Cull cow carcass traits and risk of culling of Holstein cows and 3-breed rotational crossbred cows from Viking Red,Montbéliarde,and Holstein bulls

Culled dairy cows represent a considerable source of meat production, but their carcasses may vary greatly in quality because of the wide variation in the age, stage of lactation, breed, body condition, and other characteristics of the cows at slaughter. However, the effect of crossbreeding on the value of culled cows has so far received little investigation. The aim of this observational study was to compare a range of carcass attributes of cull cows from 3-breed rotational crossbreeding using Viking Red, Montbéliarde (MO), and Holstein (HO) bulls with those of HO purebred cows. Data on 1,814 dairy cows were collected. Cows were reared together in one herd and slaughtered in 4 slaughterhouses. The carcass weight, fleshiness, and fatness scores, the total value, and the price (€/kg) of each cow carcass were recorded. The culling of a few cows in the sample (n = 86) was classified by the farm manager as “urgent” following a diagnosis of injury or sickness, and this information was recorded. Carcass traits were analyzed with a mixed model which included the fixed effects of parity, days in milk, genetic group (purebred HO, 787 cows, and crossbred cows, classified according to the breed of sire within crossbreds, with 309, 428, and 290 cows sired by Viking Red, MO, and HO bulls, respectively), and interactions, and the random effects of month × year of the date of slaughter, and slaughterhouse. Logistic regression was used to investigate the association of parity, days in milk and purebred or crossbred origin with unplanned, “urgent” culling compared with regular culling. Average carcass weight across genetic groups was 297 ± 65 kg, average price €2.03 ± 0.53/kg, and average value €631 ± 269. Compared with HO, crossbred carcasses were 7 to 12% heavier depending on the breed of sire, were graded + 0.12 to + 0.28 units higher for fleshiness and + 0.26 to + 0.30 units higher for fatness, and fetched an 8 to 11% higher price. As a consequence, compared with purebred HO, carcasses from crossbreds had 15 to 24% higher value (€84 to €133 more per cow), with crossbred cows sired by MO showing the greatest values. Moreover, compared with the HO cows, the crossbred cows had a 37% lower risk of being urgently removed from the herd, which raises welfare concerns and may reduce the salvage value of cull cows. Because cull cows represent a supplemental source of income for dairy farmers, the greater overall value of crossbred cull cows should be taken into account in evaluating the economic effectiveness of crossbreeding schemes.     

Carcass characteristics of cattle differing in Jersey proportion

Comparison of alternative dairy (cross-)breeding programs requires full appraisals of all revenues and costs, including beef merit. Few studies exist on carcass characteristics of crossbred dairy progeny originating from dairy herds as well as their dams. The objective of the present study was to quantify, using a national database, the carcass characteristics of young animals and cows differing in their fraction of Jersey. The data set consisted of 117,593 young animals and 42,799 cows. The associations between a combination of sire and dam breed proportion (just animal breed proportion when the dependent variable was on cows) with age at slaughter (just for young animals), carcass weight, conformation, fat score, price per kilogram, and total carcass value were estimated using mixed models that accounted for covariances among herdmates of the same sex slaughtered in close proximity in time; we also accounted for age at slaughter in young animals (which was substituted with carcass weight and carcass fat score when the dependent variable was age at slaughter), animal sex, parity of the cow or dam (where relevant), and temporal effects represented by a year-by-month 2-way interaction. For young animals, the heaviest of the dairy carcasses were from the mating of a Holstein-Friesian dam and a Holstein-Friesian sire (323.34 kg), whereas the lightest carcasses were from the mating of a purebred Jersey dam to a purebred Jersey sire which were 46.31 kg lighter (standard error of the difference = 1.21 kg). The young animal carcass weight of an F₁ Holstein-Friesian × Jersey cross was 20.4 to 27.0 kg less than that of a purebred Holstein-Friesian animal. The carcass conformation of a Holstein-Friesian young animal was 26% superior to that of a purebred Jersey, translating to a difference of 0.78 conformation units on a scale of 1 to 15. Purebred Holstein-Friesians produced carcasses with less fat than their purebred Jersey counterparts. The difference in carcass price per kilogram among the alternative sire-dam breed combinations investigated was minimal, although large differences existed among the different breed types for overall carcass value; the carcass value of a Holstein-Friesian animal was 20% greater than that of a Jersey animal. Purebred Jersey animals required, on average, 21 d longer to reach a given carcass weight and fat score relative to a purebred Holstein-Friesian. The difference in age at slaughter between a purebred Holstein-Friesian animal and the mating between a Holstein-Friesian sire with a Jersey dam, and vice versa, was between 7.0 and 8.9 d. A 75.8-kg difference in carcass weight existed between the carcass of a purebred Jersey cow and that of a Holstein-Friesian cow; a 50% Holstein–Friesian-50% Jersey cow had a carcass 42.0 kg lighter than that of a purebred Holstein-Friesian cow. Carcass conformation was superior in purebred Holstein-Friesian compared with purebred Jersey cows. Results from this study represent useful input parameters to populate simulation models of alternative breeding programs on dairy farms, and to help beef farmers evaluate the cost-benefit of rearing, for slaughter, animals differing in Jersey fraction.     

