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Lipopolysaccharide (LPS) is a common pathogenic agent that causes many diseases and metabolic disorders. Hypoglycemia is often observed when animals are infected with LPS. To explore the influence of LPS on blood glucose and hepatic gluconeogenesis in goats, 12 goats were randomly assigned to 1 of 2 groups: the LPS-treated group (60 μg/kg BW of LPS; jugular vein injections) or the control group (saline vehicle; jugular vein injections). Blood samples were collected from jugular veins at 0, 1, 2, 4, 6, and 8 h, and liver tissue samples were biopsied 8 h after the injections. The dynamic changes in blood glucose levels as well as key hepatic gluconeogenic enzyme mRNA and protein expression, ATP and ADP levels, and glutathione reductase (GR) activity were determined. The results showed that blood glucose levels in the LPS group were dramatically reduced after an initial, short-term increase. In liver tissue, the mRNA of key gluconeogenic enzymes, phosphoenolpyruvate carboxykinase 1 (PEPCK1;P < 0.05), fructose-1,6-bisphosphatase 1 (FBP1;P < 0.01), pyruvate carboxylase (PCB;P < 0.05), and acyl-CoA synthetase short-chain family member 3 (ACSS3; < 0.01), in the related pathways and PPAR-γ coactivator 1α (PGC-1α;P < 0.05) were decreased in the LPS group compared with those in the control group, whereas glucose-6-phosphatase (G6Pase-α) was not different (P > 0.05). The protein expression of PEPCK1 decreased (P < 0.01), whereas that of G6Pase-α increased (P < 0.05) significantly. The ratio of ADP to ATP ( < 0.05) and the activity of GR (P < 0.01) were markedly increased in the LPS group compared with those in controls. This research showed that LPS markedly affects and reduces blood glucose in dairy goats. The crucial reasons for the marked change in blood glucose are the altered expression of key gluconeogenic enzymes in different pathways and of essential factors associated with gluconeogenesis in the liver.

The purpose of this study was to determine the effects of short-term, preslaughter stress on physiological responses and meat quality in goats of different age groups. The goats (n = 28) were classified into young (6 to 12 mo of age) and old (24 to 30 mo of age) groups, feed deprived overnight, and slaughtered at three different times (replicates). On each slaughter day, goats were either subjected to a 2-h transportation stressor (TS) or remained unstressed in holding pens (NS) before slaughter. Blood samples were collected via jugular venipuncture from TS and NS goats at 2, 1, and 0 h before slaughter. Muscle glycogen and pH were measured on samples from longissimus muscle (LM) collected at 15 min and 24 h postmortem, and instrumental measures of meat color were obtained on the LM after a 24-h chilling period at 4 degrees C. The TS goats had higher plasma cortisol (P < 0.01) and glucose (P < 0.05) concentrations than NS goats. The rates of increase in plasma cortisol, glucose, and nonesterified fatty acid concentrations were greater in TS than in NS goats (stressor treatment x blood sampling time, P < 0.01). Muscle glycogen concentrations were greater (P < 0.05) in NS than in TS goats and higher (P < 0.01) in old vs. young goats; however, pH measured at 15 min and 24 h postmortem was not (P > 0.05) influenced by stressor treatment. Water-holding capacity of meat was not (P > 0.05) influenced by stressor treatment. Older goats had lower (P < 0.01) L* values and greater (P < 0.01) a* and chroma values than the younger goats. The a* and chroma values of loin cuts from young goat carcasses were lower in the TS than NS treatment groups, but this effect was absent in the old goat carcasses (stressor treatment x age, P < 0.05). Cooking loss percentages and shear force values for loin chops aged for 7 d were not (P < 0.05) affected by stressor treatment; however, old goats produced tougher (P < 0.01) loin chops than young goats. These results indicate that short-term preslaughter transport can cause noticeable changes in stress responses and muscle metabolism in goats.

The objective of this experiment was to determine the effects of preslaughter isolation and feed withdrawal duration on physiological responses and shrinkage in goats. A total of 84 Spanish does (36 mo of age, average weight 35 kg) were individually weighed and scored for excitability before two replicate (day) trials. The does were feed-deprived (FD) or fed (F) in holding pens (treatment, TRT) for either 0, 7, 14, or 21 h (TIME). At the end of the holding periods, FD and F does were blood-sampled (n = 6 does/treatment/time/replicate) and weighed again to assess physiological responses and shrinkage, respectively. Individual does from each pen were blood-sampled again after imposing one of three handling post-treatments: a 15-min isolation with no visual contact with other does (I); a 15-min isolation with visual contact (IV); or no isolation (C, control). Plasma cortisol concentrations were higher at 0 h than at other holding time periods (P < 0.01). Plasma triiodothyronine, thyroxine, and leptin concentrations, and differential leukocyte counts were not influenced by any of the factors. The rate of decline in glucose concentrations over TIME was greater in FD than in F group (TRT x TIME, P < 0.05). The overall plasma creatine kinase activity peaked at 7 h before reaching a lower level at 14- and 21-h holding (P < 0.05). Plasma urea nitrogen concentrations were higher at 0- and 21-h than at 7- and 14-h holding (P < 0.01). Plasma nonesterified FA concentrations in the FD group remained at an elevated level during holding, but in the F group the levels decreased at 7 h and remained at that level (TRT x TIME, P < 0.01). Excitability scores did not have any effect on the variables measured. Shrinkage increased with longer holding time, but more prominently in the FD group (TRT x TIME, P < 0.01). Plasma cortisol concentrations were greater in I and IV groups than in the C group (P < 0.01). The novelty of environment during preslaughter holding, and social isolation may be more potent stressors than feed deprivation in goats, although shrinkage may increase with increasing feed-withdrawal times.

