Effects of supplemental fat source on nutrient digestion and ruminal fermentation in steers

Five Holstein steers (235 kg of BW) fitted with ruminal, duodenal, and ileal cannulas were used in a 5 x 5 Latin square design experiment to determine the effects of supplemental fat source on site and extent of nutrient digestion and ruminal fermentation. Treatments were diets based on steam-flaked corn containing no supplemental fat (control) or 4% (DM basis) supplemental fat as tallow, dried full-fat corn germ (corn germ), corn oil, or flax oil. Fat supplementation decreased (P < 0.08) ruminal starch digestion but increased (P < 0.03) small intestinal starch digestion as a percentage of intake. Feeding corn germ decreased (P < 0.09) ruminal starch digestion and increased (P < 0.03) large intestinal starch digestion compared with steers fed corn oil. Large intestinal starch digestion was less (P < 0.04), and ruminal NDF digestion was greater (P < 0.09) for steers fed tallow compared with steers fed other fat sources. Small intestinal (P < 0.08) and total tract NDF digestibilities were greater (P < 0.02) for steers fed corn germ than for those fed corn oil. Feeding tallow increased total ruminal VFA (P < 0.03) and NH(3) (P < 0.07) concentrations compared with steers fed the other fat sources. Feeding corn germ led to a greater (P < 0.02) rate of ruminal liquid outflow compared with corn oil. A diet x hour interaction (P < 0.04) occurred for ruminal pH, with steers fed corn oil having the greatest ruminal pH 18 h after feeding, without differences at other time points. Fat supplementation increased (P < 0.09) ruminal concentrations of Fusobacterium necrophorum. Duodenal flow of C18:3n-3 was greater (P < 0.01) for steers fed flax oil compared with those fed corn oil. Feeding corn germ led to less (P < 0.01) ruminal biohydrogenation of fatty acids compared with corn oil. Steers fed tallow had greater small intestinal digestibility of C14:0 (P < 0.02) and C16:1 (P < 0.04) than steers fed the other fat sources. Fat supplementation decreased (P < 0.06) small intestinal digestibility of C18:0. Feeding corn germ decreased (P < 0.10) small intestinal digestibility of C18:1 compared with corn oil. It appears that source of supplemental fat can affect the site and extent of fatty acid and nutrient digestion in steers fed diets based on steam-flaked corn.     

Primitive neuroectodermal tumor in the spinal cord of a brahman crossbred calf

A variety of embryonal tumors of the central nervous system, typically malignant and occurring in young individuals, are recognized in humans and animals. This report describes an invasive subdural but predominantly extramedullary primitive neuroectodermal tumor developing at the lumbosacral junction in a 6-month-old Brahman crossbred calf. The tumor was composed of spindloid embryonal cells organized in interlacing fascicles. The cells had oval to elongate or round hyperchromic nuclei, single to double nucleoli, and scant discernible cytoplasm. Immunohistochemical staining for neuron-specific enolase, synaptophysin, and S-100 protein and formation of pseudorosettes suggested neuronal and possibly ependymal differentiation.     

The emergence of Mycobacterium paratuberculosis in farmed deer in New Zealand - a review of 619 cases

