Preslaughter diet management in sheep and goats: effects on physiological responses and microbial loads on skin and carcass

Abstract

Sixteen crossbred buck goats (Kiko x Spanish; BW = 32.8 kg) and wether sheep (Dorset x Suffolk; BW = 39.9 kg) were used to determine the effect of preslaughter diet and feed deprivation time (FDT) on physiological responses and microbial loads on skin and carcasses. Experimental animals were fed either a concentrate (CD) or a hay diet (HD) for 4 d and then deprived of feed for either 12-h or 24-h before slaughter. Blood samples were collected for plasma cortisol and blood metabolite analyses. Longisimus muscle (LM) pH was measured. Skin and carcass swabs were obtained to assess microbial loads. Plasma creatine kinase activity (863.9 and 571.7 ± 95.21 IU) and non-esterified fatty acid concentrations (1,056.1 and 589.8 ± 105.01 mEq/L) were different (P < 0.05) between sheep and goats. Species and diet treatments had significant effects on the ultimate pH of LM. Pre-holding total coliform (TCC) and aerobic plate counts (APC) of skin were significantly different between species. Goats had lower (P < 0.05) TCC (2.1 vs. 3.0 log10 CFU/cm2) and APC (8.2 vs. 8.5 log10 CFU/cm2) counts in the skin compared to sheep. Preslaughter skin E. coli counts and TCC were different (P < 0.05) between species. Goats had lower (P < 0.05) counts of E. coli (2.2 vs. 2.9 log10 CFU/cm2) and TCC (2.3 vs. 3.0 log10 CFU/cm2) in the skin compared with those in sheep. Diet, species, and FDT had no effect (P > 0.05) on E. coli and TCC in carcass swab samples. The APC of carcass swab samples were only affected (P < 0.05) by the FDT. The results indicated that preslaughter dietary management had no significant changes on hormone and blood metabolite concentrations and sheep might be more prone for fecal contamination than goats in the holding pens at abattoir.

Elucidating a molecular mechanism that the deterioration of porcine meat quality responds to increased cortisol based on transcriptome sequencing

“…In general, plasma concentrations of cortisol are reported to change when animals are subjected to stressors3. Previous studies have shown that pre-slaughter factors, such as the feeding system and fasting period, also negatively affect meat quality by increasing serum cortisol levels4. In addition, other studies suggested that when pigs were transported during the cold season, there were higher levels of cortisol and a greater quantity of tough meat5.…”

Preharvest Management and Postharvest Intervention Strategies to Reduce Escherichia coli Contamination in Goat Meat: A Review

“…Gutta et al [13] reported that feed deprivation for 24 h increased E. coli, total coliform counts, and Enterobacteriaceae counts in the rumen of Kiko × Spanish goats and Dorset × Suffolk sheep, compared with 12 h deprivation and with no significant change in the pH of rumen liquor. However, no difference in E. coli or total coliform counts were observed on sheep and goat (Kiko × Spanish) carcasses as a result of feed deprivation time [11]. In contrast, experimentally infected adult sheep showed no increase in fecal shedding of E. coli O157:H7 during feed withdrawal [48].…”

“…Preharvest meat goat management, slaughter and processing, and postharvest carcass and meat handling methods vary among different countries and regions. The E. coli counts on goat skin prior to slaughter generally range from 2.2 to 2.5 log 10 CFU cm −2, and those on carcasses before washing range from 2.1 to 2.3 log10 CFU cm −2 [10,11]. It is not clear to what extent factors such as sex, age, and breed can influence E. coli shedding in goats.…”

“…Gutta et al [13] reported that concentrate-fed goats and sheep had higher E. coli (6.44 vs. 4.01 ± 0.468 log 10 CFU g −1 ), total coliform (6.74 vs. 4.16 ± 0.469 log 10 CFU g −1 ), Enterobacteriaceae (6.93 vs. 3.83 ± 0.651 log 10 CFU g −1 ), and total plate counts (7.79 vs. 7.28 ± 0.170 log 10 CFU g −1 ) in the rectum than the hayfed animals. The authors suggested that microbial loads in the gastrointestinal tract of goats and sheep can be reduced by feeding hay for four days before slaughter, although diet did not have any effect on skin bacterial contamination in goats and sheep [11]. To determine the effect of diet on gastrointestinal tract bacterial populations in goats, Lee et al [37] conducted a feeding trial involving three dietary treatments: 90-day alfalfa hay alone, 90-day concentrate alone (18% crude protein), or 45-day alfalfa hay diet followed by 45-day concentrate.…”

“…An important factor that can influence the efficacy of spray washing in small ruminants is the length of hair/wool and smoothness of the animal's coat. Kannan et al [11] observed that under identical preslaughter management conditions, sheep may be more prone to skin bacterial contamination than goats. This is probably because the goat breeds used for meat production in the US generally have smoother and thinner coats.…”