The management of food animals prior to slaughter influences both profitability and animal well-being. This experiment was conducted as a split-unit design to determine live weight shrink and stress responses in goats due to differences in stocking density during transportation and holding. A total of 150 Spanish does were transported on two different days (replicate) and held overnight (18 h) without feed in low- (LD) or high-density (HD) groups. On each day, 75 does were transported 2.5 h with floor spaces of .18 m2 and .37 m2/animal in LD (25 does) and HD (50 does) groups, respectively. The average temperatures in the trailer during transportation were 34.6 and 35 degrees C, respectively, on d 1 and 2. All animals were blood-sampled before loading (PRELOAD) and four does from each treatment were sampled immediately after loading (POSTLOAD). Animals were blood-sampled in holding pens either at 0, 1, 2, 3, 4, or 18 h after transportation (time) to assess the time course (n = 8 does per time per replicate) of stress responses. Individual animals were weighed just before loading onto a trailer and after overnight holding to assess shrinkage. Treatment or treatment x time did not have a significant effect on any of the dependent variables studied. There were significant effects of time (P < .01) on plasma cortisol, glucose, and urea nitrogen (PUN) concentrations. Time also had significant effects (P < .01) on plasma creatine kinase (CK) activity, differential leukocyte counts (neutrophils, lymphocytes, monocytes, and eosinophils), and ratio of neutrophils to lymphocytes (N:L). However, plasma leptin concentrations were not influenced by time. Cortisol concentrations increased at POSTLOAD sampling, peaked at 0 h, and decreased thereafter before spiking again at 18 h of holding. The PUN was higher at 18 h than at other time periods studied. Plasma glucose concentrations increased and remained at higher levels at 0, 1, and 2 h and began decreasing at 3 h, reaching PRELOAD levels at 18 h. Plasma CK kinase activity peaked at approximately 2 h after transportation. The N:L ratio was higher at all time periods after transportation than prior to starting the journey, indicating a prolonged effect of transportation stress on the immune system. The mean (+/- SE) shrinkage losses were 10.2 +/- .68 and 9.8 +/- .68 in HD and LD treatment groups, respectively. The results indicate that the stress responses of goats due to transportation begin decreasing within 3 h after transportation. However, prolonged holding periods without feed may increase stress responses and bring about metabolic changes.

Migration of neutrophils into mammary tissue provides the first immunological line of defense against bacteria that penetrate the physical barrier of the teat canal. Evasion of neutrophil defenses provides an opportunity for invading bacteria to become established. Depletion of neutrophils results in a dramatic increase in susceptibility to intramammary infection. Numerous cytoplasmic particles are shed from the apical surface of mammary secretory cells during milk secretion in goats. Only those counting methods that are specific for deoxyribonucleic acid can distinguish cell-like particles from somatic cells and thereby give reliable estimates of somatic cell numbers in goat milk. Unlike in milk from dairy cows, the somatic cell count in goat milk is influenced by the presence of nucleated cytoplasmic particles, stage of lactation, parity, and caprine arthritis-encephalitis. Investigations indicate that a dry period is necessary for optimal milk production in dairy cows but may not be necessary in goats. However, in many other respects regulation of bovine and caprine lactation seems to be quite similar. Studies have demonstrated additive galactopoietic effects of growth hormone and frequent milking in both species and a recently isolated chemical feedback inhibitor of lactation seems effective across both species. Increasing lactational performance has the potential for decreasing milk somatic cell counts in late lactation.

Thirty-two mature dwarf goats weighing between 16 and 30 kg (22.7 +/- 3.7, SD) were used to study the effect of Trypanosoma vivax infection on rectal temperature (RT), feed intake (DMI), and metabolic rate. Sixteen of the goats were infected intravenously with 14 X 10(6) T. vivax each; the 16 others served as controls. Animals were fed at about 1.1 times maintenance. Heat production was measured from 1 wk preinfection to 6 wk postinfection. From data on successive 9-min periods, heat production was calculated per 24-h period and separately for 0700 to 2000 (day period) and for 2000 to 0700 (night period). Rectal temperature was measured twice weekly. Compared with controls, animals infected with T. vivax developed and maintained a 1 degree C higher RT and a higher metabolic rate. After the prepatent period of 5 to 7 d, during which RT remained normal, all infected goats had a period of about 7 d with constant high temperatures. After that initial episode, RT fluctuated. Heat production of infected animals was increased by 15.6 kcal.d-1.kg-.75, or about 16%. This increase in heat production was greater during the night (22 kcal.d-1.kg-.75) than during the day (14 kcal.d-1.kg-.75). After T. vivax infection, large differences in DMI among animals were apparent. In four animals, a clear relation between DMI and RT was noted, but in 12 animals no such relationship was apparent.