AIM: To review cases in which Mycobacterium paratuberculosis was identified in farmed deer in New Zealand. METHODS: Case histories were reviewed where M. paratuberculosis was identified in deer by either culture or a polymerase chain reaction (PCR) test using primers from IS900. RESULTS: Between 1986 and 2000, M. paratuberculosis was identified by bacterial culture and/or PCR in 619 farmed deer from 299 herds, representing approximately 6% of deer herds in New Zealand. Over 85% of cases were identified during the last 6 years. In 60% of the infected herds, only one infected animal was identified. The maximum number of cases identified in a single deer herd was 47, and these were identified over a period of 8 years. Only 36 (5.8%) cases came from clinically affected animals identified on farms by veterinarians. The majority (89.7%) of the 619 cases were identified from lesions in mesenteric lymph nodes, including the ileocaecal lymph nodes, identified at meat inspection as being macroscopically either typical or equivocal of bovine tuberculosis (M. bovis). While the overwhelming majority of lesions were identified in mesenteric lymph nodes, M. paratuberculosis was also identified in 27 lesions in lymph nodes of the head, especially the retropharyngeal lymph node. CONCLUSIONS: The figures presented underestimate the true prevalence of infection with M. paratuberculosis, especially since not all suspect cases were submitted for culture or PCR. However, they do show that M. paratuberculosis appears to be spreading in farmed deer in New Zealand and highlight the possibility that Johne's disease is emerging as a potential major problem affecting this species. Identification of the organism by bacterial culture or PCR is required in many cases to distinguish lesions in mesenteric lymph nodes and lymph nodes of the head caused by M. paratuberculosis from those caused by M. bovis and M. avium.     

Protein turnover and sensory traits of longissimus muscle from implanted and nonimplanted heifers

Primary bovine muscle cell culture studies were conducted to determine whether implanting heifers had a direct effect on in vitro protein synthesis and degradation and to determine the effect of implanting heifers on longissimus muscle palatability. Feedlot heifers (n = 96) were administered one of six implant regimens to characterize their effect on in vitro amino acid uptake and protein degradation. Treatments consisted of: 1) a nonimplanted control (NI/NI); 2) no implant on d 1 and Revalor-H administered on d 84 of the experiment (NI/Rev); 3) Revalor-H on d 1, but no implant given at d 84 (Rev/NI); 4) Revalor-H administered on d 1 and d 84 (Rev/Rev); 5) Revalor-IH administered on d 1 and Revalor-H at d 84 (RIH/Rev); and 6) Synovex-H given at d 1 and Revalor-H administered at d 84 (Syn/Rev). Blood and longissimus lumborum muscle were collected 20 min postmortem, and serum and muscle extracts were incubated with primary bovine muscle cells. Implant treatments had minimal effects on shear force and sensory traits; however, steaks from Rev/Rev heifers were 0.31 kg more tender (P < 0.05) than steaks from NI/NI heifers. Serum protein synthesis and degradation were not affected (P > 0.10) by any implant treatment. When primary bovine muscle cells were treated with muscle extract, amino acid uptake was greater for heifers implanted with Rev/ Rev than for the average of all other treatments (P < 0.01). The Rev/Rev implant regimen also increased (P < 0.05) amino acid uptake compared with heifers treated with RIH/Rev, Syn/Rev, NI/NI, NI/Rev, or Rev/NI. Cellular protein degradation of the muscle cell culture treated with muscle extract tended (P < 0.10) to be higher in NI/NI-treated cells compared with the average of all implant treatments. In addition, cells treated with muscle extract from heifers implanted with Rev/Rev had lower (P < 0.05) protein degradation than the NI/NI control heifers. These results indicate that anabolic implant strategies can directly affect both muscle protein synthesis and degradation via effects that seem to be more autocrine than paracrine in nature.     

Status spongiosus of white matter in newborn Gelbvieh-cross calves.

Various forms of status spongiosus occur in neonatal cattle, the best characterized of which is due to mutations of the branched-chain alpha-keto acid dehydrogenase complex (BCKD), resulting in bovine maple syrup urine disease (MSUD, branched-chain ketoaciduria). A distinctive neurological syndrome was identified between 1998 and 2003 in 9 calves in a 250-cow stabilized Gelbvieh-Red Angus herd. Both sexes were affected (6 heifers, 3 bulls), with a low annual incidence (3 cases in 1998; no cases in 1999; 2 cases in 2000; 2 in 2001; 1 in 2002; 1 in 2003). Affected calves were born full-term, unable to stand, and had constant whole-body tremors when stimulated. Animals remained in lateral recumbency until death or euthanasia; the longest survival time was 10 days postpartum. The principal histological change in 2 affected calves was diffuse, moderately severe bilaterally symmetrical status spongiosus with Alzheimer type II cells throughout the white matter of the brain. Myelin deficits were not evident and vacuoles were due to cleaved myelin sheaths. Neither recognized mutation of MSUD was identified in the E1a subunit of BCKD in 2 affected calves, 8 dams that gave birth to affected calves, a grand-dam of 3 affected calves, or a sire of 1 calf. Amino acid analysis of serum from 1 affected calf revealed normal concentrations of branched-chain amino acids, indicating that this disease is distinct from MSUD. The genetic and biochemical basis for the disorder, provisionally named congenital status spongiosus of Gelbvieh-cross cattle, is undetermined. The pattern of inheritance was not established.     