On-farm management decisions to improve beef quality of market dairy cows

A 3-phase study was conducted to assess on-farm management decisions to reduce antibiotic residue violations and improve carcass characteristics in market (cull) dairy cows. In Phase 1, questionnaires were mailed to dairy producers (n = 142) to determine current on-farm management strategies for reducing antibiotic residues in market dairy cattle. In Phase 2, Holstein market cows (n = 77) were assigned randomly to each of the 3 feeding treatments (0, 30, or 60 d). Average daily gain (ADG), body condition score (BCS), and carcass characteristics were assessed. Phase 3 determined the meat withdrawal time of Holstein cows (n = 62) administered procaine penicillin G. Eighty-six percent of dairy farms responding to the questionnaire had at least one cow condemned annually, and no producer had a designated feeding protocol for market cows prior to selling. In Phase 2, ADG was greater in cows fed for 30 d (1.4+/-0.6 kg/d) than in cows fed for 60 d (0.9+/-0.4 kg/d). Additional feeding did not influence the carcass characteristics studied with the exception of kidney, pelvic and heart fat, which was higher in cows fed for 60 d compared with those fed for 0 and 30 d. In Phase 3, 31% of cows treated with procaine penicillin G exceeded the 10-d label withdrawal recommendation by an average of 3.1+/-1.9 d. Feeding market cows may not influence carcass characteristics, but can increase ADG and may ensure that recommended meat withdrawal times for antibiotics are exceeded.     

Comparing local and commercial breeds on functional traits and profitability: the case of Reggiana dairy cattle

The objective of this study was to compare fertility, longevity, milkability, and profitability of cows from the Reggiana and Holstein breeds in northern Italy. Profitability was gauged for each breed, with consideration of economic incentive programs and alternative milk pricing scenarios. Calving to first service interval, days open, and calving interval were significantly shorter in Reggiana than in Holstein cows. Reggiana cows conceived approximately one estrus cycle before Holstein and had a calving interval 33 d shorter. Holstein cows released a significantly higher quantity of milk per unit of time (1.81 vs. 1.28 kg/min). Reggiana cows had longer expected total and productive lives than Holstein cows, by 5.8 and 10.0 mo, respectively. Replacement rate was 26% higher in the Holstein. Standard 305-d milk production was 5,360 and 7,870 kg in Reggiana and Holstein, respectively. Comparing breeds on annual milk and meat production, instead of standard 305-d milk yield, changed marginally the difference in annual profitability between the Reggiana and Holstein, from −€696 to −€679 per cow per year. Including feeding, milking, replacement, and insemination costs reduced the gap between breeds by 32%, from −€679, measured on annual milk and meat production, to −€460. These differences in profitability assumed a pricing scenario referring to milk sold to the dairy industry where protein and fat contents are valued but not the breed origin of milk. Incentive payments to farmers of endangered cattle compensated partially (22%) the lower income from Reggiana cows. When Reggiana milk production was sold as branded Parmigiano Reggiano cheese, Reggiana cows were more profitable than Holstein cows by €1,953 per cow per year.     

