Nutritionally altering weight gain patterns of pregnant heifers and young cows changes the time that feed resources are offered without any differences in production

We hypothesized that feed resources could be deferred to a later time in the production cycle without a decrease in fertility or weight of calf produced in heifers and young cows. One-hundred and thirty-one MARC III (four breed composite: (1/4) Hereford, (1/4) Angus, (1/4) Red Poll, and (1/4) Pinzgauer) heifers were divided into three treatments: M-M-M-M (n = 46), L-H-M-M (n = 41), and L-L-L-H (n = 44). The experiment consisted of four feeding periods. Period 1 was 94 to 186 d of gestation, and heifers were fed a moderate (M) or low (L) level of feed. Period 2 was 187 d of gestation to parturition, and heifers were fed moderate, high (H), or low levels of feed. Period 3 was from parturition through 27 d of lactation, and heifers were fed moderate or low levels of feed. Period 4 was from 28 d to approximately 63 d of lactation, and heifers were fed moderate or high levels of feed. Females remained within treatments through their first parity (heifers) and second parity (cows). Feed intake of L-H-M-M and M-M-M-M treatments did not differ from each other either as heifers (P = 0.23) or as second-parity cows (P > 0.59). The L-L-L-H heifers ate less feed than L-H-M-M and M-M-M-M heifers (P < 0.001), and second-parity L-L-L-H cows ate less feed than second-parity L-H-M-M and M-M-M-M cows (P < 0.002). In the first parity, treatments did not differ in the percentage of calves weaned (P = 0.11), weight of calf weaned (P = 0.50), or percentage of cows diagnosed pregnant (P = 0.29) with a second calf. In the second parity, treatments did not differ in the percentage of calves weaned (P = 0.77), weight of calf weaned (P = 0.63), or percentage of cows expressing a corpus luteum at the start of breeding for their third calf (P = 0.21). Our findings suggest that timing nutrient availability to heifers and primiparous cows can be used to change the time that feed resources are used.     

Effects of alternative lamb production systems, maternal line, and culling strategy on flock age structure.

The 5-yr attrition of 1/4 (n = 411) or 1/2 (n = 403) Finnsheep (Finn) ewes exposed to terminal sire breeds in either an accelerated or semi-intensive annual lambing system was recorded to test the effects of system and percentage Finn on flock age structure at equilibrium. Ewes were culled for discernible ailments and failure to lamb after two consecutive non-spring exposures in yr 3, 4, or 5 only. Additionally, four progressively more intensive culling strategies for nonconception were practiced in retrospect. Flock productivity (kilograms of lamb weaned per ewe maintained per year) at age structure equilibrium was estimated for all culling strategies. The majority of all systems (cull strategy x lambing system x percentage Finn combination) were composed of ewes less than or equal to 3 yr old. Replacement requirements ranged from 24 to 38% in the accelerated system and 22 to 26% in the annual system. Quarter-Finns yielded greater replacement needs and shorter productive lives in accelerated lambing but fewer replacement requirements and longer productive lives than 1/2 Finns in annual lambing. Replacement requirements greatly increased with culling intensity in accelerated lambing (up to 54% above original levels) but only slightly in annual lambing (up to 8% above original levels). Mean (reproductive) lifetime estimated from fitted Weibull survival curves ranged from 3.1 to 5.1 yr in accelerated lambing and 4.5 to 5.4 yr in annual lambing. Increased culling for non-lambing decreased productivity at flock age structure equilibrium in accelerated lambing but did not change productivity in annual lambing. Repeatability of ewe effects on conception was generally low. Overall, system, percentage Finn, and culling strategy interact to influence system productivity through flock age structure. Intensive culling for non-lambing and replacement with ewe lambs of equal genetic merit should not be practiced in accelerated lambing systems.     

Pyloric obstruction in a dog related to a gastrotomy incision closed with polypropylene

A five-year-old male, West Highland terrier was treated for a gastrointestinal foreign body via a gastrotomy incision and enterotomies. The dog was asymptomatic for several months but was eventually re-presented because of vomiting. Endoscopic and surgical evaluation confirmed a large mass within the pyloric canal that probably resulted from a reaction to the polypropylene suture material used to close the original gastrotomy incision. The mass was excised via a Y-U pyloroplasty incision and the dog has been free of vomiting for over a year.     

Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and unadapted Bos taurus breeds

Production data were collected on mature cows produced by mating Angus and Hereford (pooled AH), Brahman (Bh) and Boran (Br), and Tuli, a tropically adapted Bos taurus, sires by AI or natural service to Angus and Hereford cows. These cows were mated to Charolais bulls for the purpose of this study. Within each sire breed of cow, cows were assigned randomly to one of three feeding rates, 49 or 76 g of DMI/ BW0.75 or ad libitum (10 to 12 cows/feeding rate group), with weekly individual animal feed consumption recorded. Lactation yields were recorded via the weigh-suckle-weigh protocol at approximately 14, 28, 56, 84, 112, 140, 168, and 196 d postpartum for each cow/calf pair. Means for milk yield at peak lactation, total milk yields, calf birth weight, age-adjusted weaning weights, preweaning daily gain, and feed efficiency were estimated. Peak yield (kg/d) for Bh (10.3 +/- 0.36) was greater (P < 0.05) than for Tuli (9.0 +/- 0.31). Total yield (kg, 212 d) for Bh (1802 +/- 68) was greater (P < 0.05) than for Tuli (1532 +/- 59). Birth weight of AH (44 +/- 0.9) was heavier than for Bh and Br (P < 0.05). Preweaning daily calf gain (g/d) and adjusted weaning weight (kg) of Bh (813 +/- 28, 212 +/- 6.1) and Br (766 +/- 24, 202 +/- 5.1) differed (P < 0.05) from AH (589 +/- 24, 169 +/- 5.2) and Tuli (634 +/- 24, 176 +/- 5.3). Efficiency estimates (grams of adjusted weaning weight/kilograms DMI of the cow) for Bh (88 +/- 2.5) and Br (85 +/- 2.1) exceeded (P < 0.05) those for Tuli (74 +/- 2.1) and AH (73 +/- 2.1). Bos indicus breed crosses exhibited greater peak and total yield, lower birth weight, greater daily gain and adjusted weaning weight, and higher feed efficiency than did Bos taurus breed crosses (P < 0.05). Total yield, daily gain, adjusted weaning weight, and feed efficiency were higher (P < 0.05) for cows sired by bulls from tropically adapted breeds, and the peak yield was less (P < 0.10). Tuli exhibited lower total yield and birth weight than did Angus/Hereford (P < 0.05). The efficiency of crossbred Tuli cows did not differ from Angus/Hereford F1 females, but neither equaled the efficiency of crossbred cows produced using Bos indicus breeds.     

Naive and memory CD4+ T cell survival controlled by clonal abundance

Immunity to a plethora of microbes depends on a diverse repertoire of na?ve lymphocytes and the production of long-lived memory cells. We present evidence here that low clonal abundance in a polyclonal repertoire favors the survival and activation of na?ve CD4(+) T cells as well as the survival of their memory cell progeny. The inverse relation between clonal frequency and survival suggests that intraclonal competition could help maintain an optimally diverse repertoire of T cells and an optimal environment for the generation of long-lived memory cells.     

Application of polymerase chain reaction based on ITS1 rDNA to speciate Eimeria

A method was developed to recover Eimeria spp. oocysts directly from poultry litter and determine which species of Eimeria were present using polymerase chain reaction (PCR) based on the ITS1 rDNA sequence. The species composition of Eimeria oocysts was also compared before and after propagation in susceptible chickens to determine if the relative proportion of each species changed after expansion. In samples from two broiler operations, ITS1-PCR was able to detect Eimeria spp. oocysts recovered from litter, with Eimeria acervulina, Eimeria maxima, and Eimeria praecox being the predominant species present therein. Although Eimeria tenella was found in one sample, the other species--Eimeria brunetti, Eimeria necatrix, and Eimeria mitis-were not detected. The species composition as determined by ITS1-PCR did not appear to appreciably alter after expansion in susceptible chickens. The described method represents a rapid means for determining the major Eimeria species in a poultry operation and may be helpful in choosing a particular live oocyst vaccine formulation to protect chickens against coccidiosis.     

Detecting epistatic effects associated with cotton traits by a modified MDR approach

Genetic expression of a trait is complicated and it is usually associated with many genes including their interactions (epistasis) and genotype-by-environment interactions. Genetic mapping currently focuses primarily on additive models or marginal genetic effects due to the complexity of epistatic effects. Thus, there exists a need to appropriately identify favorable epistatic effects for important biological traits. Several multifactor dimensionality reduction (MDR) based methods are important resources to identify high-order gene–gene interactions. These methods are mainly focused on human genetic studies. Many traits in plant systems are not only quantitatively inherited but also are often measured in repeated field plots under multiple environments. In this study, we proposed a mixed model based MDR approach, which is suitable for inclusion of various fixed and random effects. This approach was used to analyze a cotton data set that included eight agronomic and fiber traits and 20 DNA markers. The results revealed high order epistatic effects were detected for most of these traits using this modified MDR approach.     

Gel-Bead Delivery of Eimeria oocysts protects chickens against coccidiosis

Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.