Effects of Age and Rice Straw Inclusion Levels in the Diet of Yiling Cull Cows on Growth Performance, Meat Quality, and Antioxidant Status of Tissues

The objectives of this study were to investigate the effects of age and dietary straw levels on growth performance, carcass and meat traits, as well as tissue antioxidant status of Yiling cull cows. Twenty-four Yiling cull cows were arranged in a 2 × 2 factorial design: two age classes consisting of younger cull cows (YCC; appearing with three or four pairs of permanent teeth) and older cull cows (OCC; worn out teeth); two dietary treatments consisting of lower and higher rice straw levels (LRS and HRS; providing 0.7 kg/d and 1.2 kg/d rice straw per head based on air-dry basis, respectively). Cows were fed twice a day. Straw was offered at half of the predetermined weight each meal; concentrate was separately supplied ad libitum. After 300 d of feeding, final body weight (BW), total BW gain, average daily gain and gain:feed intake were higher (p < 0.01) in the YCC group than in the OCC group. Total dry matter intake was higher (p = 0.03) in the HRS group than in the LRS group, but neutral detergent fiber apparent digestibility was negatively affected (p = 0.01) by increased straw levels. Decreased C15:0, C17:0, C20:5n3c, and saturated fatty acids (SFAs) proportion as well as increased C18:1n9c and monounsaturated fatty acids (MUFAs) proportion in meat from YCC with HRS diet were observed as compared to that in meat from YCC with LRS diet (p < 0.05). Meat from HRS group had higher (p = 0.04) C18:3n3c proportion than meat from LRS group. No significant differences (p > 0.05) were found for meat quality attributes except for cooking loss, which was higher (p = 0.02) in the HRS group than in the LRS group. Both YCC group and HRS group had higher (p < 0.05) cold carcass weight compared to OCC group and LRS group. Moreover, catalase activity of liver tissue was higher (p = 0.045) in YCC than in OCC, while superoxide dismutase activity of muscle tissue was higher (p = 0.01) in LRS than in HRS. Based on results, we concluded that younger age and feeding high-level straw can improve the finishing performance of Yiling cull cows.

Alternative treatment of bovine mastitis

The treatment of mastitis is based mainly on the use of antibiotics. However, in recent times, an increase in resistance phenomena and the presence of residues in milk and their derivatives has been reported. Few studies have focused on the treatment of mastitis by homeopathy elsewhere or in Algeria. The objective of this current study aimed to clarify in particular the interest of homeopathy in the treatment of mastitis. The study was carried out on two dairy farms on a total of 14 cows located in Laghouat region (southern Algeria). Before the start of the experiment, a tolerance test was performed on two cull cows free from any apparent infection (except mastitis). Local and general reactions were noted at specific times. A total of 31 mammary quarters received 4 intramammary injections of a homeopathic preparation containing several natural products every 12h over 48h. A clinical examination and an analysis of the milk samples on D0, D7 and D14 were performed on all cows and the conclusion was made on the day 14. Data showed a very good tolerance to the homeopathic preparation and a 75% cure rate of the clinical mastitis. An improvement with a decrease in CMT score was also noted. In addition, healing rates of 51.85% for subclinical mastitis on D7 and 59.29% on D14 were also reported. Ultimately, homeopathy could, in some cases, represent an alternative to antibiotic therapy and bring an advantage to breeders. Further investigations should be performed in the future.

Carcass and Primal Composition Predictions Using Camera Vision Systems (CVS) and Dual-Energy X-Ray Absorptiometry (DXA) Technologies on Mature Cows

This study determined the potential of computer vision systems, namely the whole-side carcass camera (HCC) compared to the rib-eye camera (CCC) and dual energy X-ray absorptiometry (DXA) technology to predict primal and carcass composition of cull cows. The predictability (R2) of the HCC was similar to the CCC for total fat, but higher for lean (24.0%) and bone (61.6%). Subcutaneous fat (SQ), body cavity fat, and retail cut yield (RCY) estimations showed a difference of 6.2% between both CVS. The total lean meat yield (LMY) estimate was 22.4% better for CCC than for HCC. The combination of HCC and CCC resulted in a similar prediction of total fat, SQ, and intermuscular fat, and improved predictions of total lean and bone compared to HCC/CCC. Furthermore, a 25.3% improvement was observed for LMY and RCY estimations. DXA predictions showed improvements in R2 values of 26.0% and 25.6% compared to the HCC alone or the HCC + CCC combined, respectively. These results suggest the feasibility of using HCC for predicting primal and carcass composition. This is an important finding for slaughter systems, such as those used for mature cattle in North America that do not routinely knife rib carcasses, which prevents the use of CCC.

Are Marbling and the Prediction of Beef Eating Quality Affected by Different Grading Sites?

