Additive and heterosis effects on preweaning traits, maternal ability and reproduction from crossing of the Angus and brown Swiss breeds in Florida

Angus (A), Brown Swiss (S) and A X S reciprocal F1 (AS) dams were mated to A, S and AS (also reciprocal F1) sires resulting in nine breed groups of progeny with varying proportions of Angus and Brown Swiss breeding. Breed group of dam and of sire significantly influenced birth weight, preweaning daily gain, weaning weight, 205-d weight, condition score and frame size. The means for birth weight and weaning weight were 33 and 213 kg, respectively. Brown Swiss bulls sired calves with the heaviest birth and weaning weights. Calves produced by S dams likewise were heavier at birth and weaning. Pregnancy rates were influenced significantly by year, age and breed of dam and averaged 79, 95 and 92% for S, AS and A cows, respectively. Survival rate averaged 97% and was not influenced significantly by any of the effects examined. Because survival rates were similar for all breed groups, the results for weaning rate paralleled those for pregnancy rate. Genetic influences on preweaning growth traits and survival rate were partitioned into additive breed differences (B) and heterosis (H) effects for direct (d) and maternal (m) components. Pregnancy and weaning rates were examined using similar analyses except that genotype of service sire of dam replaced that of the offspring for the direct additive breed and direct heterosis components. The Bd values indicated that the Angus breed was inferior (P less than .01) to the Brown Swiss breed for all preweaning growth traits except for condition score, in which the Angus breed surpassed (P less than .01) the Brown Swiss. The Bm values also showed an advantage for the Brown Swiss breed for all preweaning growth traits. The additive maternal effect (the genotype of the females exposed), Bm, was important for pregnancy rate and weaning rate (P less than .001 and P less than .05) but not for survival rate (P greater than .10). The direct additive breed effect was not important for any reproductive trait. Direct heterosis did not affect any of the preweaning or reproduction traits; however, maternal heterosis (Hm) significantly affected all traits except birth weight, frame score and survival rate. The Hm estimates were 12.0 and 8.4 kg for weaning weight and 205-d weight, respectively. The Hm estimates for pregnancy rate, survival rate and weaning rate were 10, 2 and 13%, respectively.     

Reduced growth of Lucilia cuprina larvae fed serum from sheep treated with anthelmintics

The effect of three commonly used anthelmintics, levamisole hydrochloride, ivermectin and closantel, on the development of the sheep blowfly, Lucilia cuprina, was determined. Sheep were treated with each anthelmintic using the manufacturers' recommended dose for helminth control. Both ivermectin and closantel significantly (p < 0.05) reduced the growth rate of larvae of L cuprina cultured in vitro on serum from these sheep. Levamisole hydrochloride had no effect. Ivermectin was effective for less than 6 days after treatment, whereas closantel significantly reduced larval growth 21 days after treatment. Dose-response experiments showed that lower concentrations of both ivermectin and closantel were not as effective in reducing larval growth.     

Rain-free requirement and physiological properties of cotton plant growth regulators

Greenhouse studies were conducted to (1) evaluate the rain-free requirement for mepiquat chloride and mepiquat chloride plus cyclanilide with and without surfactant and to (2) evaluate absorption and translocation of cyclanilide, a component of a new cotton plant growth regulator. No significant differences in the number of nodes, leaf area, and plant organ fresh and dry weight were observed with any PGR treatment and rainfall simulation combination. Both plant growth regulators responded similarly to rainfall interval. As rain-free period increased, cotton height was reduced. Based on these data, a rain-free period of 8 h is needed to maximize efficacy, regardless of the use of surfactant. Absorption of cyclanilide ranged from 11 to 15% at 3 and 48 h after treatment, respectively. Averaged over harvest intervals, 18% of the applied cyclanilide remained in the treated leaf while 1.7 and 6.5% of the applied cyclanilide was found in the above and below treated leaf tissue, respectively.     

Biodiversity assessment and conservation strategies

The efficient representation of all species in conservation planning is problematic. Often, species distribution is assessed by dividing the land into a grid; complementary sets of grids, in which each taxon is represented at least once, are then sought. To determine if this approach provides useful surrogate information, species and higher taxon data for South African plants and animals were analyzed. Complementary species sets did not coincide and overlapped little with higher taxon sets. Survey extent and taxonomic knowledge did not affect this overlap. Thus, the assumptions of surrogacy, on which so much conservation planning is based, are not supported.     

