mainly other continental crosses). • Although the proportion of continental breed crosses in the calf crop continues to increase (48% in 1993 to 52% in 1999), the use of continental sire breeds is declining in the dairy herd (from 33% in 1992 to 27% in 1998), particularly where AI is the method of breeding. However, this trend may be at an end as the 1999 AI figures to date (September 30) show substantial decreases in Hereford and Aberdeen Angus inseminations with increases in Belgian Blue, Limousin and Friesian/Holstein. • The dairy herd is a relatively unimportant source of the better quality animals accounting for only 25% of total continental breed crosses which have a lower proportion of continental breed genes than those from the suckler herd. • It was estimated that the 1999 calf crop from the suckler herd consisted of 18% early maturing breeds, 29% of half to threequarters continental breed genes and 53% containing at least three-quarters continental breed genes. • A total of 48,200 herds used bulls. The proportion of bulls of each breed used were 9% Frieisan/Holstein, 17% Hereford, 11% Aberdeen Angus, 1% Shorthorn, 29% Charolais, 12% Simmental, 16% Limousin and 5% other. Continental breeds accounted for 38% and 84% of bulls on dairy and suckler farm, respectively. • In the present study the number of animals (cows plus replacements) bred to continental sire breeds was 1.22 million of which 40% were by AI. • National AI figures show that the total number of inseminations (excluding DIY) have declined from 1.03 million in 1992 to 0.79 million in 1998. • Assuming that the suckler cow should be at least half continental breeding and that Belgian Blue crosses are unsuitable if increases in calving problems are to be avoided then the dair y herd may provide as little as 25% of suitable suckler herd replacements. Thus, the main source of replacements would be from within the suckler herd. Factors to be considered include hybrid vigour which involves crossbreeding, milk production potential of the cow and the fact that the most widely used terminal sire is Charolais. In these circumstances one suitable crossbred cow would be obtained from alternate crossing with Limousin and Simmental sires. • Heat synchronisation was used on 3% of herds. The figures for dairy and suckler herds was 6.8% and 0.5%, respectively. • Vaccination for leptospirosis was used on 29% of dairy farms and 4% of suckler farms.European Union Structural Funds (EAGGF

Optimising The Response To Supplementary Concentrates By Beef Cattle In Winter

End of project reportConcentrates are a major component of feed costs in winter finishing of beef cattle. Two separate experiments were carried out to evaluate the response to increasing supplementary concentrate level with grass silage and the effects of feeding the silage and concentrates separately or as a total mixed ration (TMR). In experiment 1, a total of 117 finishing steers (initial live weight 538 kg, s.d. 35.5) were assigned to a preexperimental slaughter group of 9 animals and to 6 feeding treatments of 18 animals each. The feeding treatments were: 1) silage (SO) only offered ad libitum, 2) SO plus a low level of concentrates offered separately (LS), 3) SO plus a low level of concentrates offered as a TMR (LM), 4) SO plus a medium level of concentrates offered separately (MS), 5) SO plus a medium level of concentrates offered as a TMR (MM), and 6) concentrates ad libitum plus a restricted silage allowance (AL). Low and medium target concentrate levels were 3 and 6 kg dry matter (DM) per head daily. When silage and concentrates were fed separately, the daily concentrate allowance was given in one morning feed. The animals were individually fed for a mean period of 132 days. After slaughter, carcasses were weighed and graded and the ribs joint was dissected into its component tissues. Silage DM intake decreased but total DM intake increased with increasing concentrate level. Live weight gains for SO, LS, LM, MS, MM and AL were 0.34, 0.86, 0.86, 1.02, 1.00 and 1.12 (s.e. 0.064) kg/day, respectively. Corresponding carcass weight gains were 0.25, 0.58, 0.58, 0.71, 0.68 and 0.82 (s.e. 0.028) kg/day. All measures of fatness increased, ribs joint bone proportion decreased, and muscle proportion was not significantly affected by dietary concentrate level. There were no significant interactions between concentrate level and method of feeding. Compared with offering the feeds separately, feeding a TMR increased silage DM intake by proportionately 0.06 and total DM intake by proportionately 0.04. Otherwise, method of feeding had no significant effect on performance, slaughter or carcass traits. Mean rumen pH decreased while ammonia concentration tended to increase with increasing concentrate level. Total volatile fatty acids and the acetate to propionate ratio were lowest for SO. Method of feeding had no significant effect on rumen fermentation