Comparison of dietary hydrated copper sulphate,dietary zinc oxide and a direct method for inducing a moult in laying hens

1. The experiment lasted for seven 28‐d periods. Laying hens of two breeds were allocated to 10 treatments. For the first 28‐d period all birds were offered the control diet and then the following dietary treatments applied: a control group not moulted, one group moulted traditionally, 4 groups moulted using CuSO₄‐ and 4 using ZnO‐containing diets. After the moulting treatments the hens were offered the control diet for the remainder of period 2 and for a further five 28‐d periods.

2. The treatments applied during period 2 significantly reduced food intake, body weight, egg number, total egg weight and efficiency of food conversion. On returning to the control diet, there were no significant differences in cumulative food intake (periods 3 to 7). Body weight had returned to the same value as the control group by the end of period 3. Dietary treatments significantly reduced the efficiency of food utilisation during periods 3 to 7 and 1 to 7 inclusive.

3. For periods 1 to 7 inclusive the birds force‐moulted using CuSO₄ and ZnO gave on average greater egg numbers and total egg weights than those moulted traditionally.

4. The Haugh unit score was significantly improved after moulting. Egg Zn concentrations were increased by the 14‐d ZnO treatments.

5. The use of a diet containing CuSO₄ (2 g added Cu/kg for 7 d) was as effective as one containing ZnO (20 g added Zn/kg for 14 d) and both were superior to a traditional force‐moulting technique.

     

Helminths of British dogs: Toxocara canis—a veterinary perspective

An important factor in the life-cycle of Toxocara canis is the dissemination of ova into the host's environment. This provides a reservoir for infection of the bitch with subsequent transmission of larvae to the fetus. Additionally, other warm-blooded animals may acquire infection, thereby acting as paratenic hosts in subsidiary predator-prey cycles. Embryonated ova are infective for man and may on occasion result in clinical disease.
Information assessing the extent of such environmental contamination in the UK and denning the sources of the T. canis ova is reviewed. These data are of immediate practical importance as each contribution to the understanding of the epidemiology of toxocariasis facilitates the formulation of effective control measures.     

Reproductive traits of sows penned individually or in groups until 35 days after breeding

We compared estrous and farrowing traits in 274 Duroc X Yorkshire sows penned either in individual gestation stalls or in groups (four or five sows/group) during the intervals from weaning to breeding and from breeding to 30 to 35 d after breeding. Sows were assigned to treatment by parity (primiparous vs multiparous), checked twice daily for estrus from 3 to 10 d after weaning and artificially inseminated (AI) twice during estrus. Ovaries of anestrous sows were examined at laparotomy. No major treatment effects on estrous response were detected and 88% (45/51) of anestrous sows had only small ovarian follicles. Litter traits were not affected by penning treatments. However, penning sows in groups postbreeding resulted in a 50% reduction (P less than .05) in early pregnancy losses as indicated by low serum progesterone 19 to 23 d after AI or return to estrus by 23 d after AI. This resulted in a 12 percentage point higher (P less than .05) farrowing rate for group-penned (78%) than for individually penned sows (66%).     

Altrenogest and fat for summer breeding of primiparous sows

Delaying the onset of estrus after weaning and adding fat to the postweaning diet were studied for their effects on estrus and fertility in 232 crossbred primiparous sows on a commercial swine farm. Sows were assigned randomly to the following treatments after weaning in June, July, August, or September, 1983: 1) altrenogest (20 mg/d) was fed for 7 d after weaning (n = 76), 2) altrenogest was fed for 7 d plus .53 kg dried animal and vegetable fat product (.45 kg actual fat/d) for 14 d after weaning (n = 78), or 3) no treatment (controls, n = 78). While a similar proportion of sows came into heat after weaning (lactation length = 4 wk), sows fed altrenogest (14.4 +/- .2 d) returned to estrus about 9 d later (P less than .01) than controls (5.6 +/- .2 d). Serum progesterone concentration was assayed in blood samples collected from a subgroup (74%) of the cows not observed in estrus by 3 wk after weaning to determine possible causes of anestrus. If serum progesterone (greater than 5 ng/ml) was elevated, we assumed that sows had ovulated without expressing estrus (behavioral anestrus) or ovulated with undetected estrus (less overt estrus or error in estrous detection), whereas low progesterone (less than or equal to 5 ng/ml) indicated that sows were anovulatory. About 53% of the sows not observed in estrus across all treatments had luteal function, probably resulting from post-weaning ovulation. Incidence of anovulation without estrus was 47%. Farrowing rate was higher (P less than .05) for sows fed only altrenogest (64%) compared with controls (46%), but similar to fat supplemented, altrenogest-treated sows (52%).(ABSTRACT TRUNCATED AT 250 WORDS)