An evaluation of over-wintering feeding strategies prior to finishing at pasture for cull dairy cows on live animal performance,carcass and meat quality characteristics

Fifty-six spring calving Holstein–Friesian dairy cows (body weight = 607 kg and body condition score = 2.75), destined for culling, were randomly assigned to one of four experimental treatments. Cows were confirmed non-pregnant by rectal palpation. The experiment was split into two periods: over-wintering period (OWP) and spring finishing period (SFP). Animals were assigned to one of four treatments: a control group (C) was slaughtered after am milking on day 0; three dietary treatments, two of which were dried pre-experiment; ad libitum grass silage (GS + G); 75% grass silage and 25% straw (GS + S); and one with the extended lactation concept applied, cows were offered grass silage plus 6 kg concentrate DM/cow/day and milked twice daily (EXTLAC). EXTLAC cows were dried-off 1 week prior to turnout. The OWP lasted 84 days. Subsequent to the OWP cows were turned out to pasture (SFP). All cows were finished to a pre-defined carcass specification; >272 kg cold carcass weight, P + carcass conformation class and 3 carcass fat class. Over the entire experimental period, average daily gain (ADG) was lower (P < 0.001) for the EXTLAC treatment compared with the two other dietary treatments. The GS + G treatment finished 33 and 38 days (P < 0.001) earlier than the GS + S and EXTLAC treatments, respectively. Total feed utilized on a DM basis was 1.9, 2.0 and 2.5 tonnes/cow for the GS + G, GS + S and EXTLAC dietary treatments, respectively. All finishing treatments resulted in a significant improvement in carcass weight, as well as carcass quality traits, compared to the C group. A significant improvement occurred in muscle redness between the C group and treatments offered a finishing period prior to slaughter.     

Effect of grass silage and concentrate based finishing strategies on cull dairy cow performance, carcass and meat quality characteristics

Sixty-eight spring calving Holstein-Friesian dairy cows on completion of lactation were randomly assigned to one of four dietary treatments. The experiment commenced on 17th December 2005 and was completed on 27th June 2006. Pre-experimental live weight and BCS were 605kg (s.d. 68.9) and 2.7 (s.d 0.28), respectively. The four treatments were: ad-lib grass silage (GS), GS+3kg concentrate (GS+3), GS+6kg concentrate (GS+6) and GS+9kg concentrate (GS+9). All cows were finished to a live weight>620kg and a BCS>3.5. Live animal, carcass and meat quality characteristics were measured. Mean (s.d.) total feed utilized was similar, at 1.5 (0.05) tonnes DM/cow across all treatments. There was a linear (P<0.001) increase in ADG (kg/day) for the first three dietary treatments, GS (0.71), GS+3 (0.91), GS+6 (1.14) with no additional response to the final increment, GS+9 (1.15). As concentrate proportion in the diet increased there was a linear decrease (P<0.001) in days to slaughter. Cows on the GS+9 treatment (84 days) finished on average 12, 25 and 38 days earlier than those on the GS+6, GS+3, and GS treatments. The GS+9 treatment had lower carcass fat yellowness ('b' value) than the GS treatment but the GS+3 and GS+6 treatments did not differ from either GS or GS+9. There was no effect of treatment (P>0.05) on muscle redness ('a' value) following exposure to oxygen. When cull cows are finished to pre-defined slaughter criteria, similar carcass classifications and carcass quality can be achieved with diets ranging from GS to GS+9, however significant difference in physical performance and days to slaughter will result.     

A survey of practices and attitudes around cull cow management by bovine veterinarians in Ontario,Canada

The removal (culling) of dairy cows from the farm is a regular and required management practice. The main objectives of this study were to describe the involvement of bovine veterinarians in Ontario, Canada, in dairy cull cow management decisions, their expectations of current producer practices, and their perspectives on welfare issues and best management practices for cull dairy cows. Between February and May 2021, a province-wide survey was conducted among all members of the Ontario Association of Bovine Practitioners (OABP), with questions addressing veterinarians' background and demographics, veterinary clinic characteristics, cull cow management, down cow management, and learning preferences. The response rate for the survey was 25.1%, with 45 responses meeting all eligibility criteria. Dairy veterinarians would like to have greater involvement in cull cow management; when asked for desired involvement in culling decisions, 57.5% of veterinarians would like to be involved in culling decisions most of the time or always. Most (70.0%) veterinarians believed that cull cow welfare has improved over the last decade. However, most respondents also identified at least one area of management (farm of origin, transportation, auction, slaughter) as currently being a high risk to cull cow welfare. Given the frequency of their visits, trust by dairy producers, and knowledge, herd veterinarians are among those in the best position to improve the care of cull dairy cows. Information generated from this survey can be used to inform the development of improved decision-making tools for culling cows, and this, along with increased veterinarians' involvement in cull cow management, could improve the economic and welfare outcomes of culling decisions for dairy producers.     

