The effects of ractopamine hydrochloride on lean carcass yields and pork quality characteristics

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P < 0.05) with increasing dietary concentrations of RAC, but feed intake did not differ (P > 0.05). Dressing percentage was higher (P < 0.05) for RAC-treated pigs. Subjective color, firmness, marbling scores, and Minolta L* reflection of the LM were not different (P > 0.05) among treatments. Carcass weights were heavier (P < 0.05) for pigs treated with RAC compared with control pigs and were higher for R20 than for R10. The RAC-fed pigs had greater (P < 0.05) yields (actual and percentage of HCW) of the following Institutional Meat Purchase Specification (IMPS) cuts than control pigs: trimmed, boneless ham (IMPS-402C and IMPS-402G), loin (IMPS-414), sirloin, and Boston butt (IMPS-406A). Pigs treated with RAC had a greater (P < 0.05) percentage of fat-free lean trimmings (IMPS-418) than did control pigs. Pigs treated with the R20 concentration had increased (P < 0.05) water-holding capacity compared with control pigs. Purge loss decreased linearly (P < 0.05) with increasing RAC compared with control for 14-d aged, non-enhanced loins. Warner-Bratzler shear (WBS) force values measured for nonenhanced chops were greater for RAC-treated pigs than for control pigs with a low dose response (P = 0.001). Enhanced chop (salt and phosphate injection) WBS values did not differ (P > 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor.     

A new single nucleotide polymorphism in CAPN1 extends the current tenderness marker test to include cattle of Bos indicus, Bos taurus, and crossbred descent

The three objectives of this study were to 1) test for the existence of beef tenderness markers in the CAPN1 gene segregating in Brahman cattle; 2) test existing CAPN1 tenderness markers in indicus-influenced crossbred cattle; and 3) produce a revised marker system for use in cattle of all subspecies backgrounds. Previously, two SNP in the CAPN1 gene have been described that could be used to guide selection in Bos taurus cattle (designated Markers 316 and 530), but neither marker segregates at high frequency in Brahman cattle. In this study, we examined three additional SNP in CAPN1 to determine whether variation in this gene could be associated with tenderness in a large, multisire American Brahman population. One marker (termed 4751) was associated with shear force on postmortem d 7 (P < 0.01), 14 (P = 0.015), and 21 (P < 0.001) in this population, demonstrating that genetic variation important for tenderness segregates in Bos indicus cattle at or near CAPN1. Marker 4751 also was associated with shear force (P < 0.01) in the same large, multisire population of cattle of strictly Bos taurus descent that was used to develop the previously reported SNP (referred to as the Germplasm Evaluation [GPE] Cycle 7 population), indicating the possibility that one marker could have wide applicability in cattle of all subspecies backgrounds. To test this hypothesis, Marker 4751 was tested in a third large, multisire cattle population of crossbred subspecies descent (including sire breeds of Brangus, Beefmaster, Bonsmara, Romosinuano, Hereford, and Angus referred to as the GPE Cycle 8 population). The highly significant association of Marker 4751 with shear force in this population (P < 0.001) confirms the usefulness of Marker 4751 in cattle of all subspecies backgrounds, including Bos taurus, Bos indicus, and crossbred descent. This wide applicability adds substantial value over previously released Markers 316 and 530. However, Marker 316, which had previously been shown to be associated with tenderness in the GPE Cycle 7 population, also was highly associated with shear force in the GPE Cycle 8 animals (P < 0.001). Thus, Marker 316 may continue to be useful in a variety of populations with a high percentage of Bos taurus backgrounds. An optimal marker strategy for CAPN1 in many cases will be to use both Markers 316 and 4751.     

Relationship between latency of brainstem auditory‐evoked potentials and head size in dogs

Summary

Cranium and brainstem dimensions were measured in 32 postmortem dog heads. Positive correlations were found between cranium length (CL) and brainstem length (BL) (r=0.87), between cranium width (CW) and brainstem width (BW) (r=0.83), and between cranium distance (CD = CL CW/2) and brainstem distance (BD = BL+BW/2) (r=0.91). Positive correlation coefficients were also found between CL and CW (r=0.90), and between BL and BW (r=0.85). It was concluded that head size accurately reflected brainstem size. A least squares estimation of the brainstem distance (BD) from CL and CW values was BD = 10.9 + 0.16 (CL CW/2) (BD, CL and CW in mm).