Evaluation of a Burdizzo Castrator for Neutering of Dogs

A Burdizzo castrator was evaluated for the neutering of dogs. Histological and morphological changes of spermatic cells and peripheral serum testosterone after challenge with a GnRH-analogue (gonadorelin) were assessed. There was a control group (G1), a surgically castrated group (G2) and a Burdizzo group (G3) divided in two, G3a receiving two crunches in each spermatic cord and G3b receiving one crunch in each spermatic cord. Sixteen days after application of the Burdizzo blood samples were taken from the dogs at 30 min interval during 2 h; after the second sample the dogs were treated with 1 mug/kg body weight of gonadorelin i.v. The same protocol of gonadorelin challenge was performed in G1 and G2 dogs. The G2 dogs were surgically castrated after the second blood sample, before the gonadorelin treatment, and the G1 dogs after the last blood sample. The excised gonads were examined histologically, and sperm smears were prepared from the caudae epididymidis. The testes and plexus pampiniformis of the G1 and G2 dogs had a normal histological appearance, and they had morphologically normal epididymal sperm cells. In all G3 dogs, there was an acute fibrosis with an inflammatory reaction in the plexus pampiniformis. The testes from the G3a dogs showed diffuse areas of infarction and degeneration of the parenchyma. Similar but less diffuse lesions were seen in group 3b dogs. The deferent ducts from all G3 dogs showed vasitis and/or sperm granulomas. Azoospermia or sperm malformations were observed in the epididymal smears from the G3 dogs. Testosterone concentration in the G1 dogs increased after gonadorelin application (p < 0.0001). The G2 dogs had basal testosterone levels after castration (p < 0.001) and did not respond to gonadorelin. Groups 3a and b showed a slight but non-significant increase in testosterone concentration after gonadorelin challenge, supposedly due to the reduction of testicular blood flow and loss of testicular interstitial tissue.     

Demodex spp. infestation and suspected demodicosis of alpacas (Vicugna pacos) in New Zealand

Extract

Ectoparasites known to cause skin lesions in alpacas (Vicugna pacos) include the mites Sarcoptes scabiei, Chorioptes bovis and Psoroptes spp., and the lice Microthoracius mazzai and Bovicola breviceps (Cicchino et al. 1998 Cicchino, AC, Munoz, Cobenas ME, Bulman, GM, Diaz, JC and Laos, A. 1998. Identification of Microthoracius mazzai (Phthiraptera: Anoplura) as an economically important parasite of alpacas. Journal of Medical Entomology, 35: 922–930.  [Google Scholar]; Foster et al. 2007 Foster, A, Jackson, A and D'alterio, GL. 2007. Skin diseases of South American camelids. In Practice, 29: 216–223. [Crossref], [Web of Science ®] , [Google Scholar]). Occasionally, Demodex spp. infestations have been reported or mentioned as incidental fi ndings in llamas (Lama glama) (Atlee et al. 1997 Atlee, BA, Stannard, AA, Fowler, ME, Willemse, T, Ihrke, PJ and Olivry, T. 1997. The histology of the normal llama skin. Veterinary Dermatology, 8: 165–176. [Crossref], [Web of Science ®] , [Google Scholar]) and alpacas (Foster et al. 2007 Foster, A, Jackson, A and D'alterio, GL. 2007. Skin diseases of South American camelids. In Practice, 29: 216–223. [Crossref], [Web of Science ®] , [Google Scholar]). So far, only Sarcoptes scabiei (McKenna et al. 2005 McKenna, PB, Hill, FI and Gillett, R. 2005. Sarcoptes scabiei infection on an alpaca (Lama pacos. New Zealand Veterinary Journal, 53: 213–213. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), Chorioptes bovis (Arthur 1997 Arthur, DG. 1997. Diseases of lamoids in New Zealand. Surveillance, 24(1): 29–30.  [Google Scholar], non-peer reviewed) and Bovicola breviceps (Palma et al. 2006 Palma, RL, McKenna, PB and Aitken, P. 2006. Confirmation of the occurrence of the chewing louse Bovicola (Lepikentron) breviceps (Insecta: Phthiraptera: Trichodectidae) on alpacas (Lamas pacos) in New Zealand. New Zealand Veterinary Journal, 54: 253–254. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) have been recorded on lamoids in New Zealand. Here, we report the first record of Demodex spp. infestation of an alpaca in New Zealand.