Changes in carcass and meat quality traits of Danish friesian cull cows with the increase of their age and body condition

Data from 98 Danish cull cows were used in this study. Cows were divided into three age groups: 'very young' (<3 years), 'young' (3-5 years) and 'mature' (>4·5 years) and three body condition classes: 'thin', 'normal' and 'fat'. Independent of body condition, age had no significant effect on carcass scores related to conformation or to fatness. However, as the cow dvances in age, the carsass (lean and fat) colour tends to become darker yellow and the longissimus dorsi has a greater area with thicker cover-fat. Meat quality appeared to be independent of age with regards to its colour-related traits and its content of dry matter and intramuscular fat. However, the meat showed an increase in shear force value with age. Independent of age, the classification of cows according to their condition score prior to slaughter revaled significant differences in the quality of carcass and meat. While passing from 'thin' to 'normal' then to 'fat' condition, the carcasses showed better conformation score, a darker yellow colour, higher score of fatness and larger longissimus dorsi area with thicker cover-fat. The mean from 'fat' cows had similar shear force.     

Prediction of genetic merit for live weight and body condition score in dairy cows using routinely available linear type and carcass data

Accurate estimates of genetic merit for both live weight and body condition score (BCS) could be useful additions to both national- and herd-breeding programs. Although recording live weight and BCS is not technologically arduous, data available for use in routine genetic evaluations are generally lacking. The objective of the present study was to explore the usefulness of routinely recorded data, namely linear type traits (which also included BCS but only assessed visually) and carcass traits in the pursuit of genetic evaluations for both live weight and BCS in dairy cows. The data consisted of on-farm records of live weight and BCS (assessed using both visual and tactile cues) from 33,242 dairy cows in 201 commercial Irish herds. These data were complemented with information on 6 body-related linear type traits (i.e., stature, angularity, chest width, body depth, BCS, and rump width) and 3 cull cow carcass measures (i.e., carcass weight, conformation, and fat cover) on a selection of these animals plus close relatives. (Co)variance components were estimated using animal linear mixed models. The genetic correlation between the type traits stature, angularity, body depth, chest width, rump width, and visually-assessed BCS with live weight was 0.68, ?0.28, 0.43, 0.64, 0.61, and 0.44, respectively. The genetic correlation between angularity and BCS measured on farm (based on both visual and tactile appraisal) was ?0.79; the genetic and phenotypic correlation between BCS assessed visually as part of the linear assessment with BCS assessed by producers using both tactile and visual cues was 0.90 and 0.27, respectively. The genetic (phenotypic) correlation between cull cow carcass weight and live weight was 0.81 (0.21), and the genetic (phenotypic) correlation between cull cow carcass fat cover and BCS assessed on live cows was 0.44 (0.12). Estimated breeding values (EBV) for live weight and BCS in a validation population of cows were generated using a multitrait evaluation with observations for just the type traits, just the carcass traits, and both the type traits and carcass traits; the EBV were compared with the respective live weight and BCS phenotypic observations. The regression of phenotypic live weight on its EBV from the multitrait evaluations was 1.00 (i.e., the expectation) when the EBV was generated using just linear type trait data, but less than 1 (0.83) when using just carcass data. However, the regression changed across parities and stages of lactation. The partial correlation (after adjusting for contemporary group, parity by stage of lactation, heterosis, and recombination loss) between phenotypic live weight and EBV for live weight estimated using the 3 different scenarios (i.e., type only, carcass only, type plus carcass) ranged from 0.38 to 0.43. Although the prediction of phenotypic BCS from its respective EBV was relatively good when using just the linear type trait data (regression coefficient of 0.83 with a partial correlation of 0.22), the predictive ability of BCS EBV based on just carcass data was poor and should not be used. Overall, linear type trait data are a useful source of information to predict live weight and BCS with minimal additional predictive value from also including carcass data. Nonetheless, in the absence of linear type trait data, information on carcass traits can be useful in predicting genetic merit for mature cow live weight. Prediction of cow BCS from cow carcass data is not recommended.     