Brainstem auditory evoked potentials (BAEPs) and cranium dimensions were measured in 43 dogs (86 ears) with different head size, body size, sex and age. Wave form, absolute and interpeak latencies and correlation coefficients, relating latencies to cranium dimensions and body weight, were analysed CL, CW, and CD were positively correlated with body weight (r=0.93, 0.70 and 0.93, respectively), and CL, CW, and CD were correlated with age (r=0.33, 0.52 and 0.40, respectively). BAEPs consisted of five distinct positive peaks (I to V). Secondary positive peaks following peaks I and II were seen in 60% (I') and 90% (II') of the recordings. Late waves were recorded in 90% (VI), 50% (VII), and 25% (VIII) of the recordings. Latencies increased with decreasing stimulus intensity level (from 90 dB to 10 dB hearing level, HL),especially for peaks I, II, V, and the I‐V interpeak interval Absolute and interpeak latencies were positively correlated with cranium distance and body weight. Correlation coefficients increased as wave latencies increased At 90 dB HL, the highest correlation coefficients, relating cranium distance to peak V and the I‐V interpeak latency, were 0.55 and 0.53 (P < 0.00001), respectively. Regression analysis showed that each 1 cm increase in cranium distance was accompanied by an increase of 0.006 ms in the latency of wave I, 0.03 ms for wave III, 0.05 ms for wave V, and 0.05 ms for the I‐V interpeak interval Regression analysis showed that an increase of 1 kg in body weight was accompanied by an increase of 0.001 ms in the latency of wave I, 0.005 ms for wave III, 0.011 ms for wave V, and 0.01 ms for the I‐V interpeak interval. It is concluded that head size, which accurately reflects brain size, is a relevant source (25%) of intersubject variance of BAEP latencies in the dog.     

Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization

Summary

The capacitation process of sperm cells involves complex changes in the composition and orientation of molecules at the surface of the sperm cell. Here we focus on the lipid architecture in the sperm plasma membrane and demonstrate that the sperm plasma membrane is not static but is an extremely dynamic structure. Advanced fluoroscopic techniques enabled continuous monitoring of lipid organization in living cells and extremely rapid lipid movements were observed. The orientation of lipids in the sperm plasma membrane changed under capacitative treatments, was found to be sensitive for temperature and also changed upon binding of sperm cells to the zona pellucida. The changes in membrane properties coincided with an activation of protein kinases resulting in tyrosine phosphorylation of specific plasma membrane proteins. The detected membrane changes relate to intrinsic membrane properties such as fluidity, permeability, adhesiveness and fusibility. We think that these results may provide a physiological basis for new assays, able to discriminate between functional and non‐physiological sperm cells.     

Artificial insemination in pigs: predicting male fertility

Efficient artificial insemination (AI) is essential for future challenges in the pig industry. Knowledge on the exact relation between semen quality characteristics and fertility can have a major impact on both the genetic merit of future animals and the efficiency of AI. Variation in fertility is caused not only by farm- or sow-related parameters but also by boar- and semen-related parameters. In pig AI there is no gold standard concerning semen quality assessment. Assessing semen quality characteristics objectively and relating them to large field fertility datasets leads to an efficient production of insemination doses, which results in an efficient dissemination/descent of the breeding program required genes. Overall, this contributes to the development of semen quality assessments, which improves the prediction of porcine male fertility. Knowing which semen characteristics, and to what extent, contribute to male fertility and makes the field fertility more predictable.     

Perinatal Maternal and Neonatal Behaviour in the Captive Reticulated Giraffe

A captive reticulated giraffe was observed constantly for three weeks prior to, and periodically for 90 days subsequent to, the birth of her calf. Extensive observations were made of the birth sequence, feeding, drinking, sleeping and one instance of an infant distress call, as well as observations of the initiation of maternal behaviour (including licking, nursing, placentophagia, and what appeared to be helping the calf to stand, guiding the calf's movements, and attempts to respond to the calf's distress call).     

Organisms associated with the sandy-beach bivalve Donax serra Röding,with a description of Cercaria serrae sp. nov. (Trematoda)

Examination of two collections of Donax serra from a South African west coast beach revealed the presence of Ciliophora, Trematoda, Nematoda and a parasitic pycnogonid. This is the first record of a pycnogonid from the genus Donax and the first published report of such a parasite from any southern African bivalve mollusc. One of the two trematode species found is described as new and its epidemiology is discussed briefly. No epibiota were found on the bivalve shell.     

Ovarian Structure and Oogenesis of Catfish Pimelodella vittata (Lütken, 1874) (Siluriformes,Heptapteridae)

The morphology of the ovaries and oogenesis of Pimelodella vittata were studied using anatomical and histological techniques to provide information of its reproductive biology. Eighty adult females were captured trimonthly during the period November 2005 to October 2006. The ovaries are paired, saculiform organs, which are coated with tunica albuginea and contain ovigerous lamellae, where the oocytes develop before being released into the ovarian lumen and following the ovarian duct until reaching the genital papilla. Oogenesis was divided into stages based on the alterations to the nucleus, ooplasm and surrounding follicular layers. Oogonia form groups from the germinal epithelium have asynchronous development and differentiate into initial perinucleolar oocytes. The formation of the zona pellucida is initiated in the advanced perinucleolar oocytes reaching a thickness of 1.46 ± 0.58 μm in the vitellogenic oocytes. The follicular cells are squamous in perinucleolar oocytes, become cubical in the pre‐vitellogenic oocytes and prismatic in the vitellogenic oocytes with a height of 11.20 ± 4.74 μm. The histochemical reactions indicate that zona pellucida, cortical alveoli and yolk globules contain neutral glycoproteins and the follicular cells contain neutral glycoproteins in association with carboxylated and sulphated glycoconjugates. Statistical analyses showed significant differences in the diameter of the oocytes and follicular cells height as oocytes matured. This study represents the first data about the ovarian structure and oogenesis of this species.