Background: Bovine brucellosis is a high-impact zoonosis that threatens both dairy productivity and public health. Despite long-standing control programs in Mexico, evidence quantifying its combined productive, reproductive, and economic effects under intensive dairy systems remains limited. Methods: Farm records from two intensively managed Holstein friesian dairies operating under fully confined housing systems in Coahuila (Mexico) were analyzed to compare brucellosis-positive (BR) and brucellosis-negative (SIN) cows across five parities (n = 32,178 lactations; 15,507 BR; and 16,671 SIN). Milk yield, days open (DOs), services per conception (SPCs), days in milk (DIMs), abortion, metritis, retained placenta (RP), and culling to abattoir were evaluated using standard linear and generalized linear models. A financial assessment estimated losses associated with unproduced milk, extra DOs, extra inseminations, abortions, hormonal protocols, feeding during extra DOs, labor, and replacement costs. Results: BR cows consistently produced less milk (−3.5 to −5.0 L·cow⁻¹·day⁻¹) and exhibited longer DOs (+10 to +34 days) and higher SPCs (+0.4 to +1.0 in four of five parities; p < 0.05). Abortion incidence was higher in BR cows (1.74–2.79%) than in SIN cows (0.69–1.59%). Estimated total economic losses reached USD 21.84 M, including unproduced milk (USD 10.20 M), extended DOs (USD 1.36 M), feed cost during extra DOs (USD 0.68 M), additional services (USD 0.21 M), hormonal protocols (USD 0.10 M), labor (USD 0.06 M), abortions (USD 0.05 M), and excess replacements (USD 0.19 M). Conclusions: Under endemic conditions, brucellosis markedly reduces dairy herd productivity and reproductive performance. Strengthened sanitary control, enhanced biosecurity, strategic culling of positive animals, and structured reproductive programs represent the most cost-effective pathway to recover milk, shorten DOs, and minimize abortions.

Limited empirical evidence is available validating the energy value assigned to steam-flaked corn (SFC) for small ruminants in current NRC feeding standards. Therefore, the objective of this study was to evaluate the effects of corn processing, including steam-flaking, on growth performance, dietary energetics, visceral fat deposition, and carcass characteristics of finishing lambs. Forty-eight Dorper × Katahdin ram lambs (42.0 ± 0.27 kg initial body weight) were assigned to one of four treatments (n = 12 per treatment) and fed high-concentrate diets for 45 d containing 50% yellow corn grain. Treatments differed only in the form of corn presentation: whole corn (WC), cracked corn (CC), ground corn (GC), or SFC. Cracked corn was produced using a roller mill without a sieve (mean particle size 4 to 6 mm), whereas ground corn was processed through a 3 mm sieve (mean particle size 1 to 2 mm). For SFC, WC was steamed for 20 min at approximately 102 °C before rolling, and flake density was adjusted to 0.36 kg/L by roller tension. Dry matter intake was 10.1% greater in SFC than in WC (p = 0.020), whereas CC and GC showed intermediate responses. Final body weight (+4.7%), average daily gain (+30.8%), and observed dietary net energy for maintenance (NE_m; +10.4%) were greater in SFC than in GC (p < 0.05), whereas WC and CC showed intermediate responses. Gain-to-feed ratio was greater in SFC than in GC and CC (p = 0.028), representing increases of 24.6% and 18.2%, respectively. Empty body weight and visceral fat deposition were also affected by treatment (p < 0.05), with greater visceral fat deposition in SFC and CC than in GC, whereas WC showed intermediate responses. Steam-flaked corn increased longissimus lumborum muscle area by 17.7% relative to GC (p = 0.048) and increased perirenal fat deposition relative to WC, CC, and GC (p = 0.048). However, most carcass characteristics and meat quality variables were not affected during the 45 d experimental period (p > 0.05). Using a replacement technique, estimated NE_m values (Mcal/kg) for CC, GC, and SFC were 2.00, 1.88, and 2.24, respectively. The NE_m value for SFC was in close agreement (2.24 vs. 2.30 Mcal/kg) with current feeding standards, whereas dry-processed corn showed lower estimated NE_m values (p = 0.025), representing reductions of 9% and 17% for CC and GC, respectively. In conclusion, SFC improved growth performance and dietary energy utilization relative to GC, while producing limited effects on carcass-related responses under the conditions of this 45 d study.