Purebreeding with sexed semen and crossbreeding with semen from double-muscled sires to improve beef production from dairy herds: Live and slaughter performances of crossbred calves

The use of sexed semen to produce purebred replacement heifers allows a large proportion of dairy cows to be mated to beef sires, and quantitative and qualitative improvements to be made to beef production from dairy herds. The major dairy and beef breeds are undergoing rapid genetic improvement as a result of more efficient selection methods, prompting a need to evaluate the meat production of crossbred beef × dairy cattle produced using current genetics. As part of a large project involving 125 commercial dairy farms, we evaluated the combined use of purebreeding with sexed semen and crossbreeding with semen from beef sires, particularly double-muscled breeds. A survey of 1,530 crossbred calves revealed that, whereas purebred dairy calves are destined almost exclusively for veal production, beef × dairy crossbred calves are also destined for beef production after fattening on either the dairy farm of birth or by specialized fatteners. In veal production, compared with Belgian Blue–sired calves (taken as the reference), double-muscled INRA 95–sired calves had a lighter slaughter weight (303 vs. 346 kg), but a greater dressing percent (62.3 vs. 58.4%). Limousin (also known as Limousine)–sired calves had a smaller average daily gain (1.26 vs. 1.34 kg/d), and lighter slaughter (314 vs. 346 kg) and carcass weights (182 vs. 201 kg). Last, Simmental-sired calves had a similar growth rate, but lighter carcass weight (177 vs. 201 kg), smaller dressing percentage (55.3 vs. 58.4%), and smaller muscularity scores (3.25 vs. 3.72). In the case of young bulls and heifers fattened on the dairy farm of birth, Belgian Blue–, Piemontese (also known as Piedmontese)-, and Limousin-sired calves performed similarly; the only exception was that Piemontese-sired calves had a greater dressing percentage. Belgian Blue– and Limousin-sired calves performed similarly when fattened by specialized beef producers. In both veal and beef production, the effects of dam breed were less important than sire breed. Considering the entire project, we can conclude that the combined use of sexed semen for purebreeding and conventional beef semen for terminal crossbreeding improves meat production from dairy herds, especially when the sires are double-muscled beef breeds.     

A survey of gross pathologic conditions in cull cows at slaughter in the Great Lakes region of the United States

The prevalence and severity of multiple gross pathologic lesions and abnormalities in cull dairy and beef cows was evaluated at a commercial abattoir in the Great Lakes region of the United States; 1,461 cattle were examined at slaughter over the course of 3 production days and evaluated for the occurrence and severity of lung, liver, rumen, and carcass abnormalities and pathologies. Of the 1,461 cattle examined at slaughter, 87% were classified as Holstein cows and 13% were classified as other cows. Liver abscesses were observed in 32% of the population and over half were classified as severe (18.5% population prevalence). The frequency distribution of cattle observed with a liver abscess was not different among production days. Severe ruminal lesions and rumenitis scars were observed in 10.0% of the population, and 25.1% of cattle were observed to have short or denuded papillae. Severe bovine respiratory disease complex lesions were observed in 10.3% of cattle. The most common reason for USDA postmortem carcass condemnation was malignant lymphoma (9 of 41). Only 45.9% of carcasses were free from bruising. Results indicate that ruminal acidosis and bovine respiratory disease complex occur at a relatively high frequency in this population. Although cows are routinely culled for reproductive failure or low milk production, the underlying reason may be causally related to these relatively prevalent conditions. Further investigation is warranted to assess this relationship and to examine the use of specific health intervention strategies within this demographic of cattle.     

Cost-effectiveness of feeding strategies to reduce greenhouse gas emissions from dairy farming