For the European abattoirs, the preferred carcass grading site is at the fifth rib, and cutting at the tenth rib as in Australia could lead to a lower economic value of the carcass. Therefore, the objective of this study was to compare the grading scores of marbling and the meat and fat color on Musculus longissimus thoracis et lumborum (LTL) at the fifth and the tenth thoracic vertebrae. The consequences on the prediction of beef eating quality using the Meat Standards Australia (MSA) grading scheme were also evaluated for cull cows, which produce the majority of beef consumed in France. Carcasses from 208 French cattle, mainly Limousine cows, were graded according to the Australian Beef Carcase Chiller Assessment System (ABCAS) used for the implementation of the MSA system. The results indicate that there was no significant difference in the marbling score, between the fifth and the tenth ribs and hence in the MSA index and in the Global Quality [meat quality (MQ4)] scores calculated from marbling values from either the fifth rib or the tenth rib. However, the meat color at the tenth rib was significantly darker than that at the fifth rib (p &lt; 0.01), and the fat color at the tenth rib was significantly yellower than that at the fifth rib (p &lt; 0.001). The results of this study suggest that the grading of marbling can be conducted on M. LTL at the fifth thoracic vertebrae for routine use of the MSA system in France and, more generally, in Europe. However, further investigation and adjustment would be needed for other critical MSA scores (such as rib fat thickness) while respecting the European carcass quartering practices.

The effect of life history events on carcass merit and price of cull dairy cows

Cull dairy cows contribute almost 10% of national beef production in the United States. However, different factors throughout the life of dairy cows affect their weight and overall body condition as well as carcass traits, and consequently affect their market price. Therefore, the objectives of this study were: 1) to assess relationships between price ratio and carcass merit of cull dairy cows sold through several sites of an auction market, and 2) to investigate the effect of animal life history events and live weight on sale barn price (BP) and price ratio (as a measure of relative price), as an indicator of carcass merit. Data from four dairy operations included 3,602 cull dairy cow records during the period of 2015 to 2019. Life history events data were collected from each dairy operation through Dairy Comp software; live weight and price were obtained periodically from the auction market, and the carcass data were provided by a local packing plant. Cow price in dollars per unit of live weight ($/cwt) and price ratio were the two outcome variables used in the analyses. Price ratio was created aiming to remove seasonality effects from BP (BP divided by the national average price for its respective month and year of sale). The association between price ratio and carcass merit traits was investigated using canonical correlation analysis (CCA), and the effect of life history events on both BP and price ratio was inferred using a multiple linear regression technique. More than 70% of the cows were culled in the first three lactations, with an average live weight of 701.5kg, carcass weight of 325kg, and dressing percentage of 46.3%. On average, cull cows were sold at $57.0/cwt during the period considered. The canonical correlation between price ratio and carcass merit traits was 0.76, indicating that price ratio reflected carcass merit of cull cows. Later lactations led to lower BP compared to cows culled during the first two lactations. Injury, and leg and feet problems negatively affected BP. Productive variables demonstrated that the greater milk production might lead to lower cow prices. A large variation between farms was also noted. In conclusion, price ratio was a good indicator of carcass merit of cull cows, and life history events significantly affected sale barn price and carcass merit of cull cows sold through auction markets.

163 Investigating relationships between life history events, carcass quality and price of cull dairy cows sold through auction markets

Cull dairy cows comprise almost 10% of the national beef production in the United States and contribute with an important additional income source for farmers. However, cull dairy cows present high variation due to many reasons, which affect live animal characteristics, carcass traits, and market price. The objectives of this study were 1) to assess relationships between price and carcass quality of cull dairy cows sold through auction market, and 2) to investigate the effect of animal life history events on price, as an indicator of carcass quality. Data from four dairy operations in Wisconsin included 3,375 cull dairy cow records during the period of 2015 to 2019. Life history events data were collected from Dairy Comp software; live weight and price were obtained periodically from an auction barn, and the carcass data were provided by a local packing plant. Price ($/cwt) and adjusted price (price divided by the national average price) were the two outcome variables. Canonical correlation analysis (CCA) and multiple linear regression were used to investigate the relationship between variables. On average (standard deviations within parenthesis), live weight was 701.54kg (123.15kg), carcass weight of 324.97kg (68.92), dressing of 46.26% (4.92%), and price of $56.98/cwt (5.57$/cwt). CCA between adjusted price and carcass quality traits was 0.76, indicating that price is a good indicator of carcass quality. Lactation number, culling reason, month, and year of sale drastically affect price (R2 0.7532) and adjusted price (R2 0.4706). Higher live weight and days open led to higher adjusted price, and longer days dry and high milk production decreased price ($/cwt). A large variation between farms was noted. In conclusion, culling and marketing decisions should consider these factors, as an attempt to increase the price received for cull cows, and ultimately improve carcass quality.