Thirty-six Dorper × Katahdin intact male lambs [44.0 ± 0.27 kg initial body weight (BW)] were used in a randomized complete block design to evaluate the effects of supplementing different organic chromium (OrCr) sources on growth performance, dietary energetics, carcass traits, meat quality, and economic return. Treatments (n = 9 lambs/treatment) were (1) Control (no Cr), (2) chromium-enriched yeast (Cr-Yeast), (3) chromium–methionine (Cr-Met), and (4) chromium–propionate (Cr-Pr). All Cr sources were provided at 1.2 mg elemental Cr/lamb/d for 45 d. Lambs received a high-energy finishing diet (78:22 concentrate/forage; steam-rolled corn-based). Dry matter intake was not affected (p = 0.583; 1.27 ± 0.034 kg/d). Compared with Control, Cr-Pr increased final BW (+5%; p = 0.025) and average daily gain (+66%; p = 0.034), and improved feed efficiency (+59%; p = 0.045) and observed-to-expected net energy ratio (+22%; p = 0.042); Cr-Met and Cr-Yeast showed intermediate responses. No differences were observed (p > 0.05) in longissimus lumborum muscle area, cold carcass weight, dressing percentage, cooling loss, or zoometric traits. Rib and rump fat thickness decreased with Cr-Met (−15 and −12%; p = 0.024 and p = 0.048) and with Cr-Pr (−19 and −13%; p = 0.024 and p = 0.048), and all OrCr sources reduced omental (−6 to −25%; p = 0.034), mesenteric (≈−7%; p = 0.042), visceral (−12 to −16%; p = 0.034), and perirenal fat (−25 to −39%; p = 0.028). Empty body weight and hot carcass weight increased with Cr-Pr (p = 0.029 and p = 0.031, respectively). Cr-Yeast and Cr-Pr increased muscle proportion (+5 to +7%; p = 0.003) and reduced carcass fat (−20 to −27%; p = 0.018), improving the muscle/fat ratio (+42 to +50%; p = 0.045). Cr-Pr improved water-holding capacity (+27%; p = 0.014) without affecting pH_24h, purge loss, cooking loss, or Warner–Bratzler shear force (p > 0.05). Cr-Pr reduced cost per kg of gain (−31%; p < 0.001) and increased income (+188% live; +105% carcass; p < 0.001), whereas Cr-Met and Cr-Yeast provided moderate benefits. In conclusion, OrCr supplementation improved dietary energy utilization, growth, carcass traits, and meat quality, enhancing profitability in lambs finished at heavier weights, with Cr-Pr producing the greatest responses.

The objective of this study was to evaluate the effects of corn processing method (ground corn, GC, vs. steam-flaked corn, SFC) and daily calcium propionate (CaPr; 0 vs. 9.45 g/lamb/d) supplementation on productive performance, dietary energetics, fat deposition, and carcass characteristics in finishing lambs. Thirty-six Dorper × Katahdin lambs (44.95 ± 3.30 kg initial body weight, IBW), blocked by IBW and randomly assigned within block to a 2 × 2 factorial arrangement, were used. Diets contained 50% corn grain and treatments consisted of: (1) GC, (2) SFC, (3) GC plus CaPr, and (4) SFC plus CaPr. There were no corn processing × CaPr interactions for growth performance, dietary energetics, or observed-to-expected dietary net energy (NE) ratios. Steam-flaked corn decreased DMI (1.30 vs. 1.35 kg/d; p = 0.0036) and increased average daily gain (ADG; 0.168 vs. 0.144 kg/d), gain-to-feed ratio (G:F), and observed-to-expected dietary NE ratios compared with GC diets (p < 0.05). In contrast, CaPr supplementation increased DMI (1.35 vs. 1.30 kg/d; p = 0.0215) without affecting ADG, G:F, or observed-to-expected dietary NE ratios (p > 0.05). Steam-flaked corn increased hot carcass weight (p = 0.0339), cold carcass weight (p = 0.0241), Longissimus lumborum muscle area (p = 0.0206), and chest depth (p = 0.0368), whereas CaPr increased carcass length (p = 0.0451). Interactions between corn processing and CaPr supplementation were observed for rib fat thickness (p = 0.0491), rump fat thickness (p = 0.0272), visceral fat (p = 0.0485), perirenal fat (p = 0.0209), and shoulder tissue composition, including muscle (p = 0.0309), fat (p = 0.0438), and muscle:fat ratio (p = 0.0348). In GC diets, CaPr supplementation decreased fat deposition and increased muscle proportion, whereas in SFC diets CaPr supplementation increased fat deposition and reduced muscle proportion. Neither corn processing nor CaPr supplementation affected visceral mass (g viscera/g empty body weight). Calcium propionate supplementation decreased hindquarter yield (p = 0.0494), increased shoulder IMPS207 yield (p = 0.0494), and increased purge loss at 24 h (p = 0.0496). Water-holding capacity showed a corn processing × CaPr interaction (p = 0.0170), whereas the remaining meat-quality variables were not affected. Overall, SFC improved productive performance and dietary energy utilization, whereas CaPr increased DMI and altered fat deposition and tissue composition responses depending on corn processing method.