The objective of this paper was to evaluate the cost-effectiveness of 3 feeding strategies to reduce enteric CH₄ production in dairy cows by calculating the effect on labor income at the farm level and on greenhouse gas (GHG) emissions at the chain level (i.e., from production of farm inputs to the farm gate). Strategies included were (1) dietary supplementation of an extruded linseed product (56% linseed; 1 kg/cow per day in summer and 2 kg/cow per day in winter), (2) dietary supplementation of a nitrate source (75% nitrate; 1% of dry matter intake), and (3) reducing the maturity stage of grass and grass silage (grazing at 1,400 instead of 1,700 kg of dry matter/ha and harvesting at 3,000 instead of 3,500 kg of dry matter/ha). A dairy farm linear programing model was used to define an average Dutch dairy farm on sandy soil without a predefined feeding strategy (reference situation). Subsequently, 1 of the 3 feeding strategies was implemented and the model was optimized again to determine the new economically optimal farm situation. Enteric CH₄ production in the reference situation and after implementing the strategies was calculated based on a mechanistic model for enteric CH₄ and empirical formulas explaining the effect of fat and nitrate supplementation on enteric CH₄ production. Other GHG emissions along the chain were calculated using life cycle assessment. Total GHG emissions in the reference situation added up to 840 kg of CO₂ equivalents (CO₂e) per t of fat- and protein-corrected milk (FPCM) and yearly labor income of €42,605. Supplementation of the extruded linseed product reduced emissions by 9 kg of CO₂e/t of FPCM and labor income by €16,041; supplementation of the dietary nitrate source reduced emissions by 32 kg of CO₂e/t of FPCM and labor income by €5,463; reducing the maturity stage of grass and grass silage reduced emissions by 11 kg of CO₂e/t of FPCM and labor income by €463. Of the 3 strategies, reducing grass maturity was the most cost-effective (€57/t of CO₂e compared with €241/t of CO₂e for nitrate supplementation and €2,594/t of CO₂e for linseed supplementation) and had the greatest potential to be used in practice because the additional costs were low.     

Factors associated with carcass contamination by Campylobacter at slaughterhouse in cecal-carrier broilers

A study was conducted in 2009 to identify risk factors of Campylobacter spp. transmission from the digestive tract to the carcasses of standard broilers (slaughter age: 37 day, carcass weight: 1.3 kg on average). Counts of Campylobacter were performed on pools of 10 ceca and 10 neck-skins from 108 Campylobacter ceca-positive batches in three slaughterhouses. Technical and health data also was collected on the broilers: age, size, carcass weight (mean and standard deviation), condemnation rate, mortality rate and nature of treatment during the rearing period.Cecal counts varied from 4.8 to 10.2 log₁₀ cfu/g. In seventeen batches (15.7%), the skin count was below the detection limit. In the 91 batches with positive neck-skin test results, the counts varied from 2.0 to 5.2 log₁₀ cfu/g. Standard deviation of carcass weight, condemnation rate, slaughter rate and cecal count were significantly lower and growth rate higher in the 17 batches where neck-skin results were not detected positive. Multivariate analysis showed that batches with higher standard deviation of carcass weight were 5 to 9 fold more at risk of having detectable carcass contamination. Among the 91 positive neck-skin batches, only slaughter rate and cecal counts were found to have a significant but limited effect on the level of neck-skin contamination. As far as body weight homogeneity may be affected by disease, better health control can contribute to a reduction of the contamination of the broiler carcasses in Campylobacter carrier batches.     

Effects of blade tenderization,aging method and aging time on meat quality characteristics of Longissimus lumborum steaks from cull Holstein cows

The effects of blade tenderization (BT), two aging methods (dry (D) and wet (W)), and aging time (2 and 23 d) on tenderness, color, and sensory properties of Longissimus lumborum muscles from 12 cull Holstein cows were evaluated. Dry-aged loins had higher combined trim and aging losses than control (C) for both D- and W-aging, mostly because of excess trim losses. BT steaks had WBSF of 33.13 N while C steaks had WBSF of 41.46 N (P = 0.09). Aging decreased WBSF. Blade tenderized steaks had higher cook loss than C steaks. Aging, W-aging, and BT × W-aging improved myofibrillar (sensory) tenderness scores. Aging and/or BT improves sensory panel tenderness cull cow Longissimus lumborum steaks. Aging and blade tenderization combined can increase tenderness and value of Longissimus steaks from cull Holstein cows.     

Analysis of the economically optimal voluntary waiting period for first insemination