Presumed primary ocular lymphangiosarcoma with metastasis in a miniature horse

A 7‐year‐old, 153.0‐kg American Miniature mare presented for evaluation of keratoconjunctivitis of the right eye (OD). A superior palpebral conjunctival mass and stromal keratitis were diagnosed. The incisional biopsy diagnosis was a presumptive corneal hemangiosarcoma. Transpalpebral enucleation was performed, and histopathologic evaluation confirmed angiosarcoma of the conjunctiva, cornea, and extraocular muscles. The horse developed progressive epistaxis and orbital swelling following surgery. A systemic workup was performed 3 months after enucleation, revealing regrowth within the orbit and marked cranial cervical lymphomegaly, suggestive of metastasis. Humane euthanasia was performed, and necropsy confirmed a locally invasive periorbital tumor with metastasis to the submandibular tissue, submandibular lymph node, and thoracic inlet. Histopathologic evaluation of necropsy specimens revealed polygonal to spindle neoplastic cells lining neoplastic vascular channels lacking erythrocytes. Immunohistochemically, the neoplastic cells labeled strongly positive for PROX‐1, vimentin, CD‐31, VEGF, weakly positive for factor VIII‐related antigen, and negative for collagen IV. Based on the clinical, histological, and immunohistochemical features of this tumor, a primary ocular lymphangiosarcoma with metastasis was diagnosed.     

A comparative study of the effects of intramuscular administration of gonadorelin,mating and intrauterine infusion of either raw seminal plasma or seminal plasma purified β‐NGF on luteal development in llamas

The aim of this study was to compare the effect of the intramuscular administration of 50 μg of gonadorelin acetate versus natural mating, intrauterine infusion (i.u.) of a physiological relevant dose of either raw llama seminal plasma (SP) or purified beta‐nerve growth factor from seminal origin (spβ‐NGF) on ovulation rate and corpus luteum (CL) development and function in llamas. Females with a follicle (≥8 mm) were assigned to groups: (i) i.m. administration of 50 μg of gonadorelin acetate (GnRH; positive control; n = 4); (ii) single mating (mating; n = 6); (iii) i.u. infusion of 4 ml of llama SP (SP; n = 4); or (iv) i.u. infusion of 10 mg of spβ‐NGF contained in 4 ml of PBS (phosphate‐buffered saline) (spβ‐NGF; n = 6). Ovaries were examined by power Doppler ultrasonography at 0, 1, 3, 6, 12 and 24 hr after treatment to determine preovulatory follicle vascularization area (VA), and additionally every 12 hr until Day 2 (Day of treatment = Day 0) to determine ovulation. Afterwards, ovaries were examined every other day until Day 8 to evaluate CL diameter and VA. Blood samples were collected on Days 0, 2, 4, 6 and 8 to determine plasma progesterone (P4) concentration. Ovulation rate did not differ (p = .7) among groups, but treatment affected (p < .0001) preovulatory follicle VA. Neither treatment administration nor treatment by time interaction affected (p ≥ .4) CL diameter, VA and plasma P4 concentration. Mating tended (p = .08) to increase CL VA when compared to the seminal plasma group by Day 8. Intrauterine administration of seminal plasma or spβ‐NGF does not increase CL size and function when compared to i.m. GnRH treatment, suggesting that the administration route of spβ‐NGF influences its luteotrophic effect in llamas.