The voluntary waiting period (VWP) is defined as the time between parturition and the time at which the cow is first eligible for insemination. Determining the optimal VWP from field data is difficult and unlikely to happen. Therefore, a Monte-Carlo dynamic-stochastic simulation model was created to calculate the economic effects of different VWP. The model is dynamic and uses time steps of 1 wk to simulate the reproductive cycle (ovulation, estrous detection, and conception), the occurrence of postpartum disorders, and the lactation curve. Inputs of the model were chosen to reflect the situation of Dutch dairy cows. In the model, we initially created a cow of a randomly selected breed, parity, month of calving, calf status of last calving, and expected 305-d milk yield. The randomly varied variables were based upon relevant distributions and adjusted for cow statuses. The lactation curve was modeled by Wood's function. The economic input values in the analysis included: cost of milk production (€0.07 to €0.20 per kg), calf price (€35 to €150 per calf), AI cost (€7 to €24 per AI), calving management cost (€137 to €167 per calving), and culling cost, expressed as the retention pay-off (€118 to €1,117). A partial budget approach was used to calculate the economic effect of varying the VWP from 7 to 15 wk postpartum, using a VWP of 6 wk as reference. Per iteration, the VWP with either the lowest economic loss or the maximum profit was determined as the optimal VWP. The optimal VWP of most cows (90%) was less than 10 wk. On average, every VWP longer than 6 wk gave economic losses. Longer VWP were in particular optimal for the first parity of breeds other than Holstein-Friesian, cows calving in winter with low milk production, high milk persistency, delayed peak milk yield time, a delayed time of first ovulation, or occurrence of a postpartum disorder, and while costs of milk production are low and costs for AI are high.     

Environmental sensitivity of milk production in extensive environments: a comparison of Simmental, Brown Swiss, and Tyrol Grey using random regression models

A total of 25,160 milk test-day records from 2,516 cows in first lactation of 3 dairy cattle breeds [Simmental (n = 1,900), Brown Swiss (n = 444), and Tyrol Grey (n = 172)] in Kosovo were analyzed using nested repeatability and random regression test-day models with varying (co)variance structures. The different models were compared based on likelihood-based criteria. The best model was a second-order random regression model, with heterogeneous cow variance per breed and heterogeneous residual variance per lactation month and breed, which was used for further analysis. The highest milk production was found in Brown Swiss, followed by Simmental and Tyrol Grey. Substantial breed differences were found for the trajectories of cow and residual variances by month of lactation, with the highest variances found for Brown Swiss, followed by Simmental and Tyrol Grey. High cow and residual variances indicated a high degree of environmental sensitivity on the macro- and microenvironmental levels, respectively. Thus, these results indicate increased environmental sensitivity for breeds with higher genetic potential for milk production. These results support the conclusion that dairy cattle production under the current environmental conditions of Kosovo should be based on a breed with moderate production that is robust to the diet offered (e.g., Tyrol Grey).     

Mortality, Culling by Sixty Days in Milk, and Production Profiles in High- and Low-Survival Pennsylvania Herds

The objectives were to describe culling patterns and reasons for culling across lactation, estimate mortality and the proportion of cows leaving from 21 d before an expected calving date through 60 d in milk (DIM; CULL60) for Pennsylvania (PA) dairy herds, and to describe production measures for herds with high and low mortality and CULL60. Weekly culling frequencies and reasons for culling from 3 wk before a reported expected calving date through ≥100 wk of lactation were calculated for all PA cows with at least 1 Dairy Herd Improvement test in 2005. It was estimated that at least 5.0% of PA dairy cows died in 2005, and that at least 7.6% were culled by 60 DIM. The majority of cows exiting the herd by 60 DIM either died (35.1%) or had a disposal code of injury/other (29.9%). A total of 137,951 test-day records from 20,864 cows in herds with high mortality (>8.0%) and CULL60 (>12.0%) and 136,906 test-day records from 12,993 cows in herds with low mortality (<1.4%) and CULL60 (<2.9%) were retained to describe differences among herds with high and low survival. Least squares means for weekly milk yield, fat and protein percentages, and somatic cell score (SCS) were estimated with a model that included fixed effects for herd environment (high or low survival) and week nested within herd environment and lactation; random effects were cow, herd-test-day, and error. Cows from herds with high mortality and CULL60 produced more milk in lactations 1 (+1.9 ± 0.15 kg/d) and 2 (+0.9 ± 0.16 kg/d), but less in lactations 4 (−0.7 ± 0.22 kg/d), 5 (−1.4 ± 0.29 kg/d), and ≥6 (−0.7 ± 0.32 kg/d) and had higher SCS (+0.24 ± 0.02), more change in early-lactation fat percentage (−1.77% vs. −1.59%), and a greater frequency of fat-protein inversions (3.6 ± 0.3%). There is an opportunity to manipulate management practices to reduce mortality and early-lactation culling rates, which will improve cow welfare and the efficiency of dairy production by capturing a greater proportion of potential lactation milk yield, increasing cow salvage values, and reducing replacement costs.     

Invited review: Beef-on-dairy—The generation of crossbred beef × dairy cattle

Because a growing proportion of the beef output in many countries originates from dairy herds, the most critical decisions about the genetic merit of most carcasses harvested are being made by dairy producers. Interest in the generation of more valuable calves from dairy females is intensifying, and the most likely vehicle is the use of appropriately selected beef bulls for mating to the dairy females. This is especially true given the growing potential to undertake more beef × dairy matings as herd metrics improve (e.g., reproductive performance) and technological advances are more widely adopted (e.g., sexed semen). Clear breed differences (among beef breeds but also compared with dairy breeds) exist for a whole plethora of performance traits, but considerable within-breed variability has also been demonstrated. Although such variability has implications for the choice of bull to mate to dairy females, the fact that dairy females themselves exhibit such genetic variability implies that “one size fits all” may not be appropriate for bull selection. Although differences in a whole series of key performance indicators have been documented between beef and beef-on-dairy animals, of particular note is the reported lower environmental hoofprint associated with beef-on-dairy production systems if the environmental overhead of the mature cow is attributed to the milk she eventually produces. Despite the known contribution of beef (i.e., both surplus calves and cull cows) to the overall gross output of most dairy herds globally, and the fact that each dairy female contributes half her genetic merit to her progeny, proxies for meat yield (i.e., veal or beef) are not directly considered in the vast majority of dairy cow breeding objectives. Breeding objectives to identify beef bulls suitable for dairy production systems are now being developed and validated, demonstrating the financial benefit of using such breeding objectives over and above a focus on dairy bulls or easy-calving, short-gestation beef bulls. When this approach is complemented by management-based decision-support tools, considerable potential exists to improve the profitability and sustainability of modern dairy production systems by exploiting beef-on-dairy breeding strategies using the most appropriate beef bulls.     

Carcass measurements and meat quality of Turkish Merino,Ramlic, Kivircik,Chios and Imroz lambs raised under an intensive production system

Effect of breed on carcass measurements and meat quality characteristics were investigated by using 46 lambs from Turkish Merino, Ramlic, Kivircik, Chios and Imroz breeds. Chios and Imroz carcasses had smaller values for carcass quality characteristics. Breed had no significant effect on pH at 45 min and 24 h post-mortem, water holding capacity and cooking loss. Kivircik and Imroz lambs had lower Warner Bratzler shear force values than those of Ramlic and Turkish Merino lambs (P < 0.01). Meat samples from Kivircik lambs had the highest redness value. Differences among breeds for sensory characteristics, except tenderness were not significant. Tenderness scores given to meat samples of Kivircik lambs were significantly higher (P < 0.01) than those of Turkish Merino, Ramlic and Imroz lambs. Indigenous Kivircik breed, which had high carcass quality as those of improved breeds, might be considered for production of better quality meat in Marmara Region of Turkey.     

REALIMENTATION OF CULL BEEF COWS. I. LIVE PERFORMANCE, CARCASS TRAITS AND MUSCLE CHARACTERISTICS

The objective of this study was to determine whether culled beef cows fed a high-concentrate diet (FED) would have improved live performance, carcass traits and muscle characteristics compared with forage fed (CON) cows. In addition, ractopamine (RAC) supplementation was evaluated for added benefits over high concentrate alone. Live weight, average daily gain, hot carcass weight, ribeye area, marbling, quality grade and carcass fat measurements increased ( P ≤  0.05) by realimentation. As a percent of hot carcass weight, muscle yields did not differ ( P >  0.05). Lipid content increased ( P ≤  0.05) in 5 out of the 10 muscles from FED cows. Cows fed ractopamine showed some numeric improvements over feeding alone, but few statistical differences ( P >  0.05). This may result from variability associated with cull cows, and warrants investigation into the best dose/duration for ractopamine. However, realimentation by itself was able to improve cull cow quality.

PRACTICAL APPLICATION

The U.S. beef industry continues to explore new avenues to enhance undervalued sectors of the production system. Through realimentation, cull cow quality can be improved. The data presented herein demonstrate that feeding a high-concentrate diet to cull cows increases both live and carcass weights. In addition, high concentrate-fed cull cows display more marbling and whiter fat cover than those fed at maintenance level. Qualification for premium programs, heavier weights and overall higher quality may lead to increased value for this underutilized sector